Method FileSize

code/Common/DefaultIOStream.cpp:137–178

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// ----------------------------------------------------------------------------------
size_t DefaultIOStream::FileSize() const {
    if (!mFile || mFilename.empty()) {
        return 0;
    }

    if (SIZE_MAX == mCachedSize) {

        // Although fseek/ftell would allow us to reuse the existing file handle here,
        // it is generally unsafe because:
        //  - For binary streams, it is not technically well-defined
        //  - For text files the results are meaningless
        // That's why we use the safer variant fstat here.
        //
        // See here for details:
        // https://www.securecoding.cert.org/confluence/display/seccode/FIO19-C.+Do+not+use+fseek()+and+ftell()+to+compute+the+size+of+a+regular+file
#if defined _WIN32 && (!defined __GNUC__ || !defined __CLANG__ && __MSVCRT_VERSION__ >= 0x0601)
        struct __stat64 fileStat;
        //using fileno + fstat avoids having to handle the filename
        int err = _fstat64(_fileno(mFile), &fileStat);
        if (0 != err)
            return 0;
        mCachedSize = (size_t)(fileStat.st_size);
#elif defined _WIN32
        struct _stat fileStat;
        //using fileno + fstat avoids having to handle the filename
        int err = _fstat(_fileno(mFile), &fileStat);
        if (0 != err)
            return 0;
        mCachedSize = (size_t)(fileStat.st_size);
#elif defined __GNUC__ || defined __APPLE__ || defined __MACH__ || defined __FreeBSD__
        struct stat fileStat;
        int err = stat(mFilename.c_str(), &fileStat);
        if (0 != err)
            return 0;
        const unsigned long long cachedSize = fileStat.st_size;
        mCachedSize = static_cast<size_t>(cachedSize);
#else
#error "Unknown platform"
#endif
    }
    return mCachedSize;
}

// ----------------------------------------------------------------------------------
void DefaultIOStream::Flush() {