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#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <qr/bitstream.h>
#include <qr/data.h>
#include "constants.h"
static enum qr_data_type read_data_type(struct qr_bitstream * stream)
{
const size_t length = 4;
unsigned int type;
if (qr_bitstream_remaining(stream) < length)
return QR_DATA_INVALID;
type = qr_bitstream_read(stream, length);
assert(type < 16);
return QR_TYPE_CODES[type];
}
static enum qr_data_type parse_numeric(const struct qr_data * data,
char ** output,
size_t * length)
{
struct qr_bitstream * stream;
size_t field_len, bits;
unsigned int digits;
unsigned int chunk;
char * p, * buffer;
stream = data->bits;
buffer = 0;
field_len = qr_data_size_field_length(data->version, QR_DATA_NUMERIC);
if (qr_bitstream_remaining(stream) < field_len)
goto invalid;
digits = qr_bitstream_read(stream, field_len);
bits = (digits / 3) * 10;
if (digits % 3 == 1)
bits += 4;
else if (digits % 3 == 2)
bits += 7;
if (qr_bitstream_remaining(stream) < bits)
goto invalid;
buffer = malloc(digits + 1);
if (!buffer)
goto invalid;
p = buffer;
for (; bits >= 10; bits -= 10) {
chunk = qr_bitstream_read(stream, 10);
if (chunk >= 1000)
goto invalid;
sprintf(p, "%03u", chunk);
p += 3;
}
if (bits > 0) {
chunk = qr_bitstream_read(stream, bits);
if (chunk >= (bits >= 7 ? 100 : 10))
goto invalid;
sprintf(p, "%0*u", bits >= 7 ? 2 : 1, chunk);
}
*output = buffer;
*length = digits;
return QR_DATA_NUMERIC;
invalid:
free(buffer);
return QR_DATA_INVALID;
}
static enum qr_data_type parse_alpha(const struct qr_data * data,
char ** output,
size_t * length)
{
static const char charset[45] =
"0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ $%*+-./:";
struct qr_bitstream * stream;
size_t field_len, bits;
unsigned int chars;
unsigned int chunk;
char * p, * buffer;
stream = data->bits;
buffer = 0;
field_len = qr_data_size_field_length(data->version, QR_DATA_ALPHA);
if (qr_bitstream_remaining(stream) < field_len)
goto invalid;
chars = qr_bitstream_read(stream, field_len);
bits = (chars / 2) * 11;
if (chars % 2 == 1)
bits += 6;
if (qr_bitstream_remaining(stream) < bits)
goto invalid;
buffer = malloc(chars + 1);
if (!buffer)
goto invalid;
p = buffer;
for (; bits >= 11; bits -= 11) {
unsigned int c1, c2;
chunk = qr_bitstream_read(stream, 11);
c1 = chunk / 45;
c2 = chunk % 45;
if (c1 >= 45)
goto invalid;
*p++ = charset[c1];
*p++ = charset[c2];
}
if (bits > 0) {
chunk = qr_bitstream_read(stream, bits);
if (chunk >= 45)
goto invalid;
*p = charset[chunk];
}
*output = buffer;
*length = chars;
return QR_DATA_ALPHA;
invalid:
free(buffer);
return QR_DATA_INVALID;
}
static enum qr_data_type parse_8bit(const struct qr_data * data,
char ** output,
size_t * length)
{
struct qr_bitstream * stream;
size_t field_len;
unsigned int bytes;
char * p;
stream = data->bits;
field_len = qr_data_size_field_length(data->version, QR_DATA_8BIT);
if (qr_bitstream_remaining(stream) < field_len)
return QR_DATA_INVALID;
bytes = qr_bitstream_read(stream, field_len);
if (qr_bitstream_remaining(stream) < bytes * 8)
return QR_DATA_INVALID;
*output = malloc(bytes + 1);
if (!*output)
return QR_DATA_INVALID;
p = *output;
*length = bytes;
while (bytes-- > 0)
*p++ = qr_bitstream_read(stream, 8);
*p = '\0';
return QR_DATA_8BIT;
}
static enum qr_data_type parse_kanji(const struct qr_data * data,
char ** output,
size_t * length)
{
return QR_DATA_INVALID;
}
enum qr_data_type qr_data_type(const struct qr_data * data)
{
qr_bitstream_seek(data->bits, data->offset);
return read_data_type(data->bits);
}
int qr_get_data_length(const struct qr_data * data)
{
size_t field_len;
enum qr_data_type type;
qr_bitstream_seek(data->bits, data->offset);
type = read_data_type(data->bits);
switch (type) {
case QR_DATA_NUMERIC:
case QR_DATA_ALPHA:
case QR_DATA_8BIT:
case QR_DATA_KANJI:
field_len = qr_data_size_field_length(data->version, type);
break;
default:
/* unsupported / invalid */
return -1;
}
if (qr_bitstream_remaining(data->bits) < field_len)
return -1;
return (int) qr_bitstream_read(data->bits, field_len);
}
enum qr_data_type qr_parse_data(const struct qr_data * input,
char ** output,
size_t * length)
{
qr_bitstream_seek(input->bits, input->offset);
*output = NULL;
*length = 0;
switch (read_data_type(input->bits)) {
case QR_DATA_NUMERIC:
return parse_numeric(input, output, length);
case QR_DATA_ALPHA:
return parse_alpha(input, output, length);
case QR_DATA_8BIT:
return parse_8bit(input, output, length);
case QR_DATA_KANJI:
return parse_kanji(input, output, length);
default:
/* unsupported / invalid */
return QR_DATA_INVALID;
}
}
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