zig/lib/std/fmt.zig
Andrew Barchuk 1f37b70344
Remove unused buf field from std.fmt.Parser (#21994)
And make the initialization less error prone by removing a default for
iter, which is required for a functional parser

std: Add a brief doc comment for `std.fmt.Parser`
2024-11-24 15:09:36 -08:00

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//! String formatting and parsing.
const std = @import("std.zig");
const builtin = @import("builtin");
const io = std.io;
const math = std.math;
const assert = std.debug.assert;
const mem = std.mem;
const unicode = std.unicode;
const meta = std.meta;
const lossyCast = math.lossyCast;
const expectFmt = std.testing.expectFmt;
pub const default_max_depth = 3;
pub const Alignment = enum {
left,
center,
right,
};
const default_alignment = .right;
const default_fill_char = ' ';
pub const FormatOptions = struct {
precision: ?usize = null,
width: ?usize = null,
alignment: Alignment = default_alignment,
fill: u21 = default_fill_char,
};
/// Renders fmt string with args, calling `writer` with slices of bytes.
/// If `writer` returns an error, the error is returned from `format` and
/// `writer` is not called again.
///
/// The format string must be comptime-known and may contain placeholders following
/// this format:
/// `{[argument][specifier]:[fill][alignment][width].[precision]}`
///
/// Above, each word including its surrounding [ and ] is a parameter which you have to replace with something:
///
/// - *argument* is either the numeric index or the field name of the argument that should be inserted
/// - when using a field name, you are required to enclose the field name (an identifier) in square
/// brackets, e.g. {[score]...} as opposed to the numeric index form which can be written e.g. {2...}
/// - *specifier* is a type-dependent formatting option that determines how a type should formatted (see below)
/// - *fill* is a single unicode codepoint which is used to pad the formatted text
/// - *alignment* is one of the three bytes '<', '^', or '>' to make the text left-, center-, or right-aligned, respectively
/// - *width* is the total width of the field in unicode codepoints
/// - *precision* specifies how many decimals a formatted number should have
///
/// Note that most of the parameters are optional and may be omitted. Also you can leave out separators like `:` and `.` when
/// all parameters after the separator are omitted.
/// Only exception is the *fill* parameter. If a non-zero *fill* character is required at the same time as *width* is specified,
/// one has to specify *alignment* as well, as otherwise the digit following `:` is interpreted as *width*, not *fill*.
///
/// The *specifier* has several options for types:
/// - `x` and `X`: output numeric value in hexadecimal notation
/// - `s`:
/// - for pointer-to-many and C pointers of u8, print as a C-string using zero-termination
/// - for slices of u8, print the entire slice as a string without zero-termination
/// - `e`: output floating point value in scientific notation
/// - `d`: output numeric value in decimal notation
/// - `b`: output integer value in binary notation
/// - `o`: output integer value in octal notation
/// - `c`: output integer as an ASCII character. Integer type must have 8 bits at max.
/// - `u`: output integer as an UTF-8 sequence. Integer type must have 21 bits at max.
/// - `?`: output optional value as either the unwrapped value, or `null`; may be followed by a format specifier for the underlying value.
/// - `!`: output error union value as either the unwrapped value, or the formatted error value; may be followed by a format specifier for the underlying value.
/// - `*`: output the address of the value instead of the value itself.
/// - `any`: output a value of any type using its default format.
///
/// If a formatted user type contains a function of the type
/// ```
/// pub fn format(value: ?, comptime fmt: []const u8, options: std.fmt.FormatOptions, writer: anytype) !void
/// ```
/// with `?` being the type formatted, this function will be called instead of the default implementation.
/// This allows user types to be formatted in a logical manner instead of dumping all fields of the type.
///
/// A user type may be a `struct`, `vector`, `union` or `enum` type.
///
/// To print literal curly braces, escape them by writing them twice, e.g. `{{` or `}}`.
pub fn format(
writer: anytype,
comptime fmt: []const u8,
args: anytype,
) !void {
const ArgsType = @TypeOf(args);
const args_type_info = @typeInfo(ArgsType);
if (args_type_info != .@"struct") {
@compileError("expected tuple or struct argument, found " ++ @typeName(ArgsType));
}
const fields_info = args_type_info.@"struct".fields;
if (fields_info.len > max_format_args) {
@compileError("32 arguments max are supported per format call");
}
@setEvalBranchQuota(2000000);
comptime var arg_state: ArgState = .{ .args_len = fields_info.len };
comptime var i = 0;
inline while (i < fmt.len) {
const start_index = i;
inline while (i < fmt.len) : (i += 1) {
switch (fmt[i]) {
'{', '}' => break,
else => {},
}
}
comptime var end_index = i;
comptime var unescape_brace = false;
// Handle {{ and }}, those are un-escaped as single braces
if (i + 1 < fmt.len and fmt[i + 1] == fmt[i]) {
unescape_brace = true;
// Make the first brace part of the literal...
end_index += 1;
// ...and skip both
i += 2;
}
// Write out the literal
if (start_index != end_index) {
try writer.writeAll(fmt[start_index..end_index]);
}
// We've already skipped the other brace, restart the loop
if (unescape_brace) continue;
if (i >= fmt.len) break;
if (fmt[i] == '}') {
@compileError("missing opening {");
}
// Get past the {
comptime assert(fmt[i] == '{');
i += 1;
const fmt_begin = i;
// Find the closing brace
inline while (i < fmt.len and fmt[i] != '}') : (i += 1) {}
const fmt_end = i;
if (i >= fmt.len) {
@compileError("missing closing }");
}
// Get past the }
comptime assert(fmt[i] == '}');
i += 1;
const placeholder = comptime Placeholder.parse(fmt[fmt_begin..fmt_end].*);
const arg_pos = comptime switch (placeholder.arg) {
.none => null,
.number => |pos| pos,
.named => |arg_name| meta.fieldIndex(ArgsType, arg_name) orelse
@compileError("no argument with name '" ++ arg_name ++ "'"),
};
const width = switch (placeholder.width) {
.none => null,
.number => |v| v,
.named => |arg_name| blk: {
const arg_i = comptime meta.fieldIndex(ArgsType, arg_name) orelse
@compileError("no argument with name '" ++ arg_name ++ "'");
_ = comptime arg_state.nextArg(arg_i) orelse @compileError("too few arguments");
break :blk @field(args, arg_name);
},
};
const precision = switch (placeholder.precision) {
.none => null,
.number => |v| v,
.named => |arg_name| blk: {
const arg_i = comptime meta.fieldIndex(ArgsType, arg_name) orelse
@compileError("no argument with name '" ++ arg_name ++ "'");
_ = comptime arg_state.nextArg(arg_i) orelse @compileError("too few arguments");
break :blk @field(args, arg_name);
},
};
const arg_to_print = comptime arg_state.nextArg(arg_pos) orelse
@compileError("too few arguments");
try formatType(
@field(args, fields_info[arg_to_print].name),
placeholder.specifier_arg,
FormatOptions{
.fill = placeholder.fill,
.alignment = placeholder.alignment,
.width = width,
.precision = precision,
},
writer,
std.options.fmt_max_depth,
);
}
if (comptime arg_state.hasUnusedArgs()) {
const missing_count = arg_state.args_len - @popCount(arg_state.used_args);
switch (missing_count) {
0 => unreachable,
1 => @compileError("unused argument in '" ++ fmt ++ "'"),
else => @compileError(comptimePrint("{d}", .{missing_count}) ++ " unused arguments in '" ++ fmt ++ "'"),
}
}
}
fn cacheString(str: anytype) []const u8 {
return &str;
}
pub const Placeholder = struct {
specifier_arg: []const u8,
fill: u21,
alignment: Alignment,
arg: Specifier,
width: Specifier,
precision: Specifier,
pub fn parse(comptime str: anytype) Placeholder {
const view = std.unicode.Utf8View.initComptime(&str);
comptime var parser = Parser{
.iter = view.iterator(),
};
// Parse the positional argument number
const arg = comptime parser.specifier() catch |err|
@compileError(@errorName(err));
// Parse the format specifier
const specifier_arg = comptime parser.until(':');
// Skip the colon, if present
if (comptime parser.char()) |ch| {
if (ch != ':') {
@compileError("expected : or }, found '" ++ unicode.utf8EncodeComptime(ch) ++ "'");
}
}
// Parse the fill character, if present.
// When the width field is also specified, the fill character must
// be followed by an alignment specifier, unless it's '0' (zero)
// (in which case it's handled as part of the width specifier)
var fill: ?u21 = comptime if (parser.peek(1)) |ch|
switch (ch) {
'<', '^', '>' => parser.char(),
else => null,
}
else
null;
// Parse the alignment parameter
const alignment: ?Alignment = comptime if (parser.peek(0)) |ch| init: {
switch (ch) {
'<', '^', '>' => {
// consume the character
break :init switch (parser.char().?) {
'<' => .left,
'^' => .center,
else => .right,
};
},
else => break :init null,
}
} else null;
// When none of the fill character and the alignment specifier have
// been provided, check whether the width starts with a zero.
if (fill == null and alignment == null) {
fill = comptime if (parser.peek(0) == '0') '0' else null;
}
// Parse the width parameter
const width = comptime parser.specifier() catch |err|
@compileError(@errorName(err));
// Skip the dot, if present
if (comptime parser.char()) |ch| {
if (ch != '.') {
@compileError("expected . or }, found '" ++ unicode.utf8EncodeComptime(ch) ++ "'");
}
}
// Parse the precision parameter
const precision = comptime parser.specifier() catch |err|
@compileError(@errorName(err));
if (comptime parser.char()) |ch| {
@compileError("extraneous trailing character '" ++ unicode.utf8EncodeComptime(ch) ++ "'");
}
return Placeholder{
.specifier_arg = cacheString(specifier_arg[0..specifier_arg.len].*),
.fill = fill orelse default_fill_char,
.alignment = alignment orelse default_alignment,
.arg = arg,
.width = width,
.precision = precision,
};
}
};
pub const Specifier = union(enum) {
none,
number: usize,
named: []const u8,
};
/// A stream based parser for format strings.
///
/// Allows to implement formatters compatible with std.fmt without replicating
/// the standard library behavior.
pub const Parser = struct {
pos: usize = 0,
iter: std.unicode.Utf8Iterator,
// Returns a decimal number or null if the current character is not a
// digit
pub fn number(self: *@This()) ?usize {
var r: ?usize = null;
while (self.peek(0)) |code_point| {
switch (code_point) {
'0'...'9' => {
if (r == null) r = 0;
r.? *= 10;
r.? += code_point - '0';
},
else => break,
}
_ = self.iter.nextCodepoint();
}
return r;
}
// Returns a substring of the input starting from the current position
// and ending where `ch` is found or until the end if not found
pub fn until(self: *@This(), ch: u21) []const u8 {
var result: []const u8 = &[_]u8{};
while (self.peek(0)) |code_point| {
if (code_point == ch)
break;
result = result ++ (self.iter.nextCodepointSlice() orelse &[_]u8{});
}
return result;
}
// Returns one character, if available
pub fn char(self: *@This()) ?u21 {
if (self.iter.nextCodepoint()) |code_point| {
return code_point;
}
return null;
}
pub fn maybe(self: *@This(), val: u21) bool {
if (self.peek(0) == val) {
_ = self.iter.nextCodepoint();
return true;
}
return false;
}
// Returns a decimal number or null if the current character is not a
// digit
pub fn specifier(self: *@This()) !Specifier {
if (self.maybe('[')) {
const arg_name = self.until(']');
if (!self.maybe(']'))
return @field(anyerror, "Expected closing ]");
return Specifier{ .named = arg_name };
}
if (self.number()) |i|
return Specifier{ .number = i };
return Specifier{ .none = {} };
}
// Returns the n-th next character or null if that's past the end
pub fn peek(self: *@This(), n: usize) ?u21 {
const original_i = self.iter.i;
defer self.iter.i = original_i;
var i: usize = 0;
var code_point: ?u21 = null;
while (i <= n) : (i += 1) {
code_point = self.iter.nextCodepoint();
if (code_point == null) return null;
}
return code_point;
}
};
pub const ArgSetType = u32;
const max_format_args = @typeInfo(ArgSetType).int.bits;
pub const ArgState = struct {
next_arg: usize = 0,
used_args: ArgSetType = 0,
args_len: usize,
pub fn hasUnusedArgs(self: *@This()) bool {
return @popCount(self.used_args) != self.args_len;
}
pub fn nextArg(self: *@This(), arg_index: ?usize) ?usize {
const next_index = arg_index orelse init: {
const arg = self.next_arg;
self.next_arg += 1;
break :init arg;
};
if (next_index >= self.args_len) {
return null;
}
// Mark this argument as used
self.used_args |= @as(ArgSetType, 1) << @as(u5, @intCast(next_index));
return next_index;
}
};
pub fn formatAddress(value: anytype, options: FormatOptions, writer: anytype) @TypeOf(writer).Error!void {
_ = options;
const T = @TypeOf(value);
switch (@typeInfo(T)) {
.pointer => |info| {
try writer.writeAll(@typeName(info.child) ++ "@");
if (info.size == .Slice)
try formatInt(@intFromPtr(value.ptr), 16, .lower, FormatOptions{}, writer)
else
try formatInt(@intFromPtr(value), 16, .lower, FormatOptions{}, writer);
return;
},
.optional => |info| {
if (@typeInfo(info.child) == .pointer) {
try writer.writeAll(@typeName(info.child) ++ "@");
try formatInt(@intFromPtr(value), 16, .lower, FormatOptions{}, writer);
return;
}
},
else => {},
}
@compileError("cannot format non-pointer type " ++ @typeName(T) ++ " with * specifier");
}
// This ANY const is a workaround for: https://github.com/ziglang/zig/issues/7948
const ANY = "any";
pub fn defaultSpec(comptime T: type) [:0]const u8 {
switch (@typeInfo(T)) {
.array, .vector => return ANY,
.pointer => |ptr_info| switch (ptr_info.size) {
.One => switch (@typeInfo(ptr_info.child)) {
.array => return ANY,
else => {},
},
.Many, .C => return "*",
.Slice => return ANY,
},
.optional => |info| return "?" ++ defaultSpec(info.child),
.error_union => |info| return "!" ++ defaultSpec(info.payload),
else => {},
}
return "";
}
fn stripOptionalOrErrorUnionSpec(comptime fmt: []const u8) []const u8 {
return if (std.mem.eql(u8, fmt[1..], ANY))
ANY
else
fmt[1..];
}
pub fn invalidFmtError(comptime fmt: []const u8, value: anytype) void {
@compileError("invalid format string '" ++ fmt ++ "' for type '" ++ @typeName(@TypeOf(value)) ++ "'");
}
pub fn formatType(
value: anytype,
comptime fmt: []const u8,
options: FormatOptions,
writer: anytype,
max_depth: usize,
) @TypeOf(writer).Error!void {
const T = @TypeOf(value);
const actual_fmt = comptime if (std.mem.eql(u8, fmt, ANY))
defaultSpec(T)
else if (fmt.len != 0 and (fmt[0] == '?' or fmt[0] == '!')) switch (@typeInfo(T)) {
.optional, .error_union => fmt,
else => stripOptionalOrErrorUnionSpec(fmt),
} else fmt;
if (comptime std.mem.eql(u8, actual_fmt, "*")) {
return formatAddress(value, options, writer);
}
if (std.meta.hasMethod(T, "format")) {
return try value.format(actual_fmt, options, writer);
}
switch (@typeInfo(T)) {
.comptime_int, .int, .comptime_float, .float => {
return formatValue(value, actual_fmt, options, writer);
},
.void => {
if (actual_fmt.len != 0) invalidFmtError(fmt, value);
return formatBuf("void", options, writer);
},
.bool => {
if (actual_fmt.len != 0) invalidFmtError(fmt, value);
return formatBuf(if (value) "true" else "false", options, writer);
},
.optional => {
if (actual_fmt.len == 0 or actual_fmt[0] != '?')
@compileError("cannot format optional without a specifier (i.e. {?} or {any})");
const remaining_fmt = comptime stripOptionalOrErrorUnionSpec(actual_fmt);
if (value) |payload| {
return formatType(payload, remaining_fmt, options, writer, max_depth);
} else {
return formatBuf("null", options, writer);
}
},
.error_union => {
if (actual_fmt.len == 0 or actual_fmt[0] != '!')
@compileError("cannot format error union without a specifier (i.e. {!} or {any})");
const remaining_fmt = comptime stripOptionalOrErrorUnionSpec(actual_fmt);
if (value) |payload| {
return formatType(payload, remaining_fmt, options, writer, max_depth);
} else |err| {
return formatType(err, "", options, writer, max_depth);
}
},
.error_set => {
if (actual_fmt.len != 0) invalidFmtError(fmt, value);
try writer.writeAll("error.");
return writer.writeAll(@errorName(value));
},
.@"enum" => |enumInfo| {
try writer.writeAll(@typeName(T));
if (enumInfo.is_exhaustive) {
if (actual_fmt.len != 0) invalidFmtError(fmt, value);
try writer.writeAll(".");
try writer.writeAll(@tagName(value));
return;
}
// Use @tagName only if value is one of known fields
@setEvalBranchQuota(3 * enumInfo.fields.len);
inline for (enumInfo.fields) |enumField| {
if (@intFromEnum(value) == enumField.value) {
try writer.writeAll(".");
try writer.writeAll(@tagName(value));
return;
}
}
try writer.writeAll("(");
try formatType(@intFromEnum(value), actual_fmt, options, writer, max_depth);
try writer.writeAll(")");
},
.@"union" => |info| {
if (actual_fmt.len != 0) invalidFmtError(fmt, value);
try writer.writeAll(@typeName(T));
if (max_depth == 0) {
return writer.writeAll("{ ... }");
}
if (info.tag_type) |UnionTagType| {
try writer.writeAll("{ .");
try writer.writeAll(@tagName(@as(UnionTagType, value)));
try writer.writeAll(" = ");
inline for (info.fields) |u_field| {
if (value == @field(UnionTagType, u_field.name)) {
try formatType(@field(value, u_field.name), ANY, options, writer, max_depth - 1);
}
}
try writer.writeAll(" }");
} else {
try format(writer, "@{x}", .{@intFromPtr(&value)});
}
},
.@"struct" => |info| {
if (actual_fmt.len != 0) invalidFmtError(fmt, value);
if (info.is_tuple) {
// Skip the type and field names when formatting tuples.
if (max_depth == 0) {
return writer.writeAll("{ ... }");
}
try writer.writeAll("{");
inline for (info.fields, 0..) |f, i| {
if (i == 0) {
try writer.writeAll(" ");
} else {
try writer.writeAll(", ");
}
try formatType(@field(value, f.name), ANY, options, writer, max_depth - 1);
}
return writer.writeAll(" }");
}
try writer.writeAll(@typeName(T));
if (max_depth == 0) {
return writer.writeAll("{ ... }");
}
try writer.writeAll("{");
inline for (info.fields, 0..) |f, i| {
if (i == 0) {
try writer.writeAll(" .");
} else {
try writer.writeAll(", .");
}
try writer.writeAll(f.name);
try writer.writeAll(" = ");
try formatType(@field(value, f.name), ANY, options, writer, max_depth - 1);
}
try writer.writeAll(" }");
},
.pointer => |ptr_info| switch (ptr_info.size) {
.One => switch (@typeInfo(ptr_info.child)) {
.array, .@"enum", .@"union", .@"struct" => {
return formatType(value.*, actual_fmt, options, writer, max_depth);
},
else => return format(writer, "{s}@{x}", .{ @typeName(ptr_info.child), @intFromPtr(value) }),
},
.Many, .C => {
if (actual_fmt.len == 0)
@compileError("cannot format pointer without a specifier (i.e. {s} or {*})");
if (ptr_info.sentinel) |_| {
return formatType(mem.span(value), actual_fmt, options, writer, max_depth);
}
if (actual_fmt[0] == 's' and ptr_info.child == u8) {
return formatBuf(mem.span(value), options, writer);
}
invalidFmtError(fmt, value);
},
.Slice => {
if (actual_fmt.len == 0)
@compileError("cannot format slice without a specifier (i.e. {s} or {any})");
if (max_depth == 0) {
return writer.writeAll("{ ... }");
}
if (actual_fmt[0] == 's' and ptr_info.child == u8) {
return formatBuf(value, options, writer);
}
try writer.writeAll("{ ");
for (value, 0..) |elem, i| {
try formatType(elem, actual_fmt, options, writer, max_depth - 1);
if (i != value.len - 1) {
try writer.writeAll(", ");
}
}
try writer.writeAll(" }");
},
},
.array => |info| {
if (actual_fmt.len == 0)
@compileError("cannot format array without a specifier (i.e. {s} or {any})");
if (max_depth == 0) {
return writer.writeAll("{ ... }");
}
if (actual_fmt[0] == 's' and info.child == u8) {
return formatBuf(&value, options, writer);
}
try writer.writeAll("{ ");
for (value, 0..) |elem, i| {
try formatType(elem, actual_fmt, options, writer, max_depth - 1);
if (i < value.len - 1) {
try writer.writeAll(", ");
}
}
try writer.writeAll(" }");
},
.vector => |info| {
try writer.writeAll("{ ");
var i: usize = 0;
while (i < info.len) : (i += 1) {
try formatType(value[i], actual_fmt, options, writer, max_depth - 1);
if (i < info.len - 1) {
try writer.writeAll(", ");
}
}
try writer.writeAll(" }");
},
.@"fn" => @compileError("unable to format function body type, use '*const " ++ @typeName(T) ++ "' for a function pointer type"),
.type => {
if (actual_fmt.len != 0) invalidFmtError(fmt, value);
return formatBuf(@typeName(value), options, writer);
},
.enum_literal => {
if (actual_fmt.len != 0) invalidFmtError(fmt, value);
const buffer = [_]u8{'.'} ++ @tagName(value);
return formatBuf(buffer, options, writer);
},
.null => {
if (actual_fmt.len != 0) invalidFmtError(fmt, value);
return formatBuf("null", options, writer);
},
else => @compileError("unable to format type '" ++ @typeName(T) ++ "'"),
}
}
fn formatValue(
value: anytype,
comptime fmt: []const u8,
options: FormatOptions,
writer: anytype,
) !void {
const T = @TypeOf(value);
switch (@typeInfo(T)) {
.float, .comptime_float => return formatFloatValue(value, fmt, options, writer),
.int, .comptime_int => return formatIntValue(value, fmt, options, writer),
.bool => return formatBuf(if (value) "true" else "false", options, writer),
else => comptime unreachable,
}
}
pub fn formatIntValue(
value: anytype,
comptime fmt: []const u8,
options: FormatOptions,
writer: anytype,
) !void {
comptime var base = 10;
comptime var case: Case = .lower;
const int_value = if (@TypeOf(value) == comptime_int) blk: {
const Int = math.IntFittingRange(value, value);
break :blk @as(Int, value);
} else value;
if (fmt.len == 0 or comptime std.mem.eql(u8, fmt, "d")) {
base = 10;
case = .lower;
} else if (comptime std.mem.eql(u8, fmt, "c")) {
if (@typeInfo(@TypeOf(int_value)).int.bits <= 8) {
return formatAsciiChar(@as(u8, int_value), options, writer);
} else {
@compileError("cannot print integer that is larger than 8 bits as an ASCII character");
}
} else if (comptime std.mem.eql(u8, fmt, "u")) {
if (@typeInfo(@TypeOf(int_value)).int.bits <= 21) {
return formatUnicodeCodepoint(@as(u21, int_value), options, writer);
} else {
@compileError("cannot print integer that is larger than 21 bits as an UTF-8 sequence");
}
} else if (comptime std.mem.eql(u8, fmt, "b")) {
base = 2;
case = .lower;
} else if (comptime std.mem.eql(u8, fmt, "x")) {
base = 16;
case = .lower;
} else if (comptime std.mem.eql(u8, fmt, "X")) {
base = 16;
case = .upper;
} else if (comptime std.mem.eql(u8, fmt, "o")) {
base = 8;
case = .lower;
} else {
invalidFmtError(fmt, value);
}
return formatInt(int_value, base, case, options, writer);
}
pub const format_float = @import("fmt/format_float.zig");
pub const formatFloat = format_float.formatFloat;
pub const FormatFloatError = format_float.FormatError;
fn formatFloatValue(
value: anytype,
comptime fmt: []const u8,
options: FormatOptions,
writer: anytype,
) !void {
var buf: [format_float.bufferSize(.decimal, f64)]u8 = undefined;
if (fmt.len == 0 or comptime std.mem.eql(u8, fmt, "e")) {
const s = formatFloat(&buf, value, .{ .mode = .scientific, .precision = options.precision }) catch |err| switch (err) {
error.BufferTooSmall => "(float)",
};
return formatBuf(s, options, writer);
} else if (comptime std.mem.eql(u8, fmt, "d")) {
const s = formatFloat(&buf, value, .{ .mode = .decimal, .precision = options.precision }) catch |err| switch (err) {
error.BufferTooSmall => "(float)",
};
return formatBuf(s, options, writer);
} else if (comptime std.mem.eql(u8, fmt, "x")) {
var buf_stream = std.io.fixedBufferStream(&buf);
formatFloatHexadecimal(value, options, buf_stream.writer()) catch |err| switch (err) {
error.NoSpaceLeft => unreachable,
};
return formatBuf(buf_stream.getWritten(), options, writer);
} else {
invalidFmtError(fmt, value);
}
}
test {
_ = &format_float;
}
pub const Case = enum { lower, upper };
fn SliceHex(comptime case: Case) type {
const charset = "0123456789" ++ if (case == .upper) "ABCDEF" else "abcdef";
return struct {
pub fn format(
bytes: []const u8,
comptime fmt: []const u8,
options: std.fmt.FormatOptions,
writer: anytype,
) !void {
_ = fmt;
_ = options;
var buf: [2]u8 = undefined;
for (bytes) |c| {
buf[0] = charset[c >> 4];
buf[1] = charset[c & 15];
try writer.writeAll(&buf);
}
}
};
}
const formatSliceHexLower = SliceHex(.lower).format;
const formatSliceHexUpper = SliceHex(.upper).format;
/// Return a Formatter for a []const u8 where every byte is formatted as a pair
/// of lowercase hexadecimal digits.
pub fn fmtSliceHexLower(bytes: []const u8) std.fmt.Formatter(formatSliceHexLower) {
return .{ .data = bytes };
}
/// Return a Formatter for a []const u8 where every byte is formatted as pair
/// of uppercase hexadecimal digits.
pub fn fmtSliceHexUpper(bytes: []const u8) std.fmt.Formatter(formatSliceHexUpper) {
return .{ .data = bytes };
}
fn SliceEscape(comptime case: Case) type {
const charset = "0123456789" ++ if (case == .upper) "ABCDEF" else "abcdef";
return struct {
pub fn format(
bytes: []const u8,
comptime fmt: []const u8,
options: std.fmt.FormatOptions,
writer: anytype,
) !void {
_ = fmt;
_ = options;
var buf: [4]u8 = undefined;
buf[0] = '\\';
buf[1] = 'x';
for (bytes) |c| {
if (std.ascii.isPrint(c)) {
try writer.writeByte(c);
} else {
buf[2] = charset[c >> 4];
buf[3] = charset[c & 15];
try writer.writeAll(&buf);
}
}
}
};
}
const formatSliceEscapeLower = SliceEscape(.lower).format;
const formatSliceEscapeUpper = SliceEscape(.upper).format;
/// Return a Formatter for a []const u8 where every non-printable ASCII
/// character is escaped as \xNN, where NN is the character in lowercase
/// hexadecimal notation.
pub fn fmtSliceEscapeLower(bytes: []const u8) std.fmt.Formatter(formatSliceEscapeLower) {
return .{ .data = bytes };
}
/// Return a Formatter for a []const u8 where every non-printable ASCII
/// character is escaped as \xNN, where NN is the character in uppercase
/// hexadecimal notation.
pub fn fmtSliceEscapeUpper(bytes: []const u8) std.fmt.Formatter(formatSliceEscapeUpper) {
return .{ .data = bytes };
}
fn Size(comptime base: comptime_int) type {
return struct {
fn format(
value: u64,
comptime fmt: []const u8,
options: FormatOptions,
writer: anytype,
) !void {
_ = fmt;
if (value == 0) {
return formatBuf("0B", options, writer);
}
// The worst case in terms of space needed is 32 bytes + 3 for the suffix.
var buf: [format_float.min_buffer_size + 3]u8 = undefined;
const mags_si = " kMGTPEZY";
const mags_iec = " KMGTPEZY";
const log2 = math.log2(value);
const magnitude = switch (base) {
1000 => @min(log2 / comptime math.log2(1000), mags_si.len - 1),
1024 => @min(log2 / 10, mags_iec.len - 1),
else => unreachable,
};
const new_value = lossyCast(f64, value) / math.pow(f64, lossyCast(f64, base), lossyCast(f64, magnitude));
const suffix = switch (base) {
1000 => mags_si[magnitude],
1024 => mags_iec[magnitude],
else => unreachable,
};
const s = switch (magnitude) {
0 => buf[0..formatIntBuf(&buf, value, 10, .lower, .{})],
else => formatFloat(&buf, new_value, .{ .mode = .decimal, .precision = options.precision }) catch |err| switch (err) {
error.BufferTooSmall => unreachable,
},
};
var i: usize = s.len;
if (suffix == ' ') {
buf[i] = 'B';
i += 1;
} else switch (base) {
1000 => {
buf[i..][0..2].* = [_]u8{ suffix, 'B' };
i += 2;
},
1024 => {
buf[i..][0..3].* = [_]u8{ suffix, 'i', 'B' };
i += 3;
},
else => unreachable,
}
return formatBuf(buf[0..i], options, writer);
}
};
}
const formatSizeDec = Size(1000).format;
const formatSizeBin = Size(1024).format;
/// Return a Formatter for a u64 value representing a file size.
/// This formatter represents the number as multiple of 1000 and uses the SI
/// measurement units (kB, MB, GB, ...).
/// Format option `precision` is ignored when `value` is less than 1kB
pub fn fmtIntSizeDec(value: u64) std.fmt.Formatter(formatSizeDec) {
return .{ .data = value };
}
/// Return a Formatter for a u64 value representing a file size.
/// This formatter represents the number as multiple of 1024 and uses the IEC
/// measurement units (KiB, MiB, GiB, ...).
/// Format option `precision` is ignored when `value` is less than 1KiB
pub fn fmtIntSizeBin(value: u64) std.fmt.Formatter(formatSizeBin) {
return .{ .data = value };
}
fn checkTextFmt(comptime fmt: []const u8) void {
if (fmt.len != 1)
@compileError("unsupported format string '" ++ fmt ++ "' when formatting text");
switch (fmt[0]) {
// Example of deprecation:
// '[deprecated_specifier]' => @compileError("specifier '[deprecated_specifier]' has been deprecated, wrap your argument in `std.some_function` instead"),
'x' => @compileError("specifier 'x' has been deprecated, wrap your argument in std.fmt.fmtSliceHexLower instead"),
'X' => @compileError("specifier 'X' has been deprecated, wrap your argument in std.fmt.fmtSliceHexUpper instead"),
else => {},
}
}
pub fn formatText(
bytes: []const u8,
comptime fmt: []const u8,
options: FormatOptions,
writer: anytype,
) !void {
comptime checkTextFmt(fmt);
return formatBuf(bytes, options, writer);
}
pub fn formatAsciiChar(
c: u8,
options: FormatOptions,
writer: anytype,
) !void {
return formatBuf(@as(*const [1]u8, &c), options, writer);
}
pub fn formatUnicodeCodepoint(
c: u21,
options: FormatOptions,
writer: anytype,
) !void {
var buf: [4]u8 = undefined;
const len = unicode.utf8Encode(c, &buf) catch |err| switch (err) {
error.Utf8CannotEncodeSurrogateHalf, error.CodepointTooLarge => {
return formatBuf(&unicode.utf8EncodeComptime(unicode.replacement_character), options, writer);
},
};
return formatBuf(buf[0..len], options, writer);
}
pub fn formatBuf(
buf: []const u8,
options: FormatOptions,
writer: anytype,
) !void {
if (options.width) |min_width| {
// In case of error assume the buffer content is ASCII-encoded
const width = unicode.utf8CountCodepoints(buf) catch buf.len;
const padding = if (width < min_width) min_width - width else 0;
if (padding == 0)
return writer.writeAll(buf);
var fill_buffer: [4]u8 = undefined;
const fill_utf8 = if (unicode.utf8Encode(options.fill, &fill_buffer)) |len|
fill_buffer[0..len]
else |err| switch (err) {
error.Utf8CannotEncodeSurrogateHalf,
error.CodepointTooLarge,
=> &unicode.utf8EncodeComptime(unicode.replacement_character),
};
switch (options.alignment) {
.left => {
try writer.writeAll(buf);
try writer.writeBytesNTimes(fill_utf8, padding);
},
.center => {
const left_padding = padding / 2;
const right_padding = (padding + 1) / 2;
try writer.writeBytesNTimes(fill_utf8, left_padding);
try writer.writeAll(buf);
try writer.writeBytesNTimes(fill_utf8, right_padding);
},
.right => {
try writer.writeBytesNTimes(fill_utf8, padding);
try writer.writeAll(buf);
},
}
} else {
// Fast path, avoid counting the number of codepoints
try writer.writeAll(buf);
}
}
pub fn formatFloatHexadecimal(
value: anytype,
options: FormatOptions,
writer: anytype,
) !void {
if (math.signbit(value)) {
try writer.writeByte('-');
}
if (math.isNan(value)) {
return writer.writeAll("nan");
}
if (math.isInf(value)) {
return writer.writeAll("inf");
}
const T = @TypeOf(value);
const TU = std.meta.Int(.unsigned, @bitSizeOf(T));
const mantissa_bits = math.floatMantissaBits(T);
const fractional_bits = math.floatFractionalBits(T);
const exponent_bits = math.floatExponentBits(T);
const mantissa_mask = (1 << mantissa_bits) - 1;
const exponent_mask = (1 << exponent_bits) - 1;
const exponent_bias = (1 << (exponent_bits - 1)) - 1;
const as_bits = @as(TU, @bitCast(value));
var mantissa = as_bits & mantissa_mask;
var exponent: i32 = @as(u16, @truncate((as_bits >> mantissa_bits) & exponent_mask));
const is_denormal = exponent == 0 and mantissa != 0;
const is_zero = exponent == 0 and mantissa == 0;
if (is_zero) {
// Handle this case here to simplify the logic below.
try writer.writeAll("0x0");
if (options.precision) |precision| {
if (precision > 0) {
try writer.writeAll(".");
try writer.writeByteNTimes('0', precision);
}
} else {
try writer.writeAll(".0");
}
try writer.writeAll("p0");
return;
}
if (is_denormal) {
// Adjust the exponent for printing.
exponent += 1;
} else {
if (fractional_bits == mantissa_bits)
mantissa |= 1 << fractional_bits; // Add the implicit integer bit.
}
const mantissa_digits = (fractional_bits + 3) / 4;
// Fill in zeroes to round the fraction width to a multiple of 4.
mantissa <<= mantissa_digits * 4 - fractional_bits;
if (options.precision) |precision| {
// Round if needed.
if (precision < mantissa_digits) {
// We always have at least 4 extra bits.
var extra_bits = (mantissa_digits - precision) * 4;
// The result LSB is the Guard bit, we need two more (Round and
// Sticky) to round the value.
while (extra_bits > 2) {
mantissa = (mantissa >> 1) | (mantissa & 1);
extra_bits -= 1;
}
// Round to nearest, tie to even.
mantissa |= @intFromBool(mantissa & 0b100 != 0);
mantissa += 1;
// Drop the excess bits.
mantissa >>= 2;
// Restore the alignment.
mantissa <<= @as(math.Log2Int(TU), @intCast((mantissa_digits - precision) * 4));
const overflow = mantissa & (1 << 1 + mantissa_digits * 4) != 0;
// Prefer a normalized result in case of overflow.
if (overflow) {
mantissa >>= 1;
exponent += 1;
}
}
}
// +1 for the decimal part.
var buf: [1 + mantissa_digits]u8 = undefined;
_ = formatIntBuf(&buf, mantissa, 16, .lower, .{ .fill = '0', .width = 1 + mantissa_digits });
try writer.writeAll("0x");
try writer.writeByte(buf[0]);
const trimmed = mem.trimRight(u8, buf[1..], "0");
if (options.precision) |precision| {
if (precision > 0) try writer.writeAll(".");
} else if (trimmed.len > 0) {
try writer.writeAll(".");
}
try writer.writeAll(trimmed);
// Add trailing zeros if explicitly requested.
if (options.precision) |precision| if (precision > 0) {
if (precision > trimmed.len)
try writer.writeByteNTimes('0', precision - trimmed.len);
};
try writer.writeAll("p");
try formatInt(exponent - exponent_bias, 10, .lower, .{}, writer);
}
pub fn formatInt(
value: anytype,
base: u8,
case: Case,
options: FormatOptions,
writer: anytype,
) !void {
assert(base >= 2);
const int_value = if (@TypeOf(value) == comptime_int) blk: {
const Int = math.IntFittingRange(value, value);
break :blk @as(Int, value);
} else value;
const value_info = @typeInfo(@TypeOf(int_value)).int;
// The type must have the same size as `base` or be wider in order for the
// division to work
const min_int_bits = comptime @max(value_info.bits, 8);
const MinInt = std.meta.Int(.unsigned, min_int_bits);
const abs_value = @abs(int_value);
// The worst case in terms of space needed is base 2, plus 1 for the sign
var buf: [1 + @max(@as(comptime_int, value_info.bits), 1)]u8 = undefined;
var a: MinInt = abs_value;
var index: usize = buf.len;
if (base == 10) {
while (a >= 100) : (a = @divTrunc(a, 100)) {
index -= 2;
buf[index..][0..2].* = digits2(@intCast(a % 100));
}
if (a < 10) {
index -= 1;
buf[index] = '0' + @as(u8, @intCast(a));
} else {
index -= 2;
buf[index..][0..2].* = digits2(@intCast(a));
}
} else {
while (true) {
const digit = a % base;
index -= 1;
buf[index] = digitToChar(@intCast(digit), case);
a /= base;
if (a == 0) break;
}
}
if (value_info.signedness == .signed) {
if (value < 0) {
// Negative integer
index -= 1;
buf[index] = '-';
} else if (options.width == null or options.width.? == 0) {
// Positive integer, omit the plus sign
} else {
// Positive integer
index -= 1;
buf[index] = '+';
}
}
return formatBuf(buf[index..], options, writer);
}
pub fn formatIntBuf(out_buf: []u8, value: anytype, base: u8, case: Case, options: FormatOptions) usize {
var fbs = std.io.fixedBufferStream(out_buf);
formatInt(value, base, case, options, fbs.writer()) catch unreachable;
return fbs.pos;
}
// Converts values in the range [0, 100) to a string.
pub fn digits2(value: usize) [2]u8 {
return "00010203040506070809101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899"[value * 2 ..][0..2].*;
}
const FormatDurationData = struct {
ns: u64,
negative: bool = false,
};
fn formatDuration(data: FormatDurationData, comptime fmt: []const u8, options: std.fmt.FormatOptions, writer: anytype) !void {
_ = fmt;
// worst case: "-XXXyXXwXXdXXhXXmXX.XXXs".len = 24
var buf: [24]u8 = undefined;
var fbs = std.io.fixedBufferStream(&buf);
var buf_writer = fbs.writer();
if (data.negative) {
buf_writer.writeByte('-') catch unreachable;
}
var ns_remaining = data.ns;
inline for (.{
.{ .ns = 365 * std.time.ns_per_day, .sep = 'y' },
.{ .ns = std.time.ns_per_week, .sep = 'w' },
.{ .ns = std.time.ns_per_day, .sep = 'd' },
.{ .ns = std.time.ns_per_hour, .sep = 'h' },
.{ .ns = std.time.ns_per_min, .sep = 'm' },
}) |unit| {
if (ns_remaining >= unit.ns) {
const units = ns_remaining / unit.ns;
formatInt(units, 10, .lower, .{}, buf_writer) catch unreachable;
buf_writer.writeByte(unit.sep) catch unreachable;
ns_remaining -= units * unit.ns;
if (ns_remaining == 0)
return formatBuf(fbs.getWritten(), options, writer);
}
}
inline for (.{
.{ .ns = std.time.ns_per_s, .sep = "s" },
.{ .ns = std.time.ns_per_ms, .sep = "ms" },
.{ .ns = std.time.ns_per_us, .sep = "us" },
}) |unit| {
const kunits = ns_remaining * 1000 / unit.ns;
if (kunits >= 1000) {
formatInt(kunits / 1000, 10, .lower, .{}, buf_writer) catch unreachable;
const frac = kunits % 1000;
if (frac > 0) {
// Write up to 3 decimal places
var decimal_buf = [_]u8{ '.', 0, 0, 0 };
_ = formatIntBuf(decimal_buf[1..], frac, 10, .lower, .{ .fill = '0', .width = 3 });
var end: usize = 4;
while (end > 1) : (end -= 1) {
if (decimal_buf[end - 1] != '0') break;
}
buf_writer.writeAll(decimal_buf[0..end]) catch unreachable;
}
buf_writer.writeAll(unit.sep) catch unreachable;
return formatBuf(fbs.getWritten(), options, writer);
}
}
formatInt(ns_remaining, 10, .lower, .{}, buf_writer) catch unreachable;
buf_writer.writeAll("ns") catch unreachable;
return formatBuf(fbs.getWritten(), options, writer);
}
/// Return a Formatter for number of nanoseconds according to its magnitude:
/// [#y][#w][#d][#h][#m]#[.###][n|u|m]s
pub fn fmtDuration(ns: u64) Formatter(formatDuration) {
const data = FormatDurationData{ .ns = ns };
return .{ .data = data };
}
test fmtDuration {
var buf: [24]u8 = undefined;
inline for (.{
.{ .s = "0ns", .d = 0 },
.{ .s = "1ns", .d = 1 },
.{ .s = "999ns", .d = std.time.ns_per_us - 1 },
.{ .s = "1us", .d = std.time.ns_per_us },
.{ .s = "1.45us", .d = 1450 },
.{ .s = "1.5us", .d = 3 * std.time.ns_per_us / 2 },
.{ .s = "14.5us", .d = 14500 },
.{ .s = "145us", .d = 145000 },
.{ .s = "999.999us", .d = std.time.ns_per_ms - 1 },
.{ .s = "1ms", .d = std.time.ns_per_ms + 1 },
.{ .s = "1.5ms", .d = 3 * std.time.ns_per_ms / 2 },
.{ .s = "1.11ms", .d = 1110000 },
.{ .s = "1.111ms", .d = 1111000 },
.{ .s = "1.111ms", .d = 1111100 },
.{ .s = "999.999ms", .d = std.time.ns_per_s - 1 },
.{ .s = "1s", .d = std.time.ns_per_s },
.{ .s = "59.999s", .d = std.time.ns_per_min - 1 },
.{ .s = "1m", .d = std.time.ns_per_min },
.{ .s = "1h", .d = std.time.ns_per_hour },
.{ .s = "1d", .d = std.time.ns_per_day },
.{ .s = "1w", .d = std.time.ns_per_week },
.{ .s = "1y", .d = 365 * std.time.ns_per_day },
.{ .s = "1y52w23h59m59.999s", .d = 730 * std.time.ns_per_day - 1 }, // 365d = 52w1d
.{ .s = "1y1h1.001s", .d = 365 * std.time.ns_per_day + std.time.ns_per_hour + std.time.ns_per_s + std.time.ns_per_ms },
.{ .s = "1y1h1s", .d = 365 * std.time.ns_per_day + std.time.ns_per_hour + std.time.ns_per_s + 999 * std.time.ns_per_us },
.{ .s = "1y1h999.999us", .d = 365 * std.time.ns_per_day + std.time.ns_per_hour + std.time.ns_per_ms - 1 },
.{ .s = "1y1h1ms", .d = 365 * std.time.ns_per_day + std.time.ns_per_hour + std.time.ns_per_ms },
.{ .s = "1y1h1ms", .d = 365 * std.time.ns_per_day + std.time.ns_per_hour + std.time.ns_per_ms + 1 },
.{ .s = "1y1m999ns", .d = 365 * std.time.ns_per_day + std.time.ns_per_min + 999 },
.{ .s = "584y49w23h34m33.709s", .d = math.maxInt(u64) },
}) |tc| {
const slice = try bufPrint(&buf, "{}", .{fmtDuration(tc.d)});
try std.testing.expectEqualStrings(tc.s, slice);
}
inline for (.{
.{ .s = "=======0ns", .f = "{s:=>10}", .d = 0 },
.{ .s = "1ns=======", .f = "{s:=<10}", .d = 1 },
.{ .s = " 999ns ", .f = "{s:^10}", .d = std.time.ns_per_us - 1 },
}) |tc| {
const slice = try bufPrint(&buf, tc.f, .{fmtDuration(tc.d)});
try std.testing.expectEqualStrings(tc.s, slice);
}
}
fn formatDurationSigned(ns: i64, comptime fmt: []const u8, options: std.fmt.FormatOptions, writer: anytype) !void {
if (ns < 0) {
const data = FormatDurationData{ .ns = @as(u64, @intCast(-ns)), .negative = true };
try formatDuration(data, fmt, options, writer);
} else {
const data = FormatDurationData{ .ns = @as(u64, @intCast(ns)) };
try formatDuration(data, fmt, options, writer);
}
}
/// Return a Formatter for number of nanoseconds according to its signed magnitude:
/// [#y][#w][#d][#h][#m]#[.###][n|u|m]s
pub fn fmtDurationSigned(ns: i64) Formatter(formatDurationSigned) {
return .{ .data = ns };
}
test fmtDurationSigned {
var buf: [24]u8 = undefined;
inline for (.{
.{ .s = "0ns", .d = 0 },
.{ .s = "1ns", .d = 1 },
.{ .s = "-1ns", .d = -(1) },
.{ .s = "999ns", .d = std.time.ns_per_us - 1 },
.{ .s = "-999ns", .d = -(std.time.ns_per_us - 1) },
.{ .s = "1us", .d = std.time.ns_per_us },
.{ .s = "-1us", .d = -(std.time.ns_per_us) },
.{ .s = "1.45us", .d = 1450 },
.{ .s = "-1.45us", .d = -(1450) },
.{ .s = "1.5us", .d = 3 * std.time.ns_per_us / 2 },
.{ .s = "-1.5us", .d = -(3 * std.time.ns_per_us / 2) },
.{ .s = "14.5us", .d = 14500 },
.{ .s = "-14.5us", .d = -(14500) },
.{ .s = "145us", .d = 145000 },
.{ .s = "-145us", .d = -(145000) },
.{ .s = "999.999us", .d = std.time.ns_per_ms - 1 },
.{ .s = "-999.999us", .d = -(std.time.ns_per_ms - 1) },
.{ .s = "1ms", .d = std.time.ns_per_ms + 1 },
.{ .s = "-1ms", .d = -(std.time.ns_per_ms + 1) },
.{ .s = "1.5ms", .d = 3 * std.time.ns_per_ms / 2 },
.{ .s = "-1.5ms", .d = -(3 * std.time.ns_per_ms / 2) },
.{ .s = "1.11ms", .d = 1110000 },
.{ .s = "-1.11ms", .d = -(1110000) },
.{ .s = "1.111ms", .d = 1111000 },
.{ .s = "-1.111ms", .d = -(1111000) },
.{ .s = "1.111ms", .d = 1111100 },
.{ .s = "-1.111ms", .d = -(1111100) },
.{ .s = "999.999ms", .d = std.time.ns_per_s - 1 },
.{ .s = "-999.999ms", .d = -(std.time.ns_per_s - 1) },
.{ .s = "1s", .d = std.time.ns_per_s },
.{ .s = "-1s", .d = -(std.time.ns_per_s) },
.{ .s = "59.999s", .d = std.time.ns_per_min - 1 },
.{ .s = "-59.999s", .d = -(std.time.ns_per_min - 1) },
.{ .s = "1m", .d = std.time.ns_per_min },
.{ .s = "-1m", .d = -(std.time.ns_per_min) },
.{ .s = "1h", .d = std.time.ns_per_hour },
.{ .s = "-1h", .d = -(std.time.ns_per_hour) },
.{ .s = "1d", .d = std.time.ns_per_day },
.{ .s = "-1d", .d = -(std.time.ns_per_day) },
.{ .s = "1w", .d = std.time.ns_per_week },
.{ .s = "-1w", .d = -(std.time.ns_per_week) },
.{ .s = "1y", .d = 365 * std.time.ns_per_day },
.{ .s = "-1y", .d = -(365 * std.time.ns_per_day) },
.{ .s = "1y52w23h59m59.999s", .d = 730 * std.time.ns_per_day - 1 }, // 365d = 52w1d
.{ .s = "-1y52w23h59m59.999s", .d = -(730 * std.time.ns_per_day - 1) }, // 365d = 52w1d
.{ .s = "1y1h1.001s", .d = 365 * std.time.ns_per_day + std.time.ns_per_hour + std.time.ns_per_s + std.time.ns_per_ms },
.{ .s = "-1y1h1.001s", .d = -(365 * std.time.ns_per_day + std.time.ns_per_hour + std.time.ns_per_s + std.time.ns_per_ms) },
.{ .s = "1y1h1s", .d = 365 * std.time.ns_per_day + std.time.ns_per_hour + std.time.ns_per_s + 999 * std.time.ns_per_us },
.{ .s = "-1y1h1s", .d = -(365 * std.time.ns_per_day + std.time.ns_per_hour + std.time.ns_per_s + 999 * std.time.ns_per_us) },
.{ .s = "1y1h999.999us", .d = 365 * std.time.ns_per_day + std.time.ns_per_hour + std.time.ns_per_ms - 1 },
.{ .s = "-1y1h999.999us", .d = -(365 * std.time.ns_per_day + std.time.ns_per_hour + std.time.ns_per_ms - 1) },
.{ .s = "1y1h1ms", .d = 365 * std.time.ns_per_day + std.time.ns_per_hour + std.time.ns_per_ms },
.{ .s = "-1y1h1ms", .d = -(365 * std.time.ns_per_day + std.time.ns_per_hour + std.time.ns_per_ms) },
.{ .s = "1y1h1ms", .d = 365 * std.time.ns_per_day + std.time.ns_per_hour + std.time.ns_per_ms + 1 },
.{ .s = "-1y1h1ms", .d = -(365 * std.time.ns_per_day + std.time.ns_per_hour + std.time.ns_per_ms + 1) },
.{ .s = "1y1m999ns", .d = 365 * std.time.ns_per_day + std.time.ns_per_min + 999 },
.{ .s = "-1y1m999ns", .d = -(365 * std.time.ns_per_day + std.time.ns_per_min + 999) },
.{ .s = "292y24w3d23h47m16.854s", .d = math.maxInt(i64) },
.{ .s = "-292y24w3d23h47m16.854s", .d = math.minInt(i64) + 1 },
}) |tc| {
const slice = try bufPrint(&buf, "{}", .{fmtDurationSigned(tc.d)});
try std.testing.expectEqualStrings(tc.s, slice);
}
inline for (.{
.{ .s = "=======0ns", .f = "{s:=>10}", .d = 0 },
.{ .s = "1ns=======", .f = "{s:=<10}", .d = 1 },
.{ .s = "-1ns======", .f = "{s:=<10}", .d = -(1) },
.{ .s = " -999ns ", .f = "{s:^10}", .d = -(std.time.ns_per_us - 1) },
}) |tc| {
const slice = try bufPrint(&buf, tc.f, .{fmtDurationSigned(tc.d)});
try std.testing.expectEqualStrings(tc.s, slice);
}
}
pub const ParseIntError = error{
/// The result cannot fit in the type specified
Overflow,
/// The input was empty or contained an invalid character
InvalidCharacter,
};
/// Creates a Formatter type from a format function. Wrapping data in Formatter(func) causes
/// the data to be formatted using the given function `func`. `func` must be of the following
/// form:
///
/// fn formatExample(
/// data: T,
/// comptime fmt: []const u8,
/// options: std.fmt.FormatOptions,
/// writer: anytype,
/// ) !void;
///
pub fn Formatter(comptime formatFn: anytype) type {
const Data = @typeInfo(@TypeOf(formatFn)).@"fn".params[0].type.?;
return struct {
data: Data,
pub fn format(
self: @This(),
comptime fmt: []const u8,
options: std.fmt.FormatOptions,
writer: anytype,
) @TypeOf(writer).Error!void {
try formatFn(self.data, fmt, options, writer);
}
};
}
/// Parses the string `buf` as signed or unsigned representation in the
/// specified base of an integral value of type `T`.
///
/// When `base` is zero the string prefix is examined to detect the true base:
/// * A prefix of "0b" implies base=2,
/// * A prefix of "0o" implies base=8,
/// * A prefix of "0x" implies base=16,
/// * Otherwise base=10 is assumed.
///
/// Ignores '_' character in `buf`.
/// See also `parseUnsigned`.
pub fn parseInt(comptime T: type, buf: []const u8, base: u8) ParseIntError!T {
return parseIntWithGenericCharacter(T, u8, buf, base);
}
/// Like `parseInt`, but with a generic `Character` type.
pub fn parseIntWithGenericCharacter(
comptime Result: type,
comptime Character: type,
buf: []const Character,
base: u8,
) ParseIntError!Result {
if (buf.len == 0) return error.InvalidCharacter;
if (buf[0] == '+') return parseIntWithSign(Result, Character, buf[1..], base, .pos);
if (buf[0] == '-') return parseIntWithSign(Result, Character, buf[1..], base, .neg);
return parseIntWithSign(Result, Character, buf, base, .pos);
}
test parseInt {
try std.testing.expectEqual(-10, try parseInt(i32, "-10", 10));
try std.testing.expectEqual(10, try parseInt(i32, "+10", 10));
try std.testing.expectEqual(10, try parseInt(u32, "+10", 10));
try std.testing.expectError(error.Overflow, parseInt(u32, "-10", 10));
try std.testing.expectError(error.InvalidCharacter, parseInt(u32, " 10", 10));
try std.testing.expectError(error.InvalidCharacter, parseInt(u32, "10 ", 10));
try std.testing.expectError(error.InvalidCharacter, parseInt(u32, "_10_", 10));
try std.testing.expectError(error.InvalidCharacter, parseInt(u32, "0x_10_", 10));
try std.testing.expectError(error.InvalidCharacter, parseInt(u32, "0x10_", 10));
try std.testing.expectError(error.InvalidCharacter, parseInt(u32, "0x_10", 10));
try std.testing.expectEqual(255, try parseInt(u8, "255", 10));
try std.testing.expectError(error.Overflow, parseInt(u8, "256", 10));
// +0 and -0 should work for unsigned
try std.testing.expectEqual(0, try parseInt(u8, "-0", 10));
try std.testing.expectEqual(0, try parseInt(u8, "+0", 10));
// ensure minInt is parsed correctly
try std.testing.expectEqual(math.minInt(i1), try parseInt(i1, "-1", 10));
try std.testing.expectEqual(math.minInt(i8), try parseInt(i8, "-128", 10));
try std.testing.expectEqual(math.minInt(i43), try parseInt(i43, "-4398046511104", 10));
// empty string or bare +- is invalid
try std.testing.expectError(error.InvalidCharacter, parseInt(u32, "", 10));
try std.testing.expectError(error.InvalidCharacter, parseInt(i32, "", 10));
try std.testing.expectError(error.InvalidCharacter, parseInt(u32, "+", 10));
try std.testing.expectError(error.InvalidCharacter, parseInt(i32, "+", 10));
try std.testing.expectError(error.InvalidCharacter, parseInt(u32, "-", 10));
try std.testing.expectError(error.InvalidCharacter, parseInt(i32, "-", 10));
// autodectect the base
try std.testing.expectEqual(111, try parseInt(i32, "111", 0));
try std.testing.expectEqual(111, try parseInt(i32, "1_1_1", 0));
try std.testing.expectEqual(111, try parseInt(i32, "1_1_1", 0));
try std.testing.expectEqual(7, try parseInt(i32, "+0b111", 0));
try std.testing.expectEqual(7, try parseInt(i32, "+0B111", 0));
try std.testing.expectEqual(7, try parseInt(i32, "+0b1_11", 0));
try std.testing.expectEqual(73, try parseInt(i32, "+0o111", 0));
try std.testing.expectEqual(73, try parseInt(i32, "+0O111", 0));
try std.testing.expectEqual(73, try parseInt(i32, "+0o11_1", 0));
try std.testing.expectEqual(273, try parseInt(i32, "+0x111", 0));
try std.testing.expectEqual(-7, try parseInt(i32, "-0b111", 0));
try std.testing.expectEqual(-7, try parseInt(i32, "-0b11_1", 0));
try std.testing.expectEqual(-73, try parseInt(i32, "-0o111", 0));
try std.testing.expectEqual(-273, try parseInt(i32, "-0x111", 0));
try std.testing.expectEqual(-273, try parseInt(i32, "-0X111", 0));
try std.testing.expectEqual(-273, try parseInt(i32, "-0x1_11", 0));
// bare binary/octal/decimal prefix is invalid
try std.testing.expectError(error.InvalidCharacter, parseInt(u32, "0b", 0));
try std.testing.expectError(error.InvalidCharacter, parseInt(u32, "0o", 0));
try std.testing.expectError(error.InvalidCharacter, parseInt(u32, "0x", 0));
// edge cases which previously errored due to base overflowing T
try std.testing.expectEqual(@as(i2, -2), try std.fmt.parseInt(i2, "-10", 2));
try std.testing.expectEqual(@as(i4, -8), try std.fmt.parseInt(i4, "-10", 8));
try std.testing.expectEqual(@as(i5, -16), try std.fmt.parseInt(i5, "-10", 16));
}
fn parseIntWithSign(
comptime Result: type,
comptime Character: type,
buf: []const Character,
base: u8,
comptime sign: enum { pos, neg },
) ParseIntError!Result {
if (buf.len == 0) return error.InvalidCharacter;
var buf_base = base;
var buf_start = buf;
if (base == 0) {
// Treat is as a decimal number by default.
buf_base = 10;
// Detect the base by looking at buf prefix.
if (buf.len > 2 and buf[0] == '0') {
if (math.cast(u8, buf[1])) |c| switch (std.ascii.toLower(c)) {
'b' => {
buf_base = 2;
buf_start = buf[2..];
},
'o' => {
buf_base = 8;
buf_start = buf[2..];
},
'x' => {
buf_base = 16;
buf_start = buf[2..];
},
else => {},
};
}
}
const add = switch (sign) {
.pos => math.add,
.neg => math.sub,
};
// accumulate into Accumulate which is always 8 bits or larger. this prevents
// `buf_base` from overflowing Result.
const info = @typeInfo(Result);
const Accumulate = std.meta.Int(info.int.signedness, @max(8, info.int.bits));
var accumulate: Accumulate = 0;
if (buf_start[0] == '_' or buf_start[buf_start.len - 1] == '_') return error.InvalidCharacter;
for (buf_start) |c| {
if (c == '_') continue;
const digit = try charToDigit(math.cast(u8, c) orelse return error.InvalidCharacter, buf_base);
if (accumulate != 0) {
accumulate = try math.mul(Accumulate, accumulate, math.cast(Accumulate, buf_base) orelse return error.Overflow);
} else if (sign == .neg) {
// The first digit of a negative number.
// Consider parsing "-4" as an i3.
// This should work, but positive 4 overflows i3, so we can't cast the digit to T and subtract.
accumulate = math.cast(Accumulate, -@as(i8, @intCast(digit))) orelse return error.Overflow;
continue;
}
accumulate = try add(Accumulate, accumulate, math.cast(Accumulate, digit) orelse return error.Overflow);
}
return if (Result == Accumulate)
accumulate
else
math.cast(Result, accumulate) orelse return error.Overflow;
}
/// Parses the string `buf` as unsigned representation in the specified base
/// of an integral value of type `T`.
///
/// When `base` is zero the string prefix is examined to detect the true base:
/// * A prefix of "0b" implies base=2,
/// * A prefix of "0o" implies base=8,
/// * A prefix of "0x" implies base=16,
/// * Otherwise base=10 is assumed.
///
/// Ignores '_' character in `buf`.
/// See also `parseInt`.
pub fn parseUnsigned(comptime T: type, buf: []const u8, base: u8) ParseIntError!T {
return parseIntWithSign(T, u8, buf, base, .pos);
}
test parseUnsigned {
try std.testing.expectEqual(50124, try parseUnsigned(u16, "050124", 10));
try std.testing.expectEqual(65535, try parseUnsigned(u16, "65535", 10));
try std.testing.expectEqual(65535, try parseUnsigned(u16, "65_535", 10));
try std.testing.expectError(error.Overflow, parseUnsigned(u16, "65536", 10));
try std.testing.expectEqual(0xffffffffffffffff, try parseUnsigned(u64, "0ffffffffffffffff", 16));
try std.testing.expectEqual(0xffffffffffffffff, try parseUnsigned(u64, "0f_fff_fff_fff_fff_fff", 16));
try std.testing.expectError(error.Overflow, parseUnsigned(u64, "10000000000000000", 16));
try std.testing.expectEqual(0xDEADBEEF, try parseUnsigned(u32, "DeadBeef", 16));
try std.testing.expectEqual(1, try parseUnsigned(u7, "1", 10));
try std.testing.expectEqual(8, try parseUnsigned(u7, "1000", 2));
try std.testing.expectError(error.InvalidCharacter, parseUnsigned(u32, "f", 10));
try std.testing.expectError(error.InvalidCharacter, parseUnsigned(u8, "109", 8));
try std.testing.expectEqual(1442151747, try parseUnsigned(u32, "NUMBER", 36));
// these numbers should fit even though the base itself doesn't fit in the destination type
try std.testing.expectEqual(0, try parseUnsigned(u1, "0", 10));
try std.testing.expectEqual(1, try parseUnsigned(u1, "1", 10));
try std.testing.expectError(error.Overflow, parseUnsigned(u1, "2", 10));
try std.testing.expectEqual(1, try parseUnsigned(u1, "001", 16));
try std.testing.expectEqual(3, try parseUnsigned(u2, "3", 16));
try std.testing.expectError(error.Overflow, parseUnsigned(u2, "4", 16));
// parseUnsigned does not expect a sign
try std.testing.expectError(error.InvalidCharacter, parseUnsigned(u8, "+0", 10));
try std.testing.expectError(error.InvalidCharacter, parseUnsigned(u8, "-0", 10));
// test empty string error
try std.testing.expectError(error.InvalidCharacter, parseUnsigned(u8, "", 10));
}
/// Parses a number like '2G', '2Gi', or '2GiB'.
pub fn parseIntSizeSuffix(buf: []const u8, digit_base: u8) ParseIntError!usize {
var without_B = buf;
if (mem.endsWith(u8, buf, "B")) without_B.len -= 1;
var without_i = without_B;
var magnitude_base: usize = 1000;
if (mem.endsWith(u8, without_B, "i")) {
without_i.len -= 1;
magnitude_base = 1024;
}
if (without_i.len == 0) return error.InvalidCharacter;
const orders_of_magnitude: usize = switch (without_i[without_i.len - 1]) {
'k', 'K' => 1,
'M' => 2,
'G' => 3,
'T' => 4,
'P' => 5,
'E' => 6,
'Z' => 7,
'Y' => 8,
'R' => 9,
'Q' => 10,
else => 0,
};
var without_suffix = without_i;
if (orders_of_magnitude > 0) {
without_suffix.len -= 1;
} else if (without_i.len != without_B.len) {
return error.InvalidCharacter;
}
const multiplier = math.powi(usize, magnitude_base, orders_of_magnitude) catch |err| switch (err) {
error.Underflow => unreachable,
error.Overflow => return error.Overflow,
};
const number = try std.fmt.parseInt(usize, without_suffix, digit_base);
return math.mul(usize, number, multiplier);
}
test parseIntSizeSuffix {
try std.testing.expectEqual(2, try parseIntSizeSuffix("2", 10));
try std.testing.expectEqual(2, try parseIntSizeSuffix("2B", 10));
try std.testing.expectEqual(2000, try parseIntSizeSuffix("2kB", 10));
try std.testing.expectEqual(2000, try parseIntSizeSuffix("2k", 10));
try std.testing.expectEqual(2048, try parseIntSizeSuffix("2KiB", 10));
try std.testing.expectEqual(2048, try parseIntSizeSuffix("2Ki", 10));
try std.testing.expectEqual(10240, try parseIntSizeSuffix("aKiB", 16));
try std.testing.expectError(error.InvalidCharacter, parseIntSizeSuffix("", 10));
try std.testing.expectError(error.InvalidCharacter, parseIntSizeSuffix("2iB", 10));
}
pub const parseFloat = @import("fmt/parse_float.zig").parseFloat;
pub const ParseFloatError = @import("fmt/parse_float.zig").ParseFloatError;
test {
_ = &parseFloat;
}
pub fn charToDigit(c: u8, base: u8) (error{InvalidCharacter}!u8) {
const value = switch (c) {
'0'...'9' => c - '0',
'A'...'Z' => c - 'A' + 10,
'a'...'z' => c - 'a' + 10,
else => return error.InvalidCharacter,
};
if (value >= base) return error.InvalidCharacter;
return value;
}
pub fn digitToChar(digit: u8, case: Case) u8 {
return switch (digit) {
0...9 => digit + '0',
10...35 => digit + ((if (case == .upper) @as(u8, 'A') else @as(u8, 'a')) - 10),
else => unreachable,
};
}
pub const BufPrintError = error{
/// As much as possible was written to the buffer, but it was too small to fit all the printed bytes.
NoSpaceLeft,
};
/// Print a Formatter string into `buf`. Actually just a thin wrapper around `format` and `fixedBufferStream`.
/// Returns a slice of the bytes printed to.
pub fn bufPrint(buf: []u8, comptime fmt: []const u8, args: anytype) BufPrintError![]u8 {
var fbs = std.io.fixedBufferStream(buf);
format(fbs.writer().any(), fmt, args) catch |err| switch (err) {
error.NoSpaceLeft => return error.NoSpaceLeft,
else => unreachable,
};
return fbs.getWritten();
}
pub fn bufPrintZ(buf: []u8, comptime fmt: []const u8, args: anytype) BufPrintError![:0]u8 {
const result = try bufPrint(buf, fmt ++ "\x00", args);
return result[0 .. result.len - 1 :0];
}
/// Count the characters needed for format. Useful for preallocating memory
pub fn count(comptime fmt: []const u8, args: anytype) u64 {
var counting_writer = std.io.countingWriter(std.io.null_writer);
format(counting_writer.writer().any(), fmt, args) catch unreachable;
return counting_writer.bytes_written;
}
pub const AllocPrintError = error{OutOfMemory};
pub fn allocPrint(allocator: mem.Allocator, comptime fmt: []const u8, args: anytype) AllocPrintError![]u8 {
const size = math.cast(usize, count(fmt, args)) orelse return error.OutOfMemory;
const buf = try allocator.alloc(u8, size);
return bufPrint(buf, fmt, args) catch |err| switch (err) {
error.NoSpaceLeft => unreachable, // we just counted the size above
};
}
pub fn allocPrintZ(allocator: mem.Allocator, comptime fmt: []const u8, args: anytype) AllocPrintError![:0]u8 {
const result = try allocPrint(allocator, fmt ++ "\x00", args);
return result[0 .. result.len - 1 :0];
}
test bufPrintIntToSlice {
var buffer: [100]u8 = undefined;
const buf = buffer[0..];
try std.testing.expectEqualSlices(u8, "-1", bufPrintIntToSlice(buf, @as(i1, -1), 10, .lower, FormatOptions{}));
try std.testing.expectEqualSlices(u8, "-101111000110000101001110", bufPrintIntToSlice(buf, @as(i32, -12345678), 2, .lower, FormatOptions{}));
try std.testing.expectEqualSlices(u8, "-12345678", bufPrintIntToSlice(buf, @as(i32, -12345678), 10, .lower, FormatOptions{}));
try std.testing.expectEqualSlices(u8, "-bc614e", bufPrintIntToSlice(buf, @as(i32, -12345678), 16, .lower, FormatOptions{}));
try std.testing.expectEqualSlices(u8, "-BC614E", bufPrintIntToSlice(buf, @as(i32, -12345678), 16, .upper, FormatOptions{}));
try std.testing.expectEqualSlices(u8, "12345678", bufPrintIntToSlice(buf, @as(u32, 12345678), 10, .upper, FormatOptions{}));
try std.testing.expectEqualSlices(u8, " 666", bufPrintIntToSlice(buf, @as(u32, 666), 10, .lower, FormatOptions{ .width = 6 }));
try std.testing.expectEqualSlices(u8, " 1234", bufPrintIntToSlice(buf, @as(u32, 0x1234), 16, .lower, FormatOptions{ .width = 6 }));
try std.testing.expectEqualSlices(u8, "1234", bufPrintIntToSlice(buf, @as(u32, 0x1234), 16, .lower, FormatOptions{ .width = 1 }));
try std.testing.expectEqualSlices(u8, "+42", bufPrintIntToSlice(buf, @as(i32, 42), 10, .lower, FormatOptions{ .width = 3 }));
try std.testing.expectEqualSlices(u8, "-42", bufPrintIntToSlice(buf, @as(i32, -42), 10, .lower, FormatOptions{ .width = 3 }));
}
pub fn bufPrintIntToSlice(buf: []u8, value: anytype, base: u8, case: Case, options: FormatOptions) []u8 {
return buf[0..formatIntBuf(buf, value, base, case, options)];
}
pub inline fn comptimePrint(comptime fmt: []const u8, args: anytype) *const [count(fmt, args):0]u8 {
comptime {
var buf: [count(fmt, args):0]u8 = undefined;
_ = bufPrint(&buf, fmt, args) catch unreachable;
buf[buf.len] = 0;
const final = buf;
return &final;
}
}
test comptimePrint {
@setEvalBranchQuota(2000);
try std.testing.expectEqual(*const [3:0]u8, @TypeOf(comptimePrint("{}", .{100})));
try std.testing.expectEqualSlices(u8, "100", comptimePrint("{}", .{100}));
try std.testing.expectEqualStrings("30", comptimePrint("{d}", .{30.0}));
try std.testing.expectEqualStrings("30.0", comptimePrint("{d:3.1}", .{30.0}));
try std.testing.expectEqualStrings("0.05", comptimePrint("{d}", .{0.05}));
try std.testing.expectEqualStrings("5e-2", comptimePrint("{e}", .{0.05}));
}
test "parse u64 digit too big" {
_ = parseUnsigned(u64, "123a", 10) catch |err| {
if (err == error.InvalidCharacter) return;
unreachable;
};
unreachable;
}
test "parse unsigned comptime" {
comptime {
try std.testing.expectEqual(2, try parseUnsigned(usize, "2", 10));
}
}
test "escaped braces" {
try expectFmt("escaped: {{foo}}\n", "escaped: {{{{foo}}}}\n", .{});
try expectFmt("escaped: {foo}\n", "escaped: {{foo}}\n", .{});
}
test "optional" {
{
const value: ?i32 = 1234;
try expectFmt("optional: 1234\n", "optional: {?}\n", .{value});
try expectFmt("optional: 1234\n", "optional: {?d}\n", .{value});
try expectFmt("optional: 4d2\n", "optional: {?x}\n", .{value});
}
{
const value: ?[]const u8 = "string";
try expectFmt("optional: string\n", "optional: {?s}\n", .{value});
}
{
const value: ?i32 = null;
try expectFmt("optional: null\n", "optional: {?}\n", .{value});
}
{
const value = @as(?*i32, @ptrFromInt(0xf000d000));
try expectFmt("optional: *i32@f000d000\n", "optional: {*}\n", .{value});
}
}
test "error" {
{
const value: anyerror!i32 = 1234;
try expectFmt("error union: 1234\n", "error union: {!}\n", .{value});
try expectFmt("error union: 1234\n", "error union: {!d}\n", .{value});
try expectFmt("error union: 4d2\n", "error union: {!x}\n", .{value});
}
{
const value: anyerror![]const u8 = "string";
try expectFmt("error union: string\n", "error union: {!s}\n", .{value});
}
{
const value: anyerror!i32 = error.InvalidChar;
try expectFmt("error union: error.InvalidChar\n", "error union: {!}\n", .{value});
}
}
test "int.small" {
{
const value: u3 = 0b101;
try expectFmt("u3: 5\n", "u3: {}\n", .{value});
}
}
test "int.specifier" {
{
const value: u8 = 'a';
try expectFmt("u8: a\n", "u8: {c}\n", .{value});
}
{
const value: u8 = 0b1100;
try expectFmt("u8: 0b1100\n", "u8: 0b{b}\n", .{value});
}
{
const value: u16 = 0o1234;
try expectFmt("u16: 0o1234\n", "u16: 0o{o}\n", .{value});
}
{
const value: u8 = 'a';
try expectFmt("UTF-8: a\n", "UTF-8: {u}\n", .{value});
}
{
const value: u21 = 0x1F310;
try expectFmt("UTF-8: 🌐\n", "UTF-8: {u}\n", .{value});
}
{
const value: u21 = 0xD800;
try expectFmt("UTF-8: <20>\n", "UTF-8: {u}\n", .{value});
}
{
const value: u21 = 0x110001;
try expectFmt("UTF-8: <20>\n", "UTF-8: {u}\n", .{value});
}
}
test "int.padded" {
try expectFmt("u8: ' 1'", "u8: '{:4}'", .{@as(u8, 1)});
try expectFmt("u8: '1000'", "u8: '{:0<4}'", .{@as(u8, 1)});
try expectFmt("u8: '0001'", "u8: '{:0>4}'", .{@as(u8, 1)});
try expectFmt("u8: '0100'", "u8: '{:0^4}'", .{@as(u8, 1)});
try expectFmt("i8: '-1 '", "i8: '{:<4}'", .{@as(i8, -1)});
try expectFmt("i8: ' -1'", "i8: '{:>4}'", .{@as(i8, -1)});
try expectFmt("i8: ' -1 '", "i8: '{:^4}'", .{@as(i8, -1)});
try expectFmt("i16: '-1234'", "i16: '{:4}'", .{@as(i16, -1234)});
try expectFmt("i16: '+1234'", "i16: '{:4}'", .{@as(i16, 1234)});
try expectFmt("i16: '-12345'", "i16: '{:4}'", .{@as(i16, -12345)});
try expectFmt("i16: '+12345'", "i16: '{:4}'", .{@as(i16, 12345)});
try expectFmt("u16: '12345'", "u16: '{:4}'", .{@as(u16, 12345)});
try expectFmt("UTF-8: 'ü '", "UTF-8: '{u:<4}'", .{'ü'});
try expectFmt("UTF-8: ' ü'", "UTF-8: '{u:>4}'", .{'ü'});
try expectFmt("UTF-8: ' ü '", "UTF-8: '{u:^4}'", .{'ü'});
}
test "buffer" {
{
var buf1: [32]u8 = undefined;
var fbs = std.io.fixedBufferStream(&buf1);
try formatType(1234, "", FormatOptions{}, fbs.writer(), std.options.fmt_max_depth);
try std.testing.expectEqualStrings("1234", fbs.getWritten());
fbs.reset();
try formatType('a', "c", FormatOptions{}, fbs.writer(), std.options.fmt_max_depth);
try std.testing.expectEqualStrings("a", fbs.getWritten());
fbs.reset();
try formatType(0b1100, "b", FormatOptions{}, fbs.writer(), std.options.fmt_max_depth);
try std.testing.expectEqualStrings("1100", fbs.getWritten());
}
}
// Test formatting of arrays by value, by single-item pointer, and as a slice
fn expectArrayFmt(expected: []const u8, comptime template: []const u8, comptime array_value: anytype) !void {
try expectFmt(expected, template, .{array_value});
try expectFmt(expected, template, .{&array_value});
var runtime_zero: usize = 0;
_ = &runtime_zero;
try expectFmt(expected, template, .{array_value[runtime_zero..]});
}
test "array" {
{
const value: [3]u8 = "abc".*;
try expectArrayFmt("array: abc\n", "array: {s}\n", value);
try expectArrayFmt("array: { 97, 98, 99 }\n", "array: {d}\n", value);
try expectArrayFmt("array: { 61, 62, 63 }\n", "array: {x}\n", value);
try expectArrayFmt("array: { 97, 98, 99 }\n", "array: {any}\n", value);
var buf: [100]u8 = undefined;
try expectFmt(
try bufPrint(buf[0..], "array: [3]u8@{x}\n", .{@intFromPtr(&value)}),
"array: {*}\n",
.{&value},
);
}
{
const value = [2][3]u8{ "abc".*, "def".* };
try expectArrayFmt("array: { abc, def }\n", "array: {s}\n", value);
try expectArrayFmt("array: { { 97, 98, 99 }, { 100, 101, 102 } }\n", "array: {d}\n", value);
try expectArrayFmt("array: { { 61, 62, 63 }, { 64, 65, 66 } }\n", "array: {x}\n", value);
}
}
test "slice" {
{
const value: []const u8 = "abc";
try expectFmt("slice: abc\n", "slice: {s}\n", .{value});
try expectFmt("slice: { 97, 98, 99 }\n", "slice: {d}\n", .{value});
try expectFmt("slice: { 61, 62, 63 }\n", "slice: {x}\n", .{value});
try expectFmt("slice: { 97, 98, 99 }\n", "slice: {any}\n", .{value});
}
{
var runtime_zero: usize = 0;
_ = &runtime_zero;
const value = @as([*]align(1) const []const u8, @ptrFromInt(0xdeadbeef))[runtime_zero..runtime_zero];
try expectFmt("slice: []const u8@deadbeef\n", "slice: {*}\n", .{value});
}
{
const null_term_slice: [:0]const u8 = "\x00hello\x00";
try expectFmt("buf: \x00hello\x00\n", "buf: {s}\n", .{null_term_slice});
}
try expectFmt("buf: Test\n", "buf: {s:5}\n", .{"Test"});
try expectFmt("buf: Test\n Other text", "buf: {s}\n Other text", .{"Test"});
{
var int_slice = [_]u32{ 1, 4096, 391891, 1111111111 };
var runtime_zero: usize = 0;
_ = &runtime_zero;
try expectFmt("int: { 1, 4096, 391891, 1111111111 }", "int: {any}", .{int_slice[runtime_zero..]});
try expectFmt("int: { 1, 4096, 391891, 1111111111 }", "int: {d}", .{int_slice[runtime_zero..]});
try expectFmt("int: { 1, 1000, 5fad3, 423a35c7 }", "int: {x}", .{int_slice[runtime_zero..]});
try expectFmt("int: { 00001, 01000, 5fad3, 423a35c7 }", "int: {x:0>5}", .{int_slice[runtime_zero..]});
}
{
const S1 = struct {
x: u8,
};
const struct_slice: []const S1 = &[_]S1{ S1{ .x = 8 }, S1{ .x = 42 } };
try expectFmt("slice: { fmt.test.slice.S1{ .x = 8 }, fmt.test.slice.S1{ .x = 42 } }", "slice: {any}", .{struct_slice});
}
{
const S2 = struct {
x: u8,
pub fn format(s: @This(), comptime _: []const u8, _: std.fmt.FormatOptions, writer: anytype) !void {
try writer.print("S2({})", .{s.x});
}
};
const struct_slice: []const S2 = &[_]S2{ S2{ .x = 8 }, S2{ .x = 42 } };
try expectFmt("slice: { S2(8), S2(42) }", "slice: {any}", .{struct_slice});
}
}
test "escape non-printable" {
try expectFmt("abc 123", "{s}", .{fmtSliceEscapeLower("abc 123")});
try expectFmt("ab\\xffc", "{s}", .{fmtSliceEscapeLower("ab\xffc")});
try expectFmt("abc 123", "{s}", .{fmtSliceEscapeUpper("abc 123")});
try expectFmt("ab\\xFFc", "{s}", .{fmtSliceEscapeUpper("ab\xffc")});
}
test "pointer" {
{
const value = @as(*align(1) i32, @ptrFromInt(0xdeadbeef));
try expectFmt("pointer: i32@deadbeef\n", "pointer: {}\n", .{value});
try expectFmt("pointer: i32@deadbeef\n", "pointer: {*}\n", .{value});
}
const FnPtr = *align(1) const fn () void;
{
const value = @as(FnPtr, @ptrFromInt(0xdeadbeef));
try expectFmt("pointer: fn () void@deadbeef\n", "pointer: {}\n", .{value});
}
{
const value = @as(FnPtr, @ptrFromInt(0xdeadbeef));
try expectFmt("pointer: fn () void@deadbeef\n", "pointer: {}\n", .{value});
}
}
test "cstr" {
try expectFmt(
"cstr: Test C\n",
"cstr: {s}\n",
.{@as([*c]const u8, @ptrCast("Test C"))},
);
try expectFmt(
"cstr: Test C\n",
"cstr: {s:10}\n",
.{@as([*c]const u8, @ptrCast("Test C"))},
);
}
test "filesize" {
try expectFmt("file size: 42B\n", "file size: {}\n", .{fmtIntSizeDec(42)});
try expectFmt("file size: 42B\n", "file size: {}\n", .{fmtIntSizeBin(42)});
try expectFmt("file size: 63MB\n", "file size: {}\n", .{fmtIntSizeDec(63 * 1000 * 1000)});
try expectFmt("file size: 63MiB\n", "file size: {}\n", .{fmtIntSizeBin(63 * 1024 * 1024)});
try expectFmt("file size: 42B\n", "file size: {:.2}\n", .{fmtIntSizeDec(42)});
try expectFmt("file size: 42B\n", "file size: {:>9.2}\n", .{fmtIntSizeDec(42)});
try expectFmt("file size: 66.06MB\n", "file size: {:.2}\n", .{fmtIntSizeDec(63 * 1024 * 1024)});
try expectFmt("file size: 60.08MiB\n", "file size: {:.2}\n", .{fmtIntSizeBin(63 * 1000 * 1000)});
try expectFmt("file size: =66.06MB=\n", "file size: {:=^9.2}\n", .{fmtIntSizeDec(63 * 1024 * 1024)});
try expectFmt("file size: 66.06MB\n", "file size: {: >9.2}\n", .{fmtIntSizeDec(63 * 1024 * 1024)});
try expectFmt("file size: 66.06MB \n", "file size: {: <9.2}\n", .{fmtIntSizeDec(63 * 1024 * 1024)});
try expectFmt("file size: 0.01844674407370955ZB\n", "file size: {}\n", .{fmtIntSizeDec(math.maxInt(u64))});
}
test "struct" {
{
const Struct = struct {
field: u8,
};
const value = Struct{ .field = 42 };
try expectFmt("struct: fmt.test.struct.Struct{ .field = 42 }\n", "struct: {}\n", .{value});
try expectFmt("struct: fmt.test.struct.Struct{ .field = 42 }\n", "struct: {}\n", .{&value});
}
{
const Struct = struct {
a: u0,
b: u1,
};
const value = Struct{ .a = 0, .b = 1 };
try expectFmt("struct: fmt.test.struct.Struct{ .a = 0, .b = 1 }\n", "struct: {}\n", .{value});
}
const S = struct {
a: u32,
b: anyerror,
};
const inst = S{
.a = 456,
.b = error.Unused,
};
try expectFmt("fmt.test.struct.S{ .a = 456, .b = error.Unused }", "{}", .{inst});
// Tuples
try expectFmt("{ }", "{}", .{.{}});
try expectFmt("{ -1 }", "{}", .{.{-1}});
try expectFmt("{ -1, 42, 2.5e4 }", "{}", .{.{ -1, 42, 0.25e5 }});
}
test "enum" {
const Enum = enum {
One,
Two,
};
const value = Enum.Two;
try expectFmt("enum: fmt.test.enum.Enum.Two\n", "enum: {}\n", .{value});
try expectFmt("enum: fmt.test.enum.Enum.Two\n", "enum: {}\n", .{&value});
try expectFmt("enum: fmt.test.enum.Enum.One\n", "enum: {}\n", .{Enum.One});
try expectFmt("enum: fmt.test.enum.Enum.Two\n", "enum: {}\n", .{Enum.Two});
// test very large enum to verify ct branch quota is large enough
// TODO: https://github.com/ziglang/zig/issues/15609
if (!((builtin.cpu.arch == .wasm32) and builtin.mode == .Debug)) {
try expectFmt("enum: os.windows.win32error.Win32Error.INVALID_FUNCTION\n", "enum: {}\n", .{std.os.windows.Win32Error.INVALID_FUNCTION});
}
const E = enum {
One,
Two,
Three,
};
const inst = E.Two;
try expectFmt("fmt.test.enum.E.Two", "{}", .{inst});
}
test "non-exhaustive enum" {
const Enum = enum(u16) {
One = 0x000f,
Two = 0xbeef,
_,
};
try expectFmt("enum: fmt.test.non-exhaustive enum.Enum.One\n", "enum: {}\n", .{Enum.One});
try expectFmt("enum: fmt.test.non-exhaustive enum.Enum.Two\n", "enum: {}\n", .{Enum.Two});
try expectFmt("enum: fmt.test.non-exhaustive enum.Enum(4660)\n", "enum: {}\n", .{@as(Enum, @enumFromInt(0x1234))});
try expectFmt("enum: fmt.test.non-exhaustive enum.Enum.One\n", "enum: {x}\n", .{Enum.One});
try expectFmt("enum: fmt.test.non-exhaustive enum.Enum.Two\n", "enum: {x}\n", .{Enum.Two});
try expectFmt("enum: fmt.test.non-exhaustive enum.Enum.Two\n", "enum: {X}\n", .{Enum.Two});
try expectFmt("enum: fmt.test.non-exhaustive enum.Enum(1234)\n", "enum: {x}\n", .{@as(Enum, @enumFromInt(0x1234))});
}
test "float.scientific" {
try expectFmt("f32: 1.34e0", "f32: {e}", .{@as(f32, 1.34)});
try expectFmt("f32: 1.234e1", "f32: {e}", .{@as(f32, 12.34)});
try expectFmt("f64: -1.234e11", "f64: {e}", .{@as(f64, -12.34e10)});
try expectFmt("f64: 9.99996e-40", "f64: {e}", .{@as(f64, 9.999960e-40)});
}
test "float.scientific.precision" {
try expectFmt("f64: 1.40971e-42", "f64: {e:.5}", .{@as(f64, 1.409706e-42)});
try expectFmt("f64: 1.00000e-9", "f64: {e:.5}", .{@as(f64, @as(f32, @bitCast(@as(u32, 814313563))))});
try expectFmt("f64: 7.81250e-3", "f64: {e:.5}", .{@as(f64, @as(f32, @bitCast(@as(u32, 1006632960))))});
// libc rounds 1.000005e5 to 1.00000e5 but zig does 1.00001e5.
// In fact, libc doesn't round a lot of 5 cases up when one past the precision point.
try expectFmt("f64: 1.00001e5", "f64: {e:.5}", .{@as(f64, @as(f32, @bitCast(@as(u32, 1203982400))))});
}
test "float.special" {
try expectFmt("f64: nan", "f64: {}", .{math.nan(f64)});
// negative nan is not defined by IEE 754,
// and ARM thus normalizes it to positive nan
if (builtin.target.cpu.arch != .arm) {
try expectFmt("f64: -nan", "f64: {}", .{-math.nan(f64)});
}
try expectFmt("f64: inf", "f64: {}", .{math.inf(f64)});
try expectFmt("f64: -inf", "f64: {}", .{-math.inf(f64)});
}
test "float.hexadecimal.special" {
try expectFmt("f64: nan", "f64: {x}", .{math.nan(f64)});
// negative nan is not defined by IEE 754,
// and ARM thus normalizes it to positive nan
if (builtin.target.cpu.arch != .arm) {
try expectFmt("f64: -nan", "f64: {x}", .{-math.nan(f64)});
}
try expectFmt("f64: inf", "f64: {x}", .{math.inf(f64)});
try expectFmt("f64: -inf", "f64: {x}", .{-math.inf(f64)});
try expectFmt("f64: 0x0.0p0", "f64: {x}", .{@as(f64, 0)});
try expectFmt("f64: -0x0.0p0", "f64: {x}", .{-@as(f64, 0)});
}
test "float.hexadecimal" {
try expectFmt("f16: 0x1.554p-2", "f16: {x}", .{@as(f16, 1.0 / 3.0)});
try expectFmt("f32: 0x1.555556p-2", "f32: {x}", .{@as(f32, 1.0 / 3.0)});
try expectFmt("f64: 0x1.5555555555555p-2", "f64: {x}", .{@as(f64, 1.0 / 3.0)});
try expectFmt("f80: 0x1.5555555555555556p-2", "f80: {x}", .{@as(f80, 1.0 / 3.0)});
try expectFmt("f128: 0x1.5555555555555555555555555555p-2", "f128: {x}", .{@as(f128, 1.0 / 3.0)});
try expectFmt("f16: 0x1p-14", "f16: {x}", .{math.floatMin(f16)});
try expectFmt("f32: 0x1p-126", "f32: {x}", .{math.floatMin(f32)});
try expectFmt("f64: 0x1p-1022", "f64: {x}", .{math.floatMin(f64)});
try expectFmt("f80: 0x1p-16382", "f80: {x}", .{math.floatMin(f80)});
try expectFmt("f128: 0x1p-16382", "f128: {x}", .{math.floatMin(f128)});
try expectFmt("f16: 0x0.004p-14", "f16: {x}", .{math.floatTrueMin(f16)});
try expectFmt("f32: 0x0.000002p-126", "f32: {x}", .{math.floatTrueMin(f32)});
try expectFmt("f64: 0x0.0000000000001p-1022", "f64: {x}", .{math.floatTrueMin(f64)});
try expectFmt("f80: 0x0.0000000000000002p-16382", "f80: {x}", .{math.floatTrueMin(f80)});
try expectFmt("f128: 0x0.0000000000000000000000000001p-16382", "f128: {x}", .{math.floatTrueMin(f128)});
try expectFmt("f16: 0x1.ffcp15", "f16: {x}", .{math.floatMax(f16)});
try expectFmt("f32: 0x1.fffffep127", "f32: {x}", .{math.floatMax(f32)});
try expectFmt("f64: 0x1.fffffffffffffp1023", "f64: {x}", .{math.floatMax(f64)});
try expectFmt("f80: 0x1.fffffffffffffffep16383", "f80: {x}", .{math.floatMax(f80)});
try expectFmt("f128: 0x1.ffffffffffffffffffffffffffffp16383", "f128: {x}", .{math.floatMax(f128)});
}
test "float.hexadecimal.precision" {
try expectFmt("f16: 0x1.5p-2", "f16: {x:.1}", .{@as(f16, 1.0 / 3.0)});
try expectFmt("f32: 0x1.555p-2", "f32: {x:.3}", .{@as(f32, 1.0 / 3.0)});
try expectFmt("f64: 0x1.55555p-2", "f64: {x:.5}", .{@as(f64, 1.0 / 3.0)});
try expectFmt("f80: 0x1.5555555p-2", "f80: {x:.7}", .{@as(f80, 1.0 / 3.0)});
try expectFmt("f128: 0x1.555555555p-2", "f128: {x:.9}", .{@as(f128, 1.0 / 3.0)});
try expectFmt("f16: 0x1.00000p0", "f16: {x:.5}", .{@as(f16, 1.0)});
try expectFmt("f32: 0x1.00000p0", "f32: {x:.5}", .{@as(f32, 1.0)});
try expectFmt("f64: 0x1.00000p0", "f64: {x:.5}", .{@as(f64, 1.0)});
try expectFmt("f80: 0x1.00000p0", "f80: {x:.5}", .{@as(f80, 1.0)});
try expectFmt("f128: 0x1.00000p0", "f128: {x:.5}", .{@as(f128, 1.0)});
}
test "float.decimal" {
try expectFmt("f64: 152314000000000000000000000000", "f64: {d}", .{@as(f64, 1.52314e29)});
try expectFmt("f32: 0", "f32: {d}", .{@as(f32, 0.0)});
try expectFmt("f32: 0", "f32: {d:.0}", .{@as(f32, 0.0)});
try expectFmt("f32: 1.1", "f32: {d:.1}", .{@as(f32, 1.1234)});
try expectFmt("f32: 1234.57", "f32: {d:.2}", .{@as(f32, 1234.567)});
// -11.1234 is converted to f64 -11.12339... internally (errol3() function takes f64).
// -11.12339... is rounded back up to -11.1234
try expectFmt("f32: -11.1234", "f32: {d:.4}", .{@as(f32, -11.1234)});
try expectFmt("f32: 91.12345", "f32: {d:.5}", .{@as(f32, 91.12345)});
try expectFmt("f64: 91.1234567890", "f64: {d:.10}", .{@as(f64, 91.12345678901235)});
try expectFmt("f64: 0.00000", "f64: {d:.5}", .{@as(f64, 0.0)});
try expectFmt("f64: 6", "f64: {d:.0}", .{@as(f64, 5.700)});
try expectFmt("f64: 10.0", "f64: {d:.1}", .{@as(f64, 9.999)});
try expectFmt("f64: 1.000", "f64: {d:.3}", .{@as(f64, 1.0)});
try expectFmt("f64: 0.00030000", "f64: {d:.8}", .{@as(f64, 0.0003)});
try expectFmt("f64: 0.00000", "f64: {d:.5}", .{@as(f64, 1.40130e-45)});
try expectFmt("f64: 0.00000", "f64: {d:.5}", .{@as(f64, 9.999960e-40)});
try expectFmt("f64: 10000000000000.00", "f64: {d:.2}", .{@as(f64, 9999999999999.999)});
try expectFmt("f64: 10000000000000000000000000000000000000", "f64: {d}", .{@as(f64, 1e37)});
try expectFmt("f64: 100000000000000000000000000000000000000", "f64: {d}", .{@as(f64, 1e38)});
}
test "float.libc.sanity" {
try expectFmt("f64: 0.00001", "f64: {d:.5}", .{@as(f64, @as(f32, @bitCast(@as(u32, 916964781))))});
try expectFmt("f64: 0.00001", "f64: {d:.5}", .{@as(f64, @as(f32, @bitCast(@as(u32, 925353389))))});
try expectFmt("f64: 0.10000", "f64: {d:.5}", .{@as(f64, @as(f32, @bitCast(@as(u32, 1036831278))))});
try expectFmt("f64: 1.00000", "f64: {d:.5}", .{@as(f64, @as(f32, @bitCast(@as(u32, 1065353133))))});
try expectFmt("f64: 10.00000", "f64: {d:.5}", .{@as(f64, @as(f32, @bitCast(@as(u32, 1092616192))))});
// libc differences
//
// This is 0.015625 exactly according to gdb. We thus round down,
// however glibc rounds up for some reason. This occurs for all
// floats of the form x.yyyy25 on a precision point.
try expectFmt("f64: 0.01563", "f64: {d:.5}", .{@as(f64, @as(f32, @bitCast(@as(u32, 1015021568))))});
// errol3 rounds to ... 630 but libc rounds to ...632. Grisu3
// also rounds to 630 so I'm inclined to believe libc is not
// optimal here.
try expectFmt("f64: 18014400656965630.00000", "f64: {d:.5}", .{@as(f64, @as(f32, @bitCast(@as(u32, 1518338049))))});
}
test "custom" {
const Vec2 = struct {
const SelfType = @This();
x: f32,
y: f32,
pub fn format(
self: SelfType,
comptime fmt: []const u8,
options: FormatOptions,
writer: anytype,
) !void {
_ = options;
if (fmt.len == 0 or comptime std.mem.eql(u8, fmt, "p")) {
return std.fmt.format(writer, "({d:.3},{d:.3})", .{ self.x, self.y });
} else if (comptime std.mem.eql(u8, fmt, "d")) {
return std.fmt.format(writer, "{d:.3}x{d:.3}", .{ self.x, self.y });
} else {
@compileError("unknown format character: '" ++ fmt ++ "'");
}
}
};
var value = Vec2{
.x = 10.2,
.y = 2.22,
};
try expectFmt("point: (10.200,2.220)\n", "point: {}\n", .{&value});
try expectFmt("dim: 10.200x2.220\n", "dim: {d}\n", .{&value});
// same thing but not passing a pointer
try expectFmt("point: (10.200,2.220)\n", "point: {}\n", .{value});
try expectFmt("dim: 10.200x2.220\n", "dim: {d}\n", .{value});
}
test "union" {
const TU = union(enum) {
float: f32,
int: u32,
};
const UU = union {
float: f32,
int: u32,
};
const EU = extern union {
float: f32,
int: u32,
};
const tu_inst = TU{ .int = 123 };
const uu_inst = UU{ .int = 456 };
const eu_inst = EU{ .float = 321.123 };
try expectFmt("fmt.test.union.TU{ .int = 123 }", "{}", .{tu_inst});
var buf: [100]u8 = undefined;
const uu_result = try bufPrint(buf[0..], "{}", .{uu_inst});
try std.testing.expectEqualStrings("fmt.test.union.UU@", uu_result[0..18]);
const eu_result = try bufPrint(buf[0..], "{}", .{eu_inst});
try std.testing.expectEqualStrings("fmt.test.union.EU@", eu_result[0..18]);
}
test "struct.self-referential" {
const S = struct {
const SelfType = @This();
a: ?*SelfType,
};
var inst = S{
.a = null,
};
inst.a = &inst;
try expectFmt("fmt.test.struct.self-referential.S{ .a = fmt.test.struct.self-referential.S{ .a = fmt.test.struct.self-referential.S{ .a = fmt.test.struct.self-referential.S{ ... } } } }", "{}", .{inst});
}
test "struct.zero-size" {
const A = struct {
fn foo() void {}
};
const B = struct {
a: A,
c: i32,
};
const a = A{};
const b = B{ .a = a, .c = 0 };
try expectFmt("fmt.test.struct.zero-size.B{ .a = fmt.test.struct.zero-size.A{ }, .c = 0 }", "{}", .{b});
}
test "bytes.hex" {
const some_bytes = "\xCA\xFE\xBA\xBE";
try expectFmt("lowercase: cafebabe\n", "lowercase: {x}\n", .{fmtSliceHexLower(some_bytes)});
try expectFmt("uppercase: CAFEBABE\n", "uppercase: {X}\n", .{fmtSliceHexUpper(some_bytes)});
//Test Slices
try expectFmt("uppercase: CAFE\n", "uppercase: {X}\n", .{fmtSliceHexUpper(some_bytes[0..2])});
try expectFmt("lowercase: babe\n", "lowercase: {x}\n", .{fmtSliceHexLower(some_bytes[2..])});
const bytes_with_zeros = "\x00\x0E\xBA\xBE";
try expectFmt("lowercase: 000ebabe\n", "lowercase: {x}\n", .{fmtSliceHexLower(bytes_with_zeros)});
}
/// Encodes a sequence of bytes as hexadecimal digits.
/// Returns an array containing the encoded bytes.
pub fn bytesToHex(input: anytype, case: Case) [input.len * 2]u8 {
if (input.len == 0) return [_]u8{};
comptime assert(@TypeOf(input[0]) == u8); // elements to encode must be unsigned bytes
const charset = "0123456789" ++ if (case == .upper) "ABCDEF" else "abcdef";
var result: [input.len * 2]u8 = undefined;
for (input, 0..) |b, i| {
result[i * 2 + 0] = charset[b >> 4];
result[i * 2 + 1] = charset[b & 15];
}
return result;
}
/// Decodes the sequence of bytes represented by the specified string of
/// hexadecimal characters.
/// Returns a slice of the output buffer containing the decoded bytes.
pub fn hexToBytes(out: []u8, input: []const u8) ![]u8 {
// Expect 0 or n pairs of hexadecimal digits.
if (input.len & 1 != 0)
return error.InvalidLength;
if (out.len * 2 < input.len)
return error.NoSpaceLeft;
var in_i: usize = 0;
while (in_i < input.len) : (in_i += 2) {
const hi = try charToDigit(input[in_i], 16);
const lo = try charToDigit(input[in_i + 1], 16);
out[in_i / 2] = (hi << 4) | lo;
}
return out[0 .. in_i / 2];
}
test bytesToHex {
const input = "input slice";
const encoded = bytesToHex(input, .lower);
var decoded: [input.len]u8 = undefined;
try std.testing.expectEqualSlices(u8, input, try hexToBytes(&decoded, &encoded));
}
test hexToBytes {
var buf: [32]u8 = undefined;
try expectFmt("90" ** 32, "{s}", .{fmtSliceHexUpper(try hexToBytes(&buf, "90" ** 32))});
try expectFmt("ABCD", "{s}", .{fmtSliceHexUpper(try hexToBytes(&buf, "ABCD"))});
try expectFmt("", "{s}", .{fmtSliceHexUpper(try hexToBytes(&buf, ""))});
try std.testing.expectError(error.InvalidCharacter, hexToBytes(&buf, "012Z"));
try std.testing.expectError(error.InvalidLength, hexToBytes(&buf, "AAA"));
try std.testing.expectError(error.NoSpaceLeft, hexToBytes(buf[0..1], "ABAB"));
}
test "formatIntValue with comptime_int" {
const value: comptime_int = 123456789123456789;
var buf: [20]u8 = undefined;
var fbs = std.io.fixedBufferStream(&buf);
try formatIntValue(value, "", FormatOptions{}, fbs.writer());
try std.testing.expectEqualStrings("123456789123456789", fbs.getWritten());
}
test "formatFloatValue with comptime_float" {
const value: comptime_float = 1.0;
var buf: [20]u8 = undefined;
var fbs = std.io.fixedBufferStream(&buf);
try formatFloatValue(value, "", FormatOptions{}, fbs.writer());
try std.testing.expectEqualStrings(fbs.getWritten(), "1e0");
try expectFmt("1e0", "{}", .{value});
try expectFmt("1e0", "{}", .{1.0});
}
test "formatType max_depth" {
const Vec2 = struct {
const SelfType = @This();
x: f32,
y: f32,
pub fn format(
self: SelfType,
comptime fmt: []const u8,
options: FormatOptions,
writer: anytype,
) !void {
_ = options;
if (fmt.len == 0) {
return std.fmt.format(writer, "({d:.3},{d:.3})", .{ self.x, self.y });
} else {
@compileError("unknown format string: '" ++ fmt ++ "'");
}
}
};
const E = enum {
One,
Two,
Three,
};
const TU = union(enum) {
const SelfType = @This();
float: f32,
int: u32,
ptr: ?*SelfType,
};
const S = struct {
const SelfType = @This();
a: ?*SelfType,
tu: TU,
e: E,
vec: Vec2,
};
var inst = S{
.a = null,
.tu = TU{ .ptr = null },
.e = E.Two,
.vec = Vec2{ .x = 10.2, .y = 2.22 },
};
inst.a = &inst;
inst.tu.ptr = &inst.tu;
var buf: [1000]u8 = undefined;
var fbs = std.io.fixedBufferStream(&buf);
try formatType(inst, "", FormatOptions{}, fbs.writer(), 0);
try std.testing.expectEqualStrings("fmt.test.formatType max_depth.S{ ... }", fbs.getWritten());
fbs.reset();
try formatType(inst, "", FormatOptions{}, fbs.writer(), 1);
try std.testing.expectEqualStrings("fmt.test.formatType max_depth.S{ .a = fmt.test.formatType max_depth.S{ ... }, .tu = fmt.test.formatType max_depth.TU{ ... }, .e = fmt.test.formatType max_depth.E.Two, .vec = (10.200,2.220) }", fbs.getWritten());
fbs.reset();
try formatType(inst, "", FormatOptions{}, fbs.writer(), 2);
try std.testing.expectEqualStrings("fmt.test.formatType max_depth.S{ .a = fmt.test.formatType max_depth.S{ .a = fmt.test.formatType max_depth.S{ ... }, .tu = fmt.test.formatType max_depth.TU{ ... }, .e = fmt.test.formatType max_depth.E.Two, .vec = (10.200,2.220) }, .tu = fmt.test.formatType max_depth.TU{ .ptr = fmt.test.formatType max_depth.TU{ ... } }, .e = fmt.test.formatType max_depth.E.Two, .vec = (10.200,2.220) }", fbs.getWritten());
fbs.reset();
try formatType(inst, "", FormatOptions{}, fbs.writer(), 3);
try std.testing.expectEqualStrings("fmt.test.formatType max_depth.S{ .a = fmt.test.formatType max_depth.S{ .a = fmt.test.formatType max_depth.S{ .a = fmt.test.formatType max_depth.S{ ... }, .tu = fmt.test.formatType max_depth.TU{ ... }, .e = fmt.test.formatType max_depth.E.Two, .vec = (10.200,2.220) }, .tu = fmt.test.formatType max_depth.TU{ .ptr = fmt.test.formatType max_depth.TU{ ... } }, .e = fmt.test.formatType max_depth.E.Two, .vec = (10.200,2.220) }, .tu = fmt.test.formatType max_depth.TU{ .ptr = fmt.test.formatType max_depth.TU{ .ptr = fmt.test.formatType max_depth.TU{ ... } } }, .e = fmt.test.formatType max_depth.E.Two, .vec = (10.200,2.220) }", fbs.getWritten());
}
test "positional" {
try expectFmt("2 1 0", "{2} {1} {0}", .{ @as(usize, 0), @as(usize, 1), @as(usize, 2) });
try expectFmt("2 1 0", "{2} {1} {}", .{ @as(usize, 0), @as(usize, 1), @as(usize, 2) });
try expectFmt("0 0", "{0} {0}", .{@as(usize, 0)});
try expectFmt("0 1", "{} {1}", .{ @as(usize, 0), @as(usize, 1) });
try expectFmt("1 0 0 1", "{1} {} {0} {}", .{ @as(usize, 0), @as(usize, 1) });
}
test "positional with specifier" {
try expectFmt("10.0", "{0d:.1}", .{@as(f64, 9.999)});
}
test "positional/alignment/width/precision" {
try expectFmt("10.0", "{0d: >3.1}", .{@as(f64, 9.999)});
}
test "vector" {
if (builtin.target.cpu.arch == .riscv64) {
// https://github.com/ziglang/zig/issues/4486
return error.SkipZigTest;
}
const vbool: @Vector(4, bool) = [_]bool{ true, false, true, false };
const vi64: @Vector(4, i64) = [_]i64{ -2, -1, 0, 1 };
const vu64: @Vector(4, u64) = [_]u64{ 1000, 2000, 3000, 4000 };
try expectFmt("{ true, false, true, false }", "{}", .{vbool});
try expectFmt("{ -2, -1, 0, 1 }", "{}", .{vi64});
try expectFmt("{ -2, -1, +0, +1 }", "{d:5}", .{vi64});
try expectFmt("{ 1000, 2000, 3000, 4000 }", "{}", .{vu64});
try expectFmt("{ 3e8, 7d0, bb8, fa0 }", "{x}", .{vu64});
const x: [4]u64 = undefined;
const vp: @Vector(4, *const u64) = [_]*const u64{ &x[0], &x[1], &x[2], &x[3] };
const vop: @Vector(4, ?*const u64) = [_]?*const u64{ &x[0], null, null, &x[3] };
var expect_buffer: [@sizeOf(usize) * 2 * 4 + 64]u8 = undefined;
try expectFmt(try bufPrint(
&expect_buffer,
"{{ {}, {}, {}, {} }}",
.{ &x[0], &x[1], &x[2], &x[3] },
), "{}", .{vp});
try expectFmt(try bufPrint(
&expect_buffer,
"{{ {?}, null, null, {?} }}",
.{ &x[0], &x[3] },
), "{any}", .{vop});
}
test "enum-literal" {
try expectFmt(".hello_world", "{}", .{.hello_world});
}
test "padding" {
try expectFmt("Simple", "{s}", .{"Simple"});
try expectFmt(" true", "{:10}", .{true});
try expectFmt(" true", "{:>10}", .{true});
try expectFmt("======true", "{:=>10}", .{true});
try expectFmt("true======", "{:=<10}", .{true});
try expectFmt(" true ", "{:^10}", .{true});
try expectFmt("===true===", "{:=^10}", .{true});
try expectFmt(" Minimum width", "{s:18} width", .{"Minimum"});
try expectFmt("==================Filled", "{s:=>24}", .{"Filled"});
try expectFmt(" Centered ", "{s:^24}", .{"Centered"});
try expectFmt("-", "{s:-^1}", .{""});
try expectFmt("==crêpe===", "{s:=^10}", .{"crêpe"});
try expectFmt("=====crêpe", "{s:=>10}", .{"crêpe"});
try expectFmt("crêpe=====", "{s:=<10}", .{"crêpe"});
try expectFmt("====a", "{c:=>5}", .{'a'});
try expectFmt("==a==", "{c:=^5}", .{'a'});
try expectFmt("a====", "{c:=<5}", .{'a'});
}
test "padding fill char utf" {
try expectFmt("──crêpe───", "{s:─^10}", .{"crêpe"});
try expectFmt("─────crêpe", "{s:─>10}", .{"crêpe"});
try expectFmt("crêpe─────", "{s:─<10}", .{"crêpe"});
try expectFmt("────a", "{c:─>5}", .{'a'});
try expectFmt("──a──", "{c:─^5}", .{'a'});
try expectFmt("a────", "{c:─<5}", .{'a'});
}
test "decimal float padding" {
const number: f32 = 3.1415;
try expectFmt("left-pad: **3.142\n", "left-pad: {d:*>7.3}\n", .{number});
try expectFmt("center-pad: *3.142*\n", "center-pad: {d:*^7.3}\n", .{number});
try expectFmt("right-pad: 3.142**\n", "right-pad: {d:*<7.3}\n", .{number});
}
test "sci float padding" {
const number: f32 = 3.1415;
try expectFmt("left-pad: ****3.142e0\n", "left-pad: {e:*>11.3}\n", .{number});
try expectFmt("center-pad: **3.142e0**\n", "center-pad: {e:*^11.3}\n", .{number});
try expectFmt("right-pad: 3.142e0****\n", "right-pad: {e:*<11.3}\n", .{number});
}
test "padding.zero" {
try expectFmt("zero-pad: '0042'", "zero-pad: '{:04}'", .{42});
try expectFmt("std-pad: ' 42'", "std-pad: '{:10}'", .{42});
try expectFmt("std-pad-1: '001'", "std-pad-1: '{:0>3}'", .{1});
try expectFmt("std-pad-2: '911'", "std-pad-2: '{:1<03}'", .{9});
try expectFmt("std-pad-3: ' 1'", "std-pad-3: '{:>03}'", .{1});
try expectFmt("center-pad: '515'", "center-pad: '{:5^03}'", .{1});
}
test "null" {
const inst = null;
try expectFmt("null", "{}", .{inst});
}
test "type" {
try expectFmt("u8", "{}", .{u8});
try expectFmt("?f32", "{}", .{?f32});
try expectFmt("[]const u8", "{}", .{[]const u8});
}
test "named arguments" {
try expectFmt("hello world!", "{s} world{c}", .{ "hello", '!' });
try expectFmt("hello world!", "{[greeting]s} world{[punctuation]c}", .{ .punctuation = '!', .greeting = "hello" });
try expectFmt("hello world!", "{[1]s} world{[0]c}", .{ '!', "hello" });
}
test "runtime width specifier" {
const width: usize = 9;
try expectFmt("~~hello~~", "{s:~^[1]}", .{ "hello", width });
try expectFmt("~~hello~~", "{s:~^[width]}", .{ .string = "hello", .width = width });
try expectFmt(" hello", "{s:[1]}", .{ "hello", width });
try expectFmt("42 hello", "{d} {s:[2]}", .{ 42, "hello", width });
}
test "runtime precision specifier" {
const number: f32 = 3.1415;
const precision: usize = 2;
try expectFmt("3.14e0", "{:1.[1]}", .{ number, precision });
try expectFmt("3.14e0", "{:1.[precision]}", .{ .number = number, .precision = precision });
}
test "recursive format function" {
const R = union(enum) {
const R = @This();
Leaf: i32,
Branch: struct { left: *const R, right: *const R },
pub fn format(self: R, comptime _: []const u8, _: std.fmt.FormatOptions, writer: anytype) !void {
return switch (self) {
.Leaf => |n| std.fmt.format(writer, "Leaf({})", .{n}),
.Branch => |b| std.fmt.format(writer, "Branch({}, {})", .{ b.left, b.right }),
};
}
};
var r = R{ .Leaf = 1 };
try expectFmt("Leaf(1)\n", "{}\n", .{&r});
}
pub const hex_charset = "0123456789abcdef";
/// Converts an unsigned integer of any multiple of u8 to an array of lowercase
/// hex bytes, little endian.
pub fn hex(x: anytype) [@sizeOf(@TypeOf(x)) * 2]u8 {
comptime assert(@typeInfo(@TypeOf(x)).int.signedness == .unsigned);
var result: [@sizeOf(@TypeOf(x)) * 2]u8 = undefined;
var i: usize = 0;
while (i < result.len / 2) : (i += 1) {
const byte: u8 = @truncate(x >> @intCast(8 * i));
result[i * 2 + 0] = hex_charset[byte >> 4];
result[i * 2 + 1] = hex_charset[byte & 15];
}
return result;
}
test hex {
{
const x = hex(@as(u32, 0xdeadbeef));
try std.testing.expect(x.len == 8);
try std.testing.expectEqualStrings("efbeadde", &x);
}
{
const s = "[" ++ hex(@as(u64, 0x12345678_abcdef00)) ++ "]";
try std.testing.expect(s.len == 18);
try std.testing.expectEqualStrings("[00efcdab78563412]", s);
}
}