From d2c1898571a6a2324593e92163e8754880e0c1fb Mon Sep 17 00:00:00 2001
From: Junio C Hamano <gitster@pobox.com>
Date: Tue, 3 Apr 2012 15:53:08 -0700
Subject: [PATCH] varint: make it available outside the context of pack
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
Makefile | 2 ++
varint.c | 29 +++++++++++++++++++++++++++++
varint.h | 9 +++++++++
3 files changed, 40 insertions(+)
create mode 100644 varint.c
create mode 100644 varint.h
diff --git a/Makefile b/Makefile
index be1957a5e9..0f26c879d8 100644
--- a/Makefile
+++ b/Makefile
@@ -627,6 +627,7 @@ LIB_H += tree-walk.h
LIB_H += unpack-trees.h
LIB_H += userdiff.h
LIB_H += utf8.h
+LIB_H += varint.h
LIB_H += xdiff-interface.h
LIB_H += xdiff/xdiff.h
@@ -752,6 +753,7 @@ LIB_OBJS += url.o
LIB_OBJS += usage.o
LIB_OBJS += userdiff.o
LIB_OBJS += utf8.o
+LIB_OBJS += varint.o
LIB_OBJS += walker.o
LIB_OBJS += wrapper.o
LIB_OBJS += write_or_die.o
diff --git a/varint.c b/varint.c
new file mode 100644
index 0000000000..4ed7729496
--- /dev/null
+++ b/varint.c
@@ -0,0 +1,29 @@
+#include "varint.h"
+
+uintmax_t decode_varint(const unsigned char **bufp)
+{
+ const unsigned char *buf = *bufp;
+ unsigned char c = *buf++;
+ uintmax_t val = c & 127;
+ while (c & 128) {
+ val += 1;
+ if (!val || MSB(val, 7))
+ return 0; /* overflow */
+ c = *buf++;
+ val = (val << 7) + (c & 127);
+ }
+ *bufp = buf;
+ return val;
+}
+
+int encode_varint(uintmax_t value, unsigned char *buf)
+{
+ unsigned char varint[16];
+ unsigned pos = sizeof(varint) - 1;
+ varint[pos] = value & 127;
+ while (value >>= 7)
+ varint[--pos] = 128 | (--value & 127);
+ if (buf)
+ memcpy(buf, varint + pos, sizeof(varint) - pos);
+ return sizeof(varint) - pos;
+}
diff --git a/varint.h b/varint.h
new file mode 100644
index 0000000000..0321195796
--- /dev/null
+++ b/varint.h
@@ -0,0 +1,9 @@
+#ifndef VARINT_H
+#define VARINT_H
+
+#include "git-compat-util.h"
+
+extern int encode_varint(uintmax_t, unsigned char *);
+extern uintmax_t decode_varint(const unsigned char **);
+
+#endif /* VARINT_H */