From e5888a1ffdae813d7575f5fb02275c6bb07e5199 Mon Sep 17 00:00:00 2001
From: Taru Karttunen <taruti@taruti.net>
Date: Wed, 30 Mar 2011 15:46:40 +0300
Subject: Import sources from 2011-03-30 iso image

---
 sys/src/liboventi/zero.c | 79 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 79 insertions(+)
 create mode 100755 sys/src/liboventi/zero.c

(limited to 'sys/src/liboventi/zero.c')

diff --git a/sys/src/liboventi/zero.c b/sys/src/liboventi/zero.c
new file mode 100755
index 000000000..75acf3bd7
--- /dev/null
+++ b/sys/src/liboventi/zero.c
@@ -0,0 +1,79 @@
+#include <u.h>
+#include <libc.h>
+#include <oventi.h>
+
+/* score of a zero length block */
+uchar	vtZeroScore[VtScoreSize] = {
+	0xda, 0x39, 0xa3, 0xee, 0x5e, 0x6b, 0x4b, 0x0d, 0x32, 0x55,
+	0xbf, 0xef, 0x95, 0x60, 0x18, 0x90, 0xaf, 0xd8, 0x07, 0x09
+};
+
+
+int
+vtZeroExtend(int type, uchar *buf, int n, int nn)
+{
+	uchar *p, *ep;
+
+	switch(type) {
+	default:
+		memset(buf+n, 0, nn-n);
+		break;
+	case VtPointerType0:
+	case VtPointerType1:
+	case VtPointerType2:
+	case VtPointerType3:
+	case VtPointerType4:
+	case VtPointerType5:
+	case VtPointerType6:
+	case VtPointerType7:
+	case VtPointerType8:
+	case VtPointerType9:
+		p = buf + (n/VtScoreSize)*VtScoreSize;
+		ep = buf + (nn/VtScoreSize)*VtScoreSize;
+		while(p < ep) {
+			memmove(p, vtZeroScore, VtScoreSize);
+			p += VtScoreSize;
+		}
+		memset(p, 0, buf+nn-p);
+		break;
+	}
+	return 1;
+}
+
+int 
+vtZeroTruncate(int type, uchar *buf, int n)
+{
+	uchar *p;
+
+	switch(type) {
+	default:
+		for(p = buf + n; p > buf; p--) {
+			if(p[-1] != 0)
+				break;
+		}
+		return p - buf;
+	case VtRootType:
+		if(n < VtRootSize)
+			return n;
+		return VtRootSize;
+	case VtPointerType0:
+	case VtPointerType1:
+	case VtPointerType2:
+	case VtPointerType3:
+	case VtPointerType4:
+	case VtPointerType5:
+	case VtPointerType6:
+	case VtPointerType7:
+	case VtPointerType8:
+	case VtPointerType9:
+		/* ignore slop at end of block */
+		p = buf + (n/VtScoreSize)*VtScoreSize;
+
+		while(p > buf) {
+			if(memcmp(p - VtScoreSize, vtZeroScore, VtScoreSize) != 0)
+				break;
+			p -= VtScoreSize;
+		}
+		return p - buf;
+	}
+}
-- 
cgit v1.2.3