#include <stdio.h>
#include <stdint.h>
#include <unistd.h>
#include <fcntl.h>
#include <string.h>
#include <malloc.h>
#include <stdlib.h>

void print_binary(FILE *fp, uint32_t n)
{
    uint8_t arr[32] = {0};
    int len = 0;
    for(len = 0; len < 32; len++){
        arr[len] = (n&1)+'0';
        n = n>>1;

    }

    len--;
    while (len >= 0 ){
        fprintf(fp,"%c", arr[len]);
        len--;
    }
    fprintf(fp,"\n");
}

int main( int argc, char *argv[] )
{
    uint8_t buf[128];
    FILE *fin = NULL, *fout = NULL;
    int i = 0;
    uint8_t val;
    off_t filesize, offset;
    size_t st = 0;
    uint32_t tmp = 0;

    if( ( fin = fopen( argv[1], "rb" ) ) == NULL ){
        printf("fopen(%s,r) failed\n", argv[1] );
        goto exit;
    }

    if( ( fout = fopen( argv[2], "w+" ) ) == NULL ){
        printf("fopen(%s,w+) failed\n", argv[2] );
        goto exit;
    }

    if( argc > 3){
        filesize = atoi(argv[3]);
    } else{
        if( ( filesize = lseek( fileno( fin ), 0, SEEK_END ) ) < 0 ){
            perror( "lseek" );
            goto exit;
        }
    }

    if( fseek( fin, 0, SEEK_SET ) < 0 ){
         printf( "fseek(0,SEEK_SET) failed\n" );
         goto exit;
    }
    memset(buf, 0x0,128);
    for( offset = 0; offset < filesize; offset += 1 ){
        st = fread( buf, 1, 4, fin );
        if ( st == 0) {
            break;
        }
        #if 0
        for(i = 0; i < 4; i++){
            val = buf[3-i];
            printf("%02x\n", val);
            printf("%02x\n", val);
            fprintf(fout, "%02x\n", val);
        }
        #else
        if ( st == 4) {
            tmp = (uint32_t)(((uint32_t)buf[3] <<24)|((uint32_t)buf[2]<<16) |(uint32_t)(buf[1]<<8)|(uint32_t)buf[0]);
        } else if (st == 3) {
            tmp = (uint32_t)(((uint32_t)buf[2]<<16) |(uint32_t)(buf[1]<<8)|(uint32_t)buf[0]);
        } else if (st == 2) {
            tmp = (uint32_t)((uint32_t)(buf[1]<<8)|(uint32_t)buf[0]);
        } else if (st == 1) {
            tmp = (uint32_t)((uint32_t)buf[0]);
        }
        //printf("%02x %02x %02x %02x\n", buf[3], buf[2], buf[1], buf[0]);
        //printf("%08x\n", tmp);
        fprintf(fout, "%08x\n", tmp);
        #endif
    }

exit:
    if(fin){
        fclose(fin);
    }

    if(fout){
        fclose(fout);
    }
}