src/crypto/common.h

   1 // Copyright (c) 2014 The Bitcoin Core developers
   2 // Distributed under the MIT software license, see the accompanying
   3 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
   4
   5 #ifndef BITCOIN_CRYPTO_COMMON_H
   6 #define BITCOIN_CRYPTO_COMMON_H
   7
   8 #if defined(HAVE_CONFIG_H)
   9 #include "bitcoin-config.h"
  10 #endif
  11
  12 #include <stdint.h>
  13 #include <string.h>
  14
  15 #include "compat/endian.h"
  16
  17 uint16_t static inline ReadLE16(const unsigned char* ptr)
  18 {
  19     uint16_t x;
  20     memcpy((char*)&x, ptr, 2);
  21     return le16toh(x);
  22 }
  23
  24 uint32_t static inline ReadLE32(const unsigned char* ptr)
  25 {
  26     uint32_t x;
  27     memcpy((char*)&x, ptr, 4);
  28     return le32toh(x);
  29 }
  30
  31 uint64_t static inline ReadLE64(const unsigned char* ptr)
  32 {
  33     uint64_t x;
  34     memcpy((char*)&x, ptr, 8);
  35     return le64toh(x);
  36 }
  37
  38 void static inline WriteLE16(unsigned char* ptr, uint16_t x)
  39 {
  40     uint16_t v = htole16(x);
  41     memcpy(ptr, (char*)&v, 2);
  42 }
  43
  44 void static inline WriteLE32(unsigned char* ptr, uint32_t x)
  45 {
  46     uint32_t v = htole32(x);
  47     memcpy(ptr, (char*)&v, 4);
  48 }
  49
  50 void static inline WriteLE64(unsigned char* ptr, uint64_t x)
  51 {
  52     uint64_t v = htole64(x);
  53     memcpy(ptr, (char*)&v, 8);
  54 }
  55
  56 uint32_t static inline ReadBE32(const unsigned char* ptr)
  57 {
  58     uint32_t x;
  59     memcpy((char*)&x, ptr, 4);
  60     return be32toh(x);
  61 }
  62
  63 uint64_t static inline ReadBE64(const unsigned char* ptr)
  64 {
  65     uint64_t x;
  66     memcpy((char*)&x, ptr, 8);
  67     return be64toh(x);
  68 }
  69
  70 void static inline WriteBE32(unsigned char* ptr, uint32_t x)
  71 {
  72     uint32_t v = htobe32(x);
  73     memcpy(ptr, (char*)&v, 4);
  74 }
  75
  76 void static inline WriteBE64(unsigned char* ptr, uint64_t x)
  77 {
  78     uint64_t v = htobe64(x);
  79     memcpy(ptr, (char*)&v, 8);
  80 }
  81
  82 /** Return the smallest number n such that (x >> n) == 0 (or 64 if the highest bit in x is set. */
  83 uint64_t static inline CountBits(uint64_t x)
  84 {
  85 #ifdef HAVE_DECL___BUILTIN_CLZL
  86     if (sizeof(unsigned long) >= sizeof(uint64_t)) {
  87         return x ? 8 * sizeof(unsigned long) - __builtin_clzl(x) : 0;
  88     }
  89 #endif
  90 #ifdef HAVE_DECL___BUILTIN_CLZLL
  91     if (sizeof(unsigned long long) >= sizeof(uint64_t)) {
  92         return x ? 8 * sizeof(unsigned long long) - __builtin_clzll(x) : 0;
  93     }
  94 #endif
  95     int ret = 0;
  96     while (x) {
  97         x >>= 1;
  98         ++ret;
  99     }
 100     return ret;
 101 }
 102
 103 #endif // BITCOIN_CRYPTO_COMMON_H