/* Splits a binary file into 1Mb chunks */
/* Note: -m flag makes it split into 1.4 Mb chunks (26/7/99  AJD)*/
#include <stdio.h>

#define BUFFER_SIZE   16384    /* 2^14 bytes				 */
#define ONE_MEGABYTE  1048576  /* 64 buffers (2^20 bytes)    */
#define MAX_FILE_SIZE 1409024  /* 86 buffers (86*2^14 bytes) */
int BUFFERS_PER_FILE;

main (argc, argv)
    int argc;
    char* argv[];
{

    FILE* infile;
    FILE* outfile = NULL;
    char * infilename;
    char outfilename [255];
    char buffer [BUFFER_SIZE];
    int finished = 0;
    int file_number = 0;
    int buffer_number = 0;
    int bytes_read;
    int bytes_written;

    if (argc<2 || argc>4) {
        fprintf(stderr,"\nUSAGE: %s [ -m | -s <size_of_chunks_in_MBs> ] filename\n\n"
					   "        -m = Use maximum size chunks which can fit on a floppy disk\n"
					   "        -s n = Use chunks which are n megabytes in size\n\n"
					   "        Default chunk size is 1 MB\n\n",argv[0]);
        exit(1);
    }

    if (!strcmp(argv[1],"-m")) {
        
        infilename=argv[2];
        BUFFERS_PER_FILE = MAX_FILE_SIZE/BUFFER_SIZE;
    }
    else if (!strcmp(argv[1],"-s"))
	{
		int nMBChunks = atoi(argv[2]);
        infilename=argv[3];
        BUFFERS_PER_FILE = (nMBChunks*ONE_MEGABYTE)/BUFFER_SIZE;
    }
    else {
        infilename=argv[1];
        BUFFERS_PER_FILE = ONE_MEGABYTE/BUFFER_SIZE;
    }

    if ((infile=fopen(infilename,"rb"))==NULL)
    {
        fprintf(stderr,"Could not open %s\n",infilename);
    }

    file_number++;
    sprintf(outfilename,"%s-%d",infilename,file_number);
    printf("Creating %s.\n",outfilename);
    if ((outfile=fopen(outfilename,"wb"))==NULL) {
        fprintf(stderr,"Could not open %s for write.\n",outfilename);
        fclose(infile);
        exit(1);
    }
    buffer_number = 0;

    while (!finished)
    {
        bytes_read = fread(buffer, sizeof(char), BUFFER_SIZE, infile);
        if (bytes_read==0)
        {
            if (outfile!=NULL) fclose(outfile);
            fclose(infile);
            finished=1;
        }
        else
        {
            if (buffer_number>=BUFFERS_PER_FILE)
            {
                fclose(outfile);
                outfile=NULL;
                file_number++;
                sprintf(outfilename,"%s-%d",infilename,file_number);
                printf("Creating %s.\n",outfilename);
                if ((outfile=fopen(outfilename,"wb"))==NULL) {
                    fprintf(stderr,"Could not open %s for write\n",outfilename);
                    fclose(infile);
                    exit(1);
                }
                buffer_number = 0;
            }

            bytes_written = fwrite(buffer, sizeof(char), bytes_read, outfile);
            if (bytes_written!=bytes_read)
            {
                fprintf(stderr,"bytes_written!=bytes_read...\n");
            }
            buffer_number++;
        }
    }
    
    if (outfile!=NULL) fclose(outfile);
    fclose(infile);
}