1 files changed, 123 insertions, 0 deletions
diff --git a/src/zix/digest.c b/src/zix/digest.c
new file mode 100644
index 00000000..889cfdef
--- /dev/null
+++ b/src/zix/digest.c
@@ -0,0 +1,123 @@
+/*
+  Copyright 2012-2020 David Robillard <http://drobilla.net>
+
+  Permission to use, copy, modify, and/or distribute this software for any
+  purpose with or without fee is hereby granted, provided that the above
+  copyright notice and this permission notice appear in all copies.
+
+  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+
+#include "zix/digest.h"
+
+#ifdef __SSE4_2__
+#    include <smmintrin.h>
+#endif
+
+#include <assert.h>
+#include <stdint.h>
+
+#ifdef __SSE4_2__
+
+// SSE 4.2 CRC32
+
+ZIX_API uint32_t
+zix_digest_start(void)
+{
+	return 1;
+}
+
+ZIX_API uint32_t
+zix_digest_add(uint32_t hash, const void* const buf, const size_t len)
+{
+	const uint8_t* str = (const uint8_t*)buf;
+
+	for (size_t i = 0; i < (len / sizeof(uint64_t)); ++i) {
+		hash = (uint32_t)_mm_crc32_u64(hash, *(const uint64_t*)str);
+		str += sizeof(uint64_t);
+	}
+	if (len & sizeof(uint32_t)) {
+		hash = _mm_crc32_u32(hash, *(const uint32_t*)str);
+		str += sizeof(uint32_t);
+	}
+	if (len & sizeof(uint16_t)) {
+		hash = _mm_crc32_u16(hash, *(const uint16_t*)str);
+		str += sizeof(uint16_t);
+	}
+	if (len & sizeof(uint8_t)) {
+		hash = _mm_crc32_u8(hash, *(const uint8_t*)str);
+	}
+
+	return hash;
+}
+
+ZIX_API uint32_t
+zix_digest_add_64(uint32_t hash, const void* const buf, const size_t len)
+{
+	assert((uintptr_t)buf % sizeof(uint64_t) == 0);
+	assert(len % sizeof(uint64_t) == 0);
+
+	const uint64_t* ptr = (const uint64_t*)buf;
+
+	for (size_t i = 0; i < (len / sizeof(uint64_t)); ++i) {
+		hash = (uint32_t)_mm_crc32_u64(hash, *ptr);
+		++ptr;
+	}
+
+	return hash;
+}
+
+ZIX_API uint32_t
+zix_digest_add_ptr(const uint32_t hash, const void* const ptr)
+{
+#if UINTPTR_MAX == UINT64_MAX
+	return (uint32_t)_mm_crc32_u64(hash, (uintptr_t)ptr);
+#else
+	return _mm_crc32_u32(hash, (uintptr_t)ptr);
+#endif
+}
+
+#else
+
+// Classic DJB hash
+
+ZIX_API uint32_t
+zix_digest_start(void)
+{
+	return 5381;
+}
+
+ZIX_API uint32_t
+zix_digest_add(uint32_t hash, const void* const buf, const size_t len)
+{
+	const uint8_t* str = (const uint8_t*)buf;
+
+	for (size_t i = 0; i < len; ++i) {
+		hash = (hash << 5u) + hash + str[i];
+	}
+
+	return hash;
+}
+
+ZIX_API uint32_t
+zix_digest_add_64(uint32_t hash, const void* const buf, const size_t len)
+{
+	assert((uintptr_t)buf % sizeof(uint64_t) == 0);
+	assert(len % sizeof(uint64_t) == 0);
+
+	return zix_digest_add(hash, buf, len);
+}
+
+ZIX_API uint32_t
+zix_digest_add_ptr(const uint32_t hash, const void* const ptr)
+{
+	return zix_digest_add(hash, &ptr, sizeof(ptr));
+}
+
+#endif