cpl_conv.cpp

mitab,读取MapInfo的地图文件

            {
                bWarned = TRUE;
                CPLDebug( "CPL", "CPLFGets() correcting for DOS text mode translation seek problem." );
            }
            chCheck = fgetc( fp );
        }
    }

    return pszBuffer;
}

/************************************************************************/
/*                         CPLReadLineBuffer()                          */
/*                                                                      */
/*      Fetch readline buffer, and ensure it is the desired size,       */
/*      reallocating if needed.  Manages TLS (thread local storage)     */
/*      issues for the buffer.                                          */
/************************************************************************/
static char *CPLReadLineBuffer( int nRequiredSize )

{
    
/* -------------------------------------------------------------------- */
/*      A required size of -1 means the buffer should be freed.         */
/* -------------------------------------------------------------------- */
    if( nRequiredSize == -1 )
    {
        if( CPLGetTLS( CTLS_RLBUFFERINFO ) != NULL )
        {
            CPLFree( CPLGetTLS( CTLS_RLBUFFERINFO ) );
            CPLSetTLS( CTLS_RLBUFFERINFO, NULL, FALSE );
        }
        return NULL;
    }

/* -------------------------------------------------------------------- */
/*      If the buffer doesn't exist yet, create it.                     */
/* -------------------------------------------------------------------- */
    GUInt32 *pnAlloc = (GUInt32 *) CPLGetTLS( CTLS_RLBUFFERINFO );

    if( pnAlloc == NULL )
    {
        pnAlloc = (GUInt32 *) CPLMalloc(200);
        *pnAlloc = 196;
        CPLSetTLS( CTLS_RLBUFFERINFO, pnAlloc, TRUE );
    }

/* -------------------------------------------------------------------- */
/*      If it is too small, grow it bigger.                             */
/* -------------------------------------------------------------------- */
    if( (int) *pnAlloc < nRequiredSize+1 )
    {
        int nNewSize = nRequiredSize + 4 + 500;

        pnAlloc = (GUInt32 *) CPLRealloc(pnAlloc,nNewSize);
        if( pnAlloc == NULL )
        {
            CPLSetTLS( CTLS_RLBUFFERINFO, NULL, FALSE );
            return NULL;
        }
            
        *pnAlloc = nNewSize - 4;
        CPLSetTLS( CTLS_RLBUFFERINFO, pnAlloc, TRUE );
    }

    return (char *) (pnAlloc+1);
}

/************************************************************************/
/*                            CPLReadLine()                             */
/************************************************************************/

/**
 * Simplified line reading from text file.
 * 
 * Read a line of text from the given file handle, taking care
 * to capture CR and/or LF and strip off ... equivelent of
 * DKReadLine().  Pointer to an internal buffer is returned.
 * The application shouldn't free it, or depend on it's value
 * past the next call to CPLReadLine().
 * 
 * Note that CPLReadLine() uses VSIFGets(), so any hooking of VSI file
 * services should apply to CPLReadLine() as well.
 *
 * CPLReadLine() maintains an internal buffer, which will appear as a 
 * single block memory leak in some circumstances.  CPLReadLine() may 
 * be called with a NULL FILE * at any time to free this working buffer.
 *
 * @param fp file pointer opened with VSIFOpen().
 *
 * @return pointer to an internal buffer containing a line of text read
 * from the file or NULL if the end of file was encountered.
 */

const char *CPLReadLine( FILE * fp )

{
    char *pszRLBuffer = CPLReadLineBuffer(1);
    int         nReadSoFar = 0;

/* -------------------------------------------------------------------- */
/*      Cleanup case.                                                   */
/* -------------------------------------------------------------------- */
    if( fp == NULL )
    {
        CPLReadLineBuffer( -1 );
        return NULL;
    }

/* -------------------------------------------------------------------- */
/*      Loop reading chunks of the line till we get to the end of       */
/*      the line.                                                       */
/* -------------------------------------------------------------------- */
    int nBytesReadThisTime;

    do {
/* -------------------------------------------------------------------- */
/*      Grow the working buffer if we have it nearly full.  Fail out    */
/*      of read line if we can't reallocate it big enough (for          */
/*      instance for a _very large_ file with no newlines).             */
/* -------------------------------------------------------------------- */
        pszRLBuffer = CPLReadLineBuffer( nReadSoFar + 129 );
        if( pszRLBuffer == NULL )
            return NULL;

/* -------------------------------------------------------------------- */
/*      Do the actual read.                                             */
/* -------------------------------------------------------------------- */
        if( CPLFGets( pszRLBuffer+nReadSoFar, 128, fp ) == NULL 
            && nReadSoFar == 0 )
            return NULL;

        nBytesReadThisTime = strlen(pszRLBuffer+nReadSoFar);
        nReadSoFar += nBytesReadThisTime;

    } while( nBytesReadThisTime >= 127
             && pszRLBuffer[nReadSoFar-1] != 13
             && pszRLBuffer[nReadSoFar-1] != 10 );

    return( pszRLBuffer );
}

/************************************************************************/
/*                            CPLReadLineL()                            */
/************************************************************************/

/**
 * Simplified line reading from text file.
 * 
 * Similar to CPLReadLine(), but reading from a large file API handle.
 *
 * @param fp file pointer opened with VSIFOpenL().
 *
 * @return pointer to an internal buffer containing a line of text read
 * from the file or NULL if the end of file was encountered.
 */

const char *CPLReadLineL( FILE * fp )

{
/* -------------------------------------------------------------------- */
/*      Cleanup case.                                                   */
/* -------------------------------------------------------------------- */
    if( fp == NULL )
    {
        CPLReadLineBuffer( -1 );
        return NULL;
    }

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

    while( TRUE )
    {
/* -------------------------------------------------------------------- */
/*      Read a chunk from the input file.                               */
/* -------------------------------------------------------------------- */
        pszRLBuffer = CPLReadLineBuffer( nBufLength + nChunkSize + 1 );

        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;

            // fresh read.
            nChunkBytesRead = VSIFReadL( szChunk, 1, nChunkSize, fp );
            if( nChunkBytesRead == 0 )
            {
                if( nBufLength == 0 )
                    return NULL;
                else
                    break;
            }
        }
        
/* -------------------------------------------------------------------- */
/*      copy over characters watching for end-of-line.                  */
/* -------------------------------------------------------------------- */
        int bBreak = FALSE;
        while( nChunkBytesConsumed < nChunkBytesRead-1 && !bBreak )
        {
            if( (szChunk[nChunkBytesConsumed] == 13
                 && szChunk[nChunkBytesConsumed+1] == 10)
                || (szChunk[nChunkBytesConsumed] == 10
                    && szChunk[nChunkBytesConsumed+1] == 13) )
            {
                nChunkBytesConsumed += 2;
                bBreak = TRUE;
            }
            else if( szChunk[nChunkBytesConsumed] == 10
                     || szChunk[nChunkBytesConsumed] == 13 )
            {
                nChunkBytesConsumed += 1;
                bBreak = TRUE;
            }
            else
                pszRLBuffer[nBufLength++] = szChunk[nChunkBytesConsumed++];
        }

        if( bBreak )
            break;

/* -------------------------------------------------------------------- */
/*      If there is a remaining character and it is not a newline       */
/*      consume it.  If it is a newline, but we are clearly at the      */
/*      end of the file then consume it.                                */
/* -------------------------------------------------------------------- */
        if( nChunkBytesConsumed == nChunkBytesRead-1 
            && nChunkBytesRead < nChunkSize )
        {
            if( szChunk[nChunkBytesConsumed] == 10
                || szChunk[nChunkBytesConsumed] == 13 )
            {
                nChunkBytesConsumed++;
                break;
            }

            pszRLBuffer[nBufLength++] = szChunk[nChunkBytesConsumed++];
            break;
        }
    }

/* -------------------------------------------------------------------- */
/*      If we have left over bytes after breaking out, seek back to     */
/*      ensure they remain to be read next time.                        */
/* -------------------------------------------------------------------- */
    if( nChunkBytesConsumed < nChunkBytesRead )
    {
        size_t nBytesToPush = nChunkBytesRead - nChunkBytesConsumed;
        
        VSIFSeekL( fp, VSIFTellL( fp ) - nBytesToPush, SEEK_SET );
    }

    pszRLBuffer[nBufLength] = '\0';

    return( pszRLBuffer );
}

/************************************************************************/
/*                            CPLScanString()                           */
/************************************************************************/

/**
 * Scan up to a maximum number of characters from a given string,
 * allocate a buffer for a new string and fill it with scanned characters.
 *
 * @param pszString String containing characters to be scanned. It may be
 * terminated with a null character.
 *
 * @param nMaxLength The maximum number of character to read. Less
 * characters will be read if a null character is encountered.
 *
 * @param bTrimSpaces If TRUE, trim ending spaces from the input string.
 * Character considered as empty using isspace(3) function.
 *
 * @param bNormalize If TRUE, replace ':' symbol with the '_'. It is needed if
 * resulting string will be used in CPL dictionaries.
 * 
 * @return Pointer to the resulting string buffer. Caller responsible to free
 * this buffer with CPLFree().
 */

char *CPLScanString( const char *pszString, int nMaxLength,
                     int bTrimSpaces, int bNormalize )
{
    char    *pszBuffer;

    if ( !pszString )
        return NULL;

    if ( !nMaxLength )
        return CPLStrdup( "" );

    pszBuffer = (char *)CPLMalloc( nMaxLength + 1 );
    if ( !pszBuffer )
        return NULL;

    strncpy( pszBuffer, pszString,  nMaxLength );
    pszBuffer[nMaxLength] = '\0';

    if ( bTrimSpaces )
    {
        size_t  i = strlen( pszBuffer );
        while ( i-- > 0 && isspace(pszBuffer[i]) )
            pszBuffer[i] = '\0';
    }

    if ( bNormalize )
    {
        size_t  i = strlen( pszBuffer );
        while ( i-- > 0 )
        {
            if ( pszBuffer[i] == ':' )
                pszBuffer[i] = '_';
        }
    }

    return pszBuffer;
}

/************************************************************************/
/*                             CPLScanLong()                            */
/************************************************************************/

/**
 * Scan up to a maximum number of characters from a string and convert
 * the result to a long.
 *
 * @param pszString String containing characters to be scanned. It may be
 * terminated with a null character.
 *
 * @param nMaxLength The maximum number of character to consider as part
 * of the number. Less characters will be considered if a null character
 * is encountered.
 * 
 * @return Long value, converted from its ASCII form.
 */

long CPLScanLong( const char *pszString, int nMaxLength )
{
    long    iValue;
    char    *pszValue = (char *)CPLMalloc( nMaxLength + 1);

/* -------------------------------------------------------------------- */
/*      Compute string into local buffer, and terminate it.             */
/* -------------------------------------------------------------------- */
    strncpy( pszValue, pszString, nMaxLength );
    pszValue[nMaxLength] = '\0';

/* -------------------------------------------------------------------- */
/*      Use atol() to fetch out the result                              */
/* -------------------------------------------------------------------- */
    iValue = atol( pszValue );

    CPLFree( pszValue );
    return iValue;
}


/************************************************************************/
/*                            CPLScanULong()                            */
/************************************************************************/