From a0d16829215f56fe42548f1014cba0f2df5a1609 Mon Sep 17 00:00:00 2001
From: Andrew Kelley <andrew@ziglang.org>
Date: Sat, 19 Jul 2025 11:49:33 -0700
Subject: [PATCH] std.hash.RapidHash: remove

Its design keeps evolving. See
https://github.com/Nicoshev/rapidhash/releases

It's great to see the design improving, but over time, this will lead to
code rot; versions that aren't widely used but would still have to live
in the standard library forever and be maintained.

Better to be maintained as an external dependency that applications can
opt into. Then, in a few years, if a version proves to be stable and
widely adopted, it could be considered for inclusion in the standard
library.
---
 lib/std/hash.zig           |   2 -
 lib/std/hash/RapidHash.zig | 125 -------------------------------------
 lib/std/hash/benchmark.zig |   6 --
 3 files changed, 133 deletions(-)
 delete mode 100644 lib/std/hash/RapidHash.zig

diff --git a/lib/std/hash.zig b/lib/std/hash.zig
index e0eca9e39173fab1f90188eacd0c123f4898901b..5f1697a236167d13aef5f1c8100516aecbfdbd8e 100644
--- a/lib/std/hash.zig
+++ b/lib/std/hash.zig
@@ -32,8 +32,6 @@ pub const CityHash64 = cityhash.CityHash64;
 const wyhash = @import("hash/wyhash.zig");
 pub const Wyhash = wyhash.Wyhash;
 
-pub const RapidHash = @import("hash/RapidHash.zig");
-
 const xxhash = @import("hash/xxhash.zig");
 pub const XxHash3 = xxhash.XxHash3;
 pub const XxHash64 = xxhash.XxHash64;
diff --git a/lib/std/hash/RapidHash.zig b/lib/std/hash/RapidHash.zig
deleted file mode 100644
index bb1b45bcc42dbcae74eeffab515614fb48034ea0..0000000000000000000000000000000000000000
--- a/lib/std/hash/RapidHash.zig
+++ /dev/null
@@ -1,125 +0,0 @@
-const std = @import("std");
-
-const readInt = std.mem.readInt;
-const assert = std.debug.assert;
-const expect = std.testing.expect;
-const expectEqual = std.testing.expectEqual;
-
-const RAPID_SEED: u64 = 0xbdd89aa982704029;
-const RAPID_SECRET: [3]u64 = .{ 0x2d358dccaa6c78a5, 0x8bb84b93962eacc9, 0x4b33a62ed433d4a3 };
-
-pub fn hash(seed: u64, input: []const u8) u64 {
-    const sc = RAPID_SECRET;
-    const len = input.len;
-    var a: u64 = 0;
-    var b: u64 = 0;
-    var k = input;
-    var is: [3]u64 = .{ seed, 0, 0 };
-
-    is[0] ^= mix(seed ^ sc[0], sc[1]) ^ len;
-
-    if (len <= 16) {
-        if (len >= 4) {
-            const d: usize = ((len & 24) >> @intCast(len >> 3));
-            const e = len - 4;
-            a = (r32(k) << 32) | r32(k[e..]);
-            b = ((r32(k[d..]) << 32) | r32(k[(e - d)..]));
-        } else if (len > 0)
-            a = (@as(u64, k[0]) << 56) | (@as(u64, k[len >> 1]) << 32) | @as(u64, k[len - 1]);
-    } else {
-        var remain = len;
-        if (len > 48) {
-            is[1] = is[0];
-            is[2] = is[0];
-            while (remain >= 96) {
-                inline for (0..6) |i| {
-                    const m1 = r64(k[8 * i * 2 ..]);
-                    const m2 = r64(k[8 * (i * 2 + 1) ..]);
-                    is[i % 3] = mix(m1 ^ sc[i % 3], m2 ^ is[i % 3]);
-                }
-                k = k[96..];
-                remain -= 96;
-            }
-            if (remain >= 48) {
-                inline for (0..3) |i| {
-                    const m1 = r64(k[8 * i * 2 ..]);
-                    const m2 = r64(k[8 * (i * 2 + 1) ..]);
-                    is[i] = mix(m1 ^ sc[i], m2 ^ is[i]);
-                }
-                k = k[48..];
-                remain -= 48;
-            }
-
-            is[0] ^= is[1] ^ is[2];
-        }
-
-        if (remain > 16) {
-            is[0] = mix(r64(k) ^ sc[2], r64(k[8..]) ^ is[0] ^ sc[1]);
-            if (remain > 32) {
-                is[0] = mix(r64(k[16..]) ^ sc[2], r64(k[24..]) ^ is[0]);
-            }
-        }
-
-        a = r64(input[len - 16 ..]);
-        b = r64(input[len - 8 ..]);
-    }
-
-    a ^= sc[1];
-    b ^= is[0];
-    mum(&a, &b);
-    return mix(a ^ sc[0] ^ len, b ^ sc[1]);
-}
-
-test "RapidHash.hash" {
-    const bytes: []const u8 = "abcdefgh" ** 128;
-
-    const sizes: [13]u64 = .{ 0, 1, 2, 3, 4, 8, 16, 32, 64, 128, 256, 512, 1024 };
-
-    const outcomes: [13]u64 = .{
-        0x5a6ef77074ebc84b,
-        0xc11328477bc0f5d1,
-        0x5644ac035e40d569,
-        0x347080fbf5fcd81,
-        0x56b66b8dc802bcc,
-        0xb6bf9055973aac7c,
-        0xed56d62eead1e402,
-        0xc19072d767da8ffb,
-        0x89bb40a9928a4f0d,
-        0xe0af7c5e7b6e29fd,
-        0x9a3ed35fbedfa11a,
-        0x4c684b2119ca19fb,
-        0x4b575f5bf25600d6,
-    };
-
-    var success: bool = true;
-    for (sizes, outcomes) |s, e| {
-        const r = hash(RAPID_SEED, bytes[0..s]);
-
-        expectEqual(e, r) catch |err| {
-            std.debug.print("Failed on {d}: {!}\n", .{ s, err });
-            success = false;
-        };
-    }
-    try expect(success);
-}
-
-inline fn mum(a: *u64, b: *u64) void {
-    const r = @as(u128, a.*) * b.*;
-    a.* = @truncate(r);
-    b.* = @truncate(r >> 64);
-}
-
-inline fn mix(a: u64, b: u64) u64 {
-    var copy_a = a;
-    var copy_b = b;
-    mum(&copy_a, &copy_b);
-    return copy_a ^ copy_b;
-}
-
-inline fn r64(p: []const u8) u64 {
-    return readInt(u64, p[0..8], .little);
-}
-
-inline fn r32(p: []const u8) u64 {
-    return readInt(u32, p[0..4], .little);
-}
diff --git a/lib/std/hash/benchmark.zig b/lib/std/hash/benchmark.zig
index 980b41b8ae29a0be13b54778196fb7094888ccd6..84d14a35db5e811241e42fdd3a63c6f1d48949ba 100644
--- a/lib/std/hash/benchmark.zig
+++ b/lib/std/hash/benchmark.zig
@@ -59,12 +59,6 @@ const hashes = [_]Hash{
         .ty = hash.crc.Crc32,
         .name = "crc32",
     },
-    Hash{
-        .ty = hash.RapidHash,
-        .name = "rapidhash",
-        .has_iterative_api = false,
-        .init_u64 = 0,
-    },
     Hash{
         .ty = hash.CityHash32,
         .name = "cityhash-32",
-- 
2.54.0