kc3-lang/libqrencode/tests/decoder.c

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  Commit

• Author : Kentaro Fukuchi
  Date : 2017-10-08 02:17:28
  Hash : 06494038
  Message : Fixed some warnings. (closing #89 and #102)

• tests/decoder.c

• #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  #include <iconv.h>
  #if HAVE_CONFIG_H
  #include "../config.h"
  #endif
  #include "../qrspec.h"
  #include "../bitstream.h"
  #include "../mask.h"
  #include "../mqrspec.h"
  #include "../mmask.h"
  #include "common.h"
  #include "decoder.h"
  
  static unsigned int bitToInt(unsigned char *bits, int length)
  {
  	int i;
  	unsigned int val = 0;
  
  	for(i=0; i<length; i++) {
  		val = val << 1;
  		val |= (bits[i] & 1);
  	}
  
  	return val;
  }
  
  static int decodeLength(int *bits_length, unsigned char **bits, QRencodeMode mode, int version, int mqr)
  {
  	int i;
  	int length = 0;
  	int lbits;
  
  	if(mqr) {
  		lbits = MQRspec_lengthIndicator(mode, version);
  	} else {
  		lbits = QRspec_lengthIndicator(mode, version);
  	}
  
  	if(*bits_length < lbits) {
  		printf("Bit length is too short: %d\n", *bits_length);
  		return 0;
  	}
  
  	length = 0;
  	for(i=0; i<lbits; i++) {
  		length = length << 1;
  		length += (*bits)[i];
  	}
  
  	*bits_length -= lbits;
  	*bits += lbits;
  
  	return length;
  }
  
  static DataChunk *decodeNum(int *bits_length, unsigned char **bits, int version, int mqr)
  {
  	int i;
  	int size, sizeInBit, words, remain;
  	unsigned char *p;
  	char *buf, *q;
  	unsigned int val;
  	DataChunk *chunk;
  
  	size = decodeLength(bits_length, bits, QR_MODE_NUM, version, mqr);
  	if(size < 0) return NULL;
  
  	words = size / 3;
  	remain = size - words * 3;
  	sizeInBit = words * 10;
  	if(remain == 2) {
  		sizeInBit += 7;
  	} else if(remain == 1) {
  		sizeInBit += 4;
  	}
  	if(*bits_length < sizeInBit) {
  		printf("Bit length is too short: %d, expected %d.\n", *bits_length, sizeInBit);
  		return NULL;
  	}
  
  	buf = (char *)malloc((size_t)size + 1);
  	p = *bits;
  	q = buf;
  	for(i=0; i<words; i++) {
  		val = bitToInt(p, 10);
  		sprintf(q, "%03d", val);
  		p += 10;
  		q += 3;
  	}
  	if(remain == 2) {
  		val = bitToInt(p, 7);
  		sprintf(q, "%02d", val);
  	} else if(remain == 1) {
  		val = bitToInt(p, 4);
  		sprintf(q, "%1d", val);
  	}
  	buf[size] = '\0';
  
  	chunk = DataChunk_new(QR_MODE_NUM);
  	chunk->size = size;
  	chunk->data = (unsigned char *)buf;
  	*bits_length -= sizeInBit;
  	*bits += sizeInBit;
  
  	return chunk;
  }
  
  static const char decodeAnTable[45] = {
  	'0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
  	'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J',
  	'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T',
  	'U', 'V', 'W', 'X', 'Y', 'Z', ' ', '$', '%', '*',
  	'+', '-', '.', '/', ':'
  };
  
  static DataChunk *decodeAn(int *bits_length, unsigned char **bits, int version, int mqr)
  {
  	int i;
  	int size, sizeInBit, words, remain;
  	unsigned char *p;
  	char *buf, *q;
  	unsigned int val;
  	int ch, cl;
  	DataChunk *chunk;
  
  	size = decodeLength(bits_length, bits, QR_MODE_AN, version, mqr);
  	if(size < 0) return NULL;
  
  	words = size / 2;
  	remain = size - words * 2;
  	sizeInBit = words * 11 + remain * 6;
  	if(*bits_length < sizeInBit) {
  		printf("Bit length is too short: %d, expected %d.\n", *bits_length, sizeInBit);
  		return NULL;
  	}
  
  	buf = (char *)malloc((size_t)size + 1);
  	p = *bits;
  	q = buf;
  	for(i=0; i<words; i++) {
  		val = bitToInt(p, 11);
  		ch = (int)(val / 45);
  		cl = (int)(val % 45);
  		sprintf(q, "%c%c", decodeAnTable[ch], decodeAnTable[cl]);
  		p += 11;
  		q += 2;
  	}
  	if(remain == 1) {
  		val = bitToInt(p, 6);
  		sprintf(q, "%c", decodeAnTable[val]);
  	}
  
  	chunk = DataChunk_new(QR_MODE_AN);
  	chunk->size = size;
  	chunk->data = (unsigned char *)buf;
  	*bits_length -= sizeInBit;
  	*bits += sizeInBit;
  
  	return chunk;
  }
  
  static DataChunk *decode8(int *bits_length, unsigned char **bits, int version, int mqr)
  {
  	int i;
  	int size, sizeInBit;
  	unsigned char *p;
  	unsigned char *buf, *q;
  	DataChunk *chunk;
  
  	size = decodeLength(bits_length, bits, QR_MODE_8, version, mqr);
  	if(size < 0) return NULL;
  
  	sizeInBit = size * 8;
  	if(*bits_length < sizeInBit) {
  		printf("Bit length is too short: %d, expected %d.\n", *bits_length, sizeInBit);
  		return NULL;
  	}
  
  	buf = (unsigned char *)malloc((size_t)size);
  	p = *bits;
  	q = buf;
  	for(i=0; i<size; i++) {
  		*q = (unsigned char)bitToInt(p, 8);
  		p += 8;
  		q += 1;
  	}
  
  	chunk = DataChunk_new(QR_MODE_8);
  	chunk->size = size;
  	chunk->data = buf;
  	*bits_length -= sizeInBit;
  	*bits += sizeInBit;
  
  	return chunk;
  }
  
  static DataChunk *decodeKanji(int *bits_length, unsigned char **bits, int version, int mqr)
  {
  	int i;
  	int size, sizeInBit;
  	unsigned char *p;
  	char *buf, *q;
  	unsigned int val;
  	unsigned int ch, cl;
  	DataChunk *chunk;
  
  	size = decodeLength(bits_length, bits, QR_MODE_KANJI, version, mqr);
  	if(size < 0) return NULL;
  
  	sizeInBit = size * 13;
  	if(*bits_length < sizeInBit) {
  		printf("Bit length is too short: %d, expected %d.\n", *bits_length, sizeInBit);
  		return NULL;
  	}
  
  	buf = (char *)malloc((size_t)size * 2 + 1);
  	p = *bits;
  	q = buf;
  	for(i=0; i<size; i++) {
  		val = bitToInt(p, 13);
  		ch = val / 0xc0;
  		cl = val - ch * 0xc0;
  		val = ch * 256 + cl;
  		if(val >= 0x1f00) {
  			val += 0xc140;
  		} else {
  			val += 0x8140;
  		}
  		sprintf(q, "%c%c", (val>>8) & 0xff, val & 0xff);
  		p += 13;
  		q += 2;
  	}
  
  	chunk = DataChunk_new(QR_MODE_KANJI);
  	chunk->size = size * 2;
  	chunk->data = (unsigned char *)buf;
  	*bits_length -= sizeInBit;
  	*bits += sizeInBit;
  
  	return chunk;
  }
  
  static DataChunk *decodeChunk(int *bits_length, unsigned char **bits, int version)
  {
  	unsigned int val;
  
  	if(*bits_length < 4) {
  		return NULL;
  	}
  	val = bitToInt(*bits, 4);
  	*bits_length -= 4;
  	*bits += 4;
  	switch(val) {
  		case 0:
  			return NULL;
  		case 1:
  			return decodeNum(bits_length, bits, version, 0);
  		case 2:
  			return decodeAn(bits_length, bits, version, 0);
  		case 4:
  			return decode8(bits_length, bits, version, 0);
  		case 8:
  			return decodeKanji(bits_length, bits, version, 0);
  		default:
  			break;
  	}
  
  	printf("Invalid mode in a chunk: %d\n", val);
  
  	return NULL;
  }
  
  static DataChunk *decodeChunkMQR(int *bits_length, unsigned char **bits, int version)
  {
  	int modebits, termbits;
  	unsigned int val;
  
  	modebits = version - 1;
  	termbits = version * 2 + 1;
  	if(*bits_length >= termbits) {
  		val = bitToInt(*bits, termbits);
  		if(val == 0) {
  			*bits += termbits;
  			*bits_length -= termbits;
  			return NULL;
  		}
  	} else {
  		if(*bits_length < modebits) {
  			val = bitToInt(*bits, *bits_length);
  		} else {
  			val = bitToInt(*bits, modebits);
  		}
  		if(val == 0) {
  			return NULL;
  		} else {
  			printf("Terminating bits include 1-bit.\n");
  			return NULL;
  		}
  	}
  	val = bitToInt(*bits, modebits);
  	if(version == 4 && val > 3) {
  		printf("Invalid mode number %d.\n", val);
  	}
  	*bits_length -= modebits;
  	*bits += modebits;
  	switch(val) {
  		case 0:
  			return decodeNum(bits_length, bits, version, 1);
  		case 1:
  			return decodeAn(bits_length, bits, version, 1);
  		case 2:
  			return decode8(bits_length, bits, version, 1);
  		case 3:
  			return decodeKanji(bits_length, bits, version, 1);
  		default:
  			break;
  	}
  
  	printf("Invalid mode in a chunk: %d\n", val);
  
  	return NULL;
  }
  
  static int appendChunk(QRdata *qrdata, int *bits_length, unsigned char **bits)
  {
  	DataChunk *chunk;
  
  	if(qrdata->mqr) {
  		chunk = decodeChunkMQR(bits_length, bits, qrdata->version);
  	} else {
  		chunk = decodeChunk(bits_length, bits, qrdata->version);
  	}
  	if(chunk == NULL) {
  		return 1;
  	}
  
  	if(qrdata->last == NULL) {
  		qrdata->chunks = chunk;
  	} else {
  		qrdata->last->next = chunk;
  	}
  	qrdata->last = chunk;
  
  	return 0;
  }
  
  QRdata *QRdata_new(void)
  {
  	QRdata *qrdata;
  
  	qrdata = (QRdata *)calloc(sizeof(QRdata), 1);
  	if(qrdata == NULL) return NULL;
  
  	qrdata->eccResult = 0;
  
  	return qrdata;
  }
  
  QRdata *QRdata_newMQR(void)
  {
  	QRdata *qrdata;
  
  	qrdata = QRdata_new();
  	if(qrdata == NULL) return NULL;
  
  	qrdata->mqr = 1;
  
  	return qrdata;
  }
  
  void QRdata_free(QRdata *qrdata)
  {
  	DataChunk_freeList(qrdata->chunks);
  	if(qrdata->data != NULL) {
  		free(qrdata->data);
  	}
  	free(qrdata);
  }
  
  static int QRdata_decodeBits(QRdata *qrdata, int length, unsigned char *bits)
  {
  	int ret = 0;
  
  	while(ret == 0) {
  		ret = appendChunk(qrdata, &length, &bits);
  	}
  
  	return length;
  }
  
  int QRdata_decodeBitStream(QRdata *qrdata, BitStream *bstream)
  {
  	return QRdata_decodeBits(qrdata, bstream->length, bstream->data);
  }
  
  void QRdata_dump(QRdata *data)
  {
  	DataChunk_dumpChunkList(data->chunks);
  }
  
  int QRcode_decodeVersion(QRcode *code)
  {
  	unsigned int v1, v2;
  	int x, y, width;
  	unsigned char *p;
  
  	width = code->width;
  	if(width < 45) {
  		return (width - 21)/ 4 + 1;
  	}
  
  	v1 = 0;
  	p = code->data + width * (width - 9) + 5;
  	for(x=0; x<6; x++) {
  		for(y=0; y<3; y++) {
  			v1 = v1 << 1;
  			v1 |= *(p - y * width - x) & 1;
  		}
  	}
  
  	v2 = 0;
  	p = code->data + width * 5 + width - 9;
  	for(y=0; y<6; y++) {
  		for(x=0; x<3; x++) {
  			v2 = v2 << 1;
  			v2 |= *(p - y * width - x) & 1;
  		}
  	}
  
  	if(v1 != v2) {
  		printf("Two verion patterns are different.\n");
  		return -1;
  	}
  
  	return (int)(v1 >> 12);
  }
  
  int QRcode_decodeFormat(QRcode *code, QRecLevel *level, int *mask)
  {
  	unsigned int v1, v2;
  	int i, width;
  	unsigned char *p;
  
  	width = code->width;
  
  	v1 = 0;
  	p = code->data + width * 8;
  	for(i=0; i<8; i++) {
  		v1 = v1 << 1;
  		if(i < 6) {
  			v1 |= *(p + i) & 1;
  		} else {
  			v1 |= *(p + i + 1) & 1;
  		}
  	}
  	p = code->data + width * 7 + 8;
  	for(i=0; i<7; i++) {
  		v1 = v1 << 1;
  		if(i < 1) {
  			v1 |= *(p - width * i) & 1;
  		} else {
  			v1 |= *(p - width * (i + 1)) & 1;
  		}
  	}
  
  	v2 = 0;
  	p = code->data + width * (width - 1) + 8;
  	for(i=0; i<7; i++) {
  		v2 = v2 << 1;
  		v2 |= *(p - width * i) & 1;
  	}
  	p = code->data + width * 8 + width - 8;
  	for(i=0; i<8; i++) {
  		v2 = v2 << 1;
  		v2 |= *(p + i) & 1;
  	}
  
  	if(v1 != v2) {
  		printf("Two format infos are different.\n");
  		return -1;
  	}
  	v1 = (v1 ^ 0x5412) >> 10;
  	*mask = v1 & 7;
  	switch((v1 >> 3) & 3) {
  		case 1:
  			*level = QR_ECLEVEL_L;
  			break;
  		case 0:
  			*level = QR_ECLEVEL_M;
  			break;
  		case 3:
  			*level = QR_ECLEVEL_Q;
  			break;
  		case 2:
  			*level = QR_ECLEVEL_H;
  			break;
  		default:
  			break;
  	}
  
  	return 0;
  }
  
  static unsigned char *unmask(QRcode *code, QRecLevel level, int mask)
  {
  	unsigned char *unmasked;
  
  	unmasked = Mask_makeMask(code->width, code->data, mask, level);
  
  	return unmasked;
  }
  
  unsigned char *QRcode_unmask(QRcode *code)
  {
  	int ret, version, mask;
  	QRecLevel level;
  
  	version = QRcode_decodeVersion(code);
  	if(version < 1) return NULL;
  	ret = QRcode_decodeFormat(code, &level, &mask);
  	if(ret < 0) return NULL;
  
  	return unmask(code, level, mask);
  }
  
  typedef struct {
  	int width;
  	unsigned char *frame;
  	int x, y;
  	int dir;
  	int bit;
  	int mqr;
  } FrameFiller;
  
  static FrameFiller *FrameFiller_new(int width, unsigned char *frame, int mqr)
  {
  	FrameFiller *filler;
  
  	filler = (FrameFiller *)malloc(sizeof(FrameFiller));
  	if(filler == NULL) return NULL;
  	filler->width = width;
  	filler->frame = frame;
  	filler->x = width - 1;
  	filler->y = width - 1;
  	filler->dir = -1;
  	filler->bit = -1;
  	filler->mqr = mqr;
  
  	return filler;
  }
  
  static unsigned char *FrameFiller_next(FrameFiller *filler)
  {
  	unsigned char *p;
  	int x, y, w;
  
  	if(filler->bit == -1) {
  		filler->bit = 0;
  		return filler->frame + filler->y * filler->width + filler->x;
  	}
  
  	x = filler->x;
  	y = filler->y;
  	p = filler->frame;
  	w = filler->width;
  
  	if(filler->bit == 0) {
  		x--;
  		filler->bit++;
  	} else {
  		x++;
  		y += filler->dir;
  		filler->bit--;
  	}
  
  	if(filler->dir < 0) {
  		if(y < 0) {
  			y = 0;
  			x -= 2;
  			filler->dir = 1;
  			if(!filler->mqr && x == 6) {
  				x--;
  				y = 9;
  			}
  		}
  	} else {
  		if(y == w) {
  			y = w - 1;
  			x -= 2;
  			filler->dir = -1;
  			if(!filler->mqr && x == 6) {
  				x--;
  				y -= 8;
  			}
  		}
  	}
  	if(x < 0 || y < 0) return NULL;
  
  	filler->x = x;
  	filler->y = y;
  
  	if(p[y * w + x] & 0x80) {
  		// This tail recursion could be optimized.
  		return FrameFiller_next(filler);
  	}
  	return &p[y * w + x];
  }
  
  static BitStream *extractBits(int width, unsigned char *frame, int spec[5])
  {
  	BitStream *bstream;
  	unsigned char *bits, *p, *q;
  	FrameFiller *filler;
  	int i, j;
  	int col, row, d1, b1, blocks, idx, words;
  
  	blocks = QRspec_rsBlockNum(spec);
  	words = QRspec_rsDataLength(spec);
  	d1 = QRspec_rsDataCodes1(spec);
  	b1 = QRspec_rsBlockNum1(spec);
  	bits = (unsigned char *)malloc((size_t)words * 8);
  	/*
  	 * 00 01 02 03 04 05 06 07 08 09
  	 * 10 11 12 13 14 15 16 17 18 19
  	 * 20 21 22 23 24 25 26 27 28 29 30
  	 * 31 32 33 34 35 36 37 38 39 40 41
  	 * 42 43 44 45 46 47 48 49 50 51 52
  	 */
  
  	row = col = 0;
  	filler = FrameFiller_new(width, frame, 0);
  	for(i=0; i<words; i++) {
  		col = i / blocks;
  		row = i % blocks + ((col >= d1)?b1:0);
  		idx = d1 * row + col + ((row > b1)?(row-b1):0);
  		q = bits + idx * 8;
  		for(j=0; j<8; j++) {
  			p = FrameFiller_next(filler);
  			q[j] = *p & 1;
  		}
  	}
  	free(filler);
  
  	bstream = BitStream_newWithBits((size_t)words * 8, bits);
  	free(bits);
  
  	return bstream;
  }
  
  BitStream *QRcode_extractBits(QRcode *code, int *dataLength, int *eccLength)
  {
  	BitStream *bstream;
  	unsigned char *unmasked;
  	int spec[5];
  	int ret, version, mask;
  	QRecLevel level;
  
  	version = QRcode_decodeVersion(code);
  	if(version < 1) return NULL;
  	ret = QRcode_decodeFormat(code, &level, &mask);
  	if(ret < 0) return NULL;
  
  	QRspec_getEccSpec(version, level, spec);
  
  	unmasked = unmask(code, level, mask);
  	if(unmasked == NULL) return NULL;
  
  	bstream = extractBits(code->width, unmasked, spec);
  	free(unmasked);
  
  	*dataLength = QRspec_rsDataLength(spec) * 8;
  	*eccLength = QRspec_rsEccLength(spec) * 8;
  
  	return bstream;
  }
  
  static int checkRemainderWords(int length, unsigned char *bits, int remainder)
  {
  	int rbits, words;
  	unsigned char *p, v;
  	int i;
  
  	words = remainder / 8;
  	rbits = remainder - words * 8;
  	bits += (length - remainder);
  	for(i=0; i<rbits; i++) {
  		if((bits[i]&1) != 0) {
  			printf("Terminating code includes 1-bit.\n");
  			printBinary(bits, remainder);
  			return -1;
  		}
  	}
  	p = bits + rbits;
  	for(i=0; i<words; i++) {
  		v = (unsigned char)bitToInt(p, 8);
  		if(v != ((i&1)?0x11:0xec)) {
  			printf("Remainder codewords wrong.\n");
  			printBinary(bits, remainder);
  			return -1;
  		}
  		p += 8;
  	}
  
  	return 0;
  }
  
  QRdata *QRcode_decodeBits(QRcode *code)
  {
  	BitStream *bstream;
  	unsigned char *unmasked;
  	int spec[5];
  	int ret, version, mask;
  	int length;
  	QRecLevel level;
  	QRdata *qrdata;
  
  	version = QRcode_decodeVersion(code);
  	if(version < 1) return NULL;
  	ret = QRcode_decodeFormat(code, &level, &mask);
  	if(ret < 0) return NULL;
  
  	QRspec_getEccSpec(version, level, spec);
  	length = QRspec_rsDataLength(spec) * 8;
  
  	unmasked = unmask(code, level, mask);
  	if(unmasked == NULL) return NULL;
  
  	bstream = extractBits(code->width, unmasked, spec);
  	free(unmasked);
  
  	qrdata = QRdata_new();
  	qrdata->version = version;
  	qrdata->level = level;
  	ret = QRdata_decodeBitStream(qrdata, bstream);
  	if(ret > 0) {
  		checkRemainderWords(length, bstream->data, ret);
  	}
  
  	BitStream_free(bstream);
  
  	return qrdata;
  }
  
  void QRdata_concatChunks(QRdata *qrdata)
  {
  	qrdata->data = DataChunk_concatChunkList(qrdata->chunks, &qrdata->size);
  }
  
  QRdata *QRcode_decode(QRcode *code)
  {
  	QRdata *qrdata;
  
  	qrdata = QRcode_decodeBits(code);
  	QRdata_concatChunks(qrdata);
  
  	return qrdata;
  }
  
  /*
   * Micro QR Code decoder
   */
  
  struct FormatInfo MQRformat[] = {
  	{1, QR_ECLEVEL_L},
  	{2, QR_ECLEVEL_L},
  	{2, QR_ECLEVEL_M},
  	{3, QR_ECLEVEL_L},
  	{3, QR_ECLEVEL_M},
  	{4, QR_ECLEVEL_L},
  	{4, QR_ECLEVEL_M},
  	{4, QR_ECLEVEL_Q}
  };
  
  int QRcode_decodeFormatMQR(QRcode *code, int *version, QRecLevel *level, int *mask)
  {
  	unsigned int v, t;
  	int i, width;
  	unsigned char *p;
  
  	width = code->width;
  
  	v = 0;
  	p = code->data + width * 8 + 1;
  	for(i=0; i<8; i++) {
  		v = v << 1;
  		v |= p[i] & 1;
  	}
  	p = code->data + width * 7 + 8;
  	for(i=0; i<7; i++) {
  		v = v << 1;
  		v |= *(p - width * i) & 1;
  	}
  	v ^= 0x4445;
  	*mask = (v >> 10) & 3;
  	t = (v >> 12) & 7;
  	*version = MQRformat[t].version;
  	*level = MQRformat[t].level;
  	if(*version * 2 + 9 != width) {
  		printf("Decoded version number does not match to the size.\n");
  		return -1;
  	}
  	return 0;
  }
  
  static unsigned char *unmaskMQR(QRcode *code, QRecLevel level, int mask)
  {
  	unsigned char *unmasked;
  
  	unmasked = MMask_makeMask(code->version, code->data, mask, level);
  
  	return unmasked;
  }
  
  unsigned char *QRcode_unmaskMQR(QRcode *code)
  {
  	int ret, version, mask;
  	QRecLevel level;
  
  	ret = QRcode_decodeFormatMQR(code, &version, &level, &mask);
  	if(ret < 0) return NULL;
  
  	return unmaskMQR(code, level, mask);
  }
  
  static BitStream *extractBitsMQR(int width, unsigned char *frame, int version, QRecLevel level)
  {
  	BitStream *bstream;
  	unsigned char *bits;
  	FrameFiller *filler;
  	int i;
  	int size;
  
  	size = MQRspec_getDataLengthBit(version, level) + MQRspec_getECCLength(version, level) * 8;
  	bits = (unsigned char *)malloc((size_t)size);
  	filler = FrameFiller_new(width, frame, 1);
  	for(i=0; i<size; i++) {
  		bits[i] = *(FrameFiller_next(filler)) & 1;
  	}
  	free(filler);
  
  	bstream = BitStream_newWithBits((size_t)size, bits);
  	free(bits);
  
  	return bstream;
  }
  
  BitStream *QRcode_extractBitsMQR(QRcode *code, int *dataLength, int *eccLength, int *version, QRecLevel *level)
  {
  	BitStream *bstream;
  	unsigned char *unmasked;
  	int ret, mask;
  
  	ret = QRcode_decodeFormatMQR(code, version, level, &mask);
  	if(ret < 0) return NULL;
  
  	unmasked = unmaskMQR(code, *level, mask);
  	if(unmasked == NULL) return NULL;
  
  	*dataLength = MQRspec_getDataLengthBit(*version, *level);
  	*eccLength = MQRspec_getECCLength(*version, *level) * 8;
  	bstream = extractBitsMQR(code->width, unmasked, *version, *level);
  	free(unmasked);
  
  	return bstream;
  }
  
  static int checkRemainderWordsMQR(int length, unsigned char *bits, int remainder, int version)
  {
  	int rbits, words, paddings;
  	unsigned char *p, v;
  	int i, decoded;
  
  	decoded = length - remainder;
  	bits += decoded;
  	words = (decoded + 7) / 8;
  	rbits = words * 8 - decoded;
  	for(i=0; i<rbits; i++) {
  		if((bits[i]&1) != 0) {
  			printf("Terminating code includes 1-bit.\n");
  			printBinary(bits, remainder);
  			return -1;
  		}
  	}
  
  	paddings = (length - words * 8) / 8;
  	p = bits + rbits;
  	for(i=0; i<paddings; i++) {
  		v = (unsigned char)bitToInt(p, 8);
  		if(v != ((i&1)?0x11:0xec)) {
  			printf("Remainder codewords wrong.\n");
  			printBinary(bits, remainder);
  			return -1;
  		}
  		p += 8;
  	}
  	rbits = length - (paddings + words)* 8;
  	if(rbits > 0) {
  		if((version == 1 || version == 3) && rbits == 4) {
  			v = (unsigned char)bitToInt(p, 4);
  			if(v != 0) {
  				printf("Last padding bits include 1-bit.\n");
  				return -1;
  			}
  		} else {
  			printf("The length of the last padding bits is %d, not %d.\n", rbits, (version == 1 || version == 3)?4:0);
  			return -1;
  		}
  	}
  
  	return 0;
  }
  
  QRdata *QRcode_decodeBitsMQR(QRcode *code)
  {
  	BitStream *bstream;
  	int ret, version, dataLength, eccLength;
  	QRecLevel level;
  	QRdata *qrdata;
  
  	bstream = QRcode_extractBitsMQR(code, &dataLength, &eccLength, &version, &level);
  	if(bstream == NULL) {
  		return NULL;
  	}
  
  	qrdata = QRdata_newMQR();
  	qrdata->version = version;
  	qrdata->level = level;
  	ret = QRdata_decodeBits(qrdata, dataLength, bstream->data);
  	if(ret > 0) {
  		ret = checkRemainderWordsMQR(dataLength, bstream->data, ret, version);
  		if(ret < 0) {
  			QRdata_free(qrdata);
  			qrdata = NULL;
  		}
  	}
  
  	BitStream_free(bstream);
  
  	return qrdata;
  }
  
  QRdata *QRcode_decodeMQR(QRcode *code)
  {
  	QRdata *qrdata;
  	qrdata = QRcode_decodeBitsMQR(code);
  	if(qrdata != NULL) {
  		QRdata_concatChunks(qrdata);
  	}
  
  	return qrdata;
  }