add libflate

1 files changed, 66 insertions, 0 deletions

diff --git a/src/libflate/inflatezlib.c b/src/libflate/inflatezlib.c
new file mode 100644
index 00000000..3f31f10a
--- /dev/null
+++ b/src/libflate/inflatezlib.c
@@ -0,0 +1,66 @@
+#include <u.h>
+#include <libc.h>
+#include <flate.h>
+#include "zlib.h"
+
+typedef struct ZWrite	ZWrite;
+
+struct ZWrite
+{
+	ulong	adler;
+	void	*wr;
+	int	(*w)(void*, void*, int);
+};
+
+static int
+zlwrite(void *vzw, void *buf, int n)
+{
+	ZWrite *zw;
+
+	zw = vzw;
+	zw->adler = adler32(zw->adler, buf, n);
+	n = (*zw->w)(zw->wr, buf, n);
+	if(n <= 0)
+		return n;
+	return n;
+}
+
+int
+inflatezlib(void *wr, int (*w)(void*, void*, int), void *getr, int (*get)(void*))
+{
+	ZWrite zw;
+	ulong v;
+	int c, i;
+
+	c = (*get)(getr);
+	if(c < 0)
+		return FlateInputFail;
+	i = (*get)(getr);
+	if(i < 0)
+		return FlateInputFail;
+
+	if(((c << 8) | i) % 31)
+		return FlateCorrupted;
+	if((c & ZlibMeth) != ZlibDeflate
+	|| (c & ZlibCInfo) > ZlibWin32k)
+		return FlateCorrupted;
+
+	zw.wr = wr;
+	zw.w = w;
+	zw.adler = 1;
+	i = inflate(&zw, zlwrite, getr, get);
+	if(i != FlateOk)
+		return i;
+
+	v = 0;
+	for(i = 0; i < 4; i++){
+		c = (*get)(getr);
+		if(c < 0)
+			return FlateInputFail;
+		v = (v << 8) | c;
+	}
+	if(zw.adler != v)
+		return FlateCorrupted;
+
+	return FlateOk;
+}