arsave.c

来自「Archive Saver Could save Segment of an 」· C语言 代码 · 共 110 行

/*
 * archive saver
 *
 * Copyright (c) 2008, Veacheslav Patkov.
 * aLL rights reserved.
 *
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdarg.h>

#define ARSAVE_VERSION "0.03"

#define BUFSIZE 128*1024
#define MAXSIGN 14

typedef struct {
    char *name;
    char *ext;
    char *sign;
    unsigned char len;
    unsigned char offset;
} signature;

signature signs[] = {
    {"ZIP",".zip","\x50\x4b\x03\x04",4,0},
    {"ZIP",".zip","\x50\x4b\x30\x30\x50\x4b",6,0},
    {"RAR",".rar","\x52\x61\x72\x21",4,0},
    {"CAB",".cab","\x4d\x53\x43\x46",4,0},
    {"UHARC",".uha","\x55\x48\x41",3,0},
    {"7-ZIP",".7z","\x37\x7a\xbc\xaf\x27\x1c",6,0},
    {"ACE",".ace","\x2a\x2a\x41\x43\x45\x2a\x2a",7,7},
    {0,0,0,0,0}
};

char *iname,oname[260],buf[BUFSIZE];

void error(char *format, ...)
{
    va_list ap;

    fprintf(stderr,"arsave: error: ");
    va_start(ap,format);
    vfprintf(stderr,format,ap);
    va_end(ap);
    fprintf(stderr,"\n");
    exit(1);
}

int main(int argc, char **argv)
{
    FILE *fi,*fo;
    unsigned int i,k,n = 0;
    char *p;

    if (argc == 1) {
        printf("archive saver version " ARSAVE_VERSION "\n"
               "usage: arsave [-s <start>] <input> [output]\n");
        return 0;
    }

    if (!strcmp(argv[1],"-s")) {
        if (argc < 4)
            error("no input files");
        else if ((int)(n = strtol(argv[2],0,16)) <= 0)
            error("incorrect argument for `-s' option: %s",argv[2]);
        argv += 2;
        argc -= 2;
    }

    iname = argv[1];
    if (!(fi = fopen(iname,"rb")))
        error("cannot open file `%s'",iname);
    if (n > 0)
        if (fseek(fi,n,SEEK_SET))
            error("cannot seek file `%s' to offset %x",iname,n);

    while ((n = fread(buf,1,BUFSIZE,fi)) > 0)
        for (i = MAXSIGN, p = buf; i < n; i++, p++)
            for (k = 0; signs[k].name; k++)
                if (!memcmp(p+signs[k].offset,signs[k].sign,signs[k].len))
                    goto found;

    fprintf(stderr,"arsave: no archives found\n");
    goto the_end;
  found:
    fprintf(stderr,"arsave: found %s archive (offset: 0x%08x)\n",
            signs[k].name,(unsigned int)ftell(fi)+i-n-MAXSIGN);
    if (argc == 2) {
        strcpy(oname,iname);
        strcat(oname,signs[k].ext);
    } else
        strcpy(oname,argv[2]);
    if (!(fo = fopen(oname,"wb")))
        error("cannot open file `%s'",oname);

    fseek(fi,i-n-MAXSIGN,SEEK_CUR);
    while ((n = fread(buf,1,BUFSIZE,fi)) > 0)
        if (fwrite(buf,1,n,fo) != n)
            error("cannot write file `%s'",oname);

    fprintf(stderr,"arsave: saved to: %s\n",oname);
    fclose(fo);
  the_end:
    fclose(fi);
    return 0;
}