From b6afd33e2f23953f00c6fac6b5d45946a9113654 Mon Sep 17 00:00:00 2001
From: rsc <devnull@localhost>
Date: Sun, 23 Nov 2003 18:19:18 +0000
Subject: add libflate

---
 src/libflate/inflatezlibblock.c | 68 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 68 insertions(+)
 create mode 100644 src/libflate/inflatezlibblock.c

(limited to 'src/libflate/inflatezlibblock.c')

diff --git a/src/libflate/inflatezlibblock.c b/src/libflate/inflatezlibblock.c
new file mode 100644
index 00000000..477bb4b0
--- /dev/null
+++ b/src/libflate/inflatezlibblock.c
@@ -0,0 +1,68 @@
+#include <u.h>
+#include <libc.h>
+#include <flate.h>
+#include "zlib.h"
+
+typedef struct Block	Block;
+
+struct Block
+{
+	uchar	*pos;
+	uchar	*limit;
+};
+
+static int
+blgetc(void *vb)
+{
+	Block *b;
+
+	b = vb;
+	if(b->pos >= b->limit)
+		return -1;
+	return *b->pos++;
+}
+
+static int
+blwrite(void *vb, void *buf, int n)
+{
+	Block *b;
+
+	b = vb;
+
+	if(n > b->limit - b->pos)
+		n = b->limit - b->pos;
+	memmove(b->pos, buf, n);
+	b->pos += n;
+	return n;
+}
+
+int
+inflatezlibblock(uchar *dst, int dsize, uchar *src, int ssize)
+{
+	Block bd, bs;
+	int ok;
+
+	if(ssize < 6)
+		return FlateInputFail;
+
+	if(((src[0] << 8) | src[1]) % 31)
+		return FlateCorrupted;
+	if((src[0] & ZlibMeth) != ZlibDeflate
+	|| (src[0] & ZlibCInfo) > ZlibWin32k)
+		return FlateCorrupted;
+
+	bs.pos = src + 2;
+	bs.limit = src + ssize - 6;
+
+	bd.pos = dst;
+	bd.limit = dst + dsize;
+
+	ok = inflate(&bd, blwrite, &bs, blgetc);
+	if(ok != FlateOk)
+		return ok;
+
+	if(adler32(1, dst, bs.pos - dst) != ((bs.pos[0] << 24) | (bs.pos[1] << 16) | (bs.pos[2] << 8) | bs.pos[3]))
+		return FlateCorrupted;
+
+	return bd.pos - dst;
+}
-- 
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