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-rw-r--r--varint.c29
1 files changed, 29 insertions, 0 deletions
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;
+}