/* File:    stringlistio.c
 * Author:  Samuel A. Rebelsky
 * Version: 1.0 of February 2000
 *
 * I/O routines for simple lists of strings.  Written as a client of
 * the other list utilities so that the system is more modular (and
 * so that I implicitly test all those routines).  Part of an examples
 * for CSC364 2000S.
 *
 * Provides:
 *   dumpList(stringlist, fileName)
 *     write a list to a file
 *   printlist(FILE *, stringlist)
 *     write a list to a file
 *   readList(fileName)
 *     read a list from a file
 */
 
/***********
 * Headers *
 *****************************************************************/

#include <stdio.h>

#include "stringlist.h"

/********************
 * Exported Methods *
 *****************************************************************/

/* Dump a list to a file. */
void dumpList(char *fname, stringlist stuff) {
  FILE *dest;      /* The file that will contain the elements. */
  /* Set up the file for writing. */
  dest = fopen(fname, "w");
  /* Sanity check. */
  if (dest == NULL)
    return;
  /* Print the list. */
  printList(dest, stuff);
  /* Clean up. */
  fclose(dest);
} /* dumpList() */

/* Print a list. */
void printList(FILE *dest, stringlist stuff) {
  char *str;       /* One string in the list.                  */
  /* Scan through the list, printing as you go. */
  reset(stuff);
  while ((str = nextElement(stuff)) != NULL)
    fprintf(dest, "%s\n", str);
} /* printList() */

/* Read a list from a file. */
stringlist readList(char *fname) {
  FILE *source;        /* The file that contains the elements. */
  stringlist stuff;    /* The list we're building.             */
  char str[MAXSTRING]; /* A buffer for reading strings.        */
  
  /* Open the file to prepare for reading. */
  source = fopen(fname, "r");
  /* Sanity check. */
  if (source == NULL)
    return NULL;
  /* Prepare the list. */
  stuff = newList();
  /* Sanity check. */
  if (stuff == NULL) {
    fclose(source);
    return NULL;
  }
  /* Read all the lines. */
  while (fgets(str,MAXSTRING,source)) {
    if (!addToEnd(stuff, str)) {
      // Whoops!  Failed to add.
      clear(stuff);
      freeList(stuff);
      fclose(source);
      return NULL;
    }
  } /* while there are strings to read */
  /* Clean up. */
  fclose(source);
  return stuff;
} /* readList() */