--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Meerwald-dir/wm_xie2_e.c	Fri Dec 20 13:08:59 2024 +0100
@@ -0,0 +1,288 @@
+#include "wm.h"
+#include "signature.h"
+#include "dwt.h"
+#include "netpbm/pgm.h"
+
+char *progname;
+
+// watermarking transformation, set median pixel to quantization boundary
+double wm_transform(int quant, double f1, double f2, double f3, int x) {
+  double s = (fabs(f3) - fabs(f1)) / (double) quant;
+  double l = x ? (f1 + s) : f1;
+  double f2new;
+  
+  while ((l + 2 * s) < f2) l += 2 * s;
+  f2new = ((f2 - l) < (l + 2 * s - f2)) ? l : (l + 2 * s);
+
+  return f2new;
+}
+
+void usage(void) {
+  fprintf(stderr, "usage: %s [-a n] [-e n] [-f n] [-F n] [-h] [-l n] [-o file] [-v n] -s file file\n\n", progname);
+  fprintf(stderr, "\t-a n\t\tembedding strength (default 0.05)\n");
+  fprintf(stderr, "\t-e n\t\twavelet filtering method\n");
+  fprintf(stderr, "\t-f n\t\tfilter number\n");
+  fprintf(stderr, "\t-F file\t\tfilter definition file\n");
+  fprintf(stderr, "\t-l n\t\tembedding level\n");
+  fprintf(stderr, "\t-h\t\tprint usage\n");
+  fprintf(stderr, "\t-o file\t\toutput (watermarked) file\n");
+  fprintf(stderr, "\t-q n\t\tquantization level\n");
+  fprintf(stderr, "\t-s file\t\tsignature to embed in input image\n");
+  fprintf(stderr, "\t-v n\t\tverbosity level\n");
+  exit(0);
+}
+
+int main(int argc, char *argv[]) {
+
+  FILE *in = stdin;
+  FILE *out = stdout;
+  FILE *sig = NULL;
+
+  char output_name[MAXPATHLEN] = "(stdout)";
+  char input_name[MAXPATHLEN] = "(stdin)";
+  char signature_name[MAXPATHLEN];
+
+  int c, n;
+  int row, col;
+
+  double alpha = 0.0;
+  int filter = 0;
+  int method = -1;
+  int level = 0;
+  int quant = 0;
+  char filter_name[MAXPATHLEN] = "";
+
+  int seed;
+  int verbose = 0;
+
+  gray **image;
+  Image_tree dwts, p;
+
+  gray maxval;
+  int rows, cols, format;
+
+  progname = argv[0];
+
+  pgm_init(&argc, argv); wm_init();
+
+  while ((c = getopt(argc, argv, "a:e:f:F:h?l:o:s:v:")) != EOF) {
+    switch (c) {
+      case 'e':
+        method = atoi(optarg);
+        if (method < 0) {
+          fprintf(stderr, "%s: wavelet filtering method %d out of range\n", progname, method);
+          exit(1);
+        }
+        break;
+      case 'f':
+        filter = atoi(optarg);
+        if (filter <= 0) {
+          fprintf(stderr, "%s: filter number %d out of range\n", progname, filter);
+          exit(1);
+        }
+        break;
+      case 'F':
+        strcpy(filter_name, optarg);
+        break;
+      case 'h':
+      case '?':
+        usage();
+        break;
+      case 'l':
+        level = atoi(optarg);
+        if (level < 1) {
+          fprintf(stderr, "%s: embedding level out of range\n", progname);
+          exit(1);
+        }
+        break;       
+      case 'o':
+        if ((out = fopen(optarg, "wb")) == NULL) {
+          fprintf(stderr, "%s: unable to open output file %s\n", progname, optarg);
+          exit(1);
+        }
+        strcpy(output_name, optarg);
+        break;
+      case 'q':
+        quant = atoi(optarg);
+        break;
+      case 'a':
+        alpha = atof(optarg);
+        if (alpha <= 0.0) {
+          fprintf(stderr, "%s: embedding strength factor %f out of range\n", progname, alpha);
+          exit(1);
+        }
+        break;
+      case 's':
+        if ((sig = fopen(optarg, "r")) == NULL) {
+          fprintf(stderr, "%s: unable to open signature file %s\n", progname, optarg);
+          exit(1);
+        }
+        strcpy(signature_name, optarg);
+        break;
+      case 'v':
+        verbose = atoi(optarg);
+        if (verbose < 0) {
+          fprintf(stderr, "%s: verbosity level %d out of range\n", progname, verbose);
+          exit(1);
+        }
+        break;
+    }
+  }
+
+  argc -= optind;
+  argv += optind;
+
+  if (argc > 1) {
+    usage();
+    exit(1);
+  }
+
+  if (argc == 1 && *argv[0] != '-') {
+    if ((in = fopen(argv[0], "rb")) == NULL) {
+      fprintf(stderr, "%s: unable to open input file %s\n", progname, argv[0]);
+      exit(1);
+    }
+    else
+      strcpy(input_name, argv[0]);
+  }
+
+  if (sig) {
+    char line[32];
+    fgets(line, sizeof(line), sig);
+    if (strspn(line, "XE2SG") >= 5) {
+      fscanf(sig, "%d\n", &nbit_signature);
+      if (alpha == 0.0)
+        fscanf(sig, "%lf\n", &alpha);
+      else
+        fscanf(sig, "%*f\n");
+      if (method < 0)
+        fscanf(sig, "%d\n", &method);
+      else
+        fscanf(sig, "%*d\n");
+      if (filter == 0)
+        fscanf(sig, "%d\n", &filter);
+      else
+        fscanf(sig, "%*d\n");
+      if (!strcmp(filter_name, ""))
+        fscanf(sig, "%[^\n\r]\n", filter_name);
+      else
+        fscanf(sig, "%*[^\n\r]\n");
+      if (quant == 0)
+        fscanf(sig, "%d\n", &quant);
+      else
+        fscanf(sig, "%*d\n");
+      if (level == 0)
+        fscanf(sig, "%d\n", &level);
+      else
+        fscanf(sig, "%*d\n");
+      fscanf(sig, "%d\n", &seed);
+      srandom(seed);
+      n_signature = NBITSTOBYTES(nbit_signature);
+      fread(signature, sizeof(char), n_signature, sig);
+      fscanf(sig, "\n");
+    }
+    else {
+      fprintf(stderr, "%s: invalid signature file %s\n", progname, signature_name);
+      exit(1);
+    }
+    fclose(sig);
+  }
+  else {
+    fprintf(stderr, "%s: signature file not specified, use -s file option\n", progname);
+    exit(1);
+  }
+
+  pgm_readpgminit(in, &cols, &rows, &maxval, &format);
+
+  if (verbose > 0) 
+    fprintf(stderr, "%s: embedding %d bits with strength %d in\n"
+                    "  %d x %d host image, decomposition level %d\n",
+                    progname, nbit_signature, quant, cols, rows, level);
+
+  image = pgm_allocarray(cols, rows);
+
+  for (row = 0; row < rows; row++)
+    pgm_readpgmrow(in, image[row], cols, maxval, format);
+
+  fclose(in);
+
+  // decomposition of image
+  init_dwt(cols, rows, filter_name, filter, level, method);
+#ifdef POLLEN_STUFF
+#include "pollen_stuff.c"
+#endif
+#ifdef PARAM_STUFF
+#include "param_stuff.c"
+#endif
+
+  dwts = fdwt(image);
+
+  p = dwts;
+
+  // consider each resolution level
+  while (p->level < level) 
+    // descend one level
+    p = p->coarse;
+
+  // repeat binary watermark by sliding a 3-pixel window of approximation image
+  n = 0;
+  for (row = 0; row < p->image->height; row++) {
+    col = 0;
+    while (col < p->image->width - 3) {
+      double MIN_DIFF = (20.0 * alpha);
+      double b1, b2, b3;
+      double *f1 = &b1, *f2 = &b2, *f3 = &b3;
+      double f2new;
+
+      // get all three approximation pixels in window
+      b1 = get_pixel(p->image, col + 0, row);
+      b2 = get_pixel(p->image, col + 1, row);
+      b3 = get_pixel(p->image, col + 2, row);
+
+      // bring selected pixels in ascending order
+#define SWAP(A, B) {double *t = A; A = B; B = t;}
+      if (*f1 > *f2) SWAP(f1, f2);
+      if (*f2 > *f3) SWAP(f2, f3);
+      if (*f1 > *f2) SWAP(f1, f2);
+
+      if ((*f3 - *f1) < MIN_DIFF) {
+        double adj = (MIN_DIFF - (*f3 - *f1)) / 2.0;
+        *f1 -= adj;
+        *f3 += adj;
+      }
+
+      // apply watermarking transformation (modify median pixel)
+      f2new = wm_transform(quant, *f1, *f2, *f3, get_signature_bit(n % nbit_signature));
+
+      if (verbose > 1)
+        fprintf(stderr, "%s: embedding #%d (= %d) at (%d/%d); %f < %f -> %f < %f\n",
+          progname, n, get_signature_bit(n % nbit_signature), col, row, *f1, *f2, f2new, *f3);
+
+      *f2 = f2new;
+
+      // write modified pixel     
+      set_pixel(p->image, col + 0, row, b1);
+      set_pixel(p->image, col + 1, row, b2);
+      set_pixel(p->image, col + 2, row, b3);
+      n++;
+      col += 3;
+      col+= (2.0 / alpha);
+    }
+  }
+
+    
+  // skip over some pixels
+
+  idwt(dwts, image);
+
+  pgm_writepgminit(out, cols, rows, maxval, 0);
+
+  for (row = 0; row < rows; row++)
+    pgm_writepgmrow(out, image[row], cols, maxval, 0);
+
+  fclose(out);
+
+  pgm_freearray(image, rows);
+
+  exit(0);
+}