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<hr><h1>rasterio.cpp</h1><div class="fragment"><pre>00001 <font class="comment">/******************************************************************************</font>
00002 <font class="comment"> * $Id: rasterio_cpp-source.html,v 1.10 2002/04/16 13:11:49 warmerda Exp $</font>
00003 <font class="comment"> *</font>
00004 <font class="comment"> * Project: GDAL Core</font>
00005 <font class="comment"> * Purpose: Contains default implementation of GDALRasterBand::IRasterIO()</font>
00006 <font class="comment"> * and supporting functions of broader utility.</font>
00007 <font class="comment"> * Author: Frank Warmerdam, warmerda@home.com</font>
00008 <font class="comment"> *</font>
00009 <font class="comment"> ******************************************************************************</font>
00010 <font class="comment"> * Copyright (c) 1998, Frank Warmerdam</font>
00011 <font class="comment"> *</font>
00012 <font class="comment"> * Permission is hereby granted, free of charge, to any person obtaining a</font>
00013 <font class="comment"> * copy of this software and associated documentation files (the "Software"),</font>
00014 <font class="comment"> * to deal in the Software without restriction, including without limitation</font>
00015 <font class="comment"> * the rights to use, copy, modify, merge, publish, distribute, sublicense,</font>
00016 <font class="comment"> * and/or sell copies of the Software, and to permit persons to whom the</font>
00017 <font class="comment"> * Software is furnished to do so, subject to the following conditions:</font>
00018 <font class="comment"> *</font>
00019 <font class="comment"> * The above copyright notice and this permission notice shall be included</font>
00020 <font class="comment"> * in all copies or substantial portions of the Software.</font>
00021 <font class="comment"> *</font>
00022 <font class="comment"> * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS</font>
00023 <font class="comment"> * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,</font>
00024 <font class="comment"> * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL</font>
00025 <font class="comment"> * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER</font>
00026 <font class="comment"> * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING</font>
00027 <font class="comment"> * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER</font>
00028 <font class="comment"> * DEALINGS IN THE SOFTWARE.</font>
00029 <font class="comment"> ******************************************************************************</font>
00030 <font class="comment"> *</font>
00031 <font class="comment"> * $Log: rasterio_cpp-source.html,v $
00031 <font class="comment"> * Revision 1.10 2002/04/16 13:11:49 warmerda
00031 <font class="comment"> * updated
00031 <font class="comment"> *</font>
00032 <font class="comment"> * Revision 1.14 2001/07/18 04:04:31 warmerda</font>
00033 <font class="comment"> * added CPL_CVSID</font>
00034 <font class="comment"> *</font>
00035 <font class="comment"> * Revision 1.13 2000/08/16 15:50:52 warmerda</font>
00036 <font class="comment"> * fixed some bugs with floating (datasetless) bands</font>
00037 <font class="comment"> *</font>
00038 <font class="comment"> * Revision 1.12 2000/07/13 13:08:53 warmerda</font>
00039 <font class="comment"> * fixed GDALSwapWords with skip value different from word size</font>
00040 <font class="comment"> *</font>
00041 <font class="comment"> * Revision 1.11 2000/06/05 17:24:05 warmerda</font>
00042 <font class="comment"> * added real complex support</font>
00043 <font class="comment"> *</font>
00044 <font class="comment"> * Revision 1.10 2000/05/15 14:33:49 warmerda</font>
00045 <font class="comment"> * don't crash on read failure</font>
00046 <font class="comment"> *</font>
00047 <font class="comment"> * Revision 1.9 2000/04/04 15:25:13 warmerda</font>
00048 <font class="comment"> * Fixed embarrasing bug in GDALCopyWords() for some cases.</font>
00049 <font class="comment"> *</font>
00050 <font class="comment"> * Revision 1.8 2000/03/06 18:57:07 warmerda</font>
00051 <font class="comment"> * Fixed bug in 1:1 special case code.</font>
00052 <font class="comment"> *</font>
00053 <font class="comment"> * Revision 1.7 2000/03/06 02:22:13 warmerda</font>
00054 <font class="comment"> * added overview support</font>
00055 <font class="comment"> *</font>
00056 <font class="comment"> * Revision 1.6 1999/11/23 18:44:10 warmerda</font>
00057 <font class="comment"> * Fixed GDALCopyWords!</font>
00058 <font class="comment"> *</font>
00059 <font class="comment"> * Revision 1.5 1999/07/23 19:36:09 warmerda</font>
00060 <font class="comment"> * added support for data type translation and a swapping function</font>
00061 <font class="comment"> *</font>
00062 <font class="comment"> * Revision 1.4 1999/01/11 15:38:38 warmerda</font>
00063 <font class="comment"> * Added optimized case for simple 1:1 copies.</font>
00064 <font class="comment"> *</font>
00065 <font class="comment"> * Revision 1.3 1999/01/02 21:14:01 warmerda</font>
00066 <font class="comment"> * Added write support</font>
00067 <font class="comment"> *</font>
00068 <font class="comment"> * Revision 1.2 1998/12/31 18:54:25 warmerda</font>
00069 <font class="comment"> * Implement initial GDALRasterBlock support, and block cache</font>
00070 <font class="comment"> *</font>
00071 <font class="comment"> * Revision 1.1 1998/12/06 22:15:42 warmerda</font>
00072 <font class="comment"> * New</font>
00073 <font class="comment"> */</font>
00074
00075 <font class="preprocessor">#include "gdal_priv.h"</font>
00076
00077 CPL_CVSID(<font class="stringliteral">"$Id: rasterio_cpp-source.html,v 1.10 2002/04/16 13:11:49 warmerda Exp $"</font>);
00078
00079 <font class="comment">/************************************************************************/</font>
00080 <font class="comment">/* IRasterIO() */</font>
00081 <font class="comment">/* */</font>
00082 <font class="comment">/* Default internal implementation of RasterIO() ... utilizes */</font>
00083 <font class="comment">/* the Block access methods to satisfy the request. This would */</font>
00084 <font class="comment">/* normally only be overridden by formats with overviews. */</font>
00085 <font class="comment">/************************************************************************/</font>
00086
00087 CPLErr GDALRasterBand::IRasterIO( GDALRWFlag eRWFlag,
00088 <font class="keywordtype">int</font> nXOff, <font class="keywordtype">int</font> nYOff, <font class="keywordtype">int</font> nXSize, <font class="keywordtype">int</font> nYSize,
00089 <font class="keywordtype">void</font> * pData, <font class="keywordtype">int</font> nBufXSize, <font class="keywordtype">int</font> nBufYSize,
00090 GDALDataType eBufType,
00091 <font class="keywordtype">int</font> nPixelSpace, <font class="keywordtype">int</font> nLineSpace )<font class="keyword"></font>
00092 <font class="keyword"></font>
00093 <font class="keyword"></font>{
00094 <font class="keywordtype">int</font> nBandDataSize = GDALGetDataTypeSize( eDataType ) / 8;
00095 GByte *pabySrcBlock = NULL;
00096 <a class="code" href="class_GDALRasterBlock.html">GDALRasterBlock</a> *poBlock;
00097 <font class="keywordtype">int</font> nLBlockX=-1, nLBlockY=-1, iBufYOff, iBufXOff, iSrcY;
00098
00099 <font class="comment">/* ==================================================================== */</font>
00100 <font class="comment">/* A common case is the data requested with it's inherent data */</font>
00101 <font class="comment">/* type, the destination is packed, and the block width is the */</font>
00102 <font class="comment">/* raster width. */</font>
00103 <font class="comment">/* ==================================================================== */</font>
00104 <font class="keywordflow">if</font>( eBufType == eDataType
00105 && nPixelSpace == GDALGetDataTypeSize(eBufType)/8
00106 && nLineSpace == nPixelSpace * nXSize
00107 && nBlockXSize == <a class="code" href="class_GDALRasterBand.html#a2">GetXSize</a>()
00108 && nBufXSize == nXSize
00109 && nBufYSize == nYSize )
00110 {
00111 <font class="keywordflow">for</font>( iBufYOff = 0; iBufYOff < nBufYSize; iBufYOff++ )
00112 {
00113 <font class="keywordtype">int</font> nSrcByteOffset;
00114
00115 iSrcY = iBufYOff + nYOff;
00116
00117 <font class="keywordflow">if</font>( iSrcY < nLBlockY * nBlockYSize
00118 || iSrcY >= (nLBlockY+1) * nBlockYSize )
00119 {
00120 nLBlockY = iSrcY / nBlockYSize;
00121
00122 poBlock = <a class="code" href="class_GDALRasterBand.html#a11">GetBlockRef</a>( 0, nLBlockY );
00123 <font class="keywordflow">if</font>( poBlock == NULL )
00124 {
00125 <font class="keywordflow">return</font>( CE_Failure );
00126 }
00127
00128 <font class="keywordflow">if</font>( eRWFlag == GF_Write )
00129 poBlock->MarkDirty();
00130
00131 pabySrcBlock = (GByte *) poBlock->GetDataRef();
00132 }
00133
00134 nSrcByteOffset = ((iSrcY-nLBlockY*nBlockYSize)*nBlockXSize + nXOff)
00135 * nPixelSpace;
00136
00137 <font class="keywordflow">if</font>( eRWFlag == GF_Write )
00138 memcpy( pabySrcBlock + nSrcByteOffset,
00139 ((GByte *) pData) + iBufYOff * nLineSpace,
00140 nLineSpace );
00141 <font class="keywordflow">else</font>
00142 memcpy( ((GByte *) pData) + iBufYOff * nLineSpace,
00143 pabySrcBlock + nSrcByteOffset,
00144 nLineSpace );
00145 }
00146
00147 <font class="keywordflow">return</font> CE_None;
00148 }
00149
00150 <font class="comment">/* ==================================================================== */</font>
00151 <font class="comment">/* Do we have overviews that would be appropriate to satisfy */</font>
00152 <font class="comment">/* this request? */</font>
00153 <font class="comment">/* ==================================================================== */</font>
00154 <font class="keywordflow">if</font>( (nBufXSize < nXSize || nBufYSize < nYSize)
00155 && <a class="code" href="class_GDALRasterBand.html#a28">GetOverviewCount</a>() > 0 && eRWFlag == GF_Read )
00156 {
00157 <font class="keywordflow">if</font>( OverviewRasterIO( eRWFlag, nXOff, nYOff, nXSize, nYSize,
00158 pData, nBufXSize, nBufYSize,
00159 eBufType, nPixelSpace, nLineSpace ) == CE_None )
00160 <font class="keywordflow">return</font> CE_None;
00161 }
00162
00163 <font class="comment">/* ==================================================================== */</font>
00164 <font class="comment">/* Loop reading required source blocks to satisfy output */</font>
00165 <font class="comment">/* request. This is the most general implementation. */</font>
00166 <font class="comment">/* ==================================================================== */</font>
00167
00168 <font class="comment">/* -------------------------------------------------------------------- */</font>
00169 <font class="comment">/* Compute stepping increment. */</font>
00170 <font class="comment">/* -------------------------------------------------------------------- */</font>
00171 <font class="keywordtype">double</font> dfSrcX, dfSrcY, dfSrcXInc, dfSrcYInc;
00172 <font class="keywordtype">int</font> iSrcX;
00173
00174 dfSrcXInc = nXSize / (<font class="keywordtype">double</font>) nBufXSize;
00175 dfSrcYInc = nYSize / (<font class="keywordtype">double</font>) nBufYSize;
00176
00177 <font class="comment">/* -------------------------------------------------------------------- */</font>
00178 <font class="comment">/* Loop over buffer computing source locations. */</font>
00179 <font class="comment">/* -------------------------------------------------------------------- */</font>
00180 <font class="keywordflow">for</font>( iBufYOff = 0; iBufYOff < nBufYSize; iBufYOff++ )
00181 {
00182 <font class="keywordtype">int</font> iBufOffset, iSrcOffset;
00183
00184 dfSrcY = (iBufYOff+0.5) * dfSrcYInc + nYOff;
00185 iSrcY = (<font class="keywordtype">int</font>) dfSrcY;
00186
00187 iBufOffset = iBufYOff * nLineSpace;
00188
00189 <font class="keywordflow">for</font>( iBufXOff = 0; iBufXOff < nBufXSize; iBufXOff++ )
00190 {
00191 dfSrcX = (iBufXOff+0.5) * dfSrcXInc + nXOff;
00192
00193 iSrcX = (<font class="keywordtype">int</font>) dfSrcX;
00194
00195 <font class="comment">/* -------------------------------------------------------------------- */</font>
00196 <font class="comment">/* Ensure we have the appropriate block loaded. */</font>
00197 <font class="comment">/* -------------------------------------------------------------------- */</font>
00198 <font class="keywordflow">if</font>( iSrcX < nLBlockX * nBlockXSize
00199 || iSrcX >= (nLBlockX+1) * nBlockXSize
00200 || iSrcY < nLBlockY * nBlockYSize
00201 || iSrcY >= (nLBlockY+1) * nBlockYSize )
00202 {
00203 nLBlockX = iSrcX / nBlockXSize;
00204 nLBlockY = iSrcY / nBlockYSize;
00205
00206 poBlock = <a class="code" href="class_GDALRasterBand.html#a11">GetBlockRef</a>( nLBlockX, nLBlockY );
00207 <font class="keywordflow">if</font>( poBlock == NULL )
00208 {
00209 <font class="keywordflow">return</font>( CE_Failure );
00210 }
00211
00212 <font class="keywordflow">if</font>( eRWFlag == GF_Write )
00213 poBlock->MarkDirty();
00214
00215 pabySrcBlock = (GByte *) poBlock->GetDataRef();
00216 <font class="keywordflow">if</font>( pabySrcBlock == NULL )
00217 <font class="keywordflow">return</font> CE_Failure;
00218 }
00219
00220 <font class="comment">/* -------------------------------------------------------------------- */</font>
00221 <font class="comment">/* Copy over this pixel of data. */</font>
00222 <font class="comment">/* -------------------------------------------------------------------- */</font>
00223 iSrcOffset = (iSrcX - nLBlockX*nBlockXSize
00224 + (iSrcY - nLBlockY*nBlockYSize) * nBlockXSize)*nBandDataSize;
00225
00226 <font class="keywordflow">if</font>( eDataType == eBufType )
00227 {
00228 <font class="keywordflow">if</font>( eRWFlag == GF_Read )
00229 memcpy( ((GByte *) pData) + iBufOffset,
00230 pabySrcBlock + iSrcOffset, nBandDataSize );
00231 <font class="keywordflow">else</font>
00232 memcpy( pabySrcBlock + iSrcOffset,
00233 ((GByte *) pData) + iBufOffset, nBandDataSize );
00234 }
00235 <font class="keywordflow">else</font>
00236 {
00237 <font class="comment">/* type to type conversion ... ouch, this is expensive way</font>
00238 <font class="comment"> of handling single words */</font>
00239
00240 <font class="keywordflow">if</font>( eRWFlag == GF_Read )
00241 GDALCopyWords( pabySrcBlock + iSrcOffset, eDataType, 0,
00242 ((GByte *) pData) + iBufOffset, eBufType, 0,
00243 1 );
00244 <font class="keywordflow">else</font>
00245 GDALCopyWords( ((GByte *) pData) + iBufOffset, eBufType, 0,
00246 pabySrcBlock + iSrcOffset, eDataType, 0,
00247 1 );
00248 }
00249
00250 iBufOffset += nPixelSpace;
00251 }
00252 }
00253
00254 <font class="keywordflow">return</font>( CE_None );
00255 }
00256
00257 <font class="comment">/************************************************************************/</font>
00258 <font class="comment">/* GDALSwapWords() */</font>
00259 <font class="comment">/************************************************************************/</font>
00260
00261 <font class="keywordtype">void</font> GDALSwapWords( <font class="keywordtype">void</font> *pData, <font class="keywordtype">int</font> nWordSize, <font class="keywordtype">int</font> nWordCount,
00262 <font class="keywordtype">int</font> nWordSkip )<font class="keyword"></font>
00263 <font class="keyword"></font>
00264 <font class="keyword"></font>{
00265 <font class="keywordtype">int</font> i;
00266 GByte *pabyData = (GByte *) pData;
00267
00268 <font class="keywordflow">switch</font>( nWordSize )
00269 {
00270 <font class="keywordflow">case</font> 1:
00271 <font class="keywordflow">break</font>;
00272
00273 <font class="keywordflow">case</font> 2:
00274 CPLAssert( nWordSize >= 2 );
00275 <font class="keywordflow">for</font>( i = 0; i < nWordCount; i++ )
00276 {
00277 GByte byTemp;
00278
00279 byTemp = pabyData[0];
00280 pabyData[0] = pabyData[1];
00281 pabyData[1] = byTemp;
00282
00283 pabyData += nWordSkip;
00284 }
00285 <font class="keywordflow">break</font>;
00286
00287 <font class="keywordflow">case</font> 4:
00288 CPLAssert( nWordSize >= 4 );
00289 <font class="keywordflow">for</font>( i = 0; i < nWordCount; i++ )
00290 {
00291 GByte byTemp;
00292
00293 byTemp = pabyData[0];
00294 pabyData[0] = pabyData[3];
00295 pabyData[3] = byTemp;
00296
00297 byTemp = pabyData[1];
00298 pabyData[1] = pabyData[2];
00299 pabyData[2] = byTemp;
00300
00301 pabyData += nWordSkip;
00302 }
00303 <font class="keywordflow">break</font>;
00304
00305 <font class="keywordflow">case</font> 8:
00306 CPLAssert( nWordSize >= 8 );
00307 <font class="keywordflow">for</font>( i = 0; i < nWordCount; i++ )
00308 {
00309 GByte byTemp;
00310
00311 byTemp = pabyData[0];
00312 pabyData[0] = pabyData[7];
00313 pabyData[7] = byTemp;
00314
00315 byTemp = pabyData[1];
00316 pabyData[1] = pabyData[6];
00317 pabyData[6] = byTemp;
00318
00319 byTemp = pabyData[2];
00320 pabyData[2] = pabyData[5];
00321 pabyData[5] = byTemp;
00322
00323 byTemp = pabyData[3];
00324 pabyData[3] = pabyData[4];
00325 pabyData[4] = byTemp;
00326
00327 pabyData += nWordSkip;
00328 }
00329 <font class="keywordflow">break</font>;
00330
00331 <font class="keywordflow">default</font>:
00332 CPLAssert( FALSE );
00333 }
00334 }
00335
00336 <font class="comment">/************************************************************************/</font>
00337 <font class="comment">/* GDALCopyWords() */</font>
00338 <font class="comment">/************************************************************************/</font>
00339
00340 <font class="keywordtype">void</font>
00341 GDALCopyWords( <font class="keywordtype">void</font> * pSrcData, GDALDataType eSrcType, <font class="keywordtype">int</font> nSrcPixelOffset,
00342 <font class="keywordtype">void</font> * pDstData, GDALDataType eDstType, <font class="keywordtype">int</font> nDstPixelOffset,
00343 <font class="keywordtype">int</font> nWordCount )<font class="keyword"></font>
00344 <font class="keyword"></font>
00345 <font class="keyword"></font>{
00346 <font class="comment">/* -------------------------------------------------------------------- */</font>
00347 <font class="comment">/* Special case when no data type translation is required. */</font>
00348 <font class="comment">/* -------------------------------------------------------------------- */</font>
00349 <font class="keywordflow">if</font>( eSrcType == eDstType )
00350 {
00351 <font class="keywordtype">int</font> nWordSize = GDALGetDataTypeSize(eSrcType)/8;
00352 <font class="keywordtype">int</font> i;
00353
00354 <font class="comment">// contiguous blocks.</font>
00355 <font class="keywordflow">if</font>( nWordSize == nSrcPixelOffset && nWordSize == nDstPixelOffset )
00356 {
00357 memcpy( pDstData, pSrcData, nSrcPixelOffset * nWordCount );
00358 <font class="keywordflow">return</font>;
00359 }
00360
00361 <font class="comment">// source or destination is not contiguous</font>
00362 <font class="keywordflow">for</font>( i = 0; i < nWordCount; i++ )
00363 {
00364 memcpy( ((GByte *)pDstData) + i * nDstPixelOffset,
00365 ((GByte *)pSrcData) + i * nSrcPixelOffset,
00366 nWordSize );
00367 }
00368
00369 <font class="keywordflow">return</font>;
00370 }
00371
00372 <font class="comment">/* ==================================================================== */</font>
00373 <font class="comment">/* General translation case */</font>
00374 <font class="comment">/* ==================================================================== */</font>
00375 <font class="keywordflow">for</font>( <font class="keywordtype">int</font> iWord = 0; iWord < nWordCount; iWord++ )
00376 {
00377 GByte *pabySrcWord, *pabyDstWord;
00378 <font class="keywordtype">double</font> dfPixelValue, dfPixelValueI=0.0;
00379
00380 pabySrcWord = ((GByte *) pSrcData) + iWord * nSrcPixelOffset;
00381
00382 <font class="comment">/* -------------------------------------------------------------------- */</font>
00383 <font class="comment">/* Fetch source value based on data type. */</font>
00384 <font class="comment">/* -------------------------------------------------------------------- */</font>
00385 <font class="keywordflow">switch</font>( eSrcType )
00386 {
00387 <font class="keywordflow">case</font> GDT_Byte:
00388 dfPixelValue = *pabySrcWord;
00389 <font class="keywordflow">break</font>;
00390
00391 <font class="keywordflow">case</font> GDT_UInt16:
00392 {
00393 GUInt16 nVal;
00394
00395 memcpy( &nVal, pabySrcWord, 2 );
00396 dfPixelValue = nVal;
00397 }
00398 <font class="keywordflow">break</font>;
00399
00400 <font class="keywordflow">case</font> GDT_Int16:
00401 {
00402 GInt16 nVal;
00403
00404 memcpy( &nVal, pabySrcWord, 2 );
00405 dfPixelValue = nVal;
00406 }
00407 <font class="keywordflow">break</font>;
00408
00409 <font class="keywordflow">case</font> GDT_Int32:
00410 {
00411 GInt32 nVal;
00412
00413 memcpy( &nVal, pabySrcWord, 4 );
00414 dfPixelValue = nVal;
00415 }
00416 <font class="keywordflow">break</font>;
00417
00418 <font class="keywordflow">case</font> GDT_UInt32:
00419 {
00420 GUInt32 nVal;
00421
00422 memcpy( &nVal, pabySrcWord, 4 );
00423 dfPixelValue = nVal;
00424 }
00425 <font class="keywordflow">break</font>;
00426
00427 <font class="keywordflow">case</font> GDT_Float32:
00428 {
00429 <font class="keywordtype">float</font> fVal;
00430
00431 memcpy( &fVal, pabySrcWord, 4 );
00432 dfPixelValue = fVal;
00433 }
00434 <font class="keywordflow">break</font>;
00435
00436 <font class="keywordflow">case</font> GDT_Float64:
00437 {
00438 memcpy( &dfPixelValue, pabySrcWord, 8 );
00439 }
00440 <font class="keywordflow">break</font>;
00441
00442 <font class="keywordflow">case</font> GDT_CInt16:
00443 {
00444 GInt16 nVal;
00445
00446 memcpy( &nVal, pabySrcWord, 2 );
00447 dfPixelValue = nVal;
00448 memcpy( &nVal, pabySrcWord+2, 2 );
00449 dfPixelValueI = nVal;
00450 }
00451 <font class="keywordflow">break</font>;
00452
00453 <font class="keywordflow">case</font> GDT_CInt32:
00454 {
00455 GInt32 nVal;
00456
00457 memcpy( &nVal, pabySrcWord, 4 );
00458 dfPixelValue = nVal;
00459 memcpy( &nVal, pabySrcWord+4, 4 );
00460 dfPixelValueI = nVal;
00461 }
00462 <font class="keywordflow">break</font>;
00463
00464 <font class="keywordflow">case</font> GDT_CFloat32:
00465 {
00466 <font class="keywordtype">float</font> fVal;
00467
00468 memcpy( &fVal, pabySrcWord, 4 );
00469 dfPixelValue = fVal;
00470 memcpy( &fVal, pabySrcWord+4, 4 );
00471 dfPixelValueI = fVal;
00472 }
00473 <font class="keywordflow">break</font>;
00474
00475 <font class="keywordflow">case</font> GDT_CFloat64:
00476 {
00477 memcpy( &dfPixelValue, pabySrcWord, 8 );
00478 memcpy( &dfPixelValueI, pabySrcWord+8, 8 );
00479 }
00480 <font class="keywordflow">break</font>;
00481
00482 <font class="keywordflow">default</font>:
00483 CPLAssert( FALSE );
00484 }
00485
00486 <font class="comment">/* -------------------------------------------------------------------- */</font>
00487 <font class="comment">/* Set the destination pixel, doing range clipping as needed. */</font>
00488 <font class="comment">/* -------------------------------------------------------------------- */</font>
00489 pabyDstWord = ((GByte *) pDstData) + iWord * nDstPixelOffset;
00490 <font class="keywordflow">switch</font>( eDstType )
00491 {
00492 <font class="keywordflow">case</font> GDT_Byte:
00493 {
00494 <font class="keywordflow">if</font>( dfPixelValue < 0.0 )
00495 *pabyDstWord = 0;
00496 <font class="keywordflow">else</font> <font class="keywordflow">if</font>( dfPixelValue > 255.0 )
00497 *pabyDstWord = 255;
00498 <font class="keywordflow">else</font>
00499 *pabyDstWord = (GByte) dfPixelValue;
00500 }
00501 <font class="keywordflow">break</font>;
00502
00503 <font class="keywordflow">case</font> GDT_UInt16:
00504 {
00505 GUInt16 nVal;
00506
00507 <font class="keywordflow">if</font>( dfPixelValue < 0.0 )
00508 nVal = 0;
00509 <font class="keywordflow">else</font> <font class="keywordflow">if</font>( dfPixelValue > 65535.0 )
00510 nVal = 65535;
00511 <font class="keywordflow">else</font>
00512 nVal = (GUInt16) dfPixelValue;
00513
00514 memcpy( pabyDstWord, &nVal, 2 );
00515 }
00516 <font class="keywordflow">break</font>;
00517
00518 <font class="keywordflow">case</font> GDT_Int16:
00519 {
00520 GInt16 nVal;
00521
00522 <font class="keywordflow">if</font>( dfPixelValue < -32768 )
00523 nVal = -32768;
00524 <font class="keywordflow">else</font> <font class="keywordflow">if</font>( dfPixelValue > 32767 )
00525 nVal = 32767;
00526 <font class="keywordflow">else</font>
00527 nVal = (GInt16) dfPixelValue;
00528
00529 memcpy( pabyDstWord, &nVal, 2 );
00530 }
00531 <font class="keywordflow">break</font>;
00532
00533 <font class="keywordflow">case</font> GDT_UInt32:
00534 {
00535 GUInt32 nVal;
00536
00537 <font class="keywordflow">if</font>( dfPixelValue < 0 )
00538 nVal = 0;
00539 <font class="keywordflow">else</font> <font class="keywordflow">if</font>( dfPixelValue > 4294967295U )
00540 nVal = 4294967295U;
00541 <font class="keywordflow">else</font>
00542 nVal = (GInt32) dfPixelValue;
00543
00544 memcpy( pabyDstWord, &nVal, 4 );
00545 }
00546 <font class="keywordflow">break</font>;
00547
00548 <font class="keywordflow">case</font> GDT_Int32:
00549 {
00550 GInt32 nVal;
00551
00552 <font class="keywordflow">if</font>( dfPixelValue < -2147483647.0 )
00553 nVal = -2147483647;
00554 <font class="keywordflow">else</font> <font class="keywordflow">if</font>( dfPixelValue > 2147483647 )
00555 nVal = 2147483647;
00556 <font class="keywordflow">else</font>
00557 nVal = (GInt32) dfPixelValue;
00558
00559 memcpy( pabyDstWord, &nVal, 4 );
00560 }
00561 <font class="keywordflow">break</font>;
00562
00563 <font class="keywordflow">case</font> GDT_Float32:
00564 {
00565 <font class="keywordtype">float</font> fVal;
00566
00567 fVal = dfPixelValue;
00568
00569 memcpy( pabyDstWord, &fVal, 4 );
00570 }
00571 <font class="keywordflow">break</font>;
00572
00573 <font class="keywordflow">case</font> GDT_Float64:
00574 memcpy( pabyDstWord, &dfPixelValue, 8 );
00575 <font class="keywordflow">break</font>;
00576
00577 <font class="keywordflow">case</font> GDT_CInt16:
00578 {
00579 GInt16 nVal;
00580
00581 <font class="keywordflow">if</font>( dfPixelValue < -32768 )
00582 nVal = -32768;
00583 <font class="keywordflow">else</font> <font class="keywordflow">if</font>( dfPixelValue > 32767 )
00584 nVal = 32767;
00585 <font class="keywordflow">else</font>
00586 nVal = (GInt16) dfPixelValue;
00587 memcpy( pabyDstWord, &nVal, 2 );
00588
00589 <font class="keywordflow">if</font>( dfPixelValueI < -32768 )
00590 nVal = -32768;
00591 <font class="keywordflow">else</font> <font class="keywordflow">if</font>( dfPixelValueI > 32767 )
00592 nVal = 32767;
00593 <font class="keywordflow">else</font>
00594 nVal = (GInt16) dfPixelValueI;
00595 memcpy( pabyDstWord+2, &nVal, 2 );
00596 }
00597 <font class="keywordflow">break</font>;
00598
00599 <font class="keywordflow">case</font> GDT_CInt32:
00600 {
00601 GInt32 nVal;
00602
00603 <font class="keywordflow">if</font>( dfPixelValue < -2147483647.0 )
00604 nVal = -2147483647;
00605 <font class="keywordflow">else</font> <font class="keywordflow">if</font>( dfPixelValue > 2147483647 )
00606 nVal = 2147483647;
00607 <font class="keywordflow">else</font>
00608 nVal = (GInt32) dfPixelValue;
00609
00610 memcpy( pabyDstWord, &nVal, 4 );
00611
00612 <font class="keywordflow">if</font>( dfPixelValueI < -2147483647.0 )
00613 nVal = -2147483647;
00614 <font class="keywordflow">else</font> <font class="keywordflow">if</font>( dfPixelValueI > 2147483647 )
00615 nVal = 2147483647;
00616 <font class="keywordflow">else</font>
00617 nVal = (GInt32) dfPixelValueI;
00618
00619 memcpy( pabyDstWord+4, &nVal, 4 );
00620 }
00621 <font class="keywordflow">break</font>;
00622
00623 <font class="keywordflow">case</font> GDT_CFloat32:
00624 {
00625 <font class="keywordtype">float</font> fVal;
00626
00627 fVal = dfPixelValue;
00628 memcpy( pabyDstWord, &fVal, 4 );
00629 fVal = dfPixelValueI;
00630 memcpy( pabyDstWord+4, &fVal, 4 );
00631 }
00632 <font class="keywordflow">break</font>;
00633
00634 <font class="keywordflow">case</font> GDT_CFloat64:
00635 memcpy( pabyDstWord, &dfPixelValue, 8 );
00636 memcpy( pabyDstWord+8, &dfPixelValueI, 8 );
00637 <font class="keywordflow">break</font>;
00638
00639 <font class="keywordflow">default</font>:
00640 CPLAssert( FALSE );
00641 }
00642 } <font class="comment">/* next iWord */</font>
00643 }
00644
00645 <font class="comment">/************************************************************************/</font>
00646 <font class="comment">/* OverviewRasterIO() */</font>
00647 <font class="comment">/* */</font>
00648 <font class="comment">/* Special work function to utilize available overviews to */</font>
00649 <font class="comment">/* more efficiently satisfy downsampled requests. It will */</font>
00650 <font class="comment">/* return CE_Failure if there are no appropriate overviews */</font>
00651 <font class="comment">/* available but it doesn't emit any error messages. */</font>
00652 <font class="comment">/************************************************************************/</font>
00653
00654 CPLErr GDALRasterBand::OverviewRasterIO( GDALRWFlag eRWFlag,
00655 <font class="keywordtype">int</font> nXOff, <font class="keywordtype">int</font> nYOff, <font class="keywordtype">int</font> nXSize, <font class="keywordtype">int</font> nYSize,
00656 <font class="keywordtype">void</font> * pData, <font class="keywordtype">int</font> nBufXSize, <font class="keywordtype">int</font> nBufYSize,
00657 GDALDataType eBufType,
00658 <font class="keywordtype">int</font> nPixelSpace, <font class="keywordtype">int</font> nLineSpace )<font class="keyword"></font>
00659 <font class="keyword"></font>
00660 <font class="keyword"></font>
00661 <font class="keyword"></font>{
00662 <a class="code" href="class_GDALRasterBand.html">GDALRasterBand</a> *poBestOverview = NULL;
00663 <font class="keywordtype">int</font> nOverviewCount = <a class="code" href="class_GDALRasterBand.html#a28">GetOverviewCount</a>();
00664 <font class="keywordtype">double</font> dfDesiredResolution, dfBestResolution = 1.0;
00665
00666 <font class="comment">/* -------------------------------------------------------------------- */</font>
00667 <font class="comment">/* Find the Compute the desired resolution. The resolution is */</font>
00668 <font class="comment">/* based on the least reduced axis, and represents the number */</font>
00669 <font class="comment">/* of source pixels to one destination pixel. */</font>
00670 <font class="comment">/* -------------------------------------------------------------------- */</font>
00671 <font class="keywordflow">if</font>( (nXSize / (<font class="keywordtype">double</font>) nBufXSize) < (nYSize / (<font class="keywordtype">double</font>) nBufYSize )
00672 || nBufYSize == 1 )
00673 dfDesiredResolution = nXSize / (<font class="keywordtype">double</font>) nBufXSize;
00674 <font class="keywordflow">else</font>
00675 dfDesiredResolution = nYSize / (<font class="keywordtype">double</font>) nBufYSize;
00676
00677 <font class="comment">/* -------------------------------------------------------------------- */</font>
00678 <font class="comment">/* Find the overview level that largest resolution value (most */</font>
00679 <font class="comment">/* downsampled) that is still less than (or only a little more) */</font>
00680 <font class="comment">/* downsampled than the request. */</font>
00681 <font class="comment">/* -------------------------------------------------------------------- */</font>
00682 <font class="keywordflow">for</font>( <font class="keywordtype">int</font> iOverview = 0; iOverview < nOverviewCount; iOverview++ )
00683 {
00684 <a class="code" href="class_GDALRasterBand.html">GDALRasterBand</a> *poOverview = <a class="code" href="class_GDALRasterBand.html#a29">GetOverview</a>( iOverview );
00685 <font class="keywordtype">double</font> dfResolution;
00686
00687 <font class="keywordflow">if</font>( (<a class="code" href="class_GDALRasterBand.html#a2">GetXSize</a>() / (<font class="keywordtype">double</font>) poOverview-><a class="code" href="class_GDALRasterBand.html#a2">GetXSize</a>())
00688 < (<a class="code" href="class_GDALRasterBand.html#a3">GetYSize</a>() / (<font class="keywordtype">double</font>) poOverview-><a class="code" href="class_GDALRasterBand.html#a3">GetYSize</a>()) )
00689 dfResolution =
00690 <a class="code" href="class_GDALRasterBand.html#a2">GetXSize</a>() / (<font class="keywordtype">double</font>) poOverview-><a class="code" href="class_GDALRasterBand.html#a2">GetXSize</a>();
00691 <font class="keywordflow">else</font>
00692 dfResolution =
00693 <a class="code" href="class_GDALRasterBand.html#a3">GetYSize</a>() / (<font class="keywordtype">double</font>) poOverview-><a class="code" href="class_GDALRasterBand.html#a3">GetYSize</a>();
00694
00695 <font class="keywordflow">if</font>( dfResolution < dfDesiredResolution * 1.2
00696 && dfResolution > dfBestResolution )
00697 {
00698 poBestOverview = poOverview;
00699 dfBestResolution = dfResolution;
00700 }
00701 }
00702
00703 <font class="comment">/* -------------------------------------------------------------------- */</font>
00704 <font class="comment">/* If we didn't find an overview that helps us, just return */</font>
00705 <font class="comment">/* indicating failure and the full resolution image will be used. */</font>
00706 <font class="comment">/* -------------------------------------------------------------------- */</font>
00707 <font class="keywordflow">if</font>( poBestOverview == NULL )
00708 <font class="keywordflow">return</font> CE_Failure;
00709
00710 <font class="comment">/* -------------------------------------------------------------------- */</font>
00711 <font class="comment">/* Recompute the source window in terms of the selected */</font>
00712 <font class="comment">/* overview. */</font>
00713 <font class="comment">/* -------------------------------------------------------------------- */</font>
00714 <font class="keywordtype">int</font> nOXOff, nOYOff, nOXSize, nOYSize;
00715 <font class="keywordtype">double</font> dfXRes, dfYRes;
00716
00717 dfXRes = <a class="code" href="class_GDALRasterBand.html#a2">GetXSize</a>() / (<font class="keywordtype">double</font>) poBestOverview-><a class="code" href="class_GDALRasterBand.html#a2">GetXSize</a>();
00718 dfYRes = <a class="code" href="class_GDALRasterBand.html#a3">GetYSize</a>() / (<font class="keywordtype">double</font>) poBestOverview-><a class="code" href="class_GDALRasterBand.html#a3">GetYSize</a>();
00719
00720 nOXOff = MIN(poBestOverview-><a class="code" href="class_GDALRasterBand.html#a2">GetXSize</a>()-1,(<font class="keywordtype">int</font>) (nXOff/dfXRes+0.5));
00721 nOYOff = MIN(poBestOverview-><a class="code" href="class_GDALRasterBand.html#a3">GetYSize</a>()-1,(<font class="keywordtype">int</font>) (nYOff/dfYRes+0.5));
00722 nOXSize = MAX(1,(<font class="keywordtype">int</font>) (nXSize/dfXRes + 0.5));
00723 nOYSize = MAX(1,(<font class="keywordtype">int</font>) (nYSize/dfYRes + 0.5));
00724 <font class="keywordflow">if</font>( nOXOff + nOXSize > poBestOverview-><a class="code" href="class_GDALRasterBand.html#a2">GetXSize</a>() )
00725 nOXSize = poBestOverview-><a class="code" href="class_GDALRasterBand.html#a2">GetXSize</a>() - nOXOff;
00726 <font class="keywordflow">if</font>( nOYOff + nOYSize > poBestOverview-><a class="code" href="class_GDALRasterBand.html#a3">GetYSize</a>() )
00727 nOYSize = poBestOverview-><a class="code" href="class_GDALRasterBand.html#a3">GetYSize</a>() - nOYOff;
00728
00729 <font class="comment">/* -------------------------------------------------------------------- */</font>
00730 <font class="comment">/* Recast the call in terms of the new raster layer. */</font>
00731 <font class="comment">/* -------------------------------------------------------------------- */</font>
00732 <font class="keywordflow">return</font> poBestOverview-><a class="code" href="class_GDALRasterBand.html#a8">RasterIO</a>( eRWFlag, nOXOff, nOYOff, nOXSize, nOYSize,
00733 pData, nBufXSize, nBufYSize, eBufType,
00734 nPixelSpace, nLineSpace );
00735 }
00736
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