Decoded: OpenTTD (2003) v1.8 (2018)
Source file: endian_func.hpp
Line-by-line code walkthrough by MaiZure

endian_func.cpp defines architecture specific endianness functions

Original code:
https://github.com/MaiZure/OpenTTD-1.8/blob/master/src/core/endian_func.hpp





1     COMMENT (*)
2     BLANK (-)
3     *
4     *
5     *
6     *
7     *
8     *
9     -
10    *
11    -
12    Header guard
13    Header guard
14    -
15    Include the OpenTTD core endian detection header
16    Include the OpenTTD core bitmath header
17    -
18    *
19    If machine is a big endian architecture
20    No conversion necessary for FROM_BE16
21    No conversion necessary for FROM_BE32
22    No conversion necessary for TO_BE32
23    No conversion necessary for TO_BE16
24    No conversion necessary for TO_BE32X
25    Define FROM_LE16 to use BSWAP16 defined in bitmath_func.hpp
26    Define FROM_LE32 to use BSWAP32 defined in bitmath_func.hpp
27    Define TO_LE16 to use BSWAP16 defined in bitmath_func.hpp
28    Define TO_LE32 to use BSWAP32 defined in bitmath_func.hpp
29    Define TO_LE32X to use BSWAP32 defined in bitmath_func.hpp
30    Otherwise this is a little endian architecture so...
31    Define FROM_BE16 to use BSWAP16 defined in bitmath_func.hpp
32    Define FROM_BE32 to use BSWAP32 defined in bitmath_func.hpp
33    Define TO_BE16 to use BSWAP16 defined in bitmath_func.hpp
34    Define TO_BE32 to use BSWAP32 defined in bitmath_func.hpp
35    Define TO_BE32X to use BSWAP32 defined in bitmath_func.hpp
36    No conversion necessary for FROM_LE16
37    No conversion necessary for FROM_LE32
38    No conversion necessary for TO_LE16
39    No conversion necessary for TO_LE32
40    No conversion necessary for TO_LE32X
41    End check for architecture endianness
42    -
43    Defines ReadLE16Aligned with one argument
44    BLOCK START - ReadLE16Aligned, convert 16-bit LE as needed
45    Returns a 16-bit value converted from LE
46    BLOCK END - ReadLE16Aligned
47    -
48    Defines ReadLE16Unaligned
49    BLOCK START - ReadLE16Unalighted, convert 16-bit LE considering alignment
50    If this architecture requires alignment...
51    Returns swapped bytes
52    Otherwise the architecture doesn't care about alignment
53    Returns a 16-bit value converted from LE
54    End check for alignment requirements
55    BLOCK END - ReadLE16Unalighted
56    -
57    Header guard