Function CPLReadLine3L

port/cpl_conv.cpp:715–858

* Simplified line reading from text file. * * Similar to CPLReadLine(), but reading from a large file API handle. * * @param fp file pointer opened with VSIFOpenL(). * @param nMaxCars maximum number of characters allowed, or -1 for no limit. * @param papszOptions NULL-terminated array of options. Unused for now. * @param[out] pnBufLength size of output string (must be non-NULL) * @return

 *
 */
const char *CPLReadLine3L(VSILFILE *fp, int nMaxCars, int *pnBufLength,
                          CPL_UNUSED CSLConstList papszOptions)
{
    /* -------------------------------------------------------------------- */
    /*      Cleanup case.                                                   */
    /* -------------------------------------------------------------------- */
    if (fp == nullptr)
    {
        CPLReadLineBuffer(-1);
        return nullptr;
    }

    /* -------------------------------------------------------------------- */
    /*      Loop reading chunks of the line till we get to the end of       */
    /*      the line.                                                       */
    /* -------------------------------------------------------------------- */
    char *pszRLBuffer = nullptr;
    const size_t nChunkSize = 40;
    char szChunk[nChunkSize] = {};
    size_t nChunkBytesRead = 0;
    size_t nChunkBytesConsumed = 0;

    *pnBufLength = 0;
    szChunk[0] = 0;

    while (true)
    {
        /* --------------------------------------------------------------------
         */
        /*      Read a chunk from the input file. */
        /* --------------------------------------------------------------------
         */
        if (*pnBufLength > INT_MAX - static_cast<int>(nChunkSize) - 1)
        {
            CPLError(CE_Failure, CPLE_AppDefined,
                     "Too big line : more than 2 billion characters!.");
            CPLReadLineBuffer(-1);
            return nullptr;
        }

        pszRLBuffer =
            CPLReadLineBuffer(static_cast<int>(*pnBufLength + nChunkSize + 1));
        if (pszRLBuffer == nullptr)
            return nullptr;

        if (nChunkBytesRead == nChunkBytesConsumed + 1)
        {

            // case where one character is left over from last read.
            szChunk[0] = szChunk[nChunkBytesConsumed];

            nChunkBytesConsumed = 0;
            nChunkBytesRead = VSIFReadL(szChunk + 1, 1, nChunkSize - 1, fp) + 1;
        }
        else
        {
            nChunkBytesConsumed = 0;