src/cpp-common/read-fixed-len-int.hpp

   1 /*
   2  * Copyright (c) 2022 Philippe Proulx <pproulx@efficios.com>
   3  *
   4  * SPDX-License-Identifier: MIT
   5  */
   6
   7 #ifndef BABELTRACE_CPP_COMMON_READ_FIXED_LEN_INT_HPP
   8 #define BABELTRACE_CPP_COMMON_READ_FIXED_LEN_INT_HPP
   9
  10 #include <cstdint>
  11 #include <cstdlib>
  12 #include <cstring>
  13 #include <type_traits>
  14
  15 #include "cpp-common/endian.hpp"
  16
  17 namespace bt2_common {
  18
  19 /*
  20  * Reads a fixed-length integer of unknown byte order into a value of integral
  21  * type `IntT` from the buffer `buf` and returns it.
  22  */
  23 template <typename IntT>
  24 IntT readFixedLenInt(const std::uint8_t * const buf)
  25 {
  26     static_assert(std::is_integral<IntT>::value, "`IntT` is an integral type.");
  27
  28     IntT val;
  29
  30     std::memcpy(&val, buf, sizeof(val));
  31     return val;
  32 }
  33
  34 /*
  35  * Reads a fixed-length little-endian integer into a value of integral
  36  * type `IntT` from the buffer `buf` and returns it.
  37  */
  38 template <typename IntT>
  39 IntT readFixedLenIntLe(const std::uint8_t * const buf)
  40 {
  41     return bt2_common::littleEndianToNative(readFixedLenInt<IntT>(buf));
  42 }
  43
  44 /*
  45  * Reads a fixed-length big-endian integer into a value of integral
  46  * type `IntT` from the buffer `buf` and returns it.
  47  */
  48 template <typename IntT>
  49 IntT readFixedLenIntBe(const std::uint8_t * const buf)
  50 {
  51     return bt2_common::bigEndianToNative(readFixedLenInt<IntT>(buf));
  52 }
  53
  54 } /* namespace bt2_common */
  55
  56 #endif /* BABELTRACE_CPP_COMMON_READ_FIXED_LEN_INT_HPP */