ref: 2b690d6d13128e83d42a709041ea01974c72954f
dir: libvpx/vpx_dsp/bitwriter_buffer.c
/* * Copyright (c) 2013 The WebM project authors. All Rights Reserved. * * Use of this source code is governed by a BSD-style license * that can be found in the LICENSE file in the root of the source * tree. An additional intellectual property rights grant can be found * in the file PATENTS. All contributing project authors may * be found in the AUTHORS file in the root of the source tree. */ #include <limits.h> #include <stdlib.h> #include "./vpx_config.h" #include "./bitwriter_buffer.h" size_t vpx_wb_bytes_written(const struct vpx_write_bit_buffer *wb) { return wb->bit_offset / CHAR_BIT + (wb->bit_offset % CHAR_BIT > 0); } void vpx_wb_write_bit(struct vpx_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) { 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 vpx_wb_write_literal(struct vpx_write_bit_buffer *wb, int data, int bits) { int bit; for (bit = bits - 1; bit >= 0; bit--) vpx_wb_write_bit(wb, (data >> bit) & 1); } void vpx_wb_write_inv_signed_literal(struct vpx_write_bit_buffer *wb, int data, int bits) { vpx_wb_write_literal(wb, abs(data), bits); vpx_wb_write_bit(wb, data < 0); }