/*############################################################################# * 文件名：wm_cox_e.c * 功能：  加載水印 * modified by  PRTsinghua@hotmail.com#############################################################################*/#include "wm.h"#include "dct.h"#include "pgm.h"#include "sort.h"char *progname;void usage(void) {  fprintf(stderr, "usage: %s [-a n] [-h] [-o file] -s file file\n\n", progname);  fprintf(stderr, "\t-a n\t\talpha factor/embedding strength\n");  fprintf(stderr, "\t-h\t\tprint usage\n");  fprintf(stderr, "\t-o file\t\toutput (watermarked) file\n");  fprintf(stderr, "\t-s file\t\tsignature to embed in input image\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;  int row, col;  int i,j;  int n;  double alpha = 0.0;  double threshold;  double *largest;  gray **input_image;  gray **output_image;  double **dcts;  gray maxval;  int rows, cols, colors, format;  progname = argv[0];  pgm_init(&argc, argv); wm_init();  while ((c = getopt(argc, argv, "a:h?o:s:")) != EOF) {    switch (c) {      case 'a':        alpha = atof(optarg);        if (alpha <= 0.0) {          fprintf(stderr, "%s: alpha factor %f out of range\n", progname, alpha);          exit(1);        }        break;      case 'h':      case '?':        usage();        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 '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;    }  }  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, "CXSG") >= 4) {      fscanf(sig, "%d\n", &n);      if (alpha == 0.0)        fscanf(sig, "%lf\n", &alpha);      else        fscanf(sig, "%*lf\n");      fscanf(sig, "%*lf\n");      fscanf(sig, "%*lf\n");    }    else {      fprintf(stderr, "%s: invalid signature file %s\n", progname, signature_name);      exit(1);    }  }  else {    fprintf(stderr, "%s: signature file not specified, use -s file option\n", progname);    exit(1);  }  pgm_readpgminit(in, &cols, &rows, &maxval, &format);  init_dct_NxN(cols, rows);  dcts = alloc_coeffs(cols, rows);  input_image = pgm_allocarray(cols, rows);  for (row = 0; row < rows; row++)    pgm_readpgmrow(in, input_image[row], cols, maxval, format);  fclose(in);  output_image = pgm_allocarray(cols, rows);  fdct_NxN(input_image, dcts);  largest = malloc((n + 1) * sizeof(double));  select_largest_coeffs(dcts[0], cols * rows, n+1, largest);  threshold = largest[0];  free(largest);  j = 0;  for (i = 0; i < n; i++) {    double v;    while (dcts[j / cols][j % cols] < threshold) j++;    fscanf(sig, "%lf\n", &v);    dcts[j / cols][j % cols] *= (1.0 + alpha * v);    j++;  }  idct_NxN(dcts, output_image);  free_coeffs(dcts);  pgm_writepgminit(out, cols, rows, maxval, 0);  for (row = 0; row < rows; row++)    pgm_writepgmrow(out, output_image[row], cols, maxval, 0);  fclose(out);  fclose(sig);  pgm_freearray(output_image, rows);  pgm_freearray(input_image, rows);  exit(0);}