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dbfopen.c

/******************************************************************************
 * $Id: dbfopen.c,v 1.83 2008/11/12 14:28:15 fwarmerdam Exp $
 *
 * Project:  Shapelib
 * Purpose:  Implementation of .dbf access API documented in dbf_api.html.
 * Author:   Frank Warmerdam, warmerdam@pobox.com
 *
 ******************************************************************************
 * Copyright (c) 1999, Frank Warmerdam
 *
 * This software is available under the following "MIT Style" license,
 * or at the option of the licensee under the LGPL (see LICENSE.LGPL).  This
 * option is discussed in more detail in shapelib.html.
 *
 * --
 * 
 * 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.
 ******************************************************************************
 *
 * $Log: dbfopen.c,v $
 * Revision 1.83  2008/11/12 14:28:15  fwarmerdam
 * DBFCreateField() now works on files with records
 *
 * Revision 1.82  2008/11/11 17:47:09  fwarmerdam
 * added DBFDeleteField() function
 *
 * Revision 1.81  2008/01/03 17:48:13  bram
 * in DBFCreate, use default code page LDID/87 (= 0x57, ANSI)
 * instead of LDID/3.  This seems to be the same as what ESRI
 * would be doing by default.
 *
 * Revision 1.80  2007/12/30 14:36:39  fwarmerdam
 * avoid syntax issue with last comment.
 *
 * Revision 1.79  2007/12/30 14:35:48  fwarmerdam
 * Avoid char* / unsigned char* warnings.
 *
 * Revision 1.78  2007/12/18 18:28:07  bram
 * - create hook for client specific atof (bugzilla ticket 1615)
 * - check for NULL handle before closing cpCPG file, and close after reading.
 *
 * Revision 1.77  2007/12/15 20:25:21  bram
 * dbfopen.c now reads the Code Page information from the DBF file, and exports
 * this information as a string through the DBFGetCodePage function.  This is 
 * either the number from the LDID header field ("LDID/<number>") or as the 
 * content of an accompanying .CPG file.  When creating a DBF file, the code can
 * be set using DBFCreateEx.
 *
 * Revision 1.76  2007/12/12 22:21:32  bram
 * DBFClose: check for NULL psDBF handle before trying to close it.
 *
 * Revision 1.75  2007/12/06 13:58:19  fwarmerdam
 * make sure file offset calculations are done in as SAOffset
 *
 * Revision 1.74  2007/12/06 07:00:25  fwarmerdam
 * dbfopen now using SAHooks for fileio
 *
 * Revision 1.73  2007/09/03 19:48:11  fwarmerdam
 * move DBFReadAttribute() static dDoubleField into dbfinfo
 *
 * Revision 1.72  2007/09/03 19:34:06  fwarmerdam
 * Avoid use of static tuple buffer in DBFReadTuple()
 *
 * Revision 1.71  2006/06/22 14:37:18  fwarmerdam
 * avoid memory leak if dbfopen fread fails
 *
 * Revision 1.70  2006/06/17 17:47:05  fwarmerdam
 * use calloc() for dbfinfo in DBFCreate
 *
 * Revision 1.69  2006/06/17 15:34:32  fwarmerdam
 * disallow creating fields wider than 255
 *
 * Revision 1.68  2006/06/17 15:12:40  fwarmerdam
 * Fixed C++ style comments.
 *
 * Revision 1.67  2006/06/17 00:24:53  fwarmerdam
 * Don't treat non-zero decimals values as high order byte for length
 * for strings.  It causes serious corruption for some files.
 * http://bugzilla.remotesensing.org/show_bug.cgi?id=1202
 *
 * Revision 1.66  2006/03/29 18:26:20  fwarmerdam
 * fixed bug with size of pachfieldtype in dbfcloneempty
 *
 * Revision 1.65  2006/02/15 01:14:30  fwarmerdam
 * added DBFAddNativeFieldType
 *
 * Revision 1.64  2006/02/09 00:29:04  fwarmerdam
 * Changed to put spaces into string fields that are NULL as
 * per http://bugzilla.maptools.org/show_bug.cgi?id=316.
 *
 * Revision 1.63  2006/01/25 15:35:43  fwarmerdam
 * check success on DBFFlushRecord
 *
 * Revision 1.62  2006/01/10 16:28:03  fwarmerdam
 * Fixed typo in CPLError.
 *
 * Revision 1.61  2006/01/10 16:26:29  fwarmerdam
 * Push loading record buffer into DBFLoadRecord.
 * Implement CPL error reporting if USE_CPL defined.
 *
 * Revision 1.60  2006/01/05 01:27:27  fwarmerdam
 * added dbf deletion mark/fetch
 *
 * Revision 1.59  2005/03/14 15:20:28  fwarmerdam
 * Fixed last change.
 *
 * Revision 1.58  2005/03/14 15:18:54  fwarmerdam
 * Treat very wide fields with no decimals as double.  This is
 * more than 32bit integer fields.
 *
 * Revision 1.57  2005/02/10 20:16:54  fwarmerdam
 * Make the pszStringField buffer for DBFReadAttribute() static char [256]
 * as per bug 306.
 *
 * Revision 1.56  2005/02/10 20:07:56  fwarmerdam
 * Fixed bug 305 in DBFCloneEmpty() - header length problem.
 *
 * Revision 1.55  2004/09/26 20:23:46  fwarmerdam
 * avoid warnings with rcsid and signed/unsigned stuff
 *
 * Revision 1.54  2004/09/15 16:26:10  fwarmerdam
 * Treat all blank numeric fields as null too.
 */

#include "shapefil.h"

#include <math.h>
#include <stdlib.h>
#include <ctype.h>
#include <string.h>

SHP_CVSID("$Id: dbfopen.c,v 1.83 2008/11/12 14:28:15 fwarmerdam Exp $")

#ifndef FALSE
#  define FALSE         0
#  define TRUE          1
#endif

/************************************************************************/
/*                             SfRealloc()                              */
/*                                                                      */
/*      A realloc cover function that will access a NULL pointer as     */
/*      a valid input.                                                  */
/************************************************************************/

static void * SfRealloc( void * pMem, int nNewSize )

{
    if( pMem == NULL )
        return( (void *) malloc(nNewSize) );
    else
        return( (void *) realloc(pMem,nNewSize) );
}

/************************************************************************/
/*                           DBFWriteHeader()                           */
/*                                                                      */
/*      This is called to write out the file header, and field          */
/*      descriptions before writing any actual data records.  This      */
/*      also computes all the DBFDataSet field offset/size/decimals     */
/*      and so forth values.                                            */
/************************************************************************/

static void DBFWriteHeader(DBFHandle psDBF)

{
    unsigned char abyHeader[XBASE_FLDHDR_SZ];
    int           i;

    if( !psDBF->bNoHeader )
        return;

    psDBF->bNoHeader = FALSE;

/* -------------------------------------------------------------------- */
/*    Initialize the file header information.                     */
/* -------------------------------------------------------------------- */
    for( i = 0; i < XBASE_FLDHDR_SZ; i++ )
        abyHeader[i] = 0;

    abyHeader[0] = 0x03;            /* memo field? - just copying       */

    /* write out a dummy date */
    abyHeader[1] = 95;              /* YY */
    abyHeader[2] = 7;               /* MM */
    abyHeader[3] = 26;              /* DD */

    /* record count preset at zero */

    abyHeader[8] = (unsigned char) (psDBF->nHeaderLength % 256);
    abyHeader[9] = (unsigned char) (psDBF->nHeaderLength / 256);
    
    abyHeader[10] = (unsigned char) (psDBF->nRecordLength % 256);
    abyHeader[11] = (unsigned char) (psDBF->nRecordLength / 256);

    abyHeader[29] = (unsigned char) (psDBF->iLanguageDriver);

/* -------------------------------------------------------------------- */
/*      Write the initial 32 byte file header, and all the field        */
/*      descriptions.                                             */
/* -------------------------------------------------------------------- */
    psDBF->sHooks.FSeek( psDBF->fp, 0, 0 );
    psDBF->sHooks.FWrite( abyHeader, XBASE_FLDHDR_SZ, 1, psDBF->fp );
    psDBF->sHooks.FWrite( psDBF->pszHeader, XBASE_FLDHDR_SZ, psDBF->nFields, 
                          psDBF->fp );

/* -------------------------------------------------------------------- */
/*      Write out the newline character if there is room for it.        */
/* -------------------------------------------------------------------- */
    if( psDBF->nHeaderLength > 32*psDBF->nFields + 32 )
    {
        char      cNewline;

        cNewline = 0x0d;
        psDBF->sHooks.FWrite( &cNewline, 1, 1, psDBF->fp );
    }
}

/************************************************************************/
/*                           DBFFlushRecord()                           */
/*                                                                      */
/*      Write out the current record if there is one.                   */
/************************************************************************/

static int DBFFlushRecord( DBFHandle psDBF )

{
    SAOffset      nRecordOffset;

    if( psDBF->bCurrentRecordModified && psDBF->nCurrentRecord > -1 )
    {
      psDBF->bCurrentRecordModified = FALSE;

      nRecordOffset = 
            psDBF->nRecordLength * (SAOffset) psDBF->nCurrentRecord 
            + psDBF->nHeaderLength;

      if( psDBF->sHooks.FSeek( psDBF->fp, nRecordOffset, 0 ) != 0 
            || psDBF->sHooks.FWrite( psDBF->pszCurrentRecord, 
                                     psDBF->nRecordLength, 
                                     1, psDBF->fp ) != 1 )
        {
#ifdef USE_CPL
            CPLError( CE_Failure, CPLE_FileIO, 
                      "Failure writing DBF record %d.", 
                      psDBF->nCurrentRecord );
#else           
            fprintf( stderr, "Failure writing DBF record %d.", 
                     psDBF->nCurrentRecord );
#endif
            return FALSE;
        }
    }

    return TRUE;
}

/************************************************************************/
/*                           DBFLoadRecord()                            */
/************************************************************************/

static int DBFLoadRecord( DBFHandle psDBF, int iRecord )

{
    if( psDBF->nCurrentRecord != iRecord )
    {
        SAOffset nRecordOffset;

      if( !DBFFlushRecord( psDBF ) )
            return FALSE;

      nRecordOffset = 
            psDBF->nRecordLength * (SAOffset) iRecord + psDBF->nHeaderLength;

      if( psDBF->sHooks.FSeek( psDBF->fp, nRecordOffset, SEEK_SET ) != 0 )
        {
#ifdef USE_CPL
            CPLError( CE_Failure, CPLE_FileIO,
                      "fseek(%ld) failed on DBF file.\n",
                      (long) nRecordOffset );
#else
            fprintf( stderr, "fseek(%ld) failed on DBF file.\n",
                     (long) nRecordOffset );
#endif
            return FALSE;
        }

      if( psDBF->sHooks.FRead( psDBF->pszCurrentRecord, 
                                 psDBF->nRecordLength, 1, psDBF->fp ) != 1 )
        {
#ifdef USE_CPL
            CPLError( CE_Failure, CPLE_FileIO, 
                      "fread(%d) failed on DBF file.\n",
                      psDBF->nRecordLength );
#else
            fprintf( stderr, "fread(%d) failed on DBF file.\n",
                     psDBF->nRecordLength );
#endif
            return FALSE;
        }

      psDBF->nCurrentRecord = iRecord;
    }

    return TRUE;
}

/************************************************************************/
/*                          DBFUpdateHeader()                           */
/************************************************************************/

void SHPAPI_CALL
DBFUpdateHeader( DBFHandle psDBF )

{
    unsigned char       abyFileHeader[32];

    if( psDBF->bNoHeader )
        DBFWriteHeader( psDBF );

    DBFFlushRecord( psDBF );

    psDBF->sHooks.FSeek( psDBF->fp, 0, 0 );
    psDBF->sHooks.FRead( abyFileHeader, 32, 1, psDBF->fp );
    
    abyFileHeader[4] = (unsigned char) (psDBF->nRecords % 256);
    abyFileHeader[5] = (unsigned char) ((psDBF->nRecords/256) % 256);
    abyFileHeader[6] = (unsigned char) ((psDBF->nRecords/(256*256)) % 256);
    abyFileHeader[7] = (unsigned char) ((psDBF->nRecords/(256*256*256)) % 256);
    
    psDBF->sHooks.FSeek( psDBF->fp, 0, 0 );
    psDBF->sHooks.FWrite( abyFileHeader, 32, 1, psDBF->fp );

    psDBF->sHooks.FFlush( psDBF->fp );
}

/************************************************************************/
/*                              DBFOpen()                               */
/*                                                                      */
/*      Open a .dbf file.                                               */
/************************************************************************/
   
DBFHandle SHPAPI_CALL
DBFOpen( const char * pszFilename, const char * pszAccess )

{
    SAHooks sHooks;

    SASetupDefaultHooks( &sHooks );

    return DBFOpenLL( pszFilename, pszAccess, &sHooks );
}

/************************************************************************/
/*                              DBFOpen()                               */
/*                                                                      */
/*      Open a .dbf file.                                               */
/************************************************************************/
   
DBFHandle SHPAPI_CALL
DBFOpenLL( const char * pszFilename, const char * pszAccess, SAHooks *psHooks )

{
    DBFHandle           psDBF;
    SAFile        pfCPG;
    unsigned char *pabyBuf;
    int                 nFields, nHeadLen, iField, i;
    char          *pszBasename, *pszFullname;
    int                 nBufSize = 500;

/* -------------------------------------------------------------------- */
/*      We only allow the access strings "rb" and "r+".                  */
/* -------------------------------------------------------------------- */
    if( strcmp(pszAccess,"r") != 0 && strcmp(pszAccess,"r+") != 0 
        && strcmp(pszAccess,"rb") != 0 && strcmp(pszAccess,"rb+") != 0
        && strcmp(pszAccess,"r+b") != 0 )
        return( NULL );

    if( strcmp(pszAccess,"r") == 0 )
        pszAccess = "rb";
 
    if( strcmp(pszAccess,"r+") == 0 )
        pszAccess = "rb+";

/* -------------------------------------------------------------------- */
/*    Compute the base (layer) name.  If there is any extension   */
/*    on the passed in filename we will strip it off.             */
/* -------------------------------------------------------------------- */
    pszBasename = (char *) malloc(strlen(pszFilename)+5);
    strcpy( pszBasename, pszFilename );
    for( i = strlen(pszBasename)-1; 
       i > 0 && pszBasename[i] != '.' && pszBasename[i] != '/'
             && pszBasename[i] != '\\';
       i-- ) {}

    if( pszBasename[i] == '.' )
        pszBasename[i] = '\0';

    pszFullname = (char *) malloc(strlen(pszBasename) + 5);
    sprintf( pszFullname, "%s.dbf", pszBasename );
        
    psDBF = (DBFHandle) calloc( 1, sizeof(DBFInfo) );
    psDBF->fp = psHooks->FOpen( pszFullname, pszAccess );
    memcpy( &(psDBF->sHooks), psHooks, sizeof(SAHooks) );

    if( psDBF->fp == NULL )
    {
        sprintf( pszFullname, "%s.DBF", pszBasename );
        psDBF->fp = psDBF->sHooks.FOpen(pszFullname, pszAccess );
    }

    sprintf( pszFullname, "%s.cpg", pszBasename );
    pfCPG = psHooks->FOpen( pszFullname, "r" );
    if( pfCPG == NULL )
    {
        sprintf( pszFullname, "%s.CPG", pszBasename );
        pfCPG = psHooks->FOpen( pszFullname, "r" );
    }

    free( pszBasename );
    free( pszFullname );
    
    if( psDBF->fp == NULL )
    {
        free( psDBF );
        if( pfCPG ) psHooks->FClose( pfCPG );
        return( NULL );
    }

    psDBF->bNoHeader = FALSE;
    psDBF->nCurrentRecord = -1;
    psDBF->bCurrentRecordModified = FALSE;

/* -------------------------------------------------------------------- */
/*  Read Table Header info                                              */
/* -------------------------------------------------------------------- */
    pabyBuf = (unsigned char *) malloc(nBufSize);
    if( psDBF->sHooks.FRead( pabyBuf, 32, 1, psDBF->fp ) != 1 )
    {
        psDBF->sHooks.FClose( psDBF->fp );
        if( pfCPG ) psDBF->sHooks.FClose( pfCPG );
        free( pabyBuf );
        free( psDBF );
        return NULL;
    }

    psDBF->nRecords = 
     pabyBuf[4] + pabyBuf[5]*256 + pabyBuf[6]*256*256 + pabyBuf[7]*256*256*256;

    psDBF->nHeaderLength = nHeadLen = pabyBuf[8] + pabyBuf[9]*256;
    psDBF->nRecordLength = pabyBuf[10] + pabyBuf[11]*256;
    psDBF->iLanguageDriver = pabyBuf[29];

    psDBF->nFields = nFields = (nHeadLen - 32) / 32;

    psDBF->pszCurrentRecord = (char *) malloc(psDBF->nRecordLength);

/* -------------------------------------------------------------------- */
/*  Figure out the code page from the LDID and CPG                      */
/* -------------------------------------------------------------------- */

    psDBF->pszCodePage = NULL;
    if( pfCPG )
    {
        size_t n;
        char *buffer = (char *) pabyBuf;
        buffer[0] = '\0';
        psDBF->sHooks.FRead( pabyBuf, nBufSize - 1, 1, pfCPG );
        n = strcspn( (char *) pabyBuf, "\n\r" );
        if( n > 0 )
        {
            pabyBuf[n] = '\0';
            psDBF->pszCodePage = (char *) malloc(n + 1);
            memcpy( psDBF->pszCodePage, pabyBuf, n + 1 );
        }
            psDBF->sHooks.FClose( pfCPG );
    }
    if( psDBF->pszCodePage == NULL && pabyBuf[29] != 0 )
    {
        sprintf( (char *) pabyBuf, "LDID/%d", psDBF->iLanguageDriver );
        psDBF->pszCodePage = (char *) malloc(strlen((char*)pabyBuf) + 1);
        strcpy( psDBF->pszCodePage, (char *) pabyBuf );
    }

/* -------------------------------------------------------------------- */
/*  Read in Field Definitions                                           */
/* -------------------------------------------------------------------- */
    
    pabyBuf = (unsigned char *) SfRealloc(pabyBuf,nHeadLen);
    psDBF->pszHeader = (char *) pabyBuf;

    psDBF->sHooks.FSeek( psDBF->fp, 32, 0 );
    if( psDBF->sHooks.FRead( pabyBuf, nHeadLen-32, 1, psDBF->fp ) != 1 )
    {
        psDBF->sHooks.FClose( psDBF->fp );
        free( pabyBuf );
        free( psDBF->pszCurrentRecord );
        free( psDBF );
        return NULL;
    }

    psDBF->panFieldOffset = (int *) malloc(sizeof(int) * nFields);
    psDBF->panFieldSize = (int *) malloc(sizeof(int) * nFields);
    psDBF->panFieldDecimals = (int *) malloc(sizeof(int) * nFields);
    psDBF->pachFieldType = (char *) malloc(sizeof(char) * nFields);

    for( iField = 0; iField < nFields; iField++ )
    {
      unsigned char           *pabyFInfo;

      pabyFInfo = pabyBuf+iField*32;

      if( pabyFInfo[11] == 'N' || pabyFInfo[11] == 'F' )
      {
          psDBF->panFieldSize[iField] = pabyFInfo[16];
          psDBF->panFieldDecimals[iField] = pabyFInfo[17];
      }
      else
      {
          psDBF->panFieldSize[iField] = pabyFInfo[16];
          psDBF->panFieldDecimals[iField] = 0;

/*
** The following seemed to be used sometimes to handle files with long
** string fields, but in other cases (such as bug 1202) the decimals field
** just seems to indicate some sort of preferred formatting, not very
** wide fields.  So I have disabled this code.  FrankW.
          psDBF->panFieldSize[iField] = pabyFInfo[16] + pabyFInfo[17]*256;
          psDBF->panFieldDecimals[iField] = 0;
*/
      }

      psDBF->pachFieldType[iField] = (char) pabyFInfo[11];
      if( iField == 0 )
          psDBF->panFieldOffset[iField] = 1;
      else
          psDBF->panFieldOffset[iField] = 
            psDBF->panFieldOffset[iField-1] + psDBF->panFieldSize[iField-1];
    }

    return( psDBF );
}

/************************************************************************/
/*                              DBFClose()                              */
/************************************************************************/

void SHPAPI_CALL
DBFClose(DBFHandle psDBF)
{
    if( psDBF == NULL )
        return;

/* -------------------------------------------------------------------- */
/*      Write out header if not already written.                        */
/* -------------------------------------------------------------------- */
    if( psDBF->bNoHeader )
        DBFWriteHeader( psDBF );

    DBFFlushRecord( psDBF );

/* -------------------------------------------------------------------- */
/*      Update last access date, and number of records if we have */
/*    write access.                                         */
/* -------------------------------------------------------------------- */
    if( psDBF->bUpdated )
        DBFUpdateHeader( psDBF );

/* -------------------------------------------------------------------- */
/*      Close, and free resources.                                      */
/* -------------------------------------------------------------------- */
    psDBF->sHooks.FClose( psDBF->fp );

    if( psDBF->panFieldOffset != NULL )
    {
        free( psDBF->panFieldOffset );
        free( psDBF->panFieldSize );
        free( psDBF->panFieldDecimals );
        free( psDBF->pachFieldType );
    }

    if( psDBF->pszWorkField != NULL )
        free( psDBF->pszWorkField );

    free( psDBF->pszHeader );
    free( psDBF->pszCurrentRecord );
    free( psDBF->pszCodePage );

    free( psDBF );
}

/************************************************************************/
/*                             DBFCreate()                              */
/*                                                                      */
/* Create a new .dbf file with default code page LDID/87 (0x57)         */
/************************************************************************/

DBFHandle SHPAPI_CALL
DBFCreate( const char * pszFilename )

{
    return DBFCreateEx( pszFilename, "LDID/87" ); // 0x57
}

/************************************************************************/
/*                            DBFCreateEx()                             */
/*                                                                      */
/*      Create a new .dbf file.                                         */
/************************************************************************/

DBFHandle SHPAPI_CALL
DBFCreateEx( const char * pszFilename, const char* pszCodePage )

{
    SAHooks sHooks;

    SASetupDefaultHooks( &sHooks );

    return DBFCreateLL( pszFilename, pszCodePage , &sHooks );
}

/************************************************************************/
/*                             DBFCreate()                              */
/*                                                                      */
/*      Create a new .dbf file.                                         */
/************************************************************************/

DBFHandle SHPAPI_CALL
DBFCreateLL( const char * pszFilename, const char * pszCodePage, SAHooks *psHooks )

{
    DBFHandle     psDBF;
    SAFile  fp;
    char    *pszFullname, *pszBasename;
    int           i, ldid = -1;
    char chZero = '\0';

/* -------------------------------------------------------------------- */
/*    Compute the base (layer) name.  If there is any extension   */
/*    on the passed in filename we will strip it off.             */
/* -------------------------------------------------------------------- */
    pszBasename = (char *) malloc(strlen(pszFilename)+5);
    strcpy( pszBasename, pszFilename );
    for( i = strlen(pszBasename)-1; 
       i > 0 && pszBasename[i] != '.' && pszBasename[i] != '/'
             && pszBasename[i] != '\\';
       i-- ) {}

    if( pszBasename[i] == '.' )
        pszBasename[i] = '\0';

    pszFullname = (char *) malloc(strlen(pszBasename) + 5);
    sprintf( pszFullname, "%s.dbf", pszBasename );

/* -------------------------------------------------------------------- */
/*      Create the file.                                                */
/* -------------------------------------------------------------------- */
    fp = psHooks->FOpen( pszFullname, "wb" );
    if( fp == NULL )
        return( NULL );
    
    psHooks->FWrite( &chZero, 1, 1, fp );
    psHooks->FClose( fp );

    fp = psHooks->FOpen( pszFullname, "rb+" );
    if( fp == NULL )
        return( NULL );


    sprintf( pszFullname, "%s.cpg", pszBasename );
    if( pszCodePage != NULL )
    {
        if( strncmp( pszCodePage, "LDID/", 5 ) == 0 )
        {
            ldid = atoi( pszCodePage + 5 );
            if( ldid > 255 )
                ldid = -1; // don't use 0 to indicate out of range as LDID/0 is a valid one
        }
        if( ldid < 0 )
        {
            SAFile fpCPG = psHooks->FOpen( pszFullname, "w" );
            psHooks->FWrite( (char*) pszCodePage, strlen(pszCodePage), 1, fpCPG );
            psHooks->FClose( fpCPG );
        }
    }
    if( pszCodePage == NULL || ldid >= 0 )
    {
        psHooks->Remove( pszFullname );
    }

    free( pszBasename );
    free( pszFullname );

/* -------------------------------------------------------------------- */
/*    Create the info structure.                            */
/* -------------------------------------------------------------------- */
    psDBF = (DBFHandle) calloc(1,sizeof(DBFInfo));

    memcpy( &(psDBF->sHooks), psHooks, sizeof(SAHooks) );
    psDBF->fp = fp;
    psDBF->nRecords = 0;
    psDBF->nFields = 0;
    psDBF->nRecordLength = 1;
    psDBF->nHeaderLength = 33;
    
    psDBF->panFieldOffset = NULL;
    psDBF->panFieldSize = NULL;
    psDBF->panFieldDecimals = NULL;
    psDBF->pachFieldType = NULL;
    psDBF->pszHeader = NULL;

    psDBF->nCurrentRecord = -1;
    psDBF->bCurrentRecordModified = FALSE;
    psDBF->pszCurrentRecord = NULL;

    psDBF->bNoHeader = TRUE;

    psDBF->iLanguageDriver = ldid > 0 ? ldid : 0;
    psDBF->pszCodePage = NULL;
    if( pszCodePage )
    {
        psDBF->pszCodePage = (char * ) malloc( strlen(pszCodePage) + 1 );
        strcpy( psDBF->pszCodePage, pszCodePage );
    }

    return( psDBF );
}

/************************************************************************/
/*                            DBFAddField()                             */
/*                                                                      */
/*      Add a field to a newly created .dbf or to an existing one       */
/************************************************************************/

int SHPAPI_CALL
DBFAddField(DBFHandle psDBF, const char * pszFieldName, 
            DBFFieldType eType, int nWidth, int nDecimals )

{
    char chNativeType = 'C';

    if( eType == FTLogical )
        chNativeType = 'L';
    else if( eType == FTString )
        chNativeType = 'C';
    else
        chNativeType = 'N';

    return DBFAddNativeFieldType( psDBF, pszFieldName, chNativeType, 
                                  nWidth, nDecimals );
}

/************************************************************************/
/*                            DBFAddField()                             */
/*                                                                      */
/*      Add a field to a newly created .dbf file before any records     */
/*      are written.                                                    */
/************************************************************************/

int SHPAPI_CALL
DBFAddNativeFieldType(DBFHandle psDBF, const char * pszFieldName, 
                      char chType, int nWidth, int nDecimals )

{
    char    *pszFInfo;
    int           i;
    int         nOldRecordLength, nOldHeaderLength;
    char        *pszRecord;
    char        chFieldFill;
    SAOffset    nRecordOffset;

/* -------------------------------------------------------------------- */
/*      Do some checking to ensure we can add records to this file.     */
/* -------------------------------------------------------------------- */
    if( nWidth < 1 )
        return -1;

    if( nWidth > 255 )
        nWidth = 255;

    nOldRecordLength = psDBF->nRecordLength;
    nOldHeaderLength = psDBF->nHeaderLength;

/* -------------------------------------------------------------------- */
/*      SfRealloc all the arrays larger to hold the additional field      */
/*      information.                                                    */
/* -------------------------------------------------------------------- */
    psDBF->nFields++;

    psDBF->panFieldOffset = (int *) 
        SfRealloc( psDBF->panFieldOffset, sizeof(int) * psDBF->nFields );

    psDBF->panFieldSize = (int *) 
        SfRealloc( psDBF->panFieldSize, sizeof(int) * psDBF->nFields );

    psDBF->panFieldDecimals = (int *) 
        SfRealloc( psDBF->panFieldDecimals, sizeof(int) * psDBF->nFields );

    psDBF->pachFieldType = (char *) 
        SfRealloc( psDBF->pachFieldType, sizeof(char) * psDBF->nFields );

/* -------------------------------------------------------------------- */
/*      Assign the new field information fields.                        */
/* -------------------------------------------------------------------- */
    psDBF->panFieldOffset[psDBF->nFields-1] = psDBF->nRecordLength;
    psDBF->nRecordLength += nWidth;
    psDBF->panFieldSize[psDBF->nFields-1] = nWidth;
    psDBF->panFieldDecimals[psDBF->nFields-1] = nDecimals;
    psDBF->pachFieldType[psDBF->nFields-1] = chType;

/* -------------------------------------------------------------------- */
/*      Extend the required header information.                         */
/* -------------------------------------------------------------------- */
    psDBF->nHeaderLength += 32;
    psDBF->bUpdated = FALSE;

    psDBF->pszHeader = (char *) SfRealloc(psDBF->pszHeader,psDBF->nFields*32);

    pszFInfo = psDBF->pszHeader + 32 * (psDBF->nFields-1);

    for( i = 0; i < 32; i++ )
        pszFInfo[i] = '\0';

    if( (int) strlen(pszFieldName) < 10 )
        strncpy( pszFInfo, pszFieldName, strlen(pszFieldName));
    else
        strncpy( pszFInfo, pszFieldName, 10);

    pszFInfo[11] = psDBF->pachFieldType[psDBF->nFields-1];

    if( chType == 'C' )
    {
        pszFInfo[16] = (unsigned char) (nWidth % 256);
        pszFInfo[17] = (unsigned char) (nWidth / 256);
    }
    else
    {
        pszFInfo[16] = (unsigned char) nWidth;
        pszFInfo[17] = (unsigned char) nDecimals;
    }
    
/* -------------------------------------------------------------------- */
/*      Make the current record buffer appropriately larger.            */
/* -------------------------------------------------------------------- */
    psDBF->pszCurrentRecord = (char *) SfRealloc(psDBF->pszCurrentRecord,
                                                 psDBF->nRecordLength);

    /* we're done if dealing with new .dbf */
    if( psDBF->bNoHeader )
        return( psDBF->nFields - 1 );

/* -------------------------------------------------------------------- */
/*      For existing .dbf file, shift records                           */
/* -------------------------------------------------------------------- */

    /* alloc record */
    pszRecord = (char *) malloc(sizeof(char) * psDBF->nRecordLength);

    switch (chType)
    {
      case 'N':
      case 'F':
        chFieldFill = '*';
        break;
      case 'D':
        chFieldFill = '0';
        break;
      case 'L':
       chFieldFill = '?';
       break;
      default:
       chFieldFill = ' ';
       break;
    }

    for (i = psDBF->nRecords-1; i >= 0; --i)
    {
        nRecordOffset = nOldRecordLength * (SAOffset) i + nOldHeaderLength;

        /* load record */
        psDBF->sHooks.FSeek( psDBF->fp, nRecordOffset, 0 );
        psDBF->sHooks.FRead( pszRecord, nOldRecordLength, 1, psDBF->fp );

        /* set new field's value to NULL */
        memset(pszRecord + nOldRecordLength, chFieldFill, nWidth);

        nRecordOffset = psDBF->nRecordLength * (SAOffset) i + psDBF->nHeaderLength;

        /* move record to the new place*/
        psDBF->sHooks.FSeek( psDBF->fp, nRecordOffset, 0 );
        psDBF->sHooks.FWrite( pszRecord, psDBF->nRecordLength, 1, psDBF->fp );
    }

    /* free record */
    free(pszRecord);

    /* force update of header with new header, record length and new field */
    psDBF->bNoHeader = TRUE;
    DBFUpdateHeader( psDBF );

    return( psDBF->nFields-1 );
}

/************************************************************************/
/*                          DBFReadAttribute()                          */
/*                                                                      */
/*      Read one of the attribute fields of a record.                   */
/************************************************************************/

static void *DBFReadAttribute(DBFHandle psDBF, int hEntity, int iField,
                              char chReqType )

{
    unsigned char *pabyRec;
    void    *pReturnField = NULL;

/* -------------------------------------------------------------------- */
/*      Verify selection.                                               */
/* -------------------------------------------------------------------- */
    if( hEntity < 0 || hEntity >= psDBF->nRecords )
        return( NULL );

    if( iField < 0 || iField >= psDBF->nFields )
        return( NULL );

/* -------------------------------------------------------------------- */
/*    Have we read the record?                              */
/* -------------------------------------------------------------------- */
    if( !DBFLoadRecord( psDBF, hEntity ) )
        return NULL;

    pabyRec = (unsigned char *) psDBF->pszCurrentRecord;

/* -------------------------------------------------------------------- */
/*      Ensure we have room to extract the target field.                */
/* -------------------------------------------------------------------- */
    if( psDBF->panFieldSize[iField] >= psDBF->nWorkFieldLength )
    {
        psDBF->nWorkFieldLength = psDBF->panFieldSize[iField] + 100;
        if( psDBF->pszWorkField == NULL )
            psDBF->pszWorkField = (char *) malloc(psDBF->nWorkFieldLength);
        else
            psDBF->pszWorkField = (char *) realloc(psDBF->pszWorkField,
                                                   psDBF->nWorkFieldLength);
    }

/* -------------------------------------------------------------------- */
/*    Extract the requested field.                          */
/* -------------------------------------------------------------------- */
    strncpy( psDBF->pszWorkField,
           ((const char *) pabyRec) + psDBF->panFieldOffset[iField],
           psDBF->panFieldSize[iField] );
    psDBF->pszWorkField[psDBF->panFieldSize[iField]] = '\0';

    pReturnField = psDBF->pszWorkField;

/* -------------------------------------------------------------------- */
/*      Decode the field.                                               */
/* -------------------------------------------------------------------- */
    if( chReqType == 'N' )
    {
        psDBF->dfDoubleField = psDBF->sHooks.Atof(psDBF->pszWorkField);

      pReturnField = &(psDBF->dfDoubleField);
    }

/* -------------------------------------------------------------------- */
/*      Should we trim white space off the string attribute value?      */
/* -------------------------------------------------------------------- */
#ifdef TRIM_DBF_WHITESPACE
    else
    {
        char      *pchSrc, *pchDst;

        pchDst = pchSrc = psDBF->pszWorkField;
        while( *pchSrc == ' ' )
            pchSrc++;

        while( *pchSrc != '\0' )
            *(pchDst++) = *(pchSrc++);
        *pchDst = '\0';

        while( pchDst != psDBF->pszWorkField && *(--pchDst) == ' ' )
            *pchDst = '\0';
    }
#endif
    
    return( pReturnField );
}

/************************************************************************/
/*                        DBFReadIntAttribute()                         */
/*                                                                      */
/*      Read an integer attribute.                                      */
/************************************************************************/

int SHPAPI_CALL
DBFReadIntegerAttribute( DBFHandle psDBF, int iRecord, int iField )

{
    double  *pdValue;

    pdValue = (double *) DBFReadAttribute( psDBF, iRecord, iField, 'N' );

    if( pdValue == NULL )
        return 0;
    else
        return( (int) *pdValue );
}

/************************************************************************/
/*                        DBFReadDoubleAttribute()                      */
/*                                                                      */
/*      Read a double attribute.                                        */
/************************************************************************/

double SHPAPI_CALL
DBFReadDoubleAttribute( DBFHandle psDBF, int iRecord, int iField )

{
    double  *pdValue;

    pdValue = (double *) DBFReadAttribute( psDBF, iRecord, iField, 'N' );

    if( pdValue == NULL )
        return 0.0;
    else
        return( *pdValue );
}

/************************************************************************/
/*                        DBFReadStringAttribute()                      */
/*                                                                      */
/*      Read a string attribute.                                        */
/************************************************************************/

const char SHPAPI_CALL1(*)
DBFReadStringAttribute( DBFHandle psDBF, int iRecord, int iField )

{
    return( (const char *) DBFReadAttribute( psDBF, iRecord, iField, 'C' ) );
}

/************************************************************************/
/*                        DBFReadLogicalAttribute()                     */
/*                                                                      */
/*      Read a logical attribute.                                       */
/************************************************************************/

const char SHPAPI_CALL1(*)
DBFReadLogicalAttribute( DBFHandle psDBF, int iRecord, int iField )

{
    return( (const char *) DBFReadAttribute( psDBF, iRecord, iField, 'L' ) );
}

/************************************************************************/
/*                         DBFIsAttributeNULL()                         */
/*                                                                      */
/*      Return TRUE if value for field is NULL.                         */
/*                                                                      */
/*      Contributed by Jim Matthews.                                    */
/************************************************************************/

int SHPAPI_CALL
DBFIsAttributeNULL( DBFHandle psDBF, int iRecord, int iField )

{
    const char    *pszValue;
    int i;

    pszValue = DBFReadStringAttribute( psDBF, iRecord, iField );

    if( pszValue == NULL )
        return TRUE;

    switch(psDBF->pachFieldType[iField])
    {
      case 'N':
      case 'F':
        /*
        ** We accept all asterisks or all blanks as NULL 
        ** though according to the spec I think it should be all 
        ** asterisks. 
        */
        if( pszValue[0] == '*' )
            return TRUE;

        for( i = 0; pszValue[i] != '\0'; i++ )
        {
            if( pszValue[i] != ' ' )
                return FALSE;
        }
        return TRUE;

      case 'D':
        /* NULL date fields have value "00000000" */
        return strncmp(pszValue,"00000000",8) == 0;

      case 'L':
        /* NULL boolean fields have value "?" */ 
        return pszValue[0] == '?';

      default:
        /* empty string fields are considered NULL */
        return strlen(pszValue) == 0;
    }
}

/************************************************************************/
/*                          DBFGetFieldCount()                          */
/*                                                                      */
/*      Return the number of fields in this table.                      */
/************************************************************************/

int SHPAPI_CALL
DBFGetFieldCount( DBFHandle psDBF )

{
    return( psDBF->nFields );
}

/************************************************************************/
/*                         DBFGetRecordCount()                          */
/*                                                                      */
/*      Return the number of records in this table.                     */
/************************************************************************/

int SHPAPI_CALL
DBFGetRecordCount( DBFHandle psDBF )

{
    return( psDBF->nRecords );
}

/************************************************************************/
/*                          DBFGetFieldInfo()                           */
/*                                                                      */
/*      Return any requested information about the field.               */
/************************************************************************/

DBFFieldType SHPAPI_CALL
DBFGetFieldInfo( DBFHandle psDBF, int iField, char * pszFieldName,
                 int * pnWidth, int * pnDecimals )

{
    if( iField < 0 || iField >= psDBF->nFields )
        return( FTInvalid );

    if( pnWidth != NULL )
        *pnWidth = psDBF->panFieldSize[iField];

    if( pnDecimals != NULL )
        *pnDecimals = psDBF->panFieldDecimals[iField];

    if( pszFieldName != NULL )
    {
      int   i;

      strncpy( pszFieldName, (char *) psDBF->pszHeader+iField*32, 11 );
      pszFieldName[11] = '\0';
      for( i = 10; i > 0 && pszFieldName[i] == ' '; i-- )
          pszFieldName[i] = '\0';
    }

    if ( psDBF->pachFieldType[iField] == 'L' )
      return( FTLogical);

    else if( psDBF->pachFieldType[iField] == 'N' 
             || psDBF->pachFieldType[iField] == 'F' )
    {
      if( psDBF->panFieldDecimals[iField] > 0 
            || psDBF->panFieldSize[iField] > 10 )
          return( FTDouble );
      else
          return( FTInteger );
    }
    else
    {
      return( FTString );
    }
}

/************************************************************************/
/*                         DBFWriteAttribute()                          */
/*                                                    */
/*    Write an attribute record to the file.                      */
/************************************************************************/

static int DBFWriteAttribute(DBFHandle psDBF, int hEntity, int iField,
                       void * pValue )

{
    int                 i, j, nRetResult = TRUE;
    unsigned char *pabyRec;
    char    szSField[400], szFormat[20];

/* -------------------------------------------------------------------- */
/*    Is this a valid record?                               */
/* -------------------------------------------------------------------- */
    if( hEntity < 0 || hEntity > psDBF->nRecords )
        return( FALSE );

    if( psDBF->bNoHeader )
        DBFWriteHeader(psDBF);

/* -------------------------------------------------------------------- */
/*      Is this a brand new record?                                     */
/* -------------------------------------------------------------------- */
    if( hEntity == psDBF->nRecords )
    {
      if( !DBFFlushRecord( psDBF ) )
            return FALSE;

      psDBF->nRecords++;
      for( i = 0; i < psDBF->nRecordLength; i++ )
          psDBF->pszCurrentRecord[i] = ' ';

      psDBF->nCurrentRecord = hEntity;
    }

/* -------------------------------------------------------------------- */
/*      Is this an existing record, but different than the last one     */
/*      we accessed?                                                    */
/* -------------------------------------------------------------------- */
    if( !DBFLoadRecord( psDBF, hEntity ) )
        return FALSE;

    pabyRec = (unsigned char *) psDBF->pszCurrentRecord;

    psDBF->bCurrentRecordModified = TRUE;
    psDBF->bUpdated = TRUE;

/* -------------------------------------------------------------------- */
/*      Translate NULL value to valid DBF file representation.          */
/*                                                                      */
/*      Contributed by Jim Matthews.                                    */
/* -------------------------------------------------------------------- */
    if( pValue == NULL )
    {
        switch(psDBF->pachFieldType[iField])
        {
          case 'N':
          case 'F':
          /* NULL numeric fields have value "****************" */
            memset( (char *) (pabyRec+psDBF->panFieldOffset[iField]), '*', 
                    psDBF->panFieldSize[iField] );
            break;

          case 'D':
          /* NULL date fields have value "00000000" */
            memset( (char *) (pabyRec+psDBF->panFieldOffset[iField]), '0', 
                    psDBF->panFieldSize[iField] );
            break;

          case 'L':
          /* NULL boolean fields have value "?" */ 
            memset( (char *) (pabyRec+psDBF->panFieldOffset[iField]), '?', 
                    psDBF->panFieldSize[iField] );
            break;

          default:
            /* empty string fields are considered NULL */
            memset( (char *) (pabyRec+psDBF->panFieldOffset[iField]), ' ', 
                    psDBF->panFieldSize[iField] );
            break;
        }
        return TRUE;
    }

/* -------------------------------------------------------------------- */
/*      Assign all the record fields.                                   */
/* -------------------------------------------------------------------- */
    switch( psDBF->pachFieldType[iField] )
    {
      case 'D':
      case 'N':
      case 'F':
      if( psDBF->panFieldDecimals[iField] == 0 )
      {
            int         nWidth = psDBF->panFieldSize[iField];

            if( (int) sizeof(szSField)-2 < nWidth )
                nWidth = sizeof(szSField)-2;

          sprintf( szFormat, "%%%dd", nWidth );
          sprintf(szSField, szFormat, (int) *((double *) pValue) );
          if( (int)strlen(szSField) > psDBF->panFieldSize[iField] )
            {
              szSField[psDBF->panFieldSize[iField]] = '\0';
                nRetResult = FALSE;
            }

          strncpy((char *) (pabyRec+psDBF->panFieldOffset[iField]),
                szSField, strlen(szSField) );
      }
      else
      {
            int         nWidth = psDBF->panFieldSize[iField];

            if( (int) sizeof(szSField)-2 < nWidth )
                nWidth = sizeof(szSField)-2;

          sprintf( szFormat, "%%%d.%df", 
                     nWidth, psDBF->panFieldDecimals[iField] );
          sprintf(szSField, szFormat, *((double *) pValue) );
          if( (int) strlen(szSField) > psDBF->panFieldSize[iField] )
            {
              szSField[psDBF->panFieldSize[iField]] = '\0';
                nRetResult = FALSE;
            }
          strncpy((char *) (pabyRec+psDBF->panFieldOffset[iField]),
                szSField, strlen(szSField) );
      }
      break;

      case 'L':
        if (psDBF->panFieldSize[iField] >= 1  && 
            (*(char*)pValue == 'F' || *(char*)pValue == 'T'))
            *(pabyRec+psDBF->panFieldOffset[iField]) = *(char*)pValue;
        break;

      default:
      if( (int) strlen((char *) pValue) > psDBF->panFieldSize[iField] )
        {
          j = psDBF->panFieldSize[iField];
            nRetResult = FALSE;
        }
      else
        {
            memset( pabyRec+psDBF->panFieldOffset[iField], ' ',
                    psDBF->panFieldSize[iField] );
          j = strlen((char *) pValue);
        }

      strncpy((char *) (pabyRec+psDBF->panFieldOffset[iField]),
            (char *) pValue, j );
      break;
    }

    return( nRetResult );
}

/************************************************************************/
/*                     DBFWriteAttributeDirectly()                      */
/*                                                                      */
/*      Write an attribute record to the file, but without any          */
/*      reformatting based on type.  The provided buffer is written     */
/*      as is to the field position in the record.                      */
/************************************************************************/

int SHPAPI_CALL
DBFWriteAttributeDirectly(DBFHandle psDBF, int hEntity, int iField,
                              void * pValue )

{
    int                       i, j;
    unsigned char *pabyRec;

/* -------------------------------------------------------------------- */
/*    Is this a valid record?                               */
/* -------------------------------------------------------------------- */
    if( hEntity < 0 || hEntity > psDBF->nRecords )
        return( FALSE );

    if( psDBF->bNoHeader )
        DBFWriteHeader(psDBF);

/* -------------------------------------------------------------------- */
/*      Is this a brand new record?                                     */
/* -------------------------------------------------------------------- */
    if( hEntity == psDBF->nRecords )
    {
      if( !DBFFlushRecord( psDBF ) )
            return FALSE;

      psDBF->nRecords++;
      for( i = 0; i < psDBF->nRecordLength; i++ )
          psDBF->pszCurrentRecord[i] = ' ';

      psDBF->nCurrentRecord = hEntity;
    }

/* -------------------------------------------------------------------- */
/*      Is this an existing record, but different than the last one     */
/*      we accessed?                                                    */
/* -------------------------------------------------------------------- */
    if( !DBFLoadRecord( psDBF, hEntity ) )
        return FALSE;

    pabyRec = (unsigned char *) psDBF->pszCurrentRecord;

/* -------------------------------------------------------------------- */
/*      Assign all the record fields.                                   */
/* -------------------------------------------------------------------- */
    if( (int)strlen((char *) pValue) > psDBF->panFieldSize[iField] )
        j = psDBF->panFieldSize[iField];
    else
    {
        memset( pabyRec+psDBF->panFieldOffset[iField], ' ',
                psDBF->panFieldSize[iField] );
        j = strlen((char *) pValue);
    }

    strncpy((char *) (pabyRec+psDBF->panFieldOffset[iField]),
            (char *) pValue, j );

    psDBF->bCurrentRecordModified = TRUE;
    psDBF->bUpdated = TRUE;

    return( TRUE );
}

/************************************************************************/
/*                      DBFWriteDoubleAttribute()                       */
/*                                                                      */
/*      Write a double attribute.                                       */
/************************************************************************/

int SHPAPI_CALL
DBFWriteDoubleAttribute( DBFHandle psDBF, int iRecord, int iField,
                         double dValue )

{
    return( DBFWriteAttribute( psDBF, iRecord, iField, (void *) &dValue ) );
}

/************************************************************************/
/*                      DBFWriteIntegerAttribute()                      */
/*                                                                      */
/*      Write a integer attribute.                                      */
/************************************************************************/

int SHPAPI_CALL
DBFWriteIntegerAttribute( DBFHandle psDBF, int iRecord, int iField,
                          int nValue )

{
    double  dValue = nValue;

    return( DBFWriteAttribute( psDBF, iRecord, iField, (void *) &dValue ) );
}

/************************************************************************/
/*                      DBFWriteStringAttribute()                       */
/*                                                                      */
/*      Write a string attribute.                                       */
/************************************************************************/

int SHPAPI_CALL
DBFWriteStringAttribute( DBFHandle psDBF, int iRecord, int iField,
                         const char * pszValue )

{
    return( DBFWriteAttribute( psDBF, iRecord, iField, (void *) pszValue ) );
}

/************************************************************************/
/*                      DBFWriteNULLAttribute()                         */
/*                                                                      */
/*      Write a string attribute.                                       */
/************************************************************************/

int SHPAPI_CALL
DBFWriteNULLAttribute( DBFHandle psDBF, int iRecord, int iField )

{
    return( DBFWriteAttribute( psDBF, iRecord, iField, NULL ) );
}

/************************************************************************/
/*                      DBFWriteLogicalAttribute()                      */
/*                                                                      */
/*      Write a logical attribute.                                      */
/************************************************************************/

int SHPAPI_CALL
DBFWriteLogicalAttribute( DBFHandle psDBF, int iRecord, int iField,
                   const char lValue)

{
    return( DBFWriteAttribute( psDBF, iRecord, iField, (void *) (&lValue) ) );
}

/************************************************************************/
/*                         DBFWriteTuple()                              */
/*                                                    */
/*    Write an attribute record to the file.                      */
/************************************************************************/

int SHPAPI_CALL
DBFWriteTuple(DBFHandle psDBF, int hEntity, void * pRawTuple )

{
    int                       i;
    unsigned char *pabyRec;

/* -------------------------------------------------------------------- */
/*    Is this a valid record?                               */
/* -------------------------------------------------------------------- */
    if( hEntity < 0 || hEntity > psDBF->nRecords )
        return( FALSE );

    if( psDBF->bNoHeader )
        DBFWriteHeader(psDBF);

/* -------------------------------------------------------------------- */
/*      Is this a brand new record?                                     */
/* -------------------------------------------------------------------- */
    if( hEntity == psDBF->nRecords )
    {
      if( !DBFFlushRecord( psDBF ) )
            return FALSE;

      psDBF->nRecords++;
      for( i = 0; i < psDBF->nRecordLength; i++ )
          psDBF->pszCurrentRecord[i] = ' ';

      psDBF->nCurrentRecord = hEntity;
    }

/* -------------------------------------------------------------------- */
/*      Is this an existing record, but different than the last one     */
/*      we accessed?                                                    */
/* -------------------------------------------------------------------- */
    if( !DBFLoadRecord( psDBF, hEntity ) )
        return FALSE;

    pabyRec = (unsigned char *) psDBF->pszCurrentRecord;

    memcpy ( pabyRec, pRawTuple,  psDBF->nRecordLength );

    psDBF->bCurrentRecordModified = TRUE;
    psDBF->bUpdated = TRUE;

    return( TRUE );
}

/************************************************************************/
/*                            DBFReadTuple()                            */
/*                                                                      */
/*      Read a complete record.  Note that the result is only valid     */
/*      till the next record read for any reason.                       */
/************************************************************************/

const char SHPAPI_CALL1(*)
DBFReadTuple(DBFHandle psDBF, int hEntity )

{
    if( hEntity < 0 || hEntity >= psDBF->nRecords )
        return( NULL );

    if( !DBFLoadRecord( psDBF, hEntity ) )
        return NULL;

    return (const char *) psDBF->pszCurrentRecord;
}

/************************************************************************/
/*                          DBFCloneEmpty()                              */
/*                                                                      */
/*      Read one of the attribute fields of a record.                   */
/************************************************************************/

DBFHandle SHPAPI_CALL
DBFCloneEmpty(DBFHandle psDBF, const char * pszFilename ) 
{
    DBFHandle     newDBF;

   newDBF = DBFCreateEx ( pszFilename, psDBF->pszCodePage );
   if ( newDBF == NULL ) return ( NULL ); 
   
   newDBF->nFields = psDBF->nFields;
   newDBF->nRecordLength = psDBF->nRecordLength;
   newDBF->nHeaderLength = psDBF->nHeaderLength;
    
   newDBF->pszHeader = (char *) malloc ( newDBF->nHeaderLength );
   memcpy ( newDBF->pszHeader, psDBF->pszHeader, newDBF->nHeaderLength );
   
   newDBF->panFieldOffset = (int *) malloc ( sizeof(int) * psDBF->nFields ); 
   memcpy ( newDBF->panFieldOffset, psDBF->panFieldOffset, sizeof(int) * psDBF->nFields );
   newDBF->panFieldSize = (int *) malloc ( sizeof(int) * psDBF->nFields );
   memcpy ( newDBF->panFieldSize, psDBF->panFieldSize, sizeof(int) * psDBF->nFields );
   newDBF->panFieldDecimals = (int *) malloc ( sizeof(int) * psDBF->nFields );
   memcpy ( newDBF->panFieldDecimals, psDBF->panFieldDecimals, sizeof(int) * psDBF->nFields );
   newDBF->pachFieldType = (char *) malloc ( sizeof(char) * psDBF->nFields );
   memcpy ( newDBF->pachFieldType, psDBF->pachFieldType, sizeof(char)*psDBF->nFields );

   newDBF->bNoHeader = TRUE;
   newDBF->bUpdated = TRUE;
   
   DBFWriteHeader ( newDBF );
   DBFClose ( newDBF );
   
   newDBF = DBFOpen ( pszFilename, "rb+" );

   return ( newDBF );
}

/************************************************************************/
/*                       DBFGetNativeFieldType()                        */
/*                                                                      */
/*      Return the DBase field type for the specified field.            */
/*                                                                      */
/*      Value can be one of: 'C' (String), 'D' (Date), 'F' (Float),     */
/*                           'N' (Numeric, with or without decimal),    */
/*                           'L' (Logical),                             */
/*                           'M' (Memo: 10 digits .DBT block ptr)       */
/************************************************************************/

char SHPAPI_CALL
DBFGetNativeFieldType( DBFHandle psDBF, int iField )

{
    if( iField >=0 && iField < psDBF->nFields )
        return psDBF->pachFieldType[iField];

    return  ' ';
}

/************************************************************************/
/*                            str_to_upper()                            */
/************************************************************************/

static void str_to_upper (char *string)
{
    int len;
    short i = -1;

    len = strlen (string);

    while (++i < len)
        if (isalpha(string[i]) && islower(string[i]))
            string[i] = (char) toupper ((int)string[i]);
}

/************************************************************************/
/*                          DBFGetFieldIndex()                          */
/*                                                                      */
/*      Get the index number for a field in a .dbf file.                */
/*                                                                      */
/*      Contributed by Jim Matthews.                                    */
/************************************************************************/

int SHPAPI_CALL
DBFGetFieldIndex(DBFHandle psDBF, const char *pszFieldName)

{
    char          name[12], name1[12], name2[12];
    int           i;

    strncpy(name1, pszFieldName,11);
    name1[11] = '\0';
    str_to_upper(name1);

    for( i = 0; i < DBFGetFieldCount(psDBF); i++ )
    {
        DBFGetFieldInfo( psDBF, i, name, NULL, NULL );
        strncpy(name2,name,11);
        str_to_upper(name2);

        if(!strncmp(name1,name2,10))
            return(i);
    }
    return(-1);
}

/************************************************************************/
/*                         DBFIsRecordDeleted()                         */
/*                                                                      */
/*      Returns TRUE if the indicated record is deleted, otherwise      */
/*      it returns FALSE.                                               */
/************************************************************************/

int SHPAPI_CALL DBFIsRecordDeleted( DBFHandle psDBF, int iShape )

{
/* -------------------------------------------------------------------- */
/*      Verify selection.                                               */
/* -------------------------------------------------------------------- */
    if( iShape < 0 || iShape >= psDBF->nRecords )
        return TRUE;

/* -------------------------------------------------------------------- */
/*    Have we read the record?                              */
/* -------------------------------------------------------------------- */
    if( !DBFLoadRecord( psDBF, iShape ) )
        return FALSE;

/* -------------------------------------------------------------------- */
/*      '*' means deleted.                                              */
/* -------------------------------------------------------------------- */
    return psDBF->pszCurrentRecord[0] == '*';
}

/************************************************************************/
/*                        DBFMarkRecordDeleted()                        */
/************************************************************************/

int SHPAPI_CALL DBFMarkRecordDeleted( DBFHandle psDBF, int iShape, 
                                      int bIsDeleted )

{
    char chNewFlag;

/* -------------------------------------------------------------------- */
/*      Verify selection.                                               */
/* -------------------------------------------------------------------- */
    if( iShape < 0 || iShape >= psDBF->nRecords )
        return FALSE;

/* -------------------------------------------------------------------- */
/*      Is this an existing record, but different than the last one     */
/*      we accessed?                                                    */
/* -------------------------------------------------------------------- */
    if( !DBFLoadRecord( psDBF, iShape ) )
        return FALSE;

/* -------------------------------------------------------------------- */
/*      Assign value, marking record as dirty if it changes.            */
/* -------------------------------------------------------------------- */
    if( bIsDeleted )
        chNewFlag = '*';
    else 
        chNewFlag = ' ';

    if( psDBF->pszCurrentRecord[0] != chNewFlag )
    {
        psDBF->bCurrentRecordModified = TRUE;
        psDBF->bUpdated = TRUE;
        psDBF->pszCurrentRecord[0] = chNewFlag;
    }

    return TRUE;
}

/************************************************************************/
/*                            DBFGetCodePage                            */
/************************************************************************/

const char SHPAPI_CALL1(*)
DBFGetCodePage(DBFHandle psDBF )
{
    if( psDBF == NULL )
        return NULL;
    return psDBF->pszCodePage;
}

/************************************************************************/
/*                          DBFDeleteField()                            */
/*                                                                      */
/*      Remove a field from a .dbf file                                 */
/************************************************************************/

int SHPAPI_CALL
DBFDeleteField(DBFHandle psDBF, int iField)
{
    int nOldRecordLength, nOldHeaderLength;
    int nDeletedFieldOffset, nDeletedFieldSize;
    SAOffset nRecordOffset;
    char* pszRecord;
    int i, iRecord;

    if (iField < 0 || iField >= psDBF->nFields)
        return FALSE;

    /* make sure that everything is written in .dbf */
    if( !DBFFlushRecord( psDBF ) )
        return FALSE;

    /* get information about field to be deleted */
    nOldRecordLength = psDBF->nRecordLength;
    nOldHeaderLength = psDBF->nHeaderLength;
    nDeletedFieldOffset = psDBF->panFieldOffset[iField];
    nDeletedFieldSize = psDBF->panFieldSize[iField];

    /* update fields info */
    for (i = iField + 1; i < psDBF->nFields; i++)
    {
        psDBF->panFieldOffset[i-1] = psDBF->panFieldOffset[i] - nDeletedFieldSize;
        psDBF->panFieldSize[i-1] = psDBF->panFieldSize[i];
        psDBF->panFieldDecimals[i-1] = psDBF->panFieldDecimals[i];
        psDBF->pachFieldType[i-1] = psDBF->pachFieldType[i];
    }

    /* resize fields arrays */
    psDBF->nFields--;

    psDBF->panFieldOffset = (int *) 
        SfRealloc( psDBF->panFieldOffset, sizeof(int) * psDBF->nFields );

    psDBF->panFieldSize = (int *) 
        SfRealloc( psDBF->panFieldSize, sizeof(int) * psDBF->nFields );

    psDBF->panFieldDecimals = (int *) 
        SfRealloc( psDBF->panFieldDecimals, sizeof(int) * psDBF->nFields );

    psDBF->pachFieldType = (char *) 
        SfRealloc( psDBF->pachFieldType, sizeof(char) * psDBF->nFields );

    /* update header information */
    psDBF->nHeaderLength -= 32;
    psDBF->nRecordLength -= nDeletedFieldSize;

    /* overwrite field information in header */
    memcpy(psDBF->pszHeader + iField*32,
           psDBF->pszHeader + (iField+1)*32,
           sizeof(char) * (psDBF->nFields - iField)*32);

    psDBF->pszHeader = (char *) SfRealloc(psDBF->pszHeader,psDBF->nFields*32);

    /* update size of current record appropriately */
    psDBF->pszCurrentRecord = (char *) SfRealloc(psDBF->pszCurrentRecord,
                                                 psDBF->nRecordLength);

    /* we're done if we're dealing with not yet created .dbf */
    if ( psDBF->bNoHeader && psDBF->nRecords == 0 )
        return TRUE;

    /* force update of header with new header and record length */
    psDBF->bNoHeader = TRUE;
    DBFUpdateHeader( psDBF );

    /* alloc record */
    pszRecord = (char *) malloc(sizeof(char) * nOldRecordLength);

    /* shift records to their new positions */
    for (iRecord = 0; iRecord < psDBF->nRecords; iRecord++)
    {
        nRecordOffset = 
            nOldRecordLength * (SAOffset) iRecord + nOldHeaderLength;

        /* load record */
        psDBF->sHooks.FSeek( psDBF->fp, nRecordOffset, 0 );
        psDBF->sHooks.FRead( pszRecord, nOldRecordLength, 1, psDBF->fp );

        nRecordOffset = 
            psDBF->nRecordLength * (SAOffset) iRecord + psDBF->nHeaderLength;

        /* move record in two steps */
        psDBF->sHooks.FSeek( psDBF->fp, nRecordOffset, 0 );
        psDBF->sHooks.FWrite( pszRecord, nDeletedFieldOffset, 1, psDBF->fp );
        psDBF->sHooks.FWrite( pszRecord + nDeletedFieldOffset + nDeletedFieldSize,
                              nOldRecordLength - nDeletedFieldOffset - nDeletedFieldSize,
                              1, psDBF->fp );

    }

    /* TODO: truncate file */

    /* free record */
    free(pszRecord);

    return TRUE;
}

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