diff options
Diffstat (limited to 'absl/hash')
| -rw-r--r-- | absl/hash/BUILD.bazel | 1 | ||||
| -rw-r--r-- | absl/hash/CMakeLists.txt | 1 | ||||
| -rw-r--r-- | absl/hash/internal/hash.h | 51 |
3 files changed, 42 insertions, 11 deletions
diff --git a/absl/hash/BUILD.bazel b/absl/hash/BUILD.bazel index 90c6c8a8..4b2c220f 100644 --- a/absl/hash/BUILD.bazel +++ b/absl/hash/BUILD.bazel @@ -38,6 +38,7 @@ cc_library( deps = [ ":city", ":wyhash", + "//absl/base:config", "//absl/base:core_headers", "//absl/base:endian", "//absl/container:fixed_array", diff --git a/absl/hash/CMakeLists.txt b/absl/hash/CMakeLists.txt index 6d198775..b43bfa54 100644 --- a/absl/hash/CMakeLists.txt +++ b/absl/hash/CMakeLists.txt @@ -26,6 +26,7 @@ absl_cc_library( ${ABSL_DEFAULT_COPTS} DEPS absl::city + absl::config absl::core_headers absl::endian absl::fixed_array diff --git a/absl/hash/internal/hash.h b/absl/hash/internal/hash.h index eb3471d8..7fb0af0b 100644 --- a/absl/hash/internal/hash.h +++ b/absl/hash/internal/hash.h @@ -38,7 +38,8 @@ #include <utility> #include <vector> -#include "absl/base/internal/endian.h" +#include "absl/base/config.h" +#include "absl/base/internal/unaligned_access.h" #include "absl/base/port.h" #include "absl/container/fixed_array.h" #include "absl/hash/internal/wyhash.h" @@ -804,26 +805,54 @@ class ABSL_DLL HashState : public HashStateBase<HashState> { size_t len); // Reads 9 to 16 bytes from p. - // The first 8 bytes are in .first, the rest (zero padded) bytes are in - // .second. + // The least significant 8 bytes are in .first, the rest (zero padded) bytes + // are in .second. static std::pair<uint64_t, uint64_t> Read9To16(const unsigned char* p, size_t len) { - uint64_t high = little_endian::Load64(p + len - 8); - return {little_endian::Load64(p), high >> (128 - len * 8)}; + uint64_t low_mem = absl::base_internal::UnalignedLoad64(p); + uint64_t high_mem = absl::base_internal::UnalignedLoad64(p + len - 8); +#ifdef ABSL_IS_LITTLE_ENDIAN + uint64_t most_significant = high_mem; + uint64_t least_significant = low_mem; +#else + uint64_t most_significant = low_mem; + uint64_t least_significant = high_mem; +#endif + return {least_significant, most_significant >> (128 - len * 8)}; } // Reads 4 to 8 bytes from p. Zero pads to fill uint64_t. static uint64_t Read4To8(const unsigned char* p, size_t len) { - return (static_cast<uint64_t>(little_endian::Load32(p + len - 4)) - << (len - 4) * 8) | - little_endian::Load32(p); + uint32_t low_mem = absl::base_internal::UnalignedLoad32(p); + uint32_t high_mem = absl::base_internal::UnalignedLoad32(p + len - 4); +#ifdef ABSL_IS_LITTLE_ENDIAN + uint32_t most_significant = high_mem; + uint32_t least_significant = low_mem; +#else + uint32_t most_significant = low_mem; + uint32_t least_significant = high_mem; +#endif + return (static_cast<uint64_t>(most_significant) << (len - 4) * 8) | + least_significant; } // Reads 1 to 3 bytes from p. Zero pads to fill uint32_t. static uint32_t Read1To3(const unsigned char* p, size_t len) { - return static_cast<uint32_t>((p[0]) | // - (p[len / 2] << (len / 2 * 8)) | // - (p[len - 1] << ((len - 1) * 8))); + unsigned char mem0 = p[0]; + unsigned char mem1 = p[len / 2]; + unsigned char mem2 = p[len - 1]; +#ifdef ABSL_IS_LITTLE_ENDIAN + unsigned char significant2 = mem2; + unsigned char significant1 = mem1; + unsigned char significant0 = mem0; +#else + unsigned char significant2 = mem0; + unsigned char significant1 = mem1; + unsigned char significant0 = mem2; +#endif + return static_cast<uint32_t>(significant0 | // + (significant1 << (len / 2 * 8)) | // + (significant2 << ((len - 1) * 8))); } ABSL_ATTRIBUTE_ALWAYS_INLINE static uint64_t Mix(uint64_t state, uint64_t v) { |