authorgravatar for hello@nektro.netMeghan Denny <hello@nektro.net> 2026-02-12 02:24:59 -08:00
committergravatar for hello@nektro.netMeghan Denny <hello@nektro.net> 2026-02-12 02:24:59 -08:00
log815c8536f4e9e50e3ae58b191bd6d4bcd09f8796
tree83e6efde5bb2283d899b6e56d058d095d214b366
parent4ff17ef6c22c9a4fa7c4eb79ee4c46f5fb20cb56

add parseDigits

3 files changed, 41 insertions(+), 1 deletions(-)

src/lib.zig+1
......@@ -118,3 +118,4 @@ pub usingnamespace @import("./compareFnBasic.zig");
118118pub usingnamespace @import("./compareFnField.zig");
119119pub usingnamespace @import("./compareFnRange.zig");
120120pub usingnamespace @import("./asciiLower.zig");
121pub usingnamespace @import("./parseDigits.zig");
src/parseDigits.zig created+39
......@@ -0,0 +1,39 @@
1const std = @import("std");
2const string = []const u8;
3const extras = @import("./lib.zig");
4
5/// Simple number parser with no extra detection or handling. Alphabet is [0-9][a-z] with respect to base.
6/// Partially motivated by https://codeberg.org/ziglang/zig/issues/30881 + https://github.com/ziglang/zig/issues/24687
7pub fn parseDigits(comptime T: type, buf: []const u8, base: u8) !T {
8 std.debug.assert(base > 0);
9 std.debug.assert(base <= 36);
10 if (buf.len == 0) return error.InvalidCharacter;
11
12 var result: T = 0;
13 for (0..buf.len) |i| {
14 const c = buf[buf.len - 1 - i];
15 const d = switch (c) {
16 '0'...'9' => |a| a - '0',
17 'a'...'z' => |a| a - 'a' + 10,
18 'A'...'Z' => |a| a - 'A' + 10,
19 else => return error.InvalidCharacter,
20 };
21 if (d == 0) continue;
22 if (d >= base) return error.Overflow;
23 const _x = if (i == 0) 1 else std.math.powi(T, @intCast(base), @intCast(i)) catch return error.Overflow;
24 const _y = try std.math.mul(T, @intCast(d), _x);
25 const _z = try std.math.add(T, result, _y);
26 result = _z;
27 }
28 return result;
29}
30
31test {
32 try std.testing.expect(try parseDigits(u8, "10", 10) == 10);
33}
34test {
35 try std.testing.expect(try parseDigits(u8, "20", 16) == 32);
36}
37test {
38 try std.testing.expect(try parseDigits(u8, "EF", 16) == 239);
39}
src/parse_int.zig+1-1
......@@ -4,7 +4,7 @@ const extras = @import("./lib.zig");
44
55pub fn parse_int(comptime T: type, s: ?string, b: u8, d: T) T {
66 if (s == null) return d;
7 return std.fmt.parseInt(T, s.?, b) catch d;
7 return extras.parseDigits(T, s.?, b) catch d;
88}
99
1010test {