1 /* 2 * Copyright (c) 2013 The WebM project authors. All Rights Reserved. 3 * 4 * Use of this source code is governed by a BSD-style license 5 * that can be found in the LICENSE file in the root of the source 6 * tree. An additional intellectual property rights grant can be found 7 * in the file PATENTS. All contributing project authors may 8 * be found in the AUTHORS file in the root of the source tree. 9 */ 10 11 #include <limits.h> 12 #include <stdlib.h> 13 14 #include "./vpx_config.h" 15 #include "./bitwriter_buffer.h" 16 17 size_t vpx_wb_bytes_written(const struct vpx_write_bit_buffer *wb) { 18 return wb->bit_offset / CHAR_BIT + (wb->bit_offset % CHAR_BIT > 0); 19 } 20 21 void vpx_wb_write_bit(struct vpx_write_bit_buffer *wb, int bit) { 22 const int off = (int)wb->bit_offset; 23 const int p = off / CHAR_BIT; 24 const int q = CHAR_BIT - 1 - off % CHAR_BIT; 25 if (q == CHAR_BIT - 1) { 26 wb->bit_buffer[p] = bit << q; 27 } else { 28 wb->bit_buffer[p] &= ~(1 << q); 29 wb->bit_buffer[p] |= bit << q; 30 } 31 wb->bit_offset = off + 1; 32 } 33 34 void vpx_wb_write_literal(struct vpx_write_bit_buffer *wb, int data, int bits) { 35 int bit; 36 for (bit = bits - 1; bit >= 0; bit--) vpx_wb_write_bit(wb, (data >> bit) & 1); 37 } 38 39 void vpx_wb_write_inv_signed_literal(struct vpx_write_bit_buffer *wb, int data, 40 int bits) { 41 vpx_wb_write_literal(wb, abs(data), bits); 42 vpx_wb_write_bit(wb, data < 0); 43 } 44
