cplkeywordparser.cpp

/******************************************************************************
 *
 * Project:  Common Portability Library
 * Purpose:  Implementation of CPLKeywordParser - a class for parsing
 *           the keyword format used for files like QuickBird .RPB files.
 *           This is a slight variation on the NASAKeywordParser used for
 *           the PDS/ISIS2/ISIS3 formats.
 * Author:   Frank Warmerdam <warmerdam@pobox.com
 *
 ******************************************************************************
 * Copyright (c) 2008, Frank Warmerdam <warmerdam@pobox.com>
 * Copyright (c) 2009-2010, Even Rouault <even dot rouault at spatialys.com>
 *
 * SPDX-License-Identifier: MIT
 ****************************************************************************/

//! @cond Doxygen_Suppress

#include "cpl_port.h"
#include "cplkeywordparser.h"

#include <cctype>
#include <cstring>
#include <string>

#include "cpl_string.h"
#include "cpl_vsi.h"

/************************************************************************/
/* ==================================================================== */
/*                          CPLKeywordParser                           */
/* ==================================================================== */
/************************************************************************/

/************************************************************************/
/*                         CPLKeywordParser()                          */
/************************************************************************/

CPLKeywordParser::CPLKeywordParser() = default;

/************************************************************************/
/*                        ~CPLKeywordParser()                          */
/************************************************************************/

CPLKeywordParser::~CPLKeywordParser()

{
    CSLDestroy(papszKeywordList);
    papszKeywordList = nullptr;
}

/************************************************************************/
/*                               Ingest()                               */
/************************************************************************/

int CPLKeywordParser::Ingest(VSILFILE *fp)

{
    /* -------------------------------------------------------------------- */
    /*      Read in buffer till we find END all on its own line.            */
    /* -------------------------------------------------------------------- */
    for (; true;)
    {
        char szChunk[513] = {};
        const size_t nBytesRead = VSIFReadL(szChunk, 1, 512, fp);

        szChunk[nBytesRead] = '\0';
        osHeaderText += szChunk;

        if (nBytesRead < 512)
            break;

        const char *pszCheck = nullptr;
        if (osHeaderText.size() > 520)
            pszCheck = osHeaderText.c_str() + (osHeaderText.size() - 520);
        else
            pszCheck = szChunk;

        if (strstr(pszCheck, "\r\nEND;\r\n") != nullptr ||
            strstr(pszCheck, "\nEND;\n") != nullptr)
            break;
    }

    pszHeaderNext = osHeaderText.c_str();

    /* -------------------------------------------------------------------- */
    /*      Process name/value pairs, keeping track of a "path stack".      */
    /* -------------------------------------------------------------------- */
    return ReadGroup("", 0);
}

/************************************************************************/
/*                             ReadGroup()                              */
/************************************************************************/

bool CPLKeywordParser::ReadGroup(const char *pszPathPrefix, int nRecLevel)

{
    CPLString osName;
    CPLString osValue;

    // Arbitrary threshold to avoid stack overflow
    if (nRecLevel == 100)
        return false;

    for (; true;)
    {
        if (!ReadPair(osName, osValue))
            return false;

        if (EQUAL(osName, "BEGIN_GROUP") || EQUAL(osName, "GROUP"))
        {
            if (!ReadGroup((CPLString(pszPathPrefix) + osValue + ".").c_str(),
                           nRecLevel + 1))
                return false;
        }
        else if (STARTS_WITH_CI(osName, "END"))
        {
            return true;
        }
        else
        {
            osName = pszPathPrefix + osName;
            papszKeywordList =
                CSLSetNameValue(papszKeywordList, osName, osValue);
        }
    }
}

/************************************************************************/
/*                              ReadPair()                              */
/*                                                                      */
/*      Read a name/value pair from the input stream.  Strip off        */
/*      white space, ignore comments, split on '='.                     */
/************************************************************************/

bool CPLKeywordParser::ReadPair(CPLString &osName, CPLString &osValue)

{
    osName = "";
    osValue = "";

    if (!ReadWord(osName))
        return false;

    SkipWhite();

    if (EQUAL(osName, "END"))
        return TRUE;

    if (*pszHeaderNext != '=')
    {
        // ISIS3 does not have anything after the end group/object keyword.
        return EQUAL(osName, "End_Group") || EQUAL(osName, "End_Object");
    }

    pszHeaderNext++;

    SkipWhite();

    osValue = "";

    // Handle value lists like:     Name   = (Red, Red)
    // or list of lists like: TLCList = ( (0, 0.000000), (8299, 4.811014) );
    if (*pszHeaderNext == '(')
    {
        CPLString osWord;
        int nDepth = 0;
        const char *pszLastPos = pszHeaderNext;

        while (ReadWord(osWord) && pszLastPos != pszHeaderNext)
        {
            SkipWhite();
            pszLastPos = pszHeaderNext;

            osValue += osWord;
            const char *pszIter = osWord.c_str();
            bool bInQuote = false;
            while (*pszIter != '\0')
            {
                if (*pszIter == '"')
                    bInQuote = !bInQuote;
                else if (!bInQuote)
                {
                    if (*pszIter == '(')
                        nDepth++;
                    else if (*pszIter == ')')
                    {
                        nDepth--;
                        if (nDepth == 0)
                            break;
                    }
                }
                pszIter++;
            }
            if (*pszIter == ')' && nDepth == 0)
                break;
        }
    }

    else  // Handle more normal "single word" values.
    {
        // Special case to handle non-conformant IMD files generated by
        // previous GDAL version where we omit to surround values that have
        // spaces with double quotes.
        // So we use a heuristics to handle things like:
        //       key = value with spaces without single or double quotes at
        //       beginning of value;[\r]\n
        const char *pszNextLF = strchr(pszHeaderNext, '\n');
        if (pszNextLF)
        {
            std::string osTxt(pszHeaderNext, pszNextLF - pszHeaderNext);
            const auto nCRPos = osTxt.find('\r');
            const auto nSemiColonPos = osTxt.find(';');
            const auto nQuotePos = osTxt.find('\'');
            const auto nDoubleQuotePos = osTxt.find('"');
            const auto nLTPos = osTxt.find('<');
            if (nSemiColonPos != std::string::npos &&
                (nCRPos == std::string::npos || (nCRPos + 1 == osTxt.size())) &&
                ((nCRPos != std::string::npos &&
                  (nSemiColonPos + 1 == nCRPos)) ||
                 (nCRPos == std::string::npos &&
                  (nSemiColonPos + 1 == osTxt.size()))) &&
                (nQuotePos == std::string::npos || nQuotePos != 0) &&
                (nDoubleQuotePos == std::string::npos ||
                 nDoubleQuotePos != 0) &&
                (nLTPos == std::string::npos ||
                 osTxt.find('>') == std::string::npos))
            {
                pszHeaderNext = pszNextLF;
                osTxt.resize(nSemiColonPos);
                osValue = osTxt;
                while (!osValue.empty() && osValue.back() == ' ')
                    osValue.pop_back();
                return true;
            }
        }

        if (!ReadWord(osValue))
            return false;
    }

    SkipWhite();

    // No units keyword?
    if (*pszHeaderNext != '<')
        return true;

    // Append units keyword.  For lines that like like this:
    //  MAP_RESOLUTION               = 4.0 <PIXEL/DEGREE>

    CPLString osWord;

    osValue += " ";

    while (ReadWord(osWord))
    {
        SkipWhite();

        osValue += osWord;
        if (osWord.back() == '>')
            break;
    }

    return true;
}

/************************************************************************/
/*                              ReadWord()                              */
/************************************************************************/

bool CPLKeywordParser::ReadWord(CPLString &osWord)

{
    osWord = "";

    SkipWhite();

    if (*pszHeaderNext == '\0' || *pszHeaderNext == '=')
        return false;

    while (*pszHeaderNext != '\0' && *pszHeaderNext != '=' &&
           *pszHeaderNext != ';' &&
           !isspace(static_cast<unsigned char>(*pszHeaderNext)))
    {
        if (*pszHeaderNext == '"')
        {
            osWord += *(pszHeaderNext++);
            while (*pszHeaderNext != '"')
            {
                if (*pszHeaderNext == '\0')
                    return false;

                osWord += *(pszHeaderNext++);
            }
            osWord += *(pszHeaderNext++);
        }
        else if (*pszHeaderNext == '\'')
        {
            osWord += *(pszHeaderNext++);
            while (*pszHeaderNext != '\'')
            {
                if (*pszHeaderNext == '\0')
                    return false;

                osWord += *(pszHeaderNext++);
            }
            osWord += *(pszHeaderNext++);
        }
        else
        {
            osWord += *pszHeaderNext;
            pszHeaderNext++;
        }
    }

    if (*pszHeaderNext == ';')
        pszHeaderNext++;

    return true;
}

/************************************************************************/
/*                             SkipWhite()                              */
/************************************************************************/

void CPLKeywordParser::SkipWhite()

{
    for (; true;)
    {
        // Skip white space (newline, space, tab, etc )
        if (isspace(static_cast<unsigned char>(*pszHeaderNext)))
        {
            pszHeaderNext++;
            continue;
        }

        // Skip C style comments
        if (*pszHeaderNext == '/' && pszHeaderNext[1] == '*')
        {
            pszHeaderNext += 2;

            while (*pszHeaderNext != '\0' &&
                   (*pszHeaderNext != '*' || pszHeaderNext[1] != '/'))
            {
                pszHeaderNext++;
            }
            if (*pszHeaderNext == '\0')
                break;

            pszHeaderNext += 2;
            continue;
        }

        // Skip # style comments
        if (*pszHeaderNext == '#')
        {
            pszHeaderNext += 1;

            // consume till end of line.
            while (*pszHeaderNext != '\0' && *pszHeaderNext != 10 &&
                   *pszHeaderNext != 13)
            {
                pszHeaderNext++;
            }
            continue;
        }

        // not white space, return.
        return;
    }
}

/************************************************************************/
/*                             GetKeyword()                             */
/************************************************************************/

const char *CPLKeywordParser::GetKeyword(const char *pszPath,
                                         const char *pszDefault)

{
    const char *pszResult = CSLFetchNameValue(papszKeywordList, pszPath);
    if (pszResult == nullptr)
        return pszDefault;

    return pszResult;
}

//! @endcond