xxhash: Initial implementations.

2026-08-06 15:48:51 +00:00 · 2021-09-09 15:26:57 +02:00
parent e65e0b5db2
commit f5d5417af7
3 changed files with 691 additions and 0 deletions
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+/*
+	An implementation of Yann Collet's [xxhash Fast Hash Algorithm](https://cyan4973.github.io/xxHash/).
+	Copyright 2021 Jeroen van Rijn <nom@duclavier.com>.
+
+	Made available under Odin's BSD-3 license, based on the original C code.
+
+	List of contributors:
+		Jeroen van Rijn: Initial implementation.
+*/
+package xxhash
+
+import "core:intrinsics"
+import "core:runtime"
+mem_copy :: runtime.mem_copy
+
+/*
+	Version definition
+*/
+XXH_VERSION_MAJOR   :: 0
+XXH_VERSION_MINOR   :: 8
+XXH_VERSION_RELEASE :: 1
+XXH_VERSION_NUMBER  :: XXH_VERSION_MAJOR * 100 * 100 + XXH_VERSION_MINOR * 100 + XXH_VERSION_RELEASE
+
+/*
+	0 - Use memcopy, for platforms where unaligned reads are a problem
+	2 - Direct cast, for platforms where unaligned are allowed (default)
+*/
+XXH_FORCE_MEMORY_ACCESS :: #config(XXH_FORCE_MEMORY_ACCESS, 2)
+
+/*
+	`false` - Use this on platforms where unaligned reads are fast
+	`true`  - Use this on platforms where unaligned reads are slow
+*/
+XXH_FORCE_ALIGN_CHECK :: #config(XXH_FORCE_ALIGN_CHECK, false)
+
+Alignment :: enum {
+	Aligned,
+	Unaligned,
+}
+
+Error :: enum {
+	Okay = 0,
+	Error,
+}
+
+@(optimization_mode="speed")
+XXH_rotl32 :: #force_inline proc(x, r: u32) -> (res: u32) {
+	return ((x << r) | (x >> (32 - r)))
+}
+
+@(optimization_mode="speed")
+XXH_rotl64 :: #force_inline proc(x, r: u64) -> (res: u64) {
+	return ((x << r) | (x >> (64 - r)))
+}
+
+@(optimization_mode="speed")
+XXH32_read32 :: #force_inline proc(buf: []u8, alignment: Alignment) -> (res: u32) {
+	if XXH_FORCE_MEMORY_ACCESS == 2 || alignment == .Aligned {
+		#no_bounds_check b := (^u32le)(&buf[0])^
+		return u32(b)
+	} else {
+		b: u32le
+		mem_copy(&b, raw_data(buf[:]), 4)
+		return u32(b)
+	}
+}
+
+@(optimization_mode="speed")
+XXH64_read64 :: #force_inline proc(buf: []u8, alignment: Alignment) -> (res: u64) {
+	if XXH_FORCE_MEMORY_ACCESS == 2 || alignment == .Aligned {
+		#no_bounds_check b := (^u64le)(&buf[0])^
+		return u64(b)
+	} else {
+		b: u64le
+		mem_copy(&b, raw_data(buf[:]), 8)
+		return u64(b)
+	}
+}