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Subject[PATCH] 2.4.21 zlib merge #3 inffast
Reformat zlib_inflate_fast a bit, change one conditional into a loop
and fix one of three conditional cases.

Jörn

--
Beware of bugs in the above code; I have only proved it correct, but
not tried it.
-- Donald Knuth

--- linux-2.4.20/lib/zlib_inflate/inffast.c~zlib_merge_inffast 2002-11-29 00:53:15.000000000 +0100
+++ linux-2.4.20/lib/zlib_inflate/inffast.c 2003-06-10 17:00:43.000000000 +0200
@@ -88,28 +88,41 @@

/* do the copy */
m -= c;
- if ((uInt)(q - s->window) >= d) /* offset before dest */
- { /* just copy */
- r = q - d;
- *q++ = *r++; c--; /* minimum count is three, */
- *q++ = *r++; c--; /* so unroll loop a little */
- }
- else /* else offset after destination */
+ r = q - d;
+ if (r < s->window) /* wrap if needed */
{
- e = d - (uInt)(q - s->window); /* bytes from offset to end */
- r = s->end - e; /* pointer to offset */
- if (c > e) /* if source crosses, */
+ do {
+ r += s->end - s->window; /* force pointer in window */
+ } while (r < s->window); /* covers invalid distances */
+ e = s->end - r;
+ if (c > e)
{
- c -= e; /* copy to end of window */
+ c -= e; /* wrapped copy */
do {
- *q++ = *r++;
+ *q++ = *r++;
} while (--e);
- r = s->window; /* copy rest from start of window */
+ r = s->window;
+ do {
+ *q++ = *r++;
+ } while (--c);
+ }
+ else /* normal copy */
+ {
+ *q++ = *r++; c--;
+ *q++ = *r++; c--;
+ do {
+ *q++ = *r++;
+ } while (--c);
}
}
- do { /* copy all or what's left */
- *q++ = *r++;
- } while (--c);
+ else /* normal copy */
+ {
+ *q++ = *r++; c--;
+ *q++ = *r++; c--;
+ do {
+ *q++ = *r++;
+ } while (--c);
+ }
break;
}
else if ((e & 64) == 0)
-
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