/************************************************************************
*                                                                       *    
*  Copyright Digital Equipment Corporation 1998. All rights reserved.   *
*                                                                       *    
*  Restricted Rights: Use, duplication, or disclosure by the U.S.       *    
*  Government is subject to restrictions as set forth in subparagraph   *    
*  (c) (1) (ii) of DFARS 252.227-7013, or in FAR 52.227-19, or in FAR   *    
*  52.227-14 Alt. III, as applicable.                                   *    
*                                                                       *    
*  This software is proprietary to and embodies the confidential        *    
*  technology of Digital Equipment Corporation. Possession, use, or     *    
*  copying of this software and media is authorized only pursuant to a  *    
*  valid written license from Digital or an authorized sublicensor.     *    
*                                                                       *    
************************************************************************/

/*      chap_1_stream_record.c                       */

/* This program demonstrates the difference between  */
/* record mode and stream mode Input/Output.         */

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

void process_records(const char *fspec, FILE * fp);

main()
{
    FILE *fp;

    fp = fopen("example-fixed.dat", "w", "rfm=fix", "mrs=40", "rat=none");
    if (fp == NULL) {
        perror("example-fixed");
        exit(EXIT_FAILURE);
    }
    printf("Record mode\n");
    process_records("example-fixed.dat", fp);
    fclose(fp);

    printf("\nStream mode\n");
    fp = fopen("example-streamlf.dat", "w");
    if (fp == NULL) {
        perror("example-streamlf");
        exit(EXIT_FAILURE);
    }
    process_records("example-streamlf.dat", fp);
    fclose(fp);
}

void process_records(const char *fspec, FILE * fp)
{
    int i,
        sts;

    char buffer[40];

    /* Write records of all 1's, all 2's and all 3's */
    for (i = 0; i < 3; i++) {
        memset(buffer, '1' + i, 40);
        sts = fwrite(buffer, 40, 1, fp);
        if (sts != 1) {
            perror("fwrite");
            exit(EXIT_FAILURE);
        }
    }

    /* Rewind the file and write 10 characters of A's, then 10 B's, */
    /* then 10 C's.                                                 */
    /*                                                              */
    /* For stream mode, each fwrite call outputs 10 characters      */
    /* and advances the file position 10 characters                 */
    /* characters.                                                  */
    /*                                                              */
    /* For record mode, each fwrite merges the 10 characters  into  */
    /* the existing 40-character record, updates the record and     */
    /* advances the file position 40 characters to the next record. */
    rewind(fp);
    for (i = 0; i < 3; i++) {
        memset(buffer, 'A' + i, 10);
        sts = fwrite(buffer, 10, 1, fp);
        if (sts != 1) {
            perror("fwrite2");
            exit(EXIT_FAILURE);
        }
    }

    /* Now reopen the file and output the records. */

    fclose(fp);
    fp = fopen(fspec, "r");
    for (i = 0; i < 3; i++) {
        sts = fread(buffer, 40, 1, fp);
        if (sts != 1)
            perror("fread");
            printf("%.40s\n", buffer);
    }

    return;
}