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feat(libzigc): add qsort

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* also remove musl implementation
This commit is contained in:
GasInfinity
2026-01-01 13:17:26 +01:00
committed by Andrew Kelley
parent 6412aebc90
commit fa625e878f
5 changed files with 44 additions and 239 deletions
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lib/c/stdlib.zig
+44
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@@ -8,6 +8,9 @@ comptime {
@export(&abs, .{ .name = "abs", .linkage = common.linkage, .visibility = common.visibility });
@export(&labs, .{ .name = "labs", .linkage = common.linkage, .visibility = common.visibility });
@export(&llabs, .{ .name = "llabs", .linkage = common.linkage, .visibility = common.visibility });
@export(&qsort_r, .{ .name = "qsort_r", .linkage = common.linkage, .visibility = common.visibility });
@export(&qsort, .{ .name = "qsort", .linkage = common.linkage, .visibility = common.visibility });
}
}
@@ -23,6 +26,47 @@ fn llabs(a: c_longlong) callconv(.c) c_longlong {
return @intCast(@abs(a));
}
// NOTE: Despite its name, `qsort` doesn't have to use quicksort or make any complexity or stability guarantee.
fn qsort_r(base: *anyopaque, n: usize, size: usize, compare: *const fn (a: *const anyopaque, b: *const anyopaque, arg: ?*anyopaque) callconv(.c) c_int, arg: ?*anyopaque) callconv(.c) void {
const Context = struct {
base: [*]u8,
size: usize,
compare: *const fn (a: *const anyopaque, b: *const anyopaque, arg: ?*anyopaque) callconv(.c) c_int,
arg: ?*anyopaque,
pub fn lessThan(ctx: @This(), a: usize, b: usize) bool {
return ctx.compare(&ctx.base[a * ctx.size], &ctx.base[b * ctx.size], ctx.arg) < 0;
}
pub fn swap(ctx: @This(), a: usize, b: usize) void {
const a_bytes: []u8 = ctx.base[a * ctx.size ..][0..ctx.size];
const b_bytes: []u8 = ctx.base[b * ctx.size ..][0..ctx.size];
for (a_bytes, b_bytes) |*ab, *bb| {
const tmp = ab.*;
ab.* = bb.*;
bb.* = tmp;
}
}
};
std.mem.sortUnstableContext(0, n, Context{
.base = @ptrCast(base),
.size = size,
.compare = compare,
.arg = arg,
});
}
fn qsort(base: *anyopaque, n: usize, size: usize, compare: *const fn (a: *const anyopaque, b: *const anyopaque) callconv(.c) c_int) callconv(.c) void {
return qsort_r(base, n, size, (struct {
fn wrap(a: *const anyopaque, b: *const anyopaque, arg: ?*anyopaque) callconv(.c) c_int {
const cmp: *const fn (a: *const anyopaque, b: *const anyopaque) callconv(.c) c_int = @ptrCast(@alignCast(arg.?));
return cmp(a, b);
}
}).wrap, @constCast(compare));
}
test abs {
const val: c_int = -10;
try std.testing.expectEqual(10, abs(val));