inline bool remap_memory_and_truncate()

in src/annoylib.h [149:163]

• 15 lines of code
• 1 McCabe index (conditional complexity)

inline bool remap_memory_and_truncate(void** _ptr, int _fd, size_t old_size, size_t new_size) {
#ifdef __linux__
    *_ptr = mremap(*_ptr, old_size, new_size, MREMAP_MAYMOVE);
    bool ok = ftruncate(_fd, new_size) != -1;
#else
    munmap(*_ptr, old_size);
    bool ok = ftruncate(_fd, ANNOYLIB_FTRUNCATE_SIZE(new_size)) != -1;
#ifdef MAP_POPULATE
    *_ptr = mmap(*_ptr, new_size, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_POPULATE, _fd, 0);
#else
    *_ptr = mmap(*_ptr, new_size, PROT_READ | PROT_WRITE, MAP_SHARED, _fd, 0);
#endif
#endif
    return ok;
}