diff options
author | Samuel Neves <sneves@dei.uc.pt> | 2020-01-23 10:19:14 +0000 |
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committer | Samuel Neves <sneves@dei.uc.pt> | 2020-01-23 10:58:45 +0000 |
commit | 37ea737c16b5e0ad2909906e9e48856fd2e24f34 (patch) | |
tree | 80d0c8f5829440eff224329716fdf2c2b0765ba0 /c | |
parent | e17c45ddd54bb80fe8a3a2ea384ba87e7ce1dff1 (diff) |
more robust bit-trickery functions
Diffstat (limited to 'c')
-rw-r--r-- | c/blake3.c | 4 | ||||
-rw-r--r-- | c/blake3.h | 5 | ||||
-rw-r--r-- | c/blake3_impl.h | 106 | ||||
-rw-r--r-- | c/main.c | 13 |
4 files changed, 81 insertions, 47 deletions
@@ -484,7 +484,7 @@ void blake3_hasher_update(blake3_hasher *self, const void *input, // Because we might need to break up the input to form powers of 2, or to // evenly divide what we already have, this part runs in a loop. while (input_len > BLAKE3_CHUNK_LEN) { - size_t subtree_len = (size_t)round_down_to_power_of_2((uint64_t)input_len); + size_t subtree_len = round_down_to_power_of_2(input_len); uint64_t count_so_far = self->chunk.chunk_counter * BLAKE3_CHUNK_LEN; // Shrink the subtree_len until *half of it* it evenly divides the count so // far. Why half? Because compress_subtree_to_parent_node will return a @@ -522,7 +522,7 @@ void blake3_hasher_update(blake3_hasher *self, const void *input, self->chunk.chunk_counter + (subtree_chunks / 2)); } self->chunk.chunk_counter += subtree_chunks; - input_bytes = input_bytes + subtree_len; + input_bytes += subtree_len; input_len -= subtree_len; } @@ -1,4 +1,5 @@ -#pragma once +#ifndef BLAKE3_H +#define BLAKE3_H #include <stddef.h> #include <stdint.h> @@ -39,3 +40,5 @@ void blake3_hasher_update(blake3_hasher *self, const void *input, size_t input_len); void blake3_hasher_finalize(const blake3_hasher *self, uint8_t *out, size_t out_len); + +#endif /* BLAKE3_H */ diff --git a/c/blake3_impl.h b/c/blake3_impl.h index 20ef83d..84caae9 100644 --- a/c/blake3_impl.h +++ b/c/blake3_impl.h @@ -1,4 +1,5 @@ -#pragma once +#ifndef BLAKE3_IMPL_H +#define BLAKE3_IMPL_H #include <assert.h> #include <stdbool.h> @@ -6,32 +7,35 @@ #include <stdint.h> #include <string.h> -#if __POPCNT__ -#include <nmmintrin.h> -#endif - #include "blake3.h" // internal flags -#define CHUNK_START 1 -#define CHUNK_END 2 -#define PARENT 4 -#define ROOT 8 -#define KEYED_HASH 16 -#define DERIVE_KEY_CONTEXT 32 -#define DERIVE_KEY_MATERIAL 64 +enum blake3_flags { + CHUNK_START = 1 << 0, + CHUNK_END = 1 << 1, + PARENT = 1 << 2, + ROOT = 1 << 3, + KEYED_HASH = 1 << 4, + DERIVE_KEY_CONTEXT = 1 << 5, + DERIVE_KEY_MATERIAL = 1 << 6, +}; // This C implementation tries to support recent versions of GCC, Clang, and // MSVC. #if defined(_MSC_VER) -#define INLINE __forceinline static +#define INLINE static __forceinline #else -#define INLINE __attribute__((always_inline)) static inline +#define INLINE static inline __attribute__((always_inline)) +#endif + +#if defined(__x86_64__) || defined(_M_X64) +#define IS_X86 +#define IS_X86_64 #endif -#if defined(__x86_64__) || defined(__i386__) || defined(_M_IX86) || \ - defined(_M_X64) +#if defined(__i386__) || defined(_M_IX86) #define IS_X86 +#define IS_X86_32 #endif #if defined(__arm__) @@ -39,6 +43,13 @@ #endif #if defined(IS_X86) +#if defined(_MSC_VER) +#include <intrin.h> +#endif +#include <immintrin.h> +#endif + +#if defined(IS_X86) #define MAX_SIMD_DEGREE 16 #elif defined(BLAKE3_USE_NEON) #define MAX_SIMD_DEGREE 4 @@ -48,13 +59,7 @@ // There are some places where we want a static size that's equal to the // MAX_SIMD_DEGREE, but also at least 2. -#if defined(IS_X86) -#define MAX_SIMD_DEGREE_OR_2 16 -#elif defined(BLAKE3_USE_NEON) -#define MAX_SIMD_DEGREE_OR_2 4 -#else -#define MAX_SIMD_DEGREE_OR_2 2 -#endif +#define MAX_SIMD_DEGREE_OR_2 (MAX_SIMD_DEGREE > 2 ? MAX_SIMD_DEGREE : 2) static const uint32_t IV[8] = {0x6A09E667UL, 0xBB67AE85UL, 0x3C6EF372UL, 0xA54FF53AUL, 0x510E527FUL, 0x9B05688CUL, @@ -70,13 +75,44 @@ static const uint8_t MSG_SCHEDULE[7][16] = { {11, 15, 5, 0, 1, 9, 8, 6, 14, 10, 2, 12, 3, 4, 7, 13}, }; +/* Find index of the highest set bit */ +/* x is assumed to be nonzero. */ +static unsigned int fls(uint64_t x) { +#if defined(__GNUC__) || defined(__clang__) + return 63 ^ __builtin_clzll(x); +#elif defined(_MSC_VER) && defined(IS_X86_64) + unsigned long index; + _BitScanReverse64(&index, x); + return index; +#elif defined(_MSC_VER) && defined(IS_X86_32) + if(x >> 32) { + unsigned long index; + _BitScanReverse(&index, x >> 32); + return 32 + index; + } else { + unsigned long index; + _BitScanReverse(&index, x); + return index; + } +#else + unsigned int c = 0; + if(x & 0xffffffff00000000ULL) { x >>= 32; c += 32; } + if(x & 0x00000000ffff0000ULL) { x >>= 16; c += 16; } + if(x & 0x000000000000ff00ULL) { x >>= 8; c += 8; } + if(x & 0x00000000000000f0ULL) { x >>= 4; c += 4; } + if(x & 0x000000000000000cULL) { x >>= 2; c += 2; } + if(x & 0x0000000000000002ULL) { c += 1; } + return c; +#endif +} + // Count the number of 1 bits. -INLINE uint8_t popcnt(uint64_t x) { -#if __POPCNT__ - return (uint8_t)_mm_popcnt_u64(x); +INLINE unsigned int popcnt(uint64_t x) { +#if defined(__GNUC__) || defined(__clang__) + return __builtin_popcountll(x); #else - uint8_t count = 0; - while (x > 0) { + unsigned int count = 0; + while (x != 0) { count += 1; x &= x - 1; } @@ -85,16 +121,9 @@ INLINE uint8_t popcnt(uint64_t x) { } // Largest power of two less than or equal to x. As a special case, returns 1 -// when x is 0. Based on -// https://graphics.stanford.edu/~seander/bithacks.html#RoundUpPowerOf2. +// when x is 0. INLINE uint64_t round_down_to_power_of_2(uint64_t x) { - x |= x >> 1; - x |= x >> 2; - x |= x >> 4; - x |= x >> 8; - x |= x >> 16; - x |= x >> 32; - return (x >> 1) + 1; + return 1ULL << fls(x | 1); } INLINE uint32_t counter_low(uint64_t counter) { return (uint32_t)counter; } @@ -137,3 +166,6 @@ void blake3_hash_many(const uint8_t *const *inputs, size_t num_inputs, uint8_t flags_start, uint8_t flags_end, uint8_t *out); size_t blake3_simd_degree(); + + +#endif /* BLAKE3_IMPL_H */ @@ -78,14 +78,11 @@ int main(int argc, char **argv) { if (strcmp("--length", argv[1]) == 0) { char *endptr = NULL; unsigned long long out_len_ll = strtoull(argv[2], &endptr, 10); - // TODO: There are so many possible error conditions for parsing a - // non-negative size_t...I probably missed something. if (errno != 0 || out_len > SIZE_MAX || endptr == argv[2] || *endptr != 0) { fprintf(stderr, "Bad length argument.\n"); return 1; } - // TODO: A more sanitary cast? out_len = (size_t)out_len_ll; } else if (strcmp("--keyed", argv[1]) == 0) { mode = KEYED_HASH_MODE; @@ -104,9 +101,11 @@ int main(int argc, char **argv) { argv += 2; } - // We're going to hash the input multiple times, so we need to buffer it all. - // This is just for test cases, so go ahead and assume that the input is less - // than 1 MiB. + /* + * We're going to hash the input multiple times, so we need to buffer it all. + * This is just for test cases, so go ahead and assume that the input is less + * than 1 MiB. + */ size_t buf_capacity = 1 << 20; uint8_t *buf = malloc(buf_capacity); assert(buf != NULL); @@ -142,7 +141,7 @@ int main(int argc, char **argv) { blake3_hasher_update(&hasher, buf, buf_len); - // TODO: An incremental output reader API to avoid this allocation. + /* TODO: An incremental output reader API to avoid this allocation. */ uint8_t *out = malloc(out_len); memset(out, 0, out_len); if (out_len > 0 && out == NULL) { |