ncdu-zig/src/util.zig

248 lines
7.9 KiB
Zig

// SPDX-FileCopyrightText: Yorhel <projects@yorhel.nl>
// SPDX-License-Identifier: MIT
const std = @import("std");
const c = @import("c.zig").c;
// Cast any integer type to the target type, clamping the value to the supported maximum if necessary.
pub fn castClamp(comptime T: type, x: anytype) T {
// (adapted from std.math.cast)
if (std.math.maxInt(@TypeOf(x)) > std.math.maxInt(T) and x > std.math.maxInt(T)) {
return std.math.maxInt(T);
} else if (std.math.minInt(@TypeOf(x)) < std.math.minInt(T) and x < std.math.minInt(T)) {
return std.math.minInt(T);
} else {
return @intCast(x);
}
}
// Cast any integer type to the target type, truncating if necessary.
pub fn castTruncate(comptime T: type, x: anytype) T {
const Ti = @typeInfo(T).int;
const Xi = @typeInfo(@TypeOf(x)).int;
const nx: std.meta.Int(Ti.signedness, Xi.bits) = @bitCast(x);
return if (Xi.bits > Ti.bits) @truncate(nx) else nx;
}
// Multiplies by 512, saturating.
pub fn blocksToSize(b: u64) u64 {
return b *| 512;
}
// Ensure the given arraylist buffer gets zero-terminated and returns a slice
// into the buffer. The returned buffer is invalidated whenever the arraylist
// is freed or written to.
pub fn arrayListBufZ(buf: *std.ArrayListUnmanaged(u8), alloc: std.mem.Allocator) [:0]const u8 {
buf.append(alloc, 0) catch unreachable;
defer buf.items.len -= 1;
return buf.items[0..buf.items.len-1:0];
}
// Format an integer as right-aligned '###.#'.
// Pretty much equivalent to:
// std.fmt.bufPrintZ(.., "{d:>5.1}", @floatFromInt(n)/10.0);
// Except this function doesn't pull in large float formatting tables.
pub fn fmt5dec(n: u14) [5:0]u8 {
std.debug.assert(n <= 9999);
var buf: [5:0]u8 = " 0.0".*;
var v = n;
buf[4] += @intCast(v % 10);
v /= 10;
buf[2] += @intCast(v % 10);
v /= 10;
if (v == 0) return buf;
buf[1] = '0' + @as(u8, @intCast(v % 10));
v /= 10;
if (v == 0) return buf;
buf[0] = '0' + @as(u8, @intCast(v));
return buf;
}
test "fmt5dec" {
const eq = std.testing.expectEqualStrings;
try eq(" 0.0", &fmt5dec(0));
try eq(" 0.5", &fmt5dec(5));
try eq(" 9.5", &fmt5dec(95));
try eq(" 12.5", &fmt5dec(125));
try eq("123.9", &fmt5dec(1239));
try eq("999.9", &fmt5dec(9999));
}
// Straightforward Zig port of strnatcmp() from https://github.com/sourcefrog/natsort/
// (Requiring nul-terminated strings is ugly, but we've got them anyway and it does simplify the code)
pub fn strnatcmp(a: [:0]const u8, b: [:0]const u8) std.math.Order {
var ai: usize = 0;
var bi: usize = 0;
const isDigit = std.ascii.isDigit;
while (true) {
while (std.ascii.isWhitespace(a[ai])) ai += 1;
while (std.ascii.isWhitespace(b[bi])) bi += 1;
if (isDigit(a[ai]) and isDigit(b[bi])) {
if (a[ai] == '0' or b[bi] == '0') { // compare_left
while (true) {
if (!isDigit(a[ai]) and !isDigit(b[bi])) break;
if (!isDigit(a[ai])) return .lt;
if (!isDigit(b[bi])) return .gt;
if (a[ai] < b[bi]) return .lt;
if (a[ai] > b[bi]) return .gt;
ai += 1;
bi += 1;
}
} else { // compare_right - for right-aligned numbers
var bias = std.math.Order.eq;
while (true) {
if (!isDigit(a[ai]) and !isDigit(b[bi])) {
if (bias != .eq or (a[ai] == 0 and b[bi] == 0)) return bias
else break;
}
if (!isDigit(a[ai])) return .lt;
if (!isDigit(b[bi])) return .gt;
if (bias == .eq) {
if (a[ai] < b[bi]) bias = .lt;
if (a[ai] > b[bi]) bias = .gt;
}
ai += 1;
bi += 1;
}
}
}
if (a[ai] == 0 and b[bi] == 0) return .eq;
if (a[ai] < b[bi]) return .lt;
if (a[ai] > b[bi]) return .gt;
ai += 1;
bi += 1;
}
}
test "strnatcmp" {
// Test strings from https://github.com/sourcefrog/natsort/
// Includes sorted-words, sorted-dates and sorted-fractions.
const w = [_][:0]const u8{
"1-02",
"1-2",
"1-20",
"1.002.01",
"1.002.03",
"1.002.08",
"1.009.02",
"1.009.10",
"1.009.20",
"1.010.12",
"1.011.02",
"10-20",
"1999-3-3",
"1999-12-25",
"2000-1-2",
"2000-1-10",
"2000-3-23",
"fred",
"jane",
"pic01",
"pic02",
"pic02a",
"pic02000",
"pic05",
"pic2",
"pic3",
"pic4",
"pic 4 else",
"pic 5",
"pic 5 ",
"pic 5 something",
"pic 6",
"pic 7",
"pic100",
"pic100a",
"pic120",
"pic121",
"tom",
"x2-g8",
"x2-y08",
"x2-y7",
"x8-y8",
};
// Test each string against each other string, simple and thorough.
const eq = std.testing.expectEqual;
for (0..w.len) |i| {
try eq(strnatcmp(w[i], w[i]), .eq);
for (0..i) |j| try eq(strnatcmp(w[i], w[j]), .gt);
for (i+1..w.len) |j| try eq(strnatcmp(w[i], w[j]), .lt);
}
}
pub fn expanduser(path: []const u8, alloc: std.mem.Allocator) ![:0]u8 {
if (path.len == 0 or path[0] != '~') return alloc.dupeZ(u8, path);
const len = std.mem.indexOfScalar(u8, path, '/') orelse path.len;
const home_raw = blk: {
const pwd = pwd: {
if (len == 1) {
if (std.posix.getenvZ("HOME")) |p| break :blk p;
break :pwd c.getpwuid(c.getuid());
} else {
const name = try alloc.dupeZ(u8, path[1..len]);
defer alloc.free(name);
break :pwd c.getpwnam(name.ptr);
}
};
if (pwd != null)
if (@as(*c.struct_passwd, pwd).pw_dir) |p|
break :blk std.mem.span(p);
return alloc.dupeZ(u8, path);
};
const home = std.mem.trimRight(u8, home_raw, "/");
if (home.len == 0 and path.len == len) return alloc.dupeZ(u8, "/");
return try std.mem.concatWithSentinel(alloc, u8, &.{ home, path[len..] }, 0);
}
// Silly abstraction to read a file one line at a time. Only exists to help
// with supporting both Zig 0.14 and 0.15, can be removed once 0.14 support is
// dropped.
pub const LineReader = if (@hasDecl(std.io, "bufferedReader")) struct {
rd: std.io.BufferedReader(4096, std.fs.File.Reader),
fbs: std.io.FixedBufferStream([]u8),
pub fn init(f: std.fs.File, buf: []u8) @This() {
return .{
.rd = std.io.bufferedReader(f.reader()),
.fbs = std.io.fixedBufferStream(buf),
};
}
pub fn read(s: *@This()) !?[]u8 {
s.fbs.reset();
s.rd.reader().streamUntilDelimiter(s.fbs.writer(), '\n', s.fbs.buffer.len) catch |err| switch (err) {
error.EndOfStream => if (s.fbs.getPos() catch unreachable == 0) return null,
else => |e| return e,
};
return s.fbs.getWritten();
}
} else struct {
rd: std.fs.File.Reader,
pub fn init(f: std.fs.File, buf: []u8) @This() {
return .{ .rd = f.readerStreaming(buf) };
}
pub fn read(s: *@This()) !?[]u8 {
// Avoid takeDelimiterExclusive() for now, it's bugged in 0.15.2: https://github.com/ziglang/zig/issues/25664
const r = &s.rd.interface;
const result = r.peekDelimiterInclusive('\n') catch |err| switch (err) {
error.EndOfStream => {
const remaining = r.buffer[r.seek..r.end];
if (remaining.len == 0) return null;
r.toss(remaining.len);
return remaining;
},
else => |e| return e,
};
r.toss(result.len);
return result[0 .. result.len - 1];
}
};