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51 lines
1.5 KiB
C
51 lines
1.5 KiB
C
/* insert_string_sse -- insert_string variant using SSE4.2's CRC instructions
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*
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* Copyright (C) 1995-2013 Jean-loup Gailly and Mark Adler
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* For conditions of distribution and use, see copyright notice in zlib.h
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*
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*/
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#include "deflate.h"
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/* ===========================================================================
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* Insert string str in the dictionary and set match_head to the previous head
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* of the hash chain (the most recent string with same hash key). Return
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* the previous length of the hash chain.
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* IN assertion: all calls to to INSERT_STRING are made with consecutive
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* input characters and the first MIN_MATCH bytes of str are valid
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* (except for the last MIN_MATCH-1 bytes of the input file).
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*/
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#ifdef X86_SSE4_2_CRC_HASH
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Pos insert_string_sse(deflate_state *const s, const Pos str, unsigned int count) {
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Pos ret = 0;
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unsigned int idx;
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unsigned *ip, val, h = 0;
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for (idx = 0; idx < count; idx++) {
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ip = (unsigned *)&s->window[str+idx];
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val = *ip;
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h = 0;
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if (s->level >= 6)
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val &= 0xFFFFFF;
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#ifdef _MSC_VER
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h = _mm_crc32_u32(h, val);
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#else
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__asm__ __volatile__ (
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"crc32 %1,%0\n\t"
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: "+r" (h)
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: "r" (val)
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);
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#endif
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if (s->head[h & s->hash_mask] != str+idx) {
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s->prev[(str+idx) & s->w_mask] = s->head[h & s->hash_mask];
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s->head[h & s->hash_mask] = str+idx;
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}
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}
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ret = s->prev[(str+count-1) & s->w_mask];
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return ret;
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}
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#endif
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