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494 lines
13 KiB
494 lines
13 KiB
/*
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* include/haproxy/intops.h
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* Functions for integer operations.
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*
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* Copyright (C) 2020 Willy Tarreau - w@1wt.eu
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation, version 2.1
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* exclusively.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#ifndef _HAPROXY_INTOPS_H
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#define _HAPROXY_INTOPS_H
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#include <haproxy/api.h>
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/* exported functions, mostly integer parsing */
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/* rounds <i> down to the closest value having max 2 digits */
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unsigned int round_2dig(unsigned int i);
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unsigned int full_hash(unsigned int a);
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int varint_bytes(uint64_t v);
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unsigned int read_uint(const char **s, const char *end);
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long long read_int64(const char **s, const char *end);
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unsigned long long read_uint64(const char **s, const char *end);
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unsigned int str2ui(const char *s);
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unsigned int str2uic(const char *s);
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unsigned int strl2ui(const char *s, int len);
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unsigned int strl2uic(const char *s, int len);
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int strl2ic(const char *s, int len);
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int strl2irc(const char *s, int len, int *ret);
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int strl2llrc(const char *s, int len, long long *ret);
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int strl2llrc_dotted(const char *text, int len, long long *ret);
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unsigned int mask_find_rank_bit(unsigned int r, unsigned long m);
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unsigned int mask_find_rank_bit_fast(unsigned int r, unsigned long m,
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unsigned long a, unsigned long b,
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unsigned long c, unsigned long d);
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void mask_prep_rank_map(unsigned long m,
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unsigned long *a, unsigned long *b,
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unsigned long *c, unsigned long *d);
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/* Multiply the two 32-bit operands and shift the 64-bit result right 32 bits.
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* This is used to compute fixed ratios by setting one of the operands to
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* (2^32*ratio).
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*/
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static inline unsigned int mul32hi(unsigned int a, unsigned int b)
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{
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return ((unsigned long long)a * b) >> 32;
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}
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/* gcc does not know when it can safely divide 64 bits by 32 bits. Use this
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* function when you know for sure that the result fits in 32 bits, because
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* it is optimal on x86 and on 64bit processors.
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*/
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static inline unsigned int div64_32(unsigned long long o1, unsigned int o2)
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{
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unsigned long long result;
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#ifdef __i386__
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asm("divl %2"
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: "=A" (result)
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: "A"(o1), "rm"(o2));
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#else
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result = o1 / o2;
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#endif
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return result;
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}
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/* rotate left a 64-bit integer by <bits:[0-5]> bits */
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static inline uint64_t rotl64(uint64_t v, uint8_t bits)
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{
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#if !defined(__ARM_ARCH_8A) && !defined(__x86_64__)
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bits &= 63;
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#endif
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v = (v << bits) | (v >> (-bits & 63));
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return v;
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}
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/* rotate right a 64-bit integer by <bits:[0-5]> bits */
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static inline uint64_t rotr64(uint64_t v, uint8_t bits)
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{
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#if !defined(__ARM_ARCH_8A) && !defined(__x86_64__)
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bits &= 63;
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#endif
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v = (v >> bits) | (v << (-bits & 63));
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return v;
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}
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/* Simple popcountl implementation. It returns the number of ones in a word.
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* Described here : https://graphics.stanford.edu/~seander/bithacks.html
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*/
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static inline unsigned int my_popcountl(unsigned long a)
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{
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a = a - ((a >> 1) & ~0UL/3);
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a = (a & ~0UL/15*3) + ((a >> 2) & ~0UL/15*3);
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a = (a + (a >> 4)) & ~0UL/255*15;
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return (unsigned long)(a * (~0UL/255)) >> (sizeof(unsigned long) - 1) * 8;
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}
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/* returns non-zero if <a> has at least 2 bits set */
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static inline unsigned long atleast2(unsigned long a)
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{
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return a & (a - 1);
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}
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/* Simple ffs implementation. It returns the position of the lowest bit set to
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* one, starting at 1. It is illegal to call it with a==0 (undefined result).
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*/
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static inline unsigned int my_ffsl(unsigned long a)
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{
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unsigned long cnt;
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#if defined(__x86_64__)
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__asm__("bsf %1,%0\n" : "=r" (cnt) : "rm" (a));
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cnt++;
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#else
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cnt = 1;
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#if LONG_MAX > 0x7FFFFFFFL /* 64bits */
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if (!(a & 0xFFFFFFFFUL)) {
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a >>= 32;
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cnt += 32;
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}
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#endif
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if (!(a & 0XFFFFU)) {
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a >>= 16;
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cnt += 16;
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}
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if (!(a & 0XFF)) {
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a >>= 8;
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cnt += 8;
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}
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if (!(a & 0xf)) {
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a >>= 4;
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cnt += 4;
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}
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if (!(a & 0x3)) {
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a >>= 2;
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cnt += 2;
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}
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if (!(a & 0x1)) {
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cnt += 1;
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}
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#endif /* x86_64 */
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return cnt;
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}
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/* Simple fls implementation. It returns the position of the highest bit set to
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* one, starting at 1. It is illegal to call it with a==0 (undefined result).
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*/
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static inline unsigned int my_flsl(unsigned long a)
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{
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unsigned long cnt;
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#if defined(__x86_64__)
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__asm__("bsr %1,%0\n" : "=r" (cnt) : "rm" (a));
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cnt++;
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#else
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cnt = 1;
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#if LONG_MAX > 0x7FFFFFFFUL /* 64bits */
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if (a & 0xFFFFFFFF00000000UL) {
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a >>= 32;
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cnt += 32;
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}
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#endif
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if (a & 0XFFFF0000U) {
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a >>= 16;
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cnt += 16;
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}
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if (a & 0XFF00) {
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a >>= 8;
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cnt += 8;
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}
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if (a & 0xf0) {
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a >>= 4;
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cnt += 4;
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}
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if (a & 0xc) {
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a >>= 2;
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cnt += 2;
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}
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if (a & 0x2) {
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cnt += 1;
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}
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#endif /* x86_64 */
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return cnt;
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}
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/* Build a word with the <bits> lower bits set (reverse of my_popcountl) */
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static inline unsigned long nbits(int bits)
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{
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if (--bits < 0)
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return 0;
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else
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return (2UL << bits) - 1;
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}
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/* Turns 64-bit value <a> from host byte order to network byte order.
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* The principle consists in letting the compiler detect we're playing
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* with a union and simplify most or all operations. The asm-optimized
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* htonl() version involving bswap (x86) / rev (arm) / other is a single
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* operation on little endian, or a NOP on big-endian. In both cases,
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* this lets the compiler "see" that we're rebuilding a 64-bit word from
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* two 32-bit quantities that fit into a 32-bit register. In big endian,
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* the whole code is optimized out. In little endian, with a decent compiler,
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* a few bswap and 2 shifts are left, which is the minimum acceptable.
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*/
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static inline unsigned long long my_htonll(unsigned long long a)
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{
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#if defined(__x86_64__)
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__asm__ volatile("bswapq %0" : "=r"(a) : "0"(a));
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return a;
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#else
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union {
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struct {
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unsigned int w1;
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unsigned int w2;
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} by32;
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unsigned long long by64;
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} w = { .by64 = a };
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return ((unsigned long long)htonl(w.by32.w1) << 32) | htonl(w.by32.w2);
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#endif
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}
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/* Turns 64-bit value <a> from network byte order to host byte order. */
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static inline unsigned long long my_ntohll(unsigned long long a)
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{
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return my_htonll(a);
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}
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/* sets bit <bit> into map <map>, which must be long-aligned */
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static inline void ha_bit_set(unsigned long bit, long *map)
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{
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map[bit / (8 * sizeof(*map))] |= 1UL << (bit & (8 * sizeof(*map) - 1));
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}
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/* clears bit <bit> from map <map>, which must be long-aligned */
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static inline void ha_bit_clr(unsigned long bit, long *map)
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{
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map[bit / (8 * sizeof(*map))] &= ~(1UL << (bit & (8 * sizeof(*map) - 1)));
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}
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/* flips bit <bit> from map <map>, which must be long-aligned */
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static inline void ha_bit_flip(unsigned long bit, long *map)
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{
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map[bit / (8 * sizeof(*map))] ^= 1UL << (bit & (8 * sizeof(*map) - 1));
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}
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/* returns non-zero if bit <bit> from map <map> is set, otherwise 0 */
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static inline int ha_bit_test(unsigned long bit, const long *map)
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{
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return !!(map[bit / (8 * sizeof(*map))] & 1UL << (bit & (8 * sizeof(*map) - 1)));
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}
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/* hash a 32-bit integer to another 32-bit integer. This code may be large when
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* inlined, use full_hash() instead.
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*/
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static inline unsigned int __full_hash(unsigned int a)
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{
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/* This function is one of Bob Jenkins' full avalanche hashing
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* functions, which when provides quite a good distribution for little
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* input variations. The result is quite suited to fit over a 32-bit
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* space with enough variations so that a randomly picked number falls
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* equally before any server position.
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* Check http://burtleburtle.net/bob/hash/integer.html for more info.
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*/
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a = (a+0x7ed55d16) + (a<<12);
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a = (a^0xc761c23c) ^ (a>>19);
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a = (a+0x165667b1) + (a<<5);
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a = (a+0xd3a2646c) ^ (a<<9);
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a = (a+0xfd7046c5) + (a<<3);
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a = (a^0xb55a4f09) ^ (a>>16);
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/* ensure values are better spread all around the tree by multiplying
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* by a large prime close to 3/4 of the tree.
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*/
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return a * 3221225473U;
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}
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/*
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* Return integer equivalent of character <c> for a hex digit (0-9, a-f, A-F),
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* otherwise -1. This compact form helps gcc produce efficient code.
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*/
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static inline int hex2i(int c)
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{
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if ((unsigned char)(c -= '0') > 9) {
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if ((unsigned char)(c -= 'A' - '0') > 5 &&
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(unsigned char)(c -= 'a' - 'A') > 5)
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c = -11;
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c += 10;
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}
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return c;
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}
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/* This one is 6 times faster than strtoul() on athlon, but does
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* no check at all.
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*/
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static inline unsigned int __str2ui(const char *s)
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{
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unsigned int i = 0;
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while (*s) {
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i = i * 10 - '0';
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i += (unsigned char)*s++;
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}
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return i;
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}
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/* This one is 5 times faster than strtoul() on athlon with checks.
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* It returns the value of the number composed of all valid digits read.
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*/
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static inline unsigned int __str2uic(const char *s)
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{
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unsigned int i = 0;
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unsigned int j;
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while (1) {
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j = (*s++) - '0';
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if (j > 9)
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break;
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i *= 10;
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i += j;
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}
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return i;
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}
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/* This one is 28 times faster than strtoul() on athlon, but does
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* no check at all!
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*/
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static inline unsigned int __strl2ui(const char *s, int len)
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{
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unsigned int i = 0;
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while (len-- > 0) {
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i = i * 10 - '0';
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i += (unsigned char)*s++;
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}
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return i;
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}
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/* This one is 7 times faster than strtoul() on athlon with checks.
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* It returns the value of the number composed of all valid digits read.
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*/
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static inline unsigned int __strl2uic(const char *s, int len)
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{
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unsigned int i = 0;
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unsigned int j, k;
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while (len-- > 0) {
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j = (*s++) - '0';
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k = i * 10;
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if (j > 9)
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break;
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i = k + j;
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}
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return i;
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}
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/* This function reads an unsigned integer from the string pointed to by <s>
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* and returns it. The <s> pointer is adjusted to point to the first unread
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* char. The function automatically stops at <end>.
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*/
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static inline unsigned int __read_uint(const char **s, const char *end)
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{
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const char *ptr = *s;
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unsigned int i = 0;
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unsigned int j, k;
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while (ptr < end) {
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j = *ptr - '0';
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k = i * 10;
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if (j > 9)
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break;
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i = k + j;
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ptr++;
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}
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*s = ptr;
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return i;
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}
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/* returns the number of bytes needed to encode <v> as a varint. Be careful, use
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* it only with constants as it generates a large code (typ. 180 bytes). Use the
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* varint_bytes() version instead in case of doubt.
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*/
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static inline int __varint_bytes(uint64_t v)
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{
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switch (v) {
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case 0x0000000000000000 ... 0x00000000000000ef: return 1;
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case 0x00000000000000f0 ... 0x00000000000008ef: return 2;
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case 0x00000000000008f0 ... 0x00000000000408ef: return 3;
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case 0x00000000000408f0 ... 0x00000000020408ef: return 4;
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case 0x00000000020408f0 ... 0x00000001020408ef: return 5;
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case 0x00000001020408f0 ... 0x00000081020408ef: return 6;
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case 0x00000081020408f0 ... 0x00004081020408ef: return 7;
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case 0x00004081020408f0 ... 0x00204081020408ef: return 8;
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case 0x00204081020408f0 ... 0x10204081020408ef: return 9;
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default: return 10;
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}
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}
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/* Encode the integer <i> into a varint (variable-length integer). The encoded
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* value is copied in <*buf>. Here is the encoding format:
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*
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* 0 <= X < 240 : 1 byte (7.875 bits) [ XXXX XXXX ]
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* 240 <= X < 2288 : 2 bytes (11 bits) [ 1111 XXXX ] [ 0XXX XXXX ]
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* 2288 <= X < 264432 : 3 bytes (18 bits) [ 1111 XXXX ] [ 1XXX XXXX ] [ 0XXX XXXX ]
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* 264432 <= X < 33818864 : 4 bytes (25 bits) [ 1111 XXXX ] [ 1XXX XXXX ]*2 [ 0XXX XXXX ]
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* 33818864 <= X < 4328786160 : 5 bytes (32 bits) [ 1111 XXXX ] [ 1XXX XXXX ]*3 [ 0XXX XXXX ]
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* ...
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*
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* On success, it returns the number of written bytes and <*buf> is moved after
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* the encoded value. Otherwise, it returns -1. */
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static inline int encode_varint(uint64_t i, char **buf, char *end)
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{
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unsigned char *p = (unsigned char *)*buf;
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int r;
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if (p >= (unsigned char *)end)
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return -1;
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if (i < 240) {
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*p++ = i;
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*buf = (char *)p;
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return 1;
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}
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*p++ = (unsigned char)i | 240;
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i = (i - 240) >> 4;
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while (i >= 128) {
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if (p >= (unsigned char *)end)
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return -1;
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*p++ = (unsigned char)i | 128;
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i = (i - 128) >> 7;
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}
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if (p >= (unsigned char *)end)
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return -1;
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*p++ = (unsigned char)i;
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r = ((char *)p - *buf);
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*buf = (char *)p;
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return r;
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}
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/* Decode a varint from <*buf> and save the decoded value in <*i>. See
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* 'spoe_encode_varint' for details about varint.
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* On success, it returns the number of read bytes and <*buf> is moved after the
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* varint. Otherwise, it returns -1. */
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static inline int decode_varint(char **buf, char *end, uint64_t *i)
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{
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unsigned char *p = (unsigned char *)*buf;
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int r;
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if (p >= (unsigned char *)end)
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return -1;
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*i = *p++;
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if (*i < 240) {
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*buf = (char *)p;
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return 1;
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}
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r = 4;
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do {
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if (p >= (unsigned char *)end)
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return -1;
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*i += (uint64_t)*p << r;
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r += 7;
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} while (*p++ >= 128);
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r = ((char *)p - *buf);
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*buf = (char *)p;
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return r;
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}
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#endif /* _HAPROXY_INTOPS_H */
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/*
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* Local variables:
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* c-indent-level: 8
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* c-basic-offset: 8
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* End:
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*/
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