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#include <stdlib.h>
#include <limits.h>
#include <assert.h>
#include <qr/code.h>
#include "code-common.h"
#include "code-layout.h"
#include "data-common.h"
#include "rs.h"
#define MIN(a, b) ((b) < (a) ? (b) : (a))
#include <stdio.h>
static void x_dump(struct qr_bitstream * bits)
{
size_t i, n;
qr_bitstream_seek(bits, 0);
n = qr_bitstream_size(bits);
for (i = 0; i < n; ++i) {
printf("%d", qr_bitstream_read(bits, 1));
if (i % 8 == 7)
printf(" ");
if ((i+1) % (7 * 8) == 0)
printf("\n");
}
printf("\n");
}
static void setpx(struct qr_code * code, int x, int y)
{
size_t off = y * code->modules->stride + x / CHAR_BIT;
unsigned char bit = 1 << (x % CHAR_BIT);
code->modules->bits[off] |= bit;
}
static void draw_locator(struct qr_code * code, int x, int y)
{
int i;
for (i = 0; i < 6; ++i) {
setpx(code, x + i, y + 0);
setpx(code, x + 6, y + i);
setpx(code, x + i + 1, y + 6);
setpx(code, x, y + i + 1);
}
for (i = 0; i < 9; ++i)
setpx(code, x + 2 + i % 3, y + 2 + i / 3);
}
static void draw_fixed_bits(struct qr_code * code)
{
int dim = code_side_length(code->format);
int i;
/* Locator pattern */
draw_locator(code, 0, 0);
draw_locator(code, 0, dim - 7);
draw_locator(code, dim - 7, 0);
/* Timing pattern */
for (i = 8; i < dim - 8; i += 2) {
setpx(code, i, 6);
setpx(code, 6, i);
}
/* XXX: alignment pattern */
}
static int pad_data(struct qr_bitstream * bits, size_t limit)
{
/* This function is not very nice. Sorry. */
size_t count, n;
assert(qr_bitstream_size(bits) <= limit);
if (qr_bitstream_resize(bits, limit) != 0)
return -1;
n = qr_bitstream_size(bits);
qr_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);
qr_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) {
qr_bitstream_write(bits, 0xEC11, 16);
count -= 16;
}
if (count > 0) {
assert(count == 8);
qr_bitstream_write(bits, 0xEC, 8);
}
return 0;
}
static struct qr_bitstream * make_data(int format,
enum qr_ec_level ec,
struct qr_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 qr_bitstream * dcopy = 0;
struct qr_bitstream * out = 0;
struct qr_bitstream ** blocks = 0;
/* Set up the output stream */
out = qr_bitstream_create();
if (!out)
return 0;
if (qr_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 = qr_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 */
qr_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--)
qr_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 */
qr_bitstream_cat(out, dcopy);
qr_bitstream_cat(out, blocks[0]);
qr_bitstream_write(out, 0, total_bits - total_words * 8);
puts("Final bitstream:");
x_dump(out);
exit:
if (blocks) {
while (block_count--)
qr_bitstream_destroy(blocks[block_count]);
free(blocks);
}
if (dcopy)
qr_bitstream_destroy(dcopy);
return out;
fail:
qr_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 qr_bitstream * bits = 0;
struct qr_iterator * layout;
size_t dim;
code = malloc(sizeof(*code));
if (!code)
return 0;
dim = code_side_length(data->format);
code->format = data->format;
code->modules = qr_bitmap_create(dim, dim, 0);
if (!code->modules)
goto fail;
draw_fixed_bits(code);
bits = make_data(data->format, ec, data->bits);
if (!bits)
goto fail;
layout = qr_layout_begin(code);
if (!layout)
goto fail;
qr_bitstream_seek(bits, 0);
while (qr_bitstream_remaining(bits) >= 8)
qr_layout_write(layout, qr_bitstream_read(bits, 8));
qr_layout_end(layout);
exit:
if (bits)
qr_bitstream_destroy(bits);
return code;
fail:
qr_code_destroy(code);
code = 0;
goto exit;
}
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