make_chunks.c

#include <errno.h>
#include <stdio.h>
#include <math.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <stdlib.h>
#include "sha.h"
#include "chunk.h"

static int get_numchunks(char *);

int main(int argc, char *argv[]) {
    // expect one argument atleast.
    if( argc < 2 ) {
        fprintf(stderr,"usage: %s <input-file>", argv[0]);
        exit(-1);
    }

    char *input_file = argv[1];
    FILE *fp = fopen(input_file, "rb");
    int numchunks = get_numchunks(input_file), i = 0;

    // check for sanity.
    if( numchunks < 0 || fp == NULL) {
        fprintf(stderr, "Can't stat the file %s: %s\n", input_file, strerror(errno));
        exit(-1);
    }

    // create the array. 
    uint8_t **hashes = (uint8_t **) malloc(numchunks * sizeof(uint8_t *));
    if( hashes == NULL ) {
        fprintf(stderr, "Out of memory!!!");
        exit(-1);
    }

    // allocate the individual elements.
    for(i=0;i<numchunks;i++) {
        hashes[i] = malloc((SHA1_HASH_SIZE)*sizeof(uint8_t));
        if( hashes[i] == NULL ) {
            fprintf(stderr, "Out of memory!!!");
            exit(-1);
        }
    }

    int chunks = make_chunks(fp, hashes);
    char ascii[SHA1_HASH_SIZE*2+1]; // the ascii string.
    for(i=0;i<chunks;i++) {
        hex2ascii(hashes[i], SHA1_HASH_SIZE, ascii);
        printf("%d %s\n",i,ascii);
        free(hashes[i]);
    }

    // free the memory.
    free(hashes);
    // close file.
    fclose(fp);

    // return success.
    return 0;
}

int get_numchunks(char *filename) {
    struct stat file;

    // the stat returned the file.
    if( !stat(filename,&file)) {
        // return the number of chunks for the file.
        double length = (double) file.st_size;
        return ceil(length / BT_CHUNK_SIZE);
    } else {
        // return error.
        return -1;
    }
}