shpopen.c

包含详细例子的c#创建shape文件的开源码

    else
        pszAccess = "rb";

/* -------------------------------------------------------------------- */
/*	Establish the byte order on this machine.			*/
/* -------------------------------------------------------------------- */
    i = 1;
    if( *((uchar *) &i) == 1 )
        bBigEndian = FALSE;
    else
        bBigEndian = TRUE;

/* -------------------------------------------------------------------- */
/*	Initialize the info structure.					*/
/* -------------------------------------------------------------------- */
    psSHP = (SHPHandle) calloc(sizeof(SHPInfo),1);

    psSHP->bUpdated = FALSE;

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

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

/* -------------------------------------------------------------------- */
/*	Open the .shp and .shx files.  Note that files pulled from	*/
/*	a PC to Unix with upper case filenames won't work!		*/
/* -------------------------------------------------------------------- */
    pszFullname = (char *) malloc(strlen(pszBasename) + 5);
    sprintf( pszFullname, "%s.shp", pszBasename );
    psSHP->fpSHP = fopen(pszFullname, pszAccess );
    if( psSHP->fpSHP == NULL )
    {
        sprintf( pszFullname, "%s.SHP", pszBasename );
        psSHP->fpSHP = fopen(pszFullname, pszAccess );
    }

    if( psSHP->fpSHP == NULL )
    {
        free( psSHP );
        free( pszBasename );
        free( pszFullname );
        return( NULL );
    }

    sprintf( pszFullname, "%s.shx", pszBasename );
    psSHP->fpSHX = fopen(pszFullname, pszAccess );
    if( psSHP->fpSHX == NULL )
    {
        sprintf( pszFullname, "%s.SHX", pszBasename );
        psSHP->fpSHX = fopen(pszFullname, pszAccess );
    }

    if( psSHP->fpSHX == NULL )
    {
        fclose( psSHP->fpSHP );
        free( psSHP );
        free( pszBasename );
        free( pszFullname );
        return( NULL );
    }

    free( pszFullname );
    free( pszBasename );

/* -------------------------------------------------------------------- */
/*  Read the file size from the SHP file.				*/
/* -------------------------------------------------------------------- */
    pabyBuf = (uchar *) malloc(100);
    fread( pabyBuf, 100, 1, psSHP->fpSHP );

    psSHP->nFileSize = (pabyBuf[24] * 256 * 256 * 256
			+ pabyBuf[25] * 256 * 256
			+ pabyBuf[26] * 256
			+ pabyBuf[27]) * 2;

/* -------------------------------------------------------------------- */
/*  Read SHX file Header info                                           */
/* -------------------------------------------------------------------- */
    fread( pabyBuf, 100, 1, psSHP->fpSHX );

    if( pabyBuf[0] != 0
        || pabyBuf[1] != 0
        || pabyBuf[2] != 0x27
        || (pabyBuf[3] != 0x0a && pabyBuf[3] != 0x0d) )
    {
	fclose( psSHP->fpSHP );
	fclose( psSHP->fpSHX );
	free( psSHP );

	return( NULL );
    }

    psSHP->nRecords = pabyBuf[27] + pabyBuf[26] * 256
      + pabyBuf[25] * 256 * 256 + pabyBuf[24] * 256 * 256 * 256;
    psSHP->nRecords = (psSHP->nRecords*2 - 100) / 8;

    psSHP->nShapeType = pabyBuf[32];

    if( psSHP->nRecords < 0 || psSHP->nRecords > 256000000 )
    {
        /* this header appears to be corrupt.  Give up. */
	fclose( psSHP->fpSHP );
	fclose( psSHP->fpSHX );
	free( psSHP );

	return( NULL );
    }

/* -------------------------------------------------------------------- */
/*      Read the bounds.                                                */
/* -------------------------------------------------------------------- */
    if( bBigEndian ) SwapWord( 8, pabyBuf+36 );
    memcpy( &dValue, pabyBuf+36, 8 );
    psSHP->adBoundsMin[0] = dValue;

    if( bBigEndian ) SwapWord( 8, pabyBuf+44 );
    memcpy( &dValue, pabyBuf+44, 8 );
    psSHP->adBoundsMin[1] = dValue;

    if( bBigEndian ) SwapWord( 8, pabyBuf+52 );
    memcpy( &dValue, pabyBuf+52, 8 );
    psSHP->adBoundsMax[0] = dValue;

    if( bBigEndian ) SwapWord( 8, pabyBuf+60 );
    memcpy( &dValue, pabyBuf+60, 8 );
    psSHP->adBoundsMax[1] = dValue;

    if( bBigEndian ) SwapWord( 8, pabyBuf+68 );		/* z */
    memcpy( &dValue, pabyBuf+68, 8 );
    psSHP->adBoundsMin[2] = dValue;

    if( bBigEndian ) SwapWord( 8, pabyBuf+76 );
    memcpy( &dValue, pabyBuf+76, 8 );
    psSHP->adBoundsMax[2] = dValue;

    if( bBigEndian ) SwapWord( 8, pabyBuf+84 );		/* z */
    memcpy( &dValue, pabyBuf+84, 8 );
    psSHP->adBoundsMin[3] = dValue;

    if( bBigEndian ) SwapWord( 8, pabyBuf+92 );
    memcpy( &dValue, pabyBuf+92, 8 );
    psSHP->adBoundsMax[3] = dValue;

    free( pabyBuf );

/* -------------------------------------------------------------------- */
/*	Read the .shx file to get the offsets to each record in 	*/
/*	the .shp file.							*/
/* -------------------------------------------------------------------- */
    psSHP->nMaxRecords = psSHP->nRecords;

    psSHP->panRecOffset =
        (int *) malloc(sizeof(int) * MAX(1,psSHP->nMaxRecords) );
    psSHP->panRecSize =
        (int *) malloc(sizeof(int) * MAX(1,psSHP->nMaxRecords) );

    pabyBuf = (uchar *) malloc(8 * MAX(1,psSHP->nRecords) );
    fread( pabyBuf, 8, psSHP->nRecords, psSHP->fpSHX );

    for( i = 0; i < psSHP->nRecords; i++ )
    {
	int32		nOffset, nLength;

	memcpy( &nOffset, pabyBuf + i * 8, 4 );
	if( !bBigEndian ) SwapWord( 4, &nOffset );

	memcpy( &nLength, pabyBuf + i * 8 + 4, 4 );
	if( !bBigEndian ) SwapWord( 4, &nLength );

	psSHP->panRecOffset[i] = nOffset*2;
	psSHP->panRecSize[i] = nLength*2;
    }
    free( pabyBuf );

    return( psSHP );
}

/************************************************************************/
/*                              SHPClose()                              */
/*								       	*/
/*	Close the .shp and .shx files.					*/
/************************************************************************/

void SHPAPI_CALL
SHPClose(SHPHandle psSHP )

{
/* -------------------------------------------------------------------- */
/*	Update the header if we have modified anything.			*/
/* -------------------------------------------------------------------- */
    if( psSHP->bUpdated )
    {
	SHPWriteHeader( psSHP );
    }

/* -------------------------------------------------------------------- */
/*      Free all resources, and close files.                            */
/* -------------------------------------------------------------------- */
    free( psSHP->panRecOffset );
    free( psSHP->panRecSize );

    fclose( psSHP->fpSHX );
    fclose( psSHP->fpSHP );

    if( psSHP->pabyRec != NULL )
    {
        free( psSHP->pabyRec );
    }

    free( psSHP );
}

/************************************************************************/
/*                             SHPGetInfo()                             */
/*                                                                      */
/*      Fetch general information about the shape file.                 */
/************************************************************************/

void SHPAPI_CALL
SHPGetInfo(SHPHandle psSHP, int * pnEntities, int * pnShapeType,
           double * padfMinBound, double * padfMaxBound )

{
    int		i;

    if( pnEntities != NULL )
        *pnEntities = psSHP->nRecords;

    if( pnShapeType != NULL )
        *pnShapeType = psSHP->nShapeType;

    for( i = 0; i < 4; i++ )
    {
        if( padfMinBound != NULL )
            padfMinBound[i] = psSHP->adBoundsMin[i];
        if( padfMaxBound != NULL )
            padfMaxBound[i] = psSHP->adBoundsMax[i];
    }
}

/************************************************************************/
/*                             SHPCreate()                              */
/*                                                                      */
/*      Create a new shape file and return a handle to the open         */
/*      shape file with read/write access.                              */
/************************************************************************/

SHPHandle SHPAPI_CALL
SHPCreate( const char * pszLayer, int nShapeType )

{
    char	*pszBasename, *pszFullname;
    int		i;
    FILE	*fpSHP, *fpSHX;
    uchar     	abyHeader[100];
    int32	i32;
    double	dValue;

/* -------------------------------------------------------------------- */
/*      Establish the byte order on this system.                        */
/* -------------------------------------------------------------------- */
    i = 1;
    if( *((uchar *) &i) == 1 )
        bBigEndian = FALSE;
    else
        bBigEndian = TRUE;

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

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

/* -------------------------------------------------------------------- */
/*      Open the two files so we can write their headers.               */
/* -------------------------------------------------------------------- */
    pszFullname = (char *) malloc(strlen(pszBasename) + 5);
    sprintf( pszFullname, "%s.shp", pszBasename );
    fpSHP = fopen(pszFullname, "wb" );
    if( fpSHP == NULL )
        return( NULL );

    sprintf( pszFullname, "%s.shx", pszBasename );
    fpSHX = fopen(pszFullname, "wb" );
    if( fpSHX == NULL )
        return( NULL );

    free( pszFullname );
    free( pszBasename );

/* -------------------------------------------------------------------- */
/*      Prepare header block for .shp file.                             */
/* -------------------------------------------------------------------- */
    for( i = 0; i < 100; i++ )
      abyHeader[i] = 0;

    abyHeader[2] = 0x27;				/* magic cookie */
    abyHeader[3] = 0x0a;

    i32 = 50;						/* file size */
    ByteCopy( &i32, abyHeader+24, 4 );
    if( !bBigEndian ) SwapWord( 4, abyHeader+24 );

    i32 = 1000;						/* version */
    ByteCopy( &i32, abyHeader+28, 4 );
    if( bBigEndian ) SwapWord( 4, abyHeader+28 );

    i32 = nShapeType;					/* shape type */
    ByteCopy( &i32, abyHeader+32, 4 );
    if( bBigEndian ) SwapWord( 4, abyHeader+32 );

    dValue = 0.0;					/* set bounds */
    ByteCopy( &dValue, abyHeader+36, 8 );
    ByteCopy( &dValue, abyHeader+44, 8 );
    ByteCopy( &dValue, abyHeader+52, 8 );
    ByteCopy( &dValue, abyHeader+60, 8 );

/* -------------------------------------------------------------------- */
/*      Write .shp file header.                                         */
/* -------------------------------------------------------------------- */
    fwrite( abyHeader, 100, 1, fpSHP );

/* -------------------------------------------------------------------- */
/*      Prepare, and write .shx file header.                            */
/* -------------------------------------------------------------------- */
    i32 = 50;						/* file size */
    ByteCopy( &i32, abyHeader+24, 4 );
    if( !bBigEndian ) SwapWord( 4, abyHeader+24 );

    fwrite( abyHeader, 100, 1, fpSHX );

/* -------------------------------------------------------------------- */
/*      Close the files, and then open them as regular existing files.  */
/* -------------------------------------------------------------------- */
    fclose( fpSHP );
    fclose( fpSHX );

    return( SHPOpen( pszLayer, "r+b" ) );
}