| /* |
| * 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); |
| } |