| /* compare256_rle.h -- 256 byte run-length encoding comparison |
| * Copyright (C) 2022 Nathan Moinvaziri |
| * For conditions of distribution and use, see copyright notice in zlib.h |
| */ |
| |
| #include "zbuild.h" |
| #include "fallback_builtins.h" |
| |
| typedef uint32_t (*compare256_rle_func)(const uint8_t* src0, const uint8_t* src1); |
| |
| /* ALIGNED, byte comparison */ |
| static inline uint32_t compare256_rle_c(const uint8_t *src0, const uint8_t *src1) { |
| uint32_t len = 0; |
| |
| do { |
| if (*src0 != *src1) |
| return len; |
| src1 += 1, len += 1; |
| if (*src0 != *src1) |
| return len; |
| src1 += 1, len += 1; |
| if (*src0 != *src1) |
| return len; |
| src1 += 1, len += 1; |
| if (*src0 != *src1) |
| return len; |
| src1 += 1, len += 1; |
| if (*src0 != *src1) |
| return len; |
| src1 += 1, len += 1; |
| if (*src0 != *src1) |
| return len; |
| src1 += 1, len += 1; |
| if (*src0 != *src1) |
| return len; |
| src1 += 1, len += 1; |
| if (*src0 != *src1) |
| return len; |
| src1 += 1, len += 1; |
| } while (len < 256); |
| |
| return 256; |
| } |
| |
| #ifdef UNALIGNED_OK |
| /* 16-bit unaligned integer comparison */ |
| static inline uint32_t compare256_rle_unaligned_16(const uint8_t *src0, const uint8_t *src1) { |
| uint32_t len = 0; |
| uint16_t src0_cmp, src1_cmp; |
| |
| memcpy(&src0_cmp, src0, sizeof(src0_cmp)); |
| |
| do { |
| memcpy(&src1_cmp, src1, sizeof(src1_cmp)); |
| if (src0_cmp != src1_cmp) |
| return len + (*src0 == *src1); |
| src1 += 2, len += 2; |
| memcpy(&src1_cmp, src1, sizeof(src1_cmp)); |
| if (src0_cmp != src1_cmp) |
| return len + (*src0 == *src1); |
| src1 += 2, len += 2; |
| memcpy(&src1_cmp, src1, sizeof(src1_cmp)); |
| if (src0_cmp != src1_cmp) |
| return len + (*src0 == *src1); |
| src1 += 2, len += 2; |
| memcpy(&src1_cmp, src1, sizeof(src1_cmp)); |
| if (src0_cmp != src1_cmp) |
| return len + (*src0 == *src1); |
| src1 += 2, len += 2; |
| } while (len < 256); |
| |
| return 256; |
| } |
| |
| #ifdef HAVE_BUILTIN_CTZ |
| /* 32-bit unaligned integer comparison */ |
| static inline uint32_t compare256_rle_unaligned_32(const uint8_t *src0, const uint8_t *src1) { |
| uint32_t sv, len = 0; |
| uint16_t src0_cmp; |
| |
| memcpy(&src0_cmp, src0, sizeof(src0_cmp)); |
| sv = ((uint32_t)src0_cmp << 16) | src0_cmp; |
| |
| do { |
| uint32_t mv, diff; |
| |
| memcpy(&mv, src1, sizeof(mv)); |
| |
| diff = sv ^ mv; |
| if (diff) { |
| uint32_t match_byte = __builtin_ctz(diff) / 8; |
| return len + match_byte; |
| } |
| |
| src1 += 4, len += 4; |
| } while (len < 256); |
| |
| return 256; |
| } |
| |
| #endif |
| |
| #if defined(UNALIGNED64_OK) && defined(HAVE_BUILTIN_CTZLL) |
| /* 64-bit unaligned integer comparison */ |
| static inline uint32_t compare256_rle_unaligned_64(const uint8_t *src0, const uint8_t *src1) { |
| uint32_t src0_cmp32, len = 0; |
| uint16_t src0_cmp; |
| uint64_t sv; |
| |
| memcpy(&src0_cmp, src0, sizeof(src0_cmp)); |
| src0_cmp32 = ((uint32_t)src0_cmp << 16) | src0_cmp; |
| sv = ((uint64_t)src0_cmp32 << 32) | src0_cmp32; |
| |
| do { |
| uint64_t mv, diff; |
| |
| memcpy(&mv, src1, sizeof(mv)); |
| |
| diff = sv ^ mv; |
| if (diff) { |
| uint64_t match_byte = __builtin_ctzll(diff) / 8; |
| return len + (uint32_t)match_byte; |
| } |
| |
| src1 += 8, len += 8; |
| } while (len < 256); |
| |
| return 256; |
| } |
| |
| #endif |
| |
| #endif |
| |