rockbox/tools/scramble.c

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3.7 KiB
C
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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2002 by Bj<EFBFBD>rn 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>
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];
int headerlen = 6;
FILE* file;
int version;
if (argc < 3) {
printf("usage: %s [-fm] [-v2] <input file> <output file>\n",argv[0]);
return -1;
}
if(!strcmp(argv[1], "-fm")) {
headerlen = 24;
iname = argv[2];
oname = argv[3];
version = 4;
}
if(!strcmp(argv[1], "-v2")) {
headerlen = 24;
iname = argv[2];
oname = argv[3];
version = 2;
}
/* 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 ((length + headerlen) >= 0x32000) {
printf("error: max firmware size is 200KB!\n");
fclose(file);
return -1;
}
fseek(file,0,SEEK_SET);
inbuf = malloc(length);
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);
/* 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;
}
/* calculate checksum */
for (i=0;i<length;i++)
crc += inbuf[i];
/* make header */
memset(header, 0, sizeof header);
if (headerlen == 6) {
header[0] = (length >> 24) & 0xff;
header[1] = (length >> 16) & 0xff;
header[2] = (length >> 8) & 0xff;
header[3] = length & 0xff;
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? */
header[20] = (length >> 24) & 0xff;
header[21] = (length >> 16) & 0xff;
header[22] = (length >> 8) & 0xff;
header[23] = length & 0xff;
}
/* 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;
}