add some lua library

lua-protobuf/varint.c

@@ -0,0 +1,110 @@
+#include "varint.h"
+
+#include "pbc.h"
+
+#include <stdint.h>
+
+inline int
+_pbcV_encode32(uint32_t number, uint8_t buffer[10])
+{
+	if (number < 0x80) {
+		buffer[0] = (uint8_t) number ; 
+		return 1;
+	}
+	buffer[0] = (uint8_t) (number | 0x80 );
+	if (number < 0x4000) {
+		buffer[1] = (uint8_t) (number >> 7 );
+		return 2;
+	}
+	buffer[1] = (uint8_t) ((number >> 7) | 0x80 );
+	if (number < 0x200000) {
+		buffer[2] = (uint8_t) (number >> 14);
+		return 3;
+	}
+	buffer[2] = (uint8_t) ((number >> 14) | 0x80 );
+	if (number < 0x10000000) {
+		buffer[3] = (uint8_t) (number >> 21);
+		return 4;
+	}
+	buffer[3] = (uint8_t) ((number >> 21) | 0x80 );
+	buffer[4] = (uint8_t) (number >> 28);
+	return 5;
+}
+
+int
+_pbcV_encode(uint64_t number, uint8_t buffer[10]) 
+{
+	if ((number & 0xffffffff) == number) {
+		return _pbcV_encode32((uint32_t)number , buffer);
+	}
+	int i = 0;
+	do {
+		buffer[i] = (uint8_t)(number | 0x80);
+		number >>= 7;
+		++i;
+	} while (number >= 0x80);
+	buffer[i] = (uint8_t)number;
+	return i+1;
+}
+
+int
+_pbcV_decode(uint8_t buffer[10], struct longlong *result) {
+	if (!(buffer[0] & 0x80)) {
+		result->low = buffer[0];
+		result->hi = 0;
+		return 1;
+	}
+	uint32_t r = buffer[0] & 0x7f;
+	int i;
+	for (i=1;i<4;i++) {
+		r |= ((buffer[i]&0x7f) << (7*i));
+		if (!(buffer[i] & 0x80)) {
+			result->low = r;
+			result->hi = 0;
+			return i+1;
+		}
+	}
+	uint64_t lr = 0;
+	for (i=4;i<10;i++) {
+		lr |= ((buffer[i] & 0x7f) << (7*(i-4)));
+		if (!(buffer[i] & 0x80)) {
+			result->hi = (uint32_t)(lr >> 4);
+			result->low = r | (((uint32_t)lr & 0xf) << 28);
+			return i+1;
+		}
+	}
+
+	result->low = 0;
+	result->hi = 0;
+	return 10;
+}
+
+int 
+_pbcV_zigzag32(int32_t n, uint8_t buffer[10])
+{
+	n = (n << 1) ^ (n >> 31);
+	return _pbcV_encode32(n,buffer);
+}
+
+int 
+_pbcV_zigzag(int64_t n, uint8_t buffer[10])
+{
+	n = (n << 1) ^ (n >> 63);
+	return _pbcV_encode(n,buffer);
+}
+
+void
+_pbcV_dezigzag64(struct longlong *r)
+{
+	uint32_t low = r->low;
+	r->low = ((low >> 1) | ((r->hi & 1) << 31)) ^ - (low & 1);
+	r->hi = (r->hi >> 1) ^ - (low & 1);
+}
+
+void
+_pbcV_dezigzag32(struct longlong *r)
+{
+	uint32_t low = r->low;
+	r->low = (low >> 1) ^ - (low & 1);
+	r->hi = -(low >> 31);
+}