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#include <stdlib.h>
#include <limits.h>
#include <assert.h>
#include <qr/code.h>
#include "code-common.h"
#include "data-common.h"
#include "rs.h"
#define MIN(a, b) ((b) < (a) ? (b) : (a))
#include <stdio.h>
static void x_dump(struct bitstream * bits)
{
size_t i, n;
bitstream_seek(bits, 0);
n = bitstream_size(bits);
for (i = 0; i < n; ++i) {
printf("%d", bitstream_read(bits, 1));
if (i % 8 == 7)
printf(" ");
if ((i+1) % (7 * 8) == 0)
printf("\n");
}
printf("\n");
}
static int pad_data(struct bitstream * bits, size_t limit)
{
/* This function is not very nice. Sorry. */
size_t count, n;
assert(bitstream_size(bits) <= limit);
if (bitstream_resize(bits, limit) != 0)
return -1;
n = bitstream_size(bits);
bitstream_seek(bits, n);
count = limit - n;
/* First append the terminator (0000) if possible,
* and pad with zeros up to an 8-bit boundary
*/
n = (n + 4) % 8;
if (n != 0)
n = 8 - n;
n = MIN(count, n + 4);
bitstream_write(bits, 0, n);
count -= n;
assert(count % 8 == 0); /* since data codewords are 8 bits */
/* Finally pad with the repeating sequence 11101100 00010001 */
while (count >= 16) {
bitstream_write(bits, 0xEC11, 16);
count -= 16;
}
if (count > 0) {
assert(count == 8);
bitstream_write(bits, 0xEC, 8);
}
return 0;
}
static struct bitstream * make_data(int format,
enum qr_ec_level ec,
struct bitstream * data)
{
const size_t total_bits = code_total_capacity(format);
const size_t total_words = total_bits / 8;
size_t block_count, data_words, rs_words;
size_t i;
struct bitstream * dcopy = 0;
struct bitstream * out = 0;
struct bitstream ** blocks = 0;
/* Set up the output stream */
out = bitstream_create();
if (!out)
return 0;
if (bitstream_resize(out, total_bits) != 0)
goto fail;
/**
* XXX: For our test case (1-M) there is only one RS block.
* This is not the case for most other formats, so we'll
* have to deal with this eventually.
*/
block_count = 1;
data_words = 16;
rs_words = 10;
assert(data_words + rs_words == total_words);
/* Make a copy of the data and pad it */
dcopy = bitstream_copy(data);
if (!dcopy)
goto fail;
if (pad_data(dcopy, data_words * 8) != 0)
goto fail;
puts("Pad data:");
x_dump(dcopy);
/* Make space for the RS blocks */
blocks = calloc(block_count, sizeof(*blocks));
if (!blocks)
goto fail;
/* Generate RS codewords */
bitstream_seek(dcopy, 0);
puts("Generate RS blocks:");
for (i = 0; i < block_count; ++i) {
/* XXX: some blocks may be longer */
blocks[i] = rs_generate_words(dcopy, data_words, rs_words);
if (!blocks[i]) {
while (i--)
bitstream_destroy(blocks[i]);
free(blocks);
blocks = 0;
goto fail;
}
x_dump(blocks[i]);
}
/* Finally, write everything out in the correct order */
/* XXX: need to handle multiple blocks */
bitstream_cat(out, dcopy);
bitstream_cat(out, blocks[0]);
bitstream_write(out, 0, total_bits - total_words * 8);
puts("Final bitstream:");
x_dump(out);
exit:
if (blocks) {
while (block_count--)
bitstream_destroy(blocks[block_count]);
free(blocks);
}
if (dcopy)
bitstream_destroy(dcopy);
return out;
fail:
bitstream_destroy(out);
out = 0;
goto exit;
}
struct qr_code * qr_code_create(enum qr_ec_level ec,
const struct qr_data * data)
{
struct qr_code * code;
struct bitstream * ecdata;
code = malloc(sizeof(*code));
if (!code)
return 0;
code->format = data->format;
ecdata = make_data(data->format, ec, data->bits);
if (!ecdata) {
free(code);
return 0;
}
/* TODO: allocate bitmap; layout */
return 0;
}
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