/* FileExtract
   By Marc Le Douarain
   mavati@club-internet.fr
   13 April 1999
   Update:24 April 1999
   Made on an idea of Mickaël Le Quer
*/
    
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

char Version[]="$VER:FileExtract 0.8c " __AMIGADATE__;

long HexaToLong(char *str)
{
    int i;
    int pw;
    int lgt;
    static int car;
    long res=0;
    lgt=strlen(str);
    pw=1;
    for (i=lgt-1;i>=0;i--)
    {
        car=str[i];
        if (car>='A')
        {
            if (car>'a')
            {
                car=car-'a'+10;
            }
            else
            {
                car=car-'A'+10;
            }
        }
        else
        {
            car=car-'0';
        }
        res=res+(car*pw);
        pw=pw*16;
    }
    return res;
}

void main(int argc, char *argv[])
{
    char *FichierSrc;
    char *FichierDest;
    FILE *FSrc;
    FILE *FDest;
    char Octet;
    long i;
    long StartPos;
    long EndPos;

    if ( (argc>3) && (strcmp(argv[1],"?")!=0) )
    {
        FichierSrc=argv[1];
        FichierDest=argv[2];
        if (argv[3][0]=='$')
        {
            StartPos=HexaToLong(&argv[3][1]);
        }
        else
        {
            StartPos=atol(argv[3]);
        }
        if (argc>4)
        {
            if (argv[4][0]=='+')
            {
                if (argv[4][1]=='$')
                {
                    EndPos=StartPos+HexaToLong(&argv[4][2]);
                }
                else
                {
                    EndPos=StartPos+atol(&argv[4][1]);
					      }
            }
            else
            {
                if (argv[4][0]=='$')
                {
                    EndPos=HexaToLong(&argv[4][1]);
                }
                else
                {
                    EndPos=atol(argv[4]);
					      }
            }
        }
        else
        {
        		EndPos=-1;
        }

        if ((EndPos!=-1)&&(EndPos<StartPos))
        {
            printf("Error: The EndOffset (%d) must be greater than the StartOffset (%d) !\n",StartPos,EndPos);
						printf("If you use the fourth parameter as length : DO NOT FORGET the '+' behind the number!\n"); 
        }
        else
        { 
            FSrc=fopen(FichierSrc,"rb");
            if (FSrc)
            {
                FDest=fopen(FichierDest,"wb");
                if (FDest)
                {
                    fseek(FSrc, StartPos, SEEK_SET);
                    for(i=StartPos;( ( ((i<=EndPos)&&(EndPos!=-1)) || (EndPos==-1) ) && (!(feof(FSrc))) );i++)
                    {
                        if (fread(&Octet,sizeof(char),1,FSrc))
                        {
                            fwrite(&Octet,sizeof(char),1,FDest);
                        }
                    }
                    fclose(FDest);
                }
                else
                {
                    printf("Failed to write file:%s\n",FichierDest);
                }
                fclose(FSrc);
            }
            else
            {
                printf("Failed to open file:%s\n",FichierSrc);
            }
        }
    }
    else
    {
				printf("%s By Marc Le Douarain (mavati@club-internet.fr)\n",Version+sizeof(char)*5);
        printf("Usage: FileExtract <SourceFile> <DestinationFile> <StartOffset> [<EndOffset>or<+Length>]\n"
								"Numbers in hexadecimal usable with the first caracter '$'\n"
								);
    }
}