/*

 * 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);

	}

}