/* img_ren.c, 2009 Feb 19
 * (C) Copyright Prem Sobel, 2009. All Rights Reseeved.
 * 
 * This program renames all image files of types: 
 *    *.jpg, *.gif, *.png in a directory using a prefix.
 */ 


#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <io.h>

#define SIZE 20
static char name[SIZE], fn_new[SIZE+10];

static struct _finddata_t fileinfo;
static char *prefix;
static char Usage[] = "Usage:  img_ren [prefix]\n";
static int k;

void fail(char *msg) {
    fprintf(stderr,"*** %s\n",msg);
    exit(1);
} // fail

static do_rename(char *fn_old, char *ext) {
    sprintf(fn_new, "%s%03d.%s", prefix, k, &ext[2]);
    //printf("old=%s new=%s\n", fn_old, fn_new);
    rename(fn_old, fn_new);
} // do_rename

static void do_extension(char *ext) {
long h;
	h = _findfirst(ext, &fileinfo);
	if(h>=0) {
        k = 1;
        do_rename(fileinfo.name, ext);
		for(k++; !_findnext(h, &fileinfo); k++) {
            do_rename(fileinfo.name, ext);
		}
	}
	_findclose(h);
} // do_extension

int main(int argc, char* argv[]) { int n;
    if(1 == argc) {
        printf("Enter prefix: ");
        if(!fgets(name, SIZE, stdin))
            fail(Usage);
        prefix = name;
    } else if(2 == argc) {
        prefix = argv[1];
    } else {
        fail(Usage);
    }
    printf("@ prefix=%s\n", prefix);
    for(n=0; prefix[n]; n++) {
        if(('\n' == prefix[n]) || ('\r' == prefix[n])) {
            prefix[n] = 0;
            break;
        }
    }
    do_extension("*.jpg");
    do_extension("*.gif");
    do_extension("*.png");
    return 0;
} // main