diff options
Diffstat (limited to 'lpg/libqr/data-parse.c')
| -rw-r--r-- | lpg/libqr/data-parse.c | 237 |
1 files changed, 237 insertions, 0 deletions
diff --git a/lpg/libqr/data-parse.c b/lpg/libqr/data-parse.c new file mode 100644 index 0000000..9129ed7 --- /dev/null +++ b/lpg/libqr/data-parse.c @@ -0,0 +1,237 @@ +#include <assert.h> +#include <stdio.h> +#include <stdlib.h> +#include <qr/data.h> + +#include "bitstream.h" +#include "data-common.h" + +static enum qr_data_type read_data_type(struct bitstream * stream) +{ + const size_t length = 4; + unsigned int type; + + if (bitstream_remaining(stream) < length) + return QR_DATA_INVALID; + + type = 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 bitstream * stream; + size_t field_len, bits; + unsigned int digits; + unsigned int chunk; + char * p, * buffer; + + stream = data->bits; + buffer = 0; + + field_len = get_size_field_length(data->format, QR_DATA_NUMERIC); + if (bitstream_remaining(stream) < field_len) + goto invalid; + + digits = bitstream_read(stream, field_len); + + bits = (digits / 3) * 10; + if (digits % 3 == 1) + bits += 4; + else if (digits % 3 == 2) + bits += 7; + + if (bitstream_remaining(stream) < bits) + goto invalid; + + buffer = malloc(digits + 1); + if (!buffer) + goto invalid; + + p = buffer; + + for (; bits >= 10; bits -= 10) { + chunk = bitstream_read(stream, 10); + if (chunk >= 1000) + goto invalid; + sprintf(p, "%03u", chunk); + p += 3; + } + + if (bits > 0) { + chunk = 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 bitstream * stream; + size_t field_len, bits; + unsigned int chars; + unsigned int chunk; + char * p, * buffer; + + stream = data->bits; + buffer = 0; + + field_len = get_size_field_length(data->format, QR_DATA_ALPHA); + if (bitstream_remaining(stream) < field_len) + goto invalid; + + chars = bitstream_read(stream, field_len); + + bits = (chars / 2) * 11; + if (chars % 2 == 1) + bits += 6; + + if (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 = 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 = 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 bitstream * stream; + size_t field_len; + unsigned int bytes; + char * p; + + stream = data->bits; + + field_len = get_size_field_length(data->format, QR_DATA_8BIT); + if (bitstream_remaining(stream) < field_len) + return QR_DATA_INVALID; + + bytes = bitstream_read(stream, field_len); + + if (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++ = 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_get_data_type(const struct qr_data * data) +{ + 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; + + 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 = get_size_field_length(data->format, type); + break; + default: + /* unsupported / invalid */ + return -1; + } + + if (bitstream_remaining(data->bits) < field_len) + return -1; + + return (int) bitstream_read(data->bits, field_len); +} + +enum qr_data_type qr_parse_data(const struct qr_data * input, + char ** output, + size_t * length) +{ + bitstream_seek(input->bits, input->offset); + + 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; + } +} + |