/*

 *  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 "./vpx_config.h"

#include "./bitreader_buffer.h"

size_t vpx_rb_bytes_read(struct vpx_read_bit_buffer *rb) {

  return (rb->bit_offset + 7) >> 3;

}

int vpx_rb_read_bit(struct vpx_read_bit_buffer *rb) {

  const size_t off = rb->bit_offset;

  const size_t p = off >> 3;

  const int q = 7 - (int)(off & 0x7);

  if (rb->bit_buffer + p < rb->bit_buffer_end) {

    const int bit = (rb->bit_buffer[p] >> q) & 1;

    rb->bit_offset = off + 1;

    return bit;

  } else {

    if (rb->error_handler != NULL) rb->error_handler(rb->error_handler_data);

    return 0;

  }

}

int vpx_rb_read_literal(struct vpx_read_bit_buffer *rb, int bits) {

  int value = 0, bit;

  for (bit = bits - 1; bit >= 0; bit--) value |= vpx_rb_read_bit(rb) << bit;

  return value;

}

int vpx_rb_read_signed_literal(struct vpx_read_bit_buffer *rb, int bits) {

  const int value = vpx_rb_read_literal(rb, bits);

  return vpx_rb_read_bit(rb) ? -value : value;

}

int vpx_rb_read_inv_signed_literal(struct vpx_read_bit_buffer *rb, int bits) {

  return vpx_rb_read_signed_literal(rb, bits);

}