Add libhv and test http client

vendor/libhv/include/hv/hmath.h

@@ -0,0 +1,68 @@
+#ifndef HV_MATH_H_
+#define HV_MATH_H_
+
+#include <math.h>
+
+static inline unsigned long floor2e(unsigned long num) {
+    unsigned long n = num;
+    int e = 0;
+    while (n>>=1) ++e;
+    unsigned long ret = 1;
+    while (e--) ret<<=1;
+    return ret;
+}
+
+static inline unsigned long ceil2e(unsigned long num) {
+    // 2**0 = 1
+    if (num == 0 || num == 1)   return 1;
+    unsigned long n = num - 1;
+    int e = 1;
+    while (n>>=1) ++e;
+    unsigned long ret = 1;
+    while (e--) ret<<=1;
+    return ret;
+}
+
+// varint little-endian
+// MSB
+static inline int varint_encode(long long value, unsigned char* buf) {
+    unsigned char ch;
+    unsigned char *p = buf;
+    int bytes = 0;
+    do {
+        ch = value & 0x7F;
+        value >>= 7;
+        *p++ = value == 0 ? ch : (ch | 0x80);
+        ++bytes;
+    } while (value);
+    return bytes;
+}
+
+// @param[IN|OUT] len: in=>buflen, out=>varint bytesize
+static inline long long varint_decode(const unsigned char* buf, int* len) {
+    long long ret = 0;
+    int bytes = 0, bits = 0;
+    const unsigned char *p = buf;
+    do {
+        if (len && *len && bytes == *len) {
+            // Not enough length
+            *len = 0;
+            return 0;
+        }
+        ret |= ((long long)(*p & 0x7F)) << bits;
+        ++bytes;
+        if ((*p & 0x80) == 0) {
+            // Found end
+            if (len) *len = bytes;
+            return ret;
+        }
+        ++p;
+        bits += 7;
+    } while(bytes < 10);
+
+    // Not found end
+    if (len) *len = -1;
+    return ret;
+}
+
+#endif // HV_MATH_H_