First checkin

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@55 a1c6a512-1295-4272-9138-f99709370657

1 files changed, 101 insertions, 0 deletions

diff --git a/tools/scramble.c b/tools/scramble.c
new file mode 100644
index 0000000..5b59cf3
--- /dev/null
+++ b/tools/scramble.c
@@ -0,0 +1,101 @@
+/***************************************************************************
+ *             __________               __   ___.
+ *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
+ *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
+ *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
+ *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
+ *                     \/            \/     \/    \/            \/
+ * $Id$
+ *
+ * Copyright (C) 2002 by Björn 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[6];
+    FILE* file;
+
+    if (argc < 3) {
+       printf("usage: %s <input file> <output file>\n",argv[0]);
+       return -1;
+    }
+    
+    /* open file */
+    file = fopen(argv[1],"rb");
+    if (!file) {
+       perror(argv[1]);
+       return -1;
+    }
+    fseek(file,0,SEEK_END);
+    length = ftell(file);
+    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(argv[1]);
+       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 */
+    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;
+
+    /* write file */
+    file = fopen(argv[2],"wb");
+    if ( !file ) {
+       perror(argv[2]);
+       return -1;
+    }
+    if ( !fwrite(header,6,1,file) ) {
+       perror(argv[2]);
+       return -1;
+    }
+    if ( !fwrite(outbuf,length,1,file) ) {
+       perror(argv[2]);
+       return -1;
+    }
+    fclose(file);
+    
+    free(inbuf);
+    free(outbuf);
+    
+    return 0;	
+}