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-rw-r--r--third_party/aom/av1/encoder/hash.c125
1 files changed, 125 insertions, 0 deletions
diff --git a/third_party/aom/av1/encoder/hash.c b/third_party/aom/av1/encoder/hash.c
new file mode 100644
index 0000000000..180115d9f2
--- /dev/null
+++ b/third_party/aom/av1/encoder/hash.c
@@ -0,0 +1,125 @@
+/*
+ * Copyright (c) 2016, Alliance for Open Media. All rights reserved
+ *
+ * This source code is subject to the terms of the BSD 2 Clause License and
+ * the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
+ * was not distributed with this source code in the LICENSE file, you can
+ * obtain it at www.aomedia.org/license/software. If the Alliance for Open
+ * Media Patent License 1.0 was not distributed with this source code in the
+ * PATENTS file, you can obtain it at www.aomedia.org/license/patent.
+ */
+
+#include "av1/encoder/hash.h"
+
+static void crc_calculator_process_data(CRC_CALCULATOR *p_crc_calculator,
+ uint8_t *pData, uint32_t dataLength) {
+ for (uint32_t i = 0; i < dataLength; i++) {
+ const uint8_t index =
+ (p_crc_calculator->remainder >> (p_crc_calculator->bits - 8)) ^
+ pData[i];
+ p_crc_calculator->remainder <<= 8;
+ p_crc_calculator->remainder ^= p_crc_calculator->table[index];
+ }
+}
+
+static void crc_calculator_reset(CRC_CALCULATOR *p_crc_calculator) {
+ p_crc_calculator->remainder = 0;
+}
+
+static uint32_t crc_calculator_get_crc(CRC_CALCULATOR *p_crc_calculator) {
+ return p_crc_calculator->remainder & p_crc_calculator->final_result_mask;
+}
+
+static void crc_calculator_init_table(CRC_CALCULATOR *p_crc_calculator) {
+ const uint32_t high_bit = 1 << (p_crc_calculator->bits - 1);
+ const uint32_t byte_high_bit = 1 << (8 - 1);
+
+ for (uint32_t value = 0; value < 256; value++) {
+ uint32_t remainder = 0;
+ for (uint8_t mask = byte_high_bit; mask != 0; mask >>= 1) {
+ if (value & mask) {
+ remainder ^= high_bit;
+ }
+
+ if (remainder & high_bit) {
+ remainder <<= 1;
+ remainder ^= p_crc_calculator->trunc_poly;
+ } else {
+ remainder <<= 1;
+ }
+ }
+ p_crc_calculator->table[value] = remainder;
+ }
+}
+
+void av1_crc_calculator_init(CRC_CALCULATOR *p_crc_calculator, uint32_t bits,
+ uint32_t truncPoly) {
+ p_crc_calculator->remainder = 0;
+ p_crc_calculator->bits = bits;
+ p_crc_calculator->trunc_poly = truncPoly;
+ p_crc_calculator->final_result_mask = (1 << bits) - 1;
+ crc_calculator_init_table(p_crc_calculator);
+}
+
+uint32_t av1_get_crc_value(void *crc_calculator, uint8_t *p, int length) {
+ CRC_CALCULATOR *p_crc_calculator = (CRC_CALCULATOR *)crc_calculator;
+ crc_calculator_reset(p_crc_calculator);
+ crc_calculator_process_data(p_crc_calculator, p, length);
+ return crc_calculator_get_crc(p_crc_calculator);
+}
+
+/* CRC-32C (iSCSI) polynomial in reversed bit order. */
+#define POLY 0x82f63b78
+
+/* Construct table for software CRC-32C calculation. */
+void av1_crc32c_calculator_init(CRC32C *p_crc32c) {
+ uint32_t crc;
+
+ for (int n = 0; n < 256; n++) {
+ crc = n;
+ crc = crc & 1 ? (crc >> 1) ^ POLY : crc >> 1;
+ crc = crc & 1 ? (crc >> 1) ^ POLY : crc >> 1;
+ crc = crc & 1 ? (crc >> 1) ^ POLY : crc >> 1;
+ crc = crc & 1 ? (crc >> 1) ^ POLY : crc >> 1;
+ crc = crc & 1 ? (crc >> 1) ^ POLY : crc >> 1;
+ crc = crc & 1 ? (crc >> 1) ^ POLY : crc >> 1;
+ crc = crc & 1 ? (crc >> 1) ^ POLY : crc >> 1;
+ crc = crc & 1 ? (crc >> 1) ^ POLY : crc >> 1;
+ p_crc32c->table[0][n] = crc;
+ }
+ for (int n = 0; n < 256; n++) {
+ crc = p_crc32c->table[0][n];
+ for (int k = 1; k < 8; k++) {
+ crc = p_crc32c->table[0][crc & 0xff] ^ (crc >> 8);
+ p_crc32c->table[k][n] = crc;
+ }
+ }
+}
+
+/* Table-driven software version as a fall-back. This is about 15 times slower
+ than using the hardware instructions. This assumes little-endian integers,
+ as is the case on Intel processors that the assembler code here is for. */
+uint32_t av1_get_crc32c_value_c(CRC32C *p, uint8_t *buf, size_t len) {
+ const uint8_t *next = (const uint8_t *)(buf);
+ uint64_t crc;
+
+ crc = 0 ^ 0xffffffff;
+ while (len && ((uintptr_t)next & 7) != 0) {
+ crc = p->table[0][(crc ^ *next++) & 0xff] ^ (crc >> 8);
+ len--;
+ }
+ while (len >= 8) {
+ crc ^= *(uint64_t *)next;
+ crc = p->table[7][crc & 0xff] ^ p->table[6][(crc >> 8) & 0xff] ^
+ p->table[5][(crc >> 16) & 0xff] ^ p->table[4][(crc >> 24) & 0xff] ^
+ p->table[3][(crc >> 32) & 0xff] ^ p->table[2][(crc >> 40) & 0xff] ^
+ p->table[1][(crc >> 48) & 0xff] ^ p->table[0][crc >> 56];
+ next += 8;
+ len -= 8;
+ }
+ while (len) {
+ crc = p->table[0][(crc ^ *next++) & 0xff] ^ (crc >> 8);
+ len--;
+ }
+ return (uint32_t)crc ^ 0xffffffff;
+}