/*************************************************************************** *             __________               __   ___. *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___ *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  / *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  < *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \ *                     \/            \/     \/    \/            \/ * $Id: scramble.c,v 1.7 2004/01/08 21:34:52 zagor Exp $ * * Copyright (C) 2002 by Bj鰎n Stenberg * * All files in this archive are subject to the GNU General Public License. * See the file COPYING in the source tree root for full license agreement. * * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY * KIND, either express or implied. * ****************************************************************************/#include <stdio.h>#include <stdlib.h>void int2le(unsigned int val, unsigned char* addr){    addr[0] = val & 0xFF;    addr[1] = (val >> 8) & 0xff;    addr[2] = (val >> 16) & 0xff;    addr[3] = (val >> 24) & 0xff;}void int2be(unsigned int val, unsigned char* addr){    addr[0] = (val >> 24) & 0xff;    addr[1] = (val >> 16) & 0xff;    addr[2] = (val >> 8) & 0xff;    addr[3] = val & 0xFF;}int main (int argc, char** argv){    unsigned long length,i,slen;    unsigned char *inbuf,*outbuf;    unsigned short crc=0;    unsigned char header[24];    unsigned char *iname = argv[1];    unsigned char *oname = argv[2];    unsigned char *xorstring;    int headerlen = 6;    FILE* file;    int version;    enum { none, scramble, xor } method = scramble;    if (argc < 3) {       printf("usage: %s [options] <input file> <output file> [xor string]\n",argv[0]);       printf("options:\n");       printf("\t-fm    Archos FM recorder format\n");       printf("\t-v2    Archos V2 recorder format\n");       printf("\t-neo   SSI Neo format\n");       printf("\t-mm=X  Archos Multimedia format (X values: A=JBMM, B=AV1xx, C=AV3xx)\n");       printf("\nNo option results in Archos standard player/recorder format.\n");       return -1;    }    if(!strcmp(argv[1], "-fm")) {        headerlen = 24;        iname = argv[2];        oname = argv[3];        version = 4;    }        else if(!strcmp(argv[1], "-v2")) {        headerlen = 24;        iname = argv[2];        oname = argv[3];        version = 2;    }    else if(!strcmp(argv[1], "-neo")) {        headerlen = 17;        iname = argv[2];        oname = argv[3];        method = none;    }    else if(!strncmp(argv[1], "-mm=", 4)) {        headerlen = 16;        iname = argv[2];        oname = argv[3];        method = xor;        version = argv[1][4];        if (argc > 4)            xorstring = argv[4];        else {            printf("Multimedia needs an xor string\n");            return -1;        }    }    /* open file */    file = fopen(iname,"rb");    if (!file) {       perror(iname);       return -1;    }    fseek(file,0,SEEK_END);    length = ftell(file);    length = (length + 3) & ~3; /* Round up to nearest 4 byte boundary */        if ((method == scramble) && ((length + headerlen) >= 0x32000)) {        printf("error: max firmware size is 200KB!\n");        fclose(file);        return -1;    }        fseek(file,0,SEEK_SET);     inbuf = malloc(length);    if (method == xor)        outbuf = malloc(length*2);    else        outbuf = malloc(length);    if ( !inbuf || !outbuf ) {       printf("out of memory!\n");       return -1;    }    /* read file */    i=fread(inbuf,1,length,file);    if ( !i ) {       perror(iname);       return -1;    }    fclose(file);    switch (method)    {        case scramble:            slen = length/4;            for (i = 0; i < length; i++) {                unsigned long addr = (i >> 2) + ((i % 4) * slen);                unsigned char data = inbuf[i];                data = ~((data << 1) | ((data >> 7) & 1)); /* poor man's ROL */                outbuf[addr] = data;            }            break;        case xor:            /* "compress" */            slen = 0;            for (i=0; i<length; i++) {                if (!(i&7))                    outbuf[slen++] = 0xff; /* all data is uncompressed */                outbuf[slen++] = inbuf[i];            }            break;    }        /* calculate checksum */    for (i=0;i<length;i++)       crc += inbuf[i];    memset(header, 0, sizeof header);    switch (method)    {        case scramble:            if (headerlen == 6) {                int2be(length, header);                header[4] = (crc >> 8) & 0xff;                header[5] = crc & 0xff;            }            else {                header[0] =                    header[1] =                    header[2] =                    header[3] = 0xff; /* ??? */                                header[6] = (crc >> 8) & 0xff;                header[7] = crc & 0xff;                                header[11] = version;                                header[15] = headerlen; /* really? */                                int2be(length, &header[20]);            }            break;        case xor:        {            int xorlen = strlen(xorstring);            /* calculate checksum */            for (i=0; i<slen; i++)                crc += outbuf[i];            /* xor data */            for (i=0; i<slen; i++)                outbuf[i] ^= xorstring[i & (xorlen-1)];                        header[0] = header[2] = 'Z';            header[1] = header[3] = version;            int2le(length, &header[4]);            int2le(slen, &header[8]);            int2le(crc, &header[12]);            length = slen;            break;        }#define MY_FIRMWARE_TYPE "Rockbox"#define MY_HEADER_VERSION 1        default:            strncpy(header,MY_FIRMWARE_TYPE,9);            header[9]='\0'; /*shouldn't have to, but to be SURE */            header[10]=MY_HEADER_VERSION&0xFF;            header[11]=(crc>>8)&0xFF;            header[12]=crc&0xFF;            int2be(sizeof(header), &header[12]);            break;    }    /* write file */    file = fopen(oname,"wb");    if ( !file ) {       perror(oname);       return -1;    }    if ( !fwrite(header,headerlen,1,file) ) {       perror(oname);       return -1;    }    if ( !fwrite(outbuf,length,1,file) ) {       perror(oname);       return -1;    }    fclose(file);        free(inbuf);    free(outbuf);        return 0;}