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