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/*
* (C) 2013 by Christian Hesse <mail@eworm.de>
*
* This software may be used and distributed according to the terms
* of the GNU General Public License, incorporated herein by reference.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <regex.h>
#include <gdk-pixbuf/gdk-pixbuf.h>
#include <qrencode.h>
/* pixels are scaled up by this factor */
#define QRCODE_SCALE 2
/* error correction level used for QR code
* possible values: QR_ECLEVEL_L (lowest, about 7% error can be corrected)
* QR_ECLEVEL_M (about 15%)
* QR_ECLEVEL_Q (about 25%)
* QR_ECLEVEL_H (highest, about 30%)
* image size raises with higher levels */
#define QRCODE_LEVEL QR_ECLEVEL_L
GdkPixbuf * encode_qrcode (char *text) {
QRcode *qrcode;
GdkPixbuf *pixbuf, *pixbuf_scaled;
int i, j, k, rowstride, channels;
gchar *pixel;
unsigned char *data;
qrcode = QRcode_encodeData(strlen(text), text, 0, QRCODE_LEVEL);
if (qrcode == NULL)
return NULL;
data = qrcode->data;
pixbuf = gdk_pixbuf_new (GDK_COLORSPACE_RGB, FALSE, 8, qrcode->width + 2, qrcode->width + 2);
pixel = gdk_pixbuf_get_pixels (pixbuf);
rowstride = gdk_pixbuf_get_rowstride (pixbuf);
channels = gdk_pixbuf_get_n_channels (pixbuf);
gdk_pixbuf_fill(pixbuf, 0xffffffff);
for (i = 1; i <= qrcode->width; i++)
for (j = 1; j <= qrcode->width; j++) {
for (k = 0; k < channels; k++)
pixel[i * rowstride + j * channels + k] = !(*data & 0x1) * 0xff;
data++;
}
pixbuf_scaled = gdk_pixbuf_scale_simple (pixbuf,
(qrcode->width + 2) * QRCODE_SCALE,
(qrcode->width + 2) * QRCODE_SCALE,
GDK_INTERP_NEAREST);
QRcode_free(qrcode);
g_object_unref(pixbuf);
return pixbuf_scaled;
}
int main(int argc, char **argv) {
char * http_referer, * server_name, * pattern;
regex_t preg;
size_t nmatch = 1;
regmatch_t pmatch[1];
int rc = 0;
GdkPixbuf *pixbuf;
gchar *buffer;
gsize size;
/* check if we have environment variables from CGI */
if ((server_name = getenv("SERVER_NAME")) == NULL) {
fprintf(stderr, "This is a CGI executable. Running without a web service is not supported.\n"
"Note that SERVER_NAME needs to be defined, for full features the client has\n"
"to send referer information.\n");
return EXIT_FAILURE;
}
if ((http_referer = getenv("HTTP_REFERER")) == NULL) {
http_referer = server_name;
} else {
/* prepare pattern matching */
pattern = malloc(28 + strlen(server_name));
sprintf(pattern, "^[hH][tT][tT][pP][sS]\\?://%s/", server_name);
if ((rc = regcomp(&preg, pattern, 0)) != 0)
fprintf(stderr, "regcomp() failed, returning nonzero (%d)\n", rc);
/* check if the QR-Code is for the correct server */
if ((rc = regexec(&preg, http_referer, nmatch, pmatch, 0)) != 0) {
http_referer = malloc(44 + strlen(server_name));
sprintf(http_referer, "This QR Code has been stolen from %s!", server_name);
}
regfree(&preg);
free(pattern);
}
/* initialize type system for glib < 2.36 */
#ifndef GLIB_VERSION_2_36
g_type_init();
#endif
if ((pixbuf = encode_qrcode(http_referer)) == NULL) {
if ((pixbuf = encode_qrcode(server_name)) == NULL) {
fprintf(stderr, "Could not generate QR-Code.\n");
return EXIT_FAILURE;
}
}
/* print HTTP header */
printf("Content-Type: image/png\n\n");
/* cut http_referer, text in png file may have a max length of 79 chars */
if (strlen(http_referer) > 79) {
if (!rc) {
http_referer = strdup(http_referer);
rc = 1;
}
sprintf(http_referer + 76, "...");
}
/* print PNG data */
gdk_pixbuf_save_to_buffer (pixbuf, &buffer, &size, "png", NULL,
"compression", "9",
"tEXt::comment", "QR-Code created by cqrlogo - https://github.com/eworm-de/cqrlogo",
"tEXt::referer", http_referer, NULL);
fwrite (buffer, 1, size, stdout);
if (rc)
free(http_referer);
g_object_unref(pixbuf);
return EXIT_SUCCESS;
}
// vim: set syntax=c:
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