83 lines
2.8 KiB
C
Executable File
83 lines
2.8 KiB
C
Executable File
/*
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is parametrized: no (but recieves GUF_HASH_32_BIT from guf_common.h to set guf_hash_size_t depending on platform)
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*/
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#if defined(GUF_HASH_IMPL_STATIC)
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#define GUF_HASH_KWRDS static
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#else
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#define GUF_HASH_KWRDS
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#endif
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#ifndef GUF_HASH_H
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#define GUF_HASH_H
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#include "guf_common.h"
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/*
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FNV-1a (32-bit and 64-bit) hash functions.
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Generally, you should always call csr_hash with GUF_HASH_INIT as the hash argument, unless you want to create "chains" of hashes.
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cf. http://www.isthe.com/chongo/tech/comp/fnv/ (last retrieved: 2023-11-30)
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*/
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#define GUF_HASH32_INIT UINT32_C(2166136261)
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#define GUF_HASH64_INIT UINT64_C(14695981039346656037)
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GUF_HASH_KWRDS uint_least32_t guf_hash32(const void *data, ptrdiff_t num_bytes, uint_least32_t hash); // FNV-1a (32 bit)
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GUF_HASH_KWRDS uint_least64_t guf_hash64(const void *data, ptrdiff_t num_bytes, uint_least64_t hash); // FNV-1a (64 bit)
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#ifdef GUF_HASH_32_BIT
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typedef uint_least32_t guf_hash_size_t;
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#define GUF_HASH_INIT GUF_HASH32_INIT
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#define GUF_HASH_MAX GUF_UINT32_MAX
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static inline guf_hash_size_t guf_hash(const void *data, ptrdiff_t num_bytes, guf_hash_size_t hash) {
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return guf_hash32(data, num_bytes, hash);
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}
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#else
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typedef uint_least64_t guf_hash_size_t;
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#define GUF_HASH_INIT GUF_HASH64_INIT
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#define GUF_HASH_MAX GUF_UINT64_MAX
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static inline guf_hash_size_t guf_hash(const void *data, ptrdiff_t num_bytes, guf_hash_size_t hash) {
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return guf_hash64(data, num_bytes, hash);
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}
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#endif
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#endif
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#if defined(GUF_HASH_IMPL) || defined(GUF_HASH_IMPL_STATIC)
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#include "guf_assert.h"
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GUF_HASH_KWRDS uint_least32_t guf_hash32(const void *data, ptrdiff_t num_bytes, uint_least32_t hash)
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{
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hash = GUF_UWRAP_32(hash);
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GUF_ASSERT_RELEASE(data);
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GUF_ASSERT_RELEASE(num_bytes >= 0);
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const unsigned char *data_bytes = (const unsigned char*)data; // This does not break strict-aliasing rules I think...
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const uint_least32_t FNV_32_PRIME = UINT32_C(16777619);
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for (ptrdiff_t i = 0; i < num_bytes; ++i) {
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hash = GUF_UWRAP_32(1u * hash ^ data_bytes[i]);
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hash = GUF_UWRAP_32(1u * hash * FNV_32_PRIME);
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}
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return hash;
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}
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GUF_HASH_KWRDS uint_least64_t guf_hash64(const void *data, ptrdiff_t num_bytes, uint_least64_t hash)
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{
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hash = GUF_UWRAP_64(hash);
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GUF_ASSERT_RELEASE(data);
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GUF_ASSERT_RELEASE(num_bytes >= 0);
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const unsigned char *data_bytes = (const unsigned char*)data; // This does not break strict-aliasing rules I think...
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const uint_least64_t FNV_64_PRIME = UINT64_C(1099511628211);
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for (ptrdiff_t i = 0; i < num_bytes; ++i) {
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hash = GUF_UWRAP_64(1u * hash ^ data_bytes[i]);
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hash = GUF_UWRAP_64(1u * hash * FNV_64_PRIME);
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}
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return hash;
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}
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#undef GUF_HASH_IMPL
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#undef GUF_HASH_IMPL_STATIC
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#endif /* endif GUF_IMPL/GUF_IMPL_STATIC */
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#undef GUF_HASH_KWRDS
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