}
errno = 0;
if (fd == -1) {
- std::size_t ret = std::fread(ptr, len, 1, fp);
+ const size_t curr_off = tell();
+ const size_t to_read = std::min(len, size - curr_off);
+
+ std::size_t ret = std::fread(ptr, to_read, 1, fp);
if (ferror(fp)) {
throw std::runtime_error(format("read error: %s", strerror(errno)));
}
- if (ret != 1) {
+ if (to_read > 0 && ret != 1) {
throw std::runtime_error("unexpectedly reached end of file");
}
} else {