Apple-2-Tools
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nulib2
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Catch bad codes immediately.

This commit is contained in:
Andy McFadden 2003-03-14 17:30:16 +00:00
parent 4d194464db
commit 9d3ed51005
1 changed files with 22 additions and 2 deletions
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24
nufxlib-0/Lzw.c
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@ -1014,6 +1014,13 @@ Nu_ExpandLZW1(LZWExpandState* lzwState, uint expectedLen)
/* handle KwKwK case */
if (ptr >= entry) {
//DBUG_LZW(("### KwKwK (ptr=%d entry=%d)\n", ptr, entry));
if (ptr != entry) {
/* bad code -- this would make us read uninitialized data */
DBUG(("--- bad code (ptr=%d entry=%d)\n", ptr, entry));
err = kNuErrBadData;
return err;
}
Nu_LZWPush((uchar)finalc);
ptr = oldcode;
}
@ -1145,12 +1152,19 @@ clear_table:
main_loop:
while (outbuf < outbufend) {
incode = ptr = Nu_LZWGetCode(&inbuf, entry, &atBit, &lastByte);
/*DBUG_LZW(("### read incode=0x%04x\n", incode));*/
//DBUG_LZW(("### read incode=0x%04x\n", incode));
if (incode == kNuLZWClearCode) /* table clear - 0x0100 */
goto clear_table;
/* handle KwKwK case */
if (ptr >= entry) {
//DBUG_LZW(("### KwKwK (ptr=%d entry=%d)\n", ptr, entry));
if (ptr != entry) {
/* bad code -- this would make us read uninitialized data */
DBUG(("--- bad code (ptr=%d entry=%d)\n", ptr, entry));
err = kNuErrBadData;
return err;
}
Nu_LZWPush((uchar)finalc);
ptr = oldcode;
}
@ -1183,7 +1197,13 @@ main_loop:
bail:
/*DBUG_LZW(("### end of block\n"));*/
Assert(inbuf == inbufend);
if (inbuf != inbufend) {
/* data was corrupted; if we keep going this will get worse */
DBUG(("--- inbuf != inbufend in ExpandLZW2 (diff=%d)\n",
inbufend - inbuf));
err = kNuErrBadData;
return err;
}
Assert(outbuf == outbufend);
/* adjust input buffer */