cpl_csv.cpp

mitab,读取MapInfo的地图文件

/******************************************************************************
 * $Id: cpl_csv.cpp 10646 2007-01-18 02:38:10Z warmerdam $
 *
 * Project:  CPL - Common Portability Library
 * Purpose:  CSV (comma separated value) file access.
 * Author:   Frank Warmerdam, [e-mail]
 *
 ******************************************************************************
 * Copyright (c) 1999, Frank Warmerdam
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 ****************************************************************************/

#include "cpl_csv.h"
#include "cpl_conv.h"
#include "cpl_multiproc.h"

CPL_CVSID("$Id: cpl_csv.cpp 10646 2007-01-18 02:38:10Z warmerdam $");

CPL_C_START
const char * GDALDefaultCSVFilename( const char *pszBasename );
CPL_C_END

/* ==================================================================== */
/*      The CSVTable is a persistant set of info about an open CSV      */
/*      table.  While it doesn't currently maintain a record index,     */
/*      or in-memory copy of the table, it could be changed to do so    */
/*      in the future.                                                  */
/* ==================================================================== */
typedef struct ctb {
    FILE        *fp;

    struct ctb *psNext;

    char        *pszFilename;

    char        **papszFieldNames;

    char        **papszRecFields;

    int         iLastLine;

    /* Cache for whole file */
    int         nLineCount;
    char        **papszLines;
    int         *panLineIndex;
    char        *pszRawData;
} CSVTable;

/* It would likely be better to share this list between threads, but
   that will require some rework. */

/************************************************************************/
/*                             CSVAccess()                              */
/*                                                                      */
/*      This function will fetch a handle to the requested table.       */
/*      If not found in the ``open table list'' the table will be       */
/*      opened and added to the list.  Eventually this function may     */
/*      become public with an abstracted return type so that            */
/*      applications can set options about the table.  For now this     */
/*      isn't done.                                                     */
/************************************************************************/

static CSVTable *CSVAccess( const char * pszFilename )

{
    CSVTable    *psTable;
    FILE        *fp;

/* -------------------------------------------------------------------- */
/*      Fetch the table, and allocate the thread-local pointer to it    */
/*      if there isn't already one.                                     */
/* -------------------------------------------------------------------- */
    CSVTable **ppsCSVTableList;

    ppsCSVTableList = (CSVTable **) CPLGetTLS( CTLS_CSVTABLEPTR );
    if( ppsCSVTableList == NULL )
    {
        ppsCSVTableList = (CSVTable **) CPLCalloc(1,sizeof(CSVTable*));
        CPLSetTLS( CTLS_CSVTABLEPTR, ppsCSVTableList, TRUE );
    }

/* -------------------------------------------------------------------- */
/*      Is the table already in the list.                               */
/* -------------------------------------------------------------------- */
    for( psTable = *ppsCSVTableList; 
         psTable != NULL; 
         psTable = psTable->psNext )
    {
        if( EQUAL(psTable->pszFilename,pszFilename) )
        {
            /*
             * Eventually we should consider promoting to the front of
             * the list to accelerate frequently accessed tables.
             */
            
            return( psTable );
        }
    }

/* -------------------------------------------------------------------- */
/*      If not, try to open it.                                         */
/* -------------------------------------------------------------------- */
    fp = VSIFOpen( pszFilename, "rb" );
    if( fp == NULL )
        return NULL;

/* -------------------------------------------------------------------- */
/*      Create an information structure about this table, and add to    */
/*      the front of the list.                                          */
/* -------------------------------------------------------------------- */
    psTable = (CSVTable *) CPLCalloc(sizeof(CSVTable),1);

    psTable->fp = fp;
    psTable->pszFilename = CPLStrdup( pszFilename );
    psTable->psNext = *ppsCSVTableList;
    
    *ppsCSVTableList = psTable;

/* -------------------------------------------------------------------- */
/*      Read the table header record containing the field names.        */
/* -------------------------------------------------------------------- */
    psTable->papszFieldNames = CSVReadParseLine( fp );

    return( psTable );
}

/************************************************************************/
/*                            CSVDeaccess()                             */
/************************************************************************/

void CSVDeaccess( const char * pszFilename )

{
    CSVTable    *psLast, *psTable;
    
/* -------------------------------------------------------------------- */
/*      Fetch the table, and allocate the thread-local pointer to it    */
/*      if there isn't already one.                                     */
/* -------------------------------------------------------------------- */
    CSVTable **ppsCSVTableList;

    ppsCSVTableList = (CSVTable **) CPLGetTLS( CTLS_CSVTABLEPTR );
    if( ppsCSVTableList == NULL )
        return;
    
/* -------------------------------------------------------------------- */
/*      A NULL means deaccess all tables.                               */
/* -------------------------------------------------------------------- */
    if( pszFilename == NULL )
    {
        while( *ppsCSVTableList != NULL )
            CSVDeaccess( (*ppsCSVTableList)->pszFilename );
        
        return;
    }

/* -------------------------------------------------------------------- */
/*      Find this table.                                                */
/* -------------------------------------------------------------------- */
    psLast = NULL;
    for( psTable = *ppsCSVTableList;
         psTable != NULL && !EQUAL(psTable->pszFilename,pszFilename);
         psTable = psTable->psNext )
    {
        psLast = psTable;
    }

    if( psTable == NULL )
    {
        CPLDebug( "CPL_CSV", "CPLDeaccess( %s ) - no match.", pszFilename );
        return;
    }

/* -------------------------------------------------------------------- */
/*      Remove the link from the list.                                  */
/* -------------------------------------------------------------------- */
    if( psLast != NULL )
        psLast->psNext = psTable->psNext;
    else
        *ppsCSVTableList = psTable->psNext;

/* -------------------------------------------------------------------- */
/*      Free the table.                                                 */
/* -------------------------------------------------------------------- */
    if( psTable->fp != NULL )
        VSIFClose( psTable->fp );

    CSLDestroy( psTable->papszFieldNames );
    CSLDestroy( psTable->papszRecFields );
    CPLFree( psTable->pszFilename );
    CPLFree( psTable->panLineIndex );
    CPLFree( psTable->pszRawData );
    CPLFree( psTable->papszLines );

    CPLFree( psTable );

    CPLReadLine( NULL );
}

/************************************************************************/
/*                            CSVSplitLine()                            */
/*                                                                      */
/*      Tokenize a CSV line into fields in the form of a string         */
/*      list.  This is used instead of the CPLTokenizeString()          */
/*      because it provides correct CSV escaping and quoting            */
/*      semantics.                                                      */
/************************************************************************/

static char **CSVSplitLine( const char *pszString )

{
    char        **papszRetList = NULL;
    char        *pszToken;
    int         nTokenMax, nTokenLen;

    pszToken = (char *) CPLCalloc(10,1);
    nTokenMax = 10;
    
    while( pszString != NULL && *pszString != '\0' )
    {
        int     bInString = FALSE;

        nTokenLen = 0;
        
        /* Try to find the next delimeter, marking end of token */
        for( ; *pszString != '\0'; pszString++ )
        {

            /* End if this is a delimeter skip it and break. */
            if( !bInString && *pszString == ',' )
            {
                pszString++;
                break;
            }
            
            if( *pszString == '"' )
            {
                if( !bInString || pszString[1] != '"' )
                {
                    bInString = !bInString;
                    continue;
                }
                else  /* doubled quotes in string resolve to one quote */
                {
                    pszString++;
                }
            }

            if( nTokenLen >= nTokenMax-2 )
            {
                nTokenMax = nTokenMax * 2 + 10;
                pszToken = (char *) CPLRealloc( pszToken, nTokenMax );
            }

            pszToken[nTokenLen] = *pszString;
            nTokenLen++;
        }

        pszToken[nTokenLen] = '\0';
        papszRetList = CSLAddString( papszRetList, pszToken );

        /* If the last token is an empty token, then we have to catch
         * it now, otherwise we won't reenter the loop and it will be lost. 
         */
        if ( *pszString == '\0' && *(pszString-1) == ',' )
        {
            papszRetList = CSLAddString( papszRetList, "" );
        }
    }

    if( papszRetList == NULL )
        papszRetList = (char **) CPLCalloc(sizeof(char *),1);

    CPLFree( pszToken );

    return papszRetList;
}

/************************************************************************/
/*                          CSVFindNextLine()                           */
/*                                                                      */
/*      Find the start of the next line, while at the same time zero    */
/*      terminating this line.  Take into account that there may be     */
/*      newline indicators within quoted strings, and that quotes       */
/*      can be escaped with a backslash.                                */
/************************************************************************/

static char *CSVFindNextLine( char *pszThisLine )

{
    int  nQuoteCount = 0, i;

    for( i = 0; pszThisLine[i] != '\0'; i++ )
    {
        if( pszThisLine[i] == '\"'
            && (i == 0 || pszThisLine[i-1] != '\\') )
            nQuoteCount++;

        if( (pszThisLine[i] == 10 || pszThisLine[i] == 13)
            && (nQuoteCount % 2) == 0 )
            break;
    }

    while( pszThisLine[i] == 10 || pszThisLine[i] == 13 )
        pszThisLine[i++] = '\0';

    if( pszThisLine[i] == '\0' )
        return NULL;
    else
        return pszThisLine + i;
}

/************************************************************************/
/*                             CSVIngest()                              */
/*                                                                      */
/*      Load entire file into memory and setup index if possible.       */
/************************************************************************/

static void CSVIngest( const char *pszFilename )

{
    CSVTable *psTable = CSVAccess( pszFilename );