pnmio.c

it runs for blob detection with opencv

/*
**  Source file for blobdetect. (c) 2004 Johan Wiklund
**
**  This program is free software; you can redistribute it and/or modify
**  it under the terms of the GNU General Public License as published by
**  the Free Software Foundation; either version 2 of the License, or
**  (at your option) any later version.
**  
**  See the file COPYING for details.
**
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#ifndef WIN32
#include <strings.h>
#endif
#include "pnmio.h"

static char
pnm_getc(FILE *file)
{
  register int ich;
  register char ch;

  ich= getc(file);
  if (ich == EOF) {
    fprintf(stderr, "pnm_getc: EOF / read error\n");
    exit(1);
  }
  ch= (char)ich;
    
  if (ch == '#') {
    do {
      ich= getc(file);
      if (ich == EOF) {
	fprintf(stderr, "pnm_getc: EOF / read error\n");
	exit(1);
      }
      ch= (char)ich;
    } while (ch != '\n' && ch != '\r');
  }
  
  return ch;
}

static int
pnm_getint(FILE *file)
{
  register char ch;
  register int i;

  do {
    ch= pnm_getc(file);
  } while (ch == ' ' || ch == '\t' || ch == '\n' || ch == '\r');
  
  if (ch < '0' || ch > '9') {
    fprintf(stderr, "pnm_getint: junk in file where an integer should be\n");
    exit(1);
  }

  i= 0;
  do {
    i= i * 10 + ch - '0';
    ch= pnm_getc(file);
  } while (ch >= '0' && ch <= '9');

  return i;
}

static int
pnm_readmagicnumber(FILE* file)
{
  int ich1, ich2;

  ich1= getc(file);
  if (ich1 == EOF) {
    fprintf(stderr, "EOF / read error reading magic number\n");
    exit(1);
  }
  ich2= getc(file);
  if (ich2 == EOF) {
    fprintf(stderr, "EOF / read error reading magic number\n");
    exit(1);
  }
  return ich1 * 256 + ich2;
}

static void
pnm_readinitrest(FILE *file,
		 int *colsP,
		 int *rowsP,
		 int *maxvalP)
{
  /* Read size. */
  *colsP= pnm_getint(file);
  *rowsP= pnm_getint(file);

  /* Read maxval. */
  *maxvalP= pnm_getint(file);
}

/* File open/close that handles "-" as stdin and checks errors. */

static FILE*
pnm_openr(char *name)
{
  FILE* f;

  if (strcmp(name, "-") == 0)
    f= stdin;
  else {
#ifdef WIN32
    f= fopen(name, "rb");
#else /*WIN32*/
#ifndef VMS
    f= fopen(name, "r");
#else
    f= fopen(name, "r", "ctx=stm");
#endif
#endif /*WIN32*/
    if (f == NULL) {
      perror(name);
      exit(1);
    }
  }
  return f;
}

static FILE*
pnm_openw(char *name)
{
  FILE* f;

#ifdef WIN32
  f= fopen(name, "wb");
#else /*WIN32*/
#ifndef VMS
  f= fopen(name, "w");
#else
  f= fopen(name, "w", "mbc=32", "mbf=2");  /* set buffer factors */
#endif
#endif /*WIN32*/
  if (f == NULL) {
    perror(name);
    exit(1);
  }
  return f;
}

void
pnm_close(FILE *f)
{
  fflush(f);
  if (ferror(f))
    fprintf(stderr,
	    "pnm_close: A file read or write error occurred at some point" );
  if (f != stdin) {
    if (fclose(f) != 0) {
      perror("fclose");
      exit(1);
    }
  }
}

FILE *
pnm_readhead(char *name, int *format, int *hgh, int *wid)
{
  FILE *f;
  int maxvalP;

  f= pnm_openr(name);
  *format= pnm_readmagicnumber(f);
  pnm_readinitrest(f, wid, hgh, &maxvalP);

  return(f);
}

FILE *
pnm_writehead(char *name, int format, int hgh, int wid)
{
  FILE *f;
  int maxval= 255;

  f= pnm_openw(name);
  switch (format) {
  case RPPM_FORMAT:
    fprintf(f, "%c%c\n%d %d\n%d\n", PPM_MAGIC1, RPPM_MAGIC2,
	    wid, hgh, maxval);
    break;
  case RPGM_FORMAT:
    fprintf(f, "%c%c\n%d %d\n%d\n", PGM_MAGIC1, RPGM_MAGIC2,
	    wid, hgh, maxval);
    break;
  default:
    fprintf(stderr, "pnm_writehead: Can only write P5 and P6 types\n");
    exit(1);
    break;
  }

  return(f);
}