/*

 *  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 <assert.h>

#include <limits.h>

#include <stdlib.h>

#include "./vpx_config.h"

#include "./bitwriter_buffer.h"

void vpx_wb_init(struct vpx_write_bit_buffer *wb, uint8_t *bit_buffer,

                 size_t size) {

  wb->error = 0;

  wb->bit_offset = 0;

  wb->size = size;

  wb->bit_buffer = bit_buffer;

}

int vpx_wb_has_error(const struct vpx_write_bit_buffer *wb) {

  return wb->error;

}

size_t vpx_wb_bytes_written(const struct vpx_write_bit_buffer *wb) {

  assert(!wb->error);

  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) {

  if (wb->error) return;

  const int off = (int)wb->bit_offset;

  const int p = off / CHAR_BIT;

  const int q = CHAR_BIT - 1 - off % CHAR_BIT;

  if ((size_t)p >= wb->size) {

    wb->error = 1;

    return;

  }

  if (q == CHAR_BIT - 1) {

    wb->bit_buffer[p] = bit << q;

  } else {

    assert((wb->bit_buffer[p] & (1 << q)) == 0);

    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);

}