record.c

// slightly modified version of original file from assignment 1

#include "record.h"

//print a message
void print_record_message(message_record_t *message)
{
    //message cannot be NULL
    if (message == NULL) {
        fprintf(stderr, "The message is NULL\n");
        exit(0);
    }

    //print message time
    printf("Time: %02d/%02d/%04d %02d:%02d\n", message->month, message->day,
           message->year, message->hour, message->minute);

    //print message text
    printf("Text: %s\n", message->text);
}

//print a record
void print_record(record_t *record)
{
    int i;

    //record cannot be NULL
    if (record == NULL) {
        fprintf(stderr, "The record is NULL\n");
        exit(0);
    }

    //print user id
    printf("ID: %06d\n", record->id);

    //print user name
    printf("Name: %s\n", record->name);

    //print user location
    printf("Location: %s\n", record->location);

    //print message if the message number is greater than 0
    for (i = 0; i < record->message_num; i++) {
        print_record_message(&(record->messages[i]));
    }
}

//read a message from a file
void read_record_message(message_record_t *message, FILE *fp)
{
    //Assume file has been opened
    if (fp == NULL) {
        fprintf(stderr, "The file stream is NULL\n");
        exit(0);
    }

    //message cannot be NULL
    if (message == NULL) {
        fprintf(stderr, "The message is NULL\n");
        exit(0);
    }

    //read message text
    fread(&(message->text[0]), sizeof(char), TEXT_LONG, fp);

    //read message time
    fread(&(message->year), sizeof(int), 1, fp);
    fread(&(message->month), sizeof(int), 1, fp);
    fread(&(message->day), sizeof(int), 1, fp);
    fread(&(message->hour), sizeof(int), 1, fp);
    fread(&(message->minute), sizeof(int), 1, fp);
}

//read a record from a file
record_t *read_record(FILE *fp)
{
    int i;

    //Assume file has been opened
    if (fp == NULL) {
        fprintf(stderr, "The file stream is NULL\n");
        exit(0);
    }

    //allocate memory for the record
    record_t *record = (record_t *)malloc(sizeof(record_t));

    //memory error
    if (record == NULL) {
        fprintf(stderr, "Cannot allocate memory for record.\n");
        exit(0);
    }

    //read user id
    fread(&(record->id), sizeof(int), 1, fp);

    //read user name
    fread(&(record->name[0]), sizeof(char), TEXT_SHORT, fp);

    //read user location
    fread(&(record->location[0]), sizeof(char), TEXT_SHORT, fp);

    //read message number
    fread(&(record->message_num), sizeof(int), 1, fp);

    //initalize messsages
    record->messages = NULL;

    //allocate memory for messages if the message number is greater than 0
    if (record->message_num > 0) {

        //allocate memory
        record->messages = (message_record_t *)malloc(sizeof(message_record_t) *
                                               record->message_num);

        //memory error
        if (record->messages == NULL) {
            fprintf(stderr, "Cannot allocate memory for messages.\n");
            exit(0);
        }

        //read each message from file
        for(i = 0; i < record->message_num; i++) {
            read_record_message(&(record->messages[i]), fp);
        }
    }

    //return the record
    return record;
}

//free memory of a record
void free_record(record_t *record)
{
    if (record == NULL) {
        return;
    }

    //free message memory
    if (record->messages != NULL) {
        free(record->messages);
    }

    //free record memory
    free(record);
}