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/* compare258.c -- aligned and unaligned versions of compare258
* Copyright (C) 2020 Nathan Moinvaziri
* For conditions of distribution and use, see copyright notice in zlib.h
*/
#include "zbuild.h"
#include "zutil.h"
#include "fallback_builtins.h"
/* ALIGNED, byte comparison */
static inline uint32_t compare256_c_static(const unsigned char *src0, const unsigned char *src1) {
uint32_t len = 0;
do {
if (*src0 != *src1)
return len + (*src0 == *src1);
src0 += 1, src1 += 1, len += 1;
if (*src0 != *src1)
return len + (*src0 == *src1);
src0 += 1, src1 += 1, len += 1;
if (*src0 != *src1)
return len + (*src0 == *src1);
src0 += 1, src1 += 1, len += 1;
if (*src0 != *src1)
return len + (*src0 == *src1);
src0 += 1, src1 += 1, len += 1;
if (*src0 != *src1)
return len + (*src0 == *src1);
src0 += 1, src1 += 1, len += 1;
if (*src0 != *src1)
return len + (*src0 == *src1);
src0 += 1, src1 += 1, len += 1;
if (*src0 != *src1)
return len + (*src0 == *src1);
src0 += 1, src1 += 1, len += 1;
if (*src0 != *src1)
return len + (*src0 == *src1);
src0 += 1, src1 += 1, len += 1;
} while (len < 256);
return 256;
}
static inline uint32_t compare258_c_static(const unsigned char *src0, const unsigned char *src1) {
if (*src0 != *src1)
return 0;
src0 += 1, src1 += 1;
if (*src0 != *src1)
return 1;
src0 += 1, src1 += 1;
return compare256_c_static(src0, src1) + 2;
}
Z_INTERNAL uint32_t compare258_c(const unsigned char *src0, const unsigned char *src1) {
return compare258_c_static(src0, src1);
}
#define LONGEST_MATCH longest_match_c
#define COMPARE256 compare256_c_static
#define COMPARE258 compare258_c_static
#include "match_tpl.h"
#ifdef UNALIGNED_OK
/* UNALIGNED_OK, 16-bit integer comparison */
static inline uint32_t compare256_unaligned_16_static(const unsigned char *src0, const unsigned char *src1) {
uint32_t len = 0;
do {
if (*(uint16_t *)src0 != *(uint16_t *)src1)
return len + (*src0 == *src1);
src0 += 2, src1 += 2, len += 2;
if (*(uint16_t *)src0 != *(uint16_t *)src1)
return len + (*src0 == *src1);
src0 += 2, src1 += 2, len += 2;
if (*(uint16_t *)src0 != *(uint16_t *)src1)
return len + (*src0 == *src1);
src0 += 2, src1 += 2, len += 2;
if (*(uint16_t *)src0 != *(uint16_t *)src1)
return len + (*src0 == *src1);
src0 += 2, src1 += 2, len += 2;
} while (len < 256);
return 256;
}
static inline uint32_t compare258_unaligned_16_static(const unsigned char *src0, const unsigned char *src1) {
if (*(uint16_t *)src0 != *(uint16_t *)src1)
return (*src0 == *src1);
return compare256_unaligned_16_static(src0+2, src1+2) + 2;
}
Z_INTERNAL uint32_t compare258_unaligned_16(const unsigned char *src0, const unsigned char *src1) {
return compare258_unaligned_16_static(src0, src1);
}
#define LONGEST_MATCH longest_match_unaligned_16
#define COMPARE256 compare256_unaligned_16_static
#define COMPARE258 compare258_unaligned_16_static
#include "match_tpl.h"
#ifdef HAVE_BUILTIN_CTZ
/* UNALIGNED_OK, 32-bit integer comparison */
static inline uint32_t compare256_unaligned_32_static(const unsigned char *src0, const unsigned char *src1) {
uint32_t len = 0;
do {
uint32_t sv = *(uint32_t *)src0;
uint32_t mv = *(uint32_t *)src1;
uint32_t diff = sv ^ mv;
if (diff) {
uint32_t match_byte = __builtin_ctz(diff) / 8;
return len + match_byte;
}
src0 += 4, src1 += 4, len += 4;
} while (len < 256);
return 256;
}
static inline uint32_t compare258_unaligned_32_static(const unsigned char *src0, const unsigned char *src1) {
if (*(uint16_t *)src0 != *(uint16_t *)src1)
return (*src0 == *src1);
return compare256_unaligned_32_static(src0+2, src1+2) + 2;
}
Z_INTERNAL uint32_t compare258_unaligned_32(const unsigned char *src0, const unsigned char *src1) {
return compare258_unaligned_32_static(src0, src1);
}
#define LONGEST_MATCH longest_match_unaligned_32
#define COMPARE256 compare256_unaligned_32_static
#define COMPARE258 compare258_unaligned_32_static
#include "match_tpl.h"
#endif
#if defined(UNALIGNED64_OK) && defined(HAVE_BUILTIN_CTZLL)
/* UNALIGNED64_OK, 64-bit integer comparison */
static inline uint32_t compare256_unaligned_64_static(const unsigned char *src0, const unsigned char *src1) {
uint32_t len = 0;
do {
uint64_t sv = *(uint64_t *)src0;
uint64_t mv = *(uint64_t *)src1;
uint64_t diff = sv ^ mv;
if (diff) {
uint64_t match_byte = __builtin_ctzll(diff) / 8;
return len + (uint32_t)match_byte;
}
src0 += 8, src1 += 8, len += 8;
} while (len < 256);
return 256;
}
static inline uint32_t compare258_unaligned_64_static(const unsigned char *src0, const unsigned char *src1) {
if (*(uint16_t *)src0 != *(uint16_t *)src1)
return (*src0 == *src1);
return compare256_unaligned_64_static(src0+2, src1+2) + 2;
}
Z_INTERNAL uint32_t compare258_unaligned_64(const unsigned char *src0, const unsigned char *src1) {
return compare258_unaligned_64_static(src0, src1);
}
#define LONGEST_MATCH longest_match_unaligned_64
#define COMPARE256 compare256_unaligned_64_static
#define COMPARE258 compare258_unaligned_64_static
#include "match_tpl.h"
#endif
#endif
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