/*
 * qrencode - QR Code encoder
 *
 * Binary sequence class.
 * Copyright (C) 2006-2011 Kentaro Fukuchi <kentaro@fukuchi.org>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 */

#if HAVE_CONFIG_H
# include "config.h"
#endif
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "bitstream.h"

BitStream *BitStream_new(void)
{
  BitStream *bstream;

  bstream = (BitStream *)malloc(sizeof(BitStream));
  if(bstream == NULL) return NULL;

  bstream->length = 0;
  bstream->data = NULL;

  return bstream;
}

static int BitStream_allocate(BitStream *bstream, int length)
{
  unsigned char *data;

  if(bstream == NULL) {
    return -1;
  }

  data = (unsigned char *)malloc(length);
  if(data == NULL) {
    return -1;
  }

  if(bstream->data) {
    free(bstream->data);
  }
  bstream->length = length;
  bstream->data = data;

  return 0;
}

static BitStream *BitStream_newFromNum(int bits, unsigned int num)
{
  unsigned int mask;
  int i;
  unsigned char *p;
  BitStream *bstream;

  bstream = BitStream_new();
  if(bstream == NULL) return NULL;

  if(BitStream_allocate(bstream, bits)) {
    BitStream_free(bstream);
    return NULL;
  }

  p = bstream->data;
  mask = 1 << (bits - 1);
  for(i=0; i<bits; i++) {
    if(num & mask) {
      *p = 1;
    } else {
      *p = 0;
    }
    p++;
    mask = mask >> 1;
  }

  return bstream;
}

static BitStream *BitStream_newFromBytes(int size, unsigned char *data)
{
  unsigned char mask;
  int i, j;
  unsigned char *p;
  BitStream *bstream;

  bstream = BitStream_new();
  if(bstream == NULL) return NULL;

  if(BitStream_allocate(bstream, size * 8)) {
    BitStream_free(bstream);
    return NULL;
  }

  p = bstream->data;
  for(i=0; i<size; i++) {
    mask = 0x80;
    for(j=0; j<8; j++) {
      if(data[i] & mask) {
        *p = 1;
      } else {
        *p = 0;
      }
      p++;
      mask = mask >> 1;
    }
  }

  return bstream;
}

int BitStream_append(BitStream *bstream, BitStream *arg)
{
  unsigned char *data;

  if(arg == NULL) {
    return -1;
  }
  if(arg->length == 0) {
    return 0;
  }
  if(bstream->length == 0) {
    if(BitStream_allocate(bstream, arg->length)) {
      return -1;
    }
    memcpy(bstream->data, arg->data, arg->length);
    return 0;
  }

  data = (unsigned char *)malloc(bstream->length + arg->length);
  if(data == NULL) {
    return -1;
  }
  memcpy(data, bstream->data, bstream->length);
  memcpy(data + bstream->length, arg->data, arg->length);

  free(bstream->data);
  bstream->length += arg->length;
  bstream->data = data;

  return 0;
}

int BitStream_appendNum(BitStream *bstream, int bits, unsigned int num)
{
  BitStream *b;
  int ret;

  if(bits == 0) return 0;

  b = BitStream_newFromNum(bits, num);
  if(b == NULL) return -1;

  ret = BitStream_append(bstream, b);
  BitStream_free(b);

  return ret;
}

int BitStream_appendBytes(BitStream *bstream, int size, unsigned char *data)
{
  BitStream *b;
  int ret;

  if(size == 0) return 0;

  b = BitStream_newFromBytes(size, data);
  if(b == NULL) return -1;

  ret = BitStream_append(bstream, b);
  BitStream_free(b);

  return ret;
}

unsigned char *BitStream_toByte(BitStream *bstream)
{
  int i, j, size, bytes;
  unsigned char *data, v;
  unsigned char *p;

  size = BitStream_size(bstream);
  if(size == 0) {
    return NULL;
  }
  data = (unsigned char *)malloc((size + 7) / 8);
  if(data == NULL) {
    return NULL;
  }

  bytes = size  / 8;

  p = bstream->data;
  for(i=0; i<bytes; i++) {
    v = 0;
    for(j=0; j<8; j++) {
      v = v << 1;
      v |= *p;
      p++;
    }
    data[i] = v;
  }
  if(size & 7) {
    v = 0;
    for(j=0; j<(size & 7); j++) {
      v = v << 1;
      v |= *p;
      p++;
    }
    data[bytes] = v;
  }

  return data;
}

void BitStream_free(BitStream *bstream)
{
  if(bstream != NULL) {
    free(bstream->data);
    free(bstream);
  }
}
