/* Line Break Conversion by cppig1995 */

/* Jan 04, 2006 -- [cppig1995] */

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

enum { CONVERT_UNIX_WINDOWS, CONVERT_WINDOWS_UNIX };

int main(int argc, char *argv[])
{
    FILE *fi, *fo;
    char *fin, *fon;
    int c, t, o = 0;

    if(argc < 4)
    {
            printf("\nUsage : uwconv [Source] [Destination | /o] [/uw | /wu]\n");
            printf("Convert Line Break Type Between LF-only <--> CR-LF\n\n");
            printf("/o  : Overwrite into Source file\n");
            printf("/uw : UNIX(LF only) into DOS/Windows(CR/LF)\n");
            printf("/wu : DOS/Windows(CR/LF) into UNIX(LF only)\n\n");
            printf("If you pass more than 3 arguments,\n");
            printf("Only 3 arguments from first will be recognized.\n");
            printf("Else if you pass less than 3 arguments, you will "
                                                  "see this help screen.\n\n");
            printf("Exit Code 0 is Success. If else returned :\n");
            printf("Code 1 : File I/O Error. Code 2 : Parameter Error.\n");
            printf("Code 3 : Conversion Type Specification (/uw, /wu) "
                                                           "is Wrong.\n\n");
            printf("Please report bugs and send your ideas or questions "
                                           "to cppig1995@gmail.com\n");
            return 2;
    }

    if(strcmp(argv[2], "/o")) fon = argv[2];
    else
    {
        tmpnam(fon);
        o = 1;
    }
    if(!strcmp(argv[3], "/uw")) t = CONVERT_UNIX_WINDOWS;
    else if(!strcmp(argv[3], "/wu")) t = CONVERT_WINDOWS_UNIX;
    else return 3;

    fi = fopen(fin, "r");
    fo = fopen(fon, "w");
    if(!(fi && fo)) return 1;
    while((c = getc(fi)) != EOF)
    {
             if(t == CONVERT_UNIX_WINDOWS)
	     {
                  if(c == '\n') putc('\r', fo);
		  putc(c, fo);
             }
             if(t == CONVERT_WINDOWS_UNIX)
                  if(c != '\r') putc(c, fo);
    }
    if(o)
    {
           remove(fin);
           rename(fon, fin);
    }
    return 0; 
}