/* This program will convert all LFs to CRLFs */
/* Will also expand all Tabs to spaces */

/* Usage:         */
/* addcr filespec */

#include <stdio.h>

#define TAB 9
#define LF 10
#define CR 13

void Leave(char *Path)
{
  perror(Path);
  exit(1);
}

void main(int argc, char *argv[])
{
  FILE *FilePtr, *TempFile;
  int  Col, I;
  char C, PC;
  char *TempName = (char *)malloc(80);
  char *Path = (char *)malloc(80);

  /* If a command line argument was passed */
  if (argc > 1)
  {
    strcpy(Path, argv[1]);
  }
  else  /* Fail */
  {
    printf("Must specify input file\n");
    exit(0);
  }

  /* Open file to be converted */
  FilePtr = fopen(Path, "rb+");
  if (!FilePtr)
  {
    Leave(Path);
  }

  /* Set buffer size to that of a cluster */
  setvbuf(FilePtr, (char *)malloc(4096), _IOFBF, 4096);

  /* Open temporary file */
  TempFile = fopen(tmpnam(TempName), "wb+");
  if (!TempFile)
  {
    Leave("Temporary File");
  }

  /* Set buffer size to that of a cluster */
  setvbuf(TempFile, (char *)malloc(4096), _IOFBF, 4096);

  PC = '\0';
  Col = 0;

  /* Copy from InFile to Temporary file */
  while((C = fgetc(FilePtr)) != EOF)
  {
    /* If this is a Line Feed, and there wasn't a Carriage Return before it */
    /* add a Carriage Return */
    if (C == LF)
    {
      if (!(PC == CR))
        fputc(CR, TempFile);
      Col = -1;
    }

    /* Handle Tabs */
    if (C == TAB)
    {
      for (I = 0; I < 8-Col; I++)
        fputc(' ', TempFile);
      Col = -1;
    }
    else
      fputc(C, TempFile);

    PC = C;
    Col = (Col + 1) % 8;
  }

  /* Reset both file pointers to the top */
  rewind(FilePtr);
  rewind(TempFile);

  /* Copy from Temporary to original file */
  while((C = fgetc(TempFile)) != EOF)
    fputc(C, FilePtr);

  fclose(TempFile);
  fclose(FilePtr);

  /* Delete the temporary file */
  remove(TempName);
}