/******************************************************************************/
/*                                                                            */
/*                                R E P L C R                                 */
/*                                                                            */
/*  Program:      REPLCR                                                      */
/*                                                                            */
/*  Programmer:   Dr. David G. Simpson                                        */
/*                NASA Goddard Space Flight Center                            */
/*                Greenbelt, Maryland  20771                                  */
/*                                                                            */
/*  Date:         October 10, 2002                                            */
/*                                                                            */
/*  Language:     ANSI Standard C                                             */
/*                                                                            */
/*  Description:  This program converts an ASCII text file from any of the    */
/*                three possible formats to any other format:                 */
/*                                                                            */
/*                 1.  Lines end with  CR     (e.g. Macintosh)                */
/*                 2.  Lines end with  LF     (e.g. UNIX, VAX)                */
/*                 3.  Lines end with  CR/LF  (e.g. PC)                       */
/*                                                                            */
/******************************************************************************/


/******************************************************************************/
/*  #includes                                                                 */
/******************************************************************************/

#include <stdio.h>                          /* standard i/o                   */
#include <stdlib.h>                         /* standard library               */
#include <string.h>                         /* string functions               */



/******************************************************************************/
/*  #defines                                                                  */
/******************************************************************************/

#define  CR  0x0D                           /* carriage return                */
#define  LF  0x0A                           /* line feed                      */



/******************************************************************************/
/*  function prototype                                                        */
/******************************************************************************/

void chomp (char *str);                     /* remove final \n from string    */



/******************************************************************************/
/*  global variables                                                          */
/******************************************************************************/

char infilename[133];                       /* input file name                */
char outfilename[133];                      /* output file name               */
char line[133];                             /* used to read in input line     */
int  fromfmt;                               /* format to convert from         */
int  tofmt;                                 /* format to convert to           */
int  choice;                                /* both "from" and "to" formats   */
unsigned char b, c, l;                      /* temp storage for bytes         */
FILE *infp, *outfp;                         /* file pointers                  */





/******************************************************************************/
/*  main()                                                                    */
/******************************************************************************/

int main (void)
{


/*  Get input file name  */


fputs("Enter input file name:  ", stdout);
fgets(infilename, 132, stdin);
chomp(infilename);


/*  Get output file name  */


fputs("\nEnter output file name:  ", stdout);
fgets(outfilename, 132, stdin);
chomp(outfilename);


/*  Get "from" format  */


fputs("\nConvert FROM format:\n", stdout);
fputs("  1.  CR     (e.g. Macintosh)\n", stdout);
fputs("  2.  LF     (e.g. UNIX, VAX)\n", stdout);
fputs("  3.  CR/LF  (e.g. PC)\n", stdout);
fputs("?  ", stdout);
fgets(line, 132, stdin);
sscanf(line,"%d", &fromfmt);

if ((fromfmt<1) || (fromfmt>3))
   {
   fputs("Invalid selection.\n", stdout);
   exit(1);
   }


/*  Get "to" format  */


fputs("\nConvert TO format:\n", stdout);
fputs("  1.  CR     (e.g. Macintosh)\n", stdout);
fputs("  2.  LF     (e.g. UNIX, VAX)\n", stdout);
fputs("  3.  CR/LF  (e.g. PC)\n", stdout);
fputs("?  ", stdout);
fgets(line, 132, stdin);
sscanf(line,"%d", &tofmt);

if ((tofmt<1) || (tofmt>3))
   {
   fputs("Invalid selection.\n", stdout);
   exit(1);
   }


/*  Combine "from" and "to" choices into a single integer  */


choice = (fromfmt<<4) | tofmt;


/*  Open input and output files  */


if ((infp = fopen(infilename, "rb"))==NULL)
   {
   printf("Error opening file %s\n", infilename);
   exit(1);
   }

if ((outfp = fopen(outfilename, "wb"))==NULL)
   {
   printf("Error opening file %s\n", outfilename);
   exit(1);
   }


/*  Do the conversion  */


switch (choice)
   {
   case 0x11:                               /* CR -> CR                       */
   case 0x22:                               /* LF -> LF                       */
   case 0x33:                               /* CR/LF -> CR/LF                 */
      for (;;)
         {
         fread(&b, 1, 1, infp);
         if (feof(infp))
            break;
         fwrite(&b, 1, 1, outfp);
         }
      break;

   case 0x12:                               /* CR -> LF                       */
      for (;;)
         {
         fread(&b, 1, 1, infp);
         if (feof(infp))
            break;
         if (b==CR)
            b = LF;
         fwrite(&b, 1, 1, outfp);
         }
      break;

   case 0x13:                               /* CR -> CR/LF                    */
      l = LF;
      for (;;)
         {
         fread(&b, 1, 1, infp);
         if (feof(infp))
            break;
         fwrite(&b, 1, 1, outfp);
         if (b==CR)
            fwrite(&l, 1, 1, outfp);
         }
      break;

   case 0x21:                               /* LF -> CR                       */
      for (;;)
         {
         fread(&b, 1, 1, infp);
         if (feof(infp))
            break;
         if (b==LF)
            b = CR;
         fwrite(&b, 1, 1, outfp);
         }
      break;

   case 0x23:                               /* LF -> CR/LF                    */
      c = CR;
      for (;;)
         {
         fread(&b, 1, 1, infp);
         if (feof(infp))
            break;
         if (b==LF)
            fwrite(&c, 1, 1, outfp);
         fwrite(&b, 1, 1, outfp);
         }
      break;

   case 0x31:                               /* CR/LF -> CR                    */
      for (;;)
         {
         fread(&b, 1, 1, infp);
         if (feof(infp))
            break;
         if (b==LF)
            continue;
         fwrite(&b, 1, 1, outfp);
         }
      break;

   case 0x32:                               /* CR/LF -> LF                    */
      for (;;)
         {
         fread(&b, 1, 1, infp);
         if (feof(infp))
            break;
         if (b==CR)
            continue;
         fwrite(&b, 1, 1, outfp);
         }
      break;

   default:
      fputs("\nProgram error.\n", stdout);
      break;
   }


/*  Close files and exit  */


fclose (outfp);
fclose (infp);

fputs("\nDone.\n", stdout);

return 0;
}




/*****************************************************************************/
/*  chomp()                                                                  */
/*                                                                           */
/*  Remove final \n from end of string.                                      */
/*****************************************************************************/

void chomp (char *str)
{
int  len;                                   /* length of str (incl \n)       */

len = strlen (str);                         /* get length of str incl \n     */
if (str[len-1] == '\n')                     /* if final char is \n ..        */
   str[len-1] = '\0';                       /* ..then remove it              */
}