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- /*
- * 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 <assert.h>
- #include <limits.h>
- #include <stdlib.h>
- #include "config/aom_config.h"
- #include "aom_dsp/bitwriter_buffer.h"
- #include "aom_dsp/recenter.h"
- #include "aom_ports/bitops.h"
- int aom_wb_is_byte_aligned(const struct aom_write_bit_buffer *wb) {
- return (wb->bit_offset % CHAR_BIT == 0);
- }
- uint32_t aom_wb_bytes_written(const struct aom_write_bit_buffer *wb) {
- return wb->bit_offset / CHAR_BIT + (wb->bit_offset % CHAR_BIT > 0);
- }
- void aom_wb_write_bit(struct aom_write_bit_buffer *wb, int bit) {
- const int off = (int)wb->bit_offset;
- const int p = off / CHAR_BIT;
- const int q = CHAR_BIT - 1 - off % CHAR_BIT;
- if (q == CHAR_BIT - 1) {
- // Zero next char and write bit
- wb->bit_buffer[p] = bit << q;
- } else {
- wb->bit_buffer[p] &= ~(1 << q);
- wb->bit_buffer[p] |= bit << q;
- }
- wb->bit_offset = off + 1;
- }
- void aom_wb_overwrite_bit(struct aom_write_bit_buffer *wb, int bit) {
- // Do not zero bytes but overwrite exisiting values
- const int off = (int)wb->bit_offset;
- const int p = off / CHAR_BIT;
- const int q = CHAR_BIT - 1 - off % CHAR_BIT;
- wb->bit_buffer[p] &= ~(1 << q);
- wb->bit_buffer[p] |= bit << q;
- wb->bit_offset = off + 1;
- }
- void aom_wb_write_literal(struct aom_write_bit_buffer *wb, int data, int bits) {
- assert(bits <= 31);
- int bit;
- for (bit = bits - 1; bit >= 0; bit--) aom_wb_write_bit(wb, (data >> bit) & 1);
- }
- void aom_wb_write_unsigned_literal(struct aom_write_bit_buffer *wb,
- uint32_t data, int bits) {
- assert(bits <= 32);
- int bit;
- for (bit = bits - 1; bit >= 0; bit--) aom_wb_write_bit(wb, (data >> bit) & 1);
- }
- void aom_wb_overwrite_literal(struct aom_write_bit_buffer *wb, int data,
- int bits) {
- int bit;
- for (bit = bits - 1; bit >= 0; bit--)
- aom_wb_overwrite_bit(wb, (data >> bit) & 1);
- }
- void aom_wb_write_inv_signed_literal(struct aom_write_bit_buffer *wb, int data,
- int bits) {
- aom_wb_write_literal(wb, data, bits + 1);
- }
- void aom_wb_write_uvlc(struct aom_write_bit_buffer *wb, uint32_t v) {
- int64_t shift_val = ++v;
- int leading_zeroes = 1;
- assert(shift_val > 0);
- while (shift_val >>= 1) leading_zeroes += 2;
- aom_wb_write_literal(wb, 0, leading_zeroes >> 1);
- aom_wb_write_unsigned_literal(wb, v, (leading_zeroes + 1) >> 1);
- }
- static void wb_write_primitive_quniform(struct aom_write_bit_buffer *wb,
- uint16_t n, uint16_t v) {
- if (n <= 1) return;
- const int l = get_msb(n) + 1;
- const int m = (1 << l) - n;
- if (v < m) {
- aom_wb_write_literal(wb, v, l - 1);
- } else {
- aom_wb_write_literal(wb, m + ((v - m) >> 1), l - 1);
- aom_wb_write_bit(wb, (v - m) & 1);
- }
- }
- static void wb_write_primitive_subexpfin(struct aom_write_bit_buffer *wb,
- uint16_t n, uint16_t k, uint16_t v) {
- int i = 0;
- int mk = 0;
- while (1) {
- int b = (i ? k + i - 1 : k);
- int a = (1 << b);
- if (n <= mk + 3 * a) {
- wb_write_primitive_quniform(wb, n - mk, v - mk);
- break;
- } else {
- int t = (v >= mk + a);
- aom_wb_write_bit(wb, t);
- if (t) {
- i = i + 1;
- mk += a;
- } else {
- aom_wb_write_literal(wb, v - mk, b);
- break;
- }
- }
- }
- }
- static void wb_write_primitive_refsubexpfin(struct aom_write_bit_buffer *wb,
- uint16_t n, uint16_t k,
- uint16_t ref, uint16_t v) {
- wb_write_primitive_subexpfin(wb, n, k, recenter_finite_nonneg(n, ref, v));
- }
- void aom_wb_write_signed_primitive_refsubexpfin(struct aom_write_bit_buffer *wb,
- uint16_t n, uint16_t k,
- int16_t ref, int16_t v) {
- ref += n - 1;
- v += n - 1;
- const uint16_t scaled_n = (n << 1) - 1;
- wb_write_primitive_refsubexpfin(wb, scaled_n, k, ref, v);
- }
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