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@@ -0,0 +1,319 @@
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+/*
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+ An implementation of Yann Collet's [xxhash Fast Hash Algorithm](https://cyan4973.github.io/xxHash/).
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+ Copyright 2021 Jeroen van Rijn <[email protected]>.
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+
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+ Made available under Odin's BSD-3 license, based on the original C code.
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+
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+ List of contributors:
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+ Jeroen van Rijn: Initial implementation.
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+*/
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+package xxhash
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+
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+import "core:intrinsics"
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+
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+/*
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+ 32-bit hash functions
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+*/
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+XXH32_hash :: u32
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+XXH32_DEFAULT_SEED :: XXH32_hash(0)
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+
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+XXH32_state :: struct {
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+ total_len_32: XXH32_hash, /*!< Total length hashed, modulo 2^32 */
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+ large_len: XXH32_hash, /*!< Whether the hash is >= 16 (handles @ref total_len_32 overflow) */
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+ v1: XXH32_hash, /*!< First accumulator lane */
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+ v2: XXH32_hash, /*!< Second accumulator lane */
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+ v3: XXH32_hash, /*!< Third accumulator lane */
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+ v4: XXH32_hash, /*!< Fourth accumulator lane */
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+ mem32: [4]XXH32_hash, /*!< Internal buffer for partial reads. Treated as unsigned char[16]. */
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+ memsize: XXH32_hash, /*!< Amount of data in @ref mem32 */
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+ reserved: XXH32_hash, /*!< Reserved field. Do not read or write to it, it may be removed. */
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+}
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+
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+XXH32_canonical :: struct {
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+ digest: [4]u8,
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+}
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+
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+XXH_PRIME32_1 :: 0x9E3779B1 /*!< 0b10011110001101110111100110110001 */
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+XXH_PRIME32_2 :: 0x85EBCA77 /*!< 0b10000101111010111100101001110111 */
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+XXH_PRIME32_3 :: 0xC2B2AE3D /*!< 0b11000010101100101010111000111101 */
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+XXH_PRIME32_4 :: 0x27D4EB2F /*!< 0b00100111110101001110101100101111 */
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+XXH_PRIME32_5 :: 0x165667B1 /*!< 0b00010110010101100110011110110001 */
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+
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+@(optimization_mode="speed")
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+XXH32_round :: #force_inline proc(seed, input: XXH32_hash) -> (res: XXH32_hash) {
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+ seed := seed
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+
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+ seed += input * XXH_PRIME32_2
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+ seed = XXH_rotl32(seed, 13)
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+ seed *= XXH_PRIME32_1
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+ return seed
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+}
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+
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+/*
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+ Mix all bits
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+*/
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+@(optimization_mode="speed")
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+XXH32_avalanche :: #force_inline proc(h32: u32) -> (res: u32) {
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+ h32 := h32
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+
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+ h32 ~= h32 >> 15
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+ h32 *= XXH_PRIME32_2
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+ h32 ~= h32 >> 13
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+ h32 *= XXH_PRIME32_3
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+ h32 ~= h32 >> 16
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+ return h32
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+}
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+
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+@(optimization_mode="speed")
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+XXH32_finalize :: #force_inline proc(h32: u32, buf: []u8, alignment: Alignment) -> (res: u32) {
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+ process_1 :: #force_inline proc(h32: u32, buf: []u8) -> (h32_res: u32, buf_res: []u8) {
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+ #no_bounds_check b := u32(buf[0])
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+ h32_res = h32 + b * XXH_PRIME32_5
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+ h32_res = XXH_rotl32(h32_res, 11) * XXH_PRIME32_1
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+ #no_bounds_check return h32_res, buf[1:]
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+ }
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+
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+ process_4 :: #force_inline proc(h32: u32, buf: []u8, alignment: Alignment) -> (h32_res: u32, buf_res: []u8) {
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+ b := XXH32_read32(buf, alignment)
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+ h32_res = h32 + b * XXH_PRIME32_3
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+ h32_res = XXH_rotl32(h32_res, 17) * XXH_PRIME32_4
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+ #no_bounds_check return h32_res, buf[4:]
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+ }
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+
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+ buf := buf
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+ h32 := h32
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+
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+ switch len(buf) & 15 {
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+ case 12:
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+ h32, buf = process_4(h32, buf, alignment)
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+ fallthrough
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+ case 8:
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+ h32, buf = process_4(h32, buf, alignment)
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+ fallthrough
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+ case 4:
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+ h32, _ = process_4(h32, buf, alignment)
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+ return XXH32_avalanche(h32)
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+
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+ case 13:
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+ h32, buf = process_4(h32, buf, alignment)
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+ fallthrough
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+ case 9:
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+ h32, buf = process_4(h32, buf, alignment)
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+ fallthrough
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+ case 5:
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+ h32, buf = process_4(h32, buf, alignment)
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+ h32, buf = process_1(h32, buf)
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+ return XXH32_avalanche(h32)
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+
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+ case 14:
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+ h32, buf = process_4(h32, buf, alignment)
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+ fallthrough
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+ case 10:
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+ h32, buf = process_4(h32, buf, alignment)
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+ fallthrough
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+ case 6:
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+ h32, buf = process_4(h32, buf, alignment)
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+ h32, buf = process_1(h32, buf)
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+ h32, buf = process_1(h32, buf)
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+ return XXH32_avalanche(h32)
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+
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+ case 15:
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+ h32, buf = process_4(h32, buf, alignment)
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+ fallthrough
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+ case 11:
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+ h32, buf = process_4(h32, buf, alignment)
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+ fallthrough
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+ case 7:
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+ h32, buf = process_4(h32, buf, alignment)
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+ fallthrough
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+
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+ case 3:
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+ h32, buf = process_1(h32, buf)
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+ fallthrough
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+ case 2:
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+ h32, buf = process_1(h32, buf)
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+ fallthrough
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+ case 1:
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+ h32, buf = process_1(h32, buf)
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+ fallthrough
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+ case 0:
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+ return XXH32_avalanche(h32)
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+ }
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+ unreachable()
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+}
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+
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+@(optimization_mode="speed")
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+XXH32_endian_align :: #force_inline proc(input: []u8, seed := XXH32_DEFAULT_SEED, alignment: Alignment) -> (res: XXH32_hash) {
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+ buf := input
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+ length := len(input)
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+
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+ if length >= 16 {
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+ v1 := seed + XXH_PRIME32_1 + XXH_PRIME32_2
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+ v2 := seed + XXH_PRIME32_2
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+ v3 := seed + 0
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+ v4 := seed - XXH_PRIME32_1
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+
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+ for len(buf) >= 15 {
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+ #no_bounds_check v1 = XXH32_round(v1, XXH32_read32(buf, alignment)); buf = buf[4:]
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+ #no_bounds_check v2 = XXH32_round(v2, XXH32_read32(buf, alignment)); buf = buf[4:]
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+ #no_bounds_check v3 = XXH32_round(v3, XXH32_read32(buf, alignment)); buf = buf[4:]
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+ #no_bounds_check v4 = XXH32_round(v4, XXH32_read32(buf, alignment)); buf = buf[4:]
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+ }
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+
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+ res = XXH_rotl32(v1, 1) + XXH_rotl32(v2, 7) + XXH_rotl32(v3, 12) + XXH_rotl32(v4, 18)
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+ } else {
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+ res = seed + XXH_PRIME32_5
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+ }
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+
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+ res += u32(length)
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+ return XXH32_finalize(res, buf, alignment)
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+}
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+
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+XXH32 :: proc(input: []u8, seed := XXH32_DEFAULT_SEED) -> (digest: XXH32_hash) {
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+ when false {
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+ /*
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+ Simple version, good for code maintenance, but unfortunately slow for small inputs.
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+ */
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+ state: XXH32_state
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+ XXH32_reset_state(&state, seed)
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+ XXH32_update(&state, input)
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+ return XXH32_digest(&state)
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+ } else {
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+ when XXH_FORCE_ALIGN_CHECK {
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+ if uintptr(raw_data(input)) & uintptr(3) == 0 {
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+ /*
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+ Input is 4-bytes aligned, leverage the speed benefit.
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+ */
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+ return XXH32_endian_align(input, seed, .Aligned)
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+ }
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+ }
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+ return XXH32_endian_align(input, seed, .Unaligned)
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+ }
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+}
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+
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+/*
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+ ****** Hash streaming ******
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+*/
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+XXH32_create_state :: proc(allocator := context.allocator) -> (res: ^XXH32_state, err: Error) {
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+ state := new(XXH32_state, allocator)
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+ return state, nil if state != nil else .Error
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+}
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+
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+XXH32_destroy_state :: proc(state: ^XXH32_state, allocator := context.allocator) -> (err: Error) {
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+ free(state, allocator)
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+ return nil
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+}
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+
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+XXH32_copy_state :: proc(dest, src: ^XXH32_state) {
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+ assert(dest != nil && src != nil)
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+ mem_copy(dest, src, size_of(XXH32_state))
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+}
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+
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+XXH32_reset_state :: proc(state_ptr: ^XXH32_state, seed := XXH32_DEFAULT_SEED) -> (err: Error) {
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+ state := XXH32_state{}
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+
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+ state.v1 = seed + XXH_PRIME32_1 + XXH_PRIME32_2
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+ state.v2 = seed + XXH_PRIME32_2
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+ state.v3 = seed + 0
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+ state.v4 = seed - XXH_PRIME32_1
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+ /*
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+ Do not write into reserved, planned to be removed in a future version.
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+ */
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+ mem_copy(state_ptr, &state, size_of(state) - size_of(state.reserved))
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+ return nil
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+}
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+
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+XXH32_update :: proc(state: ^XXH32_state, input: []u8) -> (err: Error) {
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+
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+ buf := input
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+ length := len(buf)
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+
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+ state.total_len_32 += XXH32_hash(length)
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+ state.large_len |= 1 if length >= 16 || state.total_len_32 >= 16 else 0
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+
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+ if state.memsize + u32(length) < 16 { /* Fill in tmp buffer */
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+ ptr := uintptr(raw_data(state.mem32[:])) + uintptr(state.memsize)
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+ mem_copy(rawptr(ptr), raw_data(input), int(length))
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+ state.memsize += XXH32_hash(length)
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+ return nil
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+ }
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+
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+ if state.memsize > 0 {/* Some data left from previous update */
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+ ptr := uintptr(raw_data(state.mem32[:])) + uintptr(state.memsize)
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+ mem_copy(rawptr(ptr), raw_data(input), int(16 - state.memsize))
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+ {
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+ #no_bounds_check state.v1 = XXH32_round(state.v1, state.mem32[0])
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+ #no_bounds_check state.v2 = XXH32_round(state.v2, state.mem32[1])
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+ #no_bounds_check state.v3 = XXH32_round(state.v3, state.mem32[2])
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+ #no_bounds_check state.v4 = XXH32_round(state.v4, state.mem32[3])
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+ }
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+ buf = buf[16 - state.memsize:]
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+ state.memsize = 0
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+ }
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+
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+ if len(buf) >= 16 {
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+ v1 := state.v1
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+ v2 := state.v2
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+ v3 := state.v3
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+ v4 := state.v4
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+
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+ for len(buf) >= 15 {
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+ #no_bounds_check v1 = XXH32_round(v1, XXH32_read32(buf, .Unaligned)); buf = buf[4:]
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+ #no_bounds_check v2 = XXH32_round(v2, XXH32_read32(buf, .Unaligned)); buf = buf[4:]
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+ #no_bounds_check v3 = XXH32_round(v3, XXH32_read32(buf, .Unaligned)); buf = buf[4:]
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+ #no_bounds_check v4 = XXH32_round(v4, XXH32_read32(buf, .Unaligned)); buf = buf[4:]
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+ }
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+
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+ state.v1 = v1
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+ state.v2 = v2
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+ state.v3 = v3
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+ state.v4 = v4
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+ }
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+
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+ length = len(buf)
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+ if length > 0 {
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+ mem_copy(raw_data(state.mem32[:]), raw_data(buf[:]), int(length))
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+ state.memsize = u32(length)
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+ }
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+ return nil
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+}
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+
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+XXH32_digest :: proc(state: ^XXH32_state) -> (res: XXH32_hash) {
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+ if state.large_len > 0 {
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+ res = XXH_rotl32(state.v1, 1) + XXH_rotl32(state.v2, 7) + XXH_rotl32(state.v3, 12) + XXH_rotl32(state.v4, 18)
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+ } else {
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+ res = state.v3 /* == seed */ + XXH_PRIME32_5
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+ }
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+
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+ res += state.total_len_32
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+
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+ buf := (^[16]u8)(&state.mem32)^
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+ alignment: Alignment = .Aligned if uintptr(&state.mem32) & 15 == 0 else .Unaligned
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+ return XXH32_finalize(res, buf[:state.memsize], alignment)
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+}
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+
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+/*
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+ ****** Canonical representation ******
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+
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+ The default return values from XXH functions are unsigned 32 and 64 bit integers.
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+
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+ The canonical representation uses big endian convention,
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+ the same convention as human-readable numbers (large digits first).
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+
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+ This way, hash values can be written into a file or buffer, remaining
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+ comparable across different systems.
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+
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+ The following functions allow transformation of hash values to and from their
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+ canonical format.
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+*/
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+XXH32_canonical_from_hash :: proc(hash: XXH32_hash) -> (canonical: XXH32_canonical) {
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+ #assert(size_of(XXH32_canonical) == size_of(XXH32_hash))
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+ h := u32be(hash)
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+ mem_copy(&canonical, &h, size_of(canonical))
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+ return
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+}
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+
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+XXH32_hash_from_canonical :: proc(canonical: ^XXH32_canonical) -> (hash: XXH32_hash) {
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+ h := (^u32be)(&canonical.digest)^
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+ return XXH32_hash(h)
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+}
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