From: Ian Darwin <ian@darwinsys.com>
Date: Wed, 23 Jan 1991 13:21:44 +0000 (+0000)
Subject: Initial revision
X-Git-Tag: FILE3_27~302
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=2e2a77317e19790a5977b4f3cb07030948d5bd1c;p=file

Initial revision
---

diff --git a/src/compress.c b/src/compress.c
new file mode 100644
index 00000000..38670146
--- /dev/null
+++ b/src/compress.c
@@ -0,0 +1,34 @@
+/*
+ * compress routines:
+ *	is_compress() returns 0 if uncompressed, number of bits if compressed.
+ *	uncompress(old, n, new) - uncompress old into new, return sizeof new
+ */
+
+/* Check for compression, return nbits. Algorithm, in magic(4) format:
+ * 0       string          \037\235        compressed data
+ * >2      byte&0x80       >0              block compressed
+ * >2      byte&0x1f       x               %d bits
+ */
+int
+is_compress(p, b)
+char *p;
+int *b;
+{
+
+	if (*p != '\037' || *(p+1) != '\235')
+		return 0;	/* not compress()ed */
+
+	*b = *(p+2) & 0x80;
+	return *(p+2) & 0x1f;
+}
+
+int
+uncompress(old, n, new)
+unsigned char *old, **new;
+int n;
+{
+	*new = old;	/* TODO write this */
+	**new = 0;	/* prevent infinite loop, skeleton version only */
+	return n;
+}
+