src/common/imagbmp.cpp

/////////////////////////////////////////////////////////////////////////////
// Name:        imagbmp.cpp
// Purpose:     wxImage BMP handler
// Author:      Robert Roebling
// RCS-ID:      $Id$
// Copyright:   (c) Robert Roebling
// Licence:     wxWindows licence
/////////////////////////////////////////////////////////////////////////////

#ifdef __GNUG__
#pragma implementation "imagbmp.h"
#endif

// For compilers that support precompilation, includes "wx.h".
#include "wx/wxprec.h"

#ifdef __BORLANDC__
#pragma hdrstop
#endif

#include "wx/imagbmp.h"
#include "wx/bitmap.h"
#include "wx/debug.h"
#include "wx/log.h"
#include "wx/app.h"
#include "wx/filefn.h"
#include "wx/wfstream.h"
#include "wx/intl.h"
#include "wx/module.h"

// For memcpy
#include <string.h>

#ifdef __SALFORDC__
#ifdef FAR
#undef FAR
#endif
#endif

#ifdef __WXMSW__
#include <windows.h>
#endif

//-----------------------------------------------------------------------------
// wxBMPHandler
//-----------------------------------------------------------------------------

IMPLEMENT_DYNAMIC_CLASS(wxBMPHandler,wxImageHandler)

#if wxUSE_STREAMS

#ifndef BI_RGB
#define BI_RGB       0
#define BI_RLE8      1
#define BI_RLE4      2
#endif

#ifndef BI_BITFIELDS
#define BI_BITFIELDS 3
#endif

#define poffset (line * width * 3 + column * 3)

bool wxBMPHandler::LoadFile( wxImage *image, wxInputStream& stream, bool verbose, int WXUNUSED(index) )
{
    int             rshift = 0, gshift = 0, bshift = 0;
    wxUint8         aByte;
    wxUint16        aWord;
    wxInt32         dbuf[4], aDword,
                    rmask = 0, gmask = 0, bmask = 0;
    wxInt8          bbuf[4];
    struct _cmap {
        unsigned char r, g, b;
    } *cmap = NULL;

    off_t start_offset = stream.TellI();

    image->Destroy();

    /*
     * Read the BMP header
     */

    stream.Read( &bbuf, 2 );
    stream.Read( dbuf, 4 * 4 );

#if 0 // unused
    wxInt32 size = wxINT32_SWAP_ON_BE( dbuf[0] );
#endif
    wxInt32 offset = wxINT32_SWAP_ON_BE( dbuf[2] );

    stream.Read(dbuf, 4 * 2);
    int width = (int)wxINT32_SWAP_ON_BE( dbuf[0] );
    int height = (int)wxINT32_SWAP_ON_BE( dbuf[1] );
    if (width > 32767)
    {
        if (verbose)
            wxLogError( _("BMP: Image width > 32767 pixels for file.") );
        return FALSE;
    }
    if (height > 32767)
    {
        if (verbose)
            wxLogError( _("BMP: Image height > 32767 pixels for file.") );
        return FALSE;
    }

    stream.Read( &aWord, 2 );
/*
    TODO
    int planes = (int)wxUINT16_SWAP_ON_BE( aWord );
*/
    stream.Read( &aWord, 2 );
    int bpp = (int)wxUINT16_SWAP_ON_BE( aWord );
    if (bpp != 1 && bpp != 4 && bpp != 8 && bpp != 16 && bpp != 24 && bpp != 32)
    {
        if (verbose)
            wxLogError( _("BMP: Unknown bitdepth in file.") );
        return FALSE;
    }

    stream.Read( dbuf, 4 * 4 );
    int comp = (int)wxINT32_SWAP_ON_BE( dbuf[0] );
    if (comp != BI_RGB && comp != BI_RLE4 && comp != BI_RLE8 && comp != BI_BITFIELDS)
    {
        if (verbose)
            wxLogError( _("BMP: Unknown encoding in file.") );
        return FALSE;
    }

    stream.Read( dbuf, 4 * 2 );
    int ncolors = (int)wxINT32_SWAP_ON_BE( dbuf[0] );
    if (ncolors == 0)
        ncolors = 1 << bpp;
    /* some more sanity checks */
    if (((comp == BI_RLE4) && (bpp != 4)) ||
        ((comp == BI_RLE8) && (bpp != 8)) ||
        ((comp == BI_BITFIELDS) && (bpp != 16 && bpp != 32)))
    {
        if (verbose)
            wxLogError( _("BMP: Encoding doesn't match bitdepth.") );
        return FALSE;
    }
    if (bpp < 16)
    {
        cmap = (struct _cmap *)malloc(sizeof(struct _cmap) * ncolors);
        if (!cmap)
        {
            if (verbose)
                wxLogError( _("BMP: Couldn't allocate memory.") );
            return FALSE;
        }
    }
    else
        cmap = NULL;

    image->Create( width, height );
    unsigned char *ptr = image->GetData();
    if (!ptr)
    {
        if (verbose)
            wxLogError( _("BMP: Couldn't allocate memory.") );
        if (cmap)
            free(cmap);
        return FALSE;
    }

    /*
     * Reading the palette, if it exists.
     */
    if (bpp < 16 && ncolors != 0)
    {
        for (int j = 0; j < ncolors; j++)
        {
            stream.Read( bbuf, 4 );
            cmap[j].b = bbuf[0];
            cmap[j].g = bbuf[1];
            cmap[j].r = bbuf[2];
        }
    }
    else if (bpp == 16 || bpp == 32)
    {
        if (comp == BI_BITFIELDS)
        {
            int bit = 0;
            stream.Read( dbuf, 4 * 3 );
            bmask = wxINT32_SWAP_ON_BE( dbuf[0] );
            gmask = wxINT32_SWAP_ON_BE( dbuf[1] );
            rmask = wxINT32_SWAP_ON_BE( dbuf[2] );
            /* find shift amount.. ugly, but i can't think of a better way */
            for (bit = 0; bit < bpp; bit++)
            {
                if (bmask & (1 << bit))
                    bshift = bit;
                if (gmask & (1 << bit))
                    gshift = bit;
                if (rmask & (1 << bit))
                    rshift = bit;
            }
        }
        else if (bpp == 16)
        {
            rmask = 0x7C00;
            gmask = 0x03E0;
            bmask = 0x001F;
            rshift = 10;
            gshift = 5;
            bshift = 0;
        }
        else if (bpp == 32)
        {
            rmask = 0x00FF0000;
            gmask = 0x0000FF00;
            bmask = 0x000000FF;
            rshift = 16;
            gshift = 8;
            bshift = 0;
        }
    }

    /*
     * Reading the image data
     */
    stream.SeekI( start_offset + offset );
    unsigned char *data = ptr;

    /* set the whole image to the background color */
    if (bpp < 16 && (comp == BI_RLE4 || comp == BI_RLE8))
    {
        for (int i = 0; i < width * height; i++)
        {
            *ptr++ = cmap[0].r;
            *ptr++ = cmap[0].g;
            *ptr++ = cmap[0].b;
        }
        ptr = data;
    }

    int line = 0;
    int column = 0;
    int linesize = ((width * bpp + 31) / 32) * 4;

    /* BMPs are stored upside down */
    for (line = (height - 1); line >= 0; line--)
    {
        int linepos = 0;
        for (column = 0; column < width;)
        {
            if (bpp < 16)
            {
                int index = 0;
                linepos++;
                aByte = stream.GetC();
                if (bpp == 1)
                {
                    int bit = 0;
                    for (bit = 0; bit < 8; bit++)
                    {
                        index = ((aByte & (0x80 >> bit)) ? 1 : 0);
                        ptr[poffset] = cmap[index].r;
                        ptr[poffset + 1] = cmap[index].g;
                        ptr[poffset + 2] = cmap[index].b;
                        column++;
                    }
                }
                else if (bpp == 4)
                {
                    if (comp == BI_RLE4)
                    {
                        if (verbose)
                            wxLogError( _("BMP: Cannot deal with 4bit encoded yet.") );
                        image->Destroy();
                        free(cmap);
                        return FALSE;
                    }
                    else
                    {
                        int nibble = 0;
                        for (nibble = 0; nibble < 2; nibble++)
                        {
                            index = ((aByte & (0xF0 >> nibble * 4)) >> (!nibble * 4));
                            if (index >= 16)
                                index = 15;
                            ptr[poffset] = cmap[index].r;
                            ptr[poffset + 1] = cmap[index].g;
                            ptr[poffset + 2] = cmap[index].b;
                            column++;
                        }
                    }
                }
                else if (bpp == 8)
                {
                    if (comp == BI_RLE8)
                    {
                        unsigned char first;
                        first = aByte;
                        aByte = stream.GetC();
                        if (first == 0)
                        {
                            if (aByte == 0)
                            {
                                /* column = width; */
                            }
                            else if (aByte == 1)
                            {
                                column = width;
                                line = -1;
                            }
                            else if (aByte == 2)
                            {
                                aByte = stream.GetC();
                                column += aByte;
                                linepos = column * bpp / 8;
                                aByte = stream.GetC();
                                line += aByte;
                            }
                            else
                            {
                                int absolute = aByte;
                                for (int k = 0; k < absolute; k++)
                                {
                                    linepos++;
                                    aByte = stream.GetC();
                                    ptr[poffset    ] = cmap[aByte].r;
                                    ptr[poffset + 1] = cmap[aByte].g;
                                    ptr[poffset + 2] = cmap[aByte].b;
                                    column++;
                                }
                                if (absolute & 0x01)
                                    aByte = stream.GetC();
                            }
                        }
                        else
                        {
                            for (int l = 0; l < first; l++)
                            {
                                ptr[poffset    ] = cmap[aByte].r;
                                ptr[poffset + 1] = cmap[aByte].g;
                                ptr[poffset + 2] = cmap[aByte].b;
                                column++;
                                linepos++;
                            }
                        }
                    }
                    else
                    {
                        ptr[poffset    ] = cmap[aByte].r;
                        ptr[poffset + 1] = cmap[aByte].g;
                        ptr[poffset + 2] = cmap[aByte].b;
                        column++;
                        // linepos += size;    seems to be wrong, RR
                    }
                }
               }
               else if (bpp == 24)
               {
                   stream.Read( &bbuf, 3 );
                   linepos += 3;
                   ptr[poffset    ] = (unsigned char)bbuf[2];
                   ptr[poffset + 1] = (unsigned char)bbuf[1];
                   ptr[poffset + 2] = (unsigned char)bbuf[0];
                   column++;
               }
               else if (bpp == 16)
               {
                   unsigned char temp;
                   stream.Read( &aWord, 2 );
                   aWord = wxUINT16_SWAP_ON_BE( aWord );
                   linepos += 2;
                   temp = (aWord & rmask) >> rshift;
                   ptr[poffset] = temp;
                   temp = (aWord & gmask) >> gshift;
                   ptr[poffset + 1] = temp;
                   temp = (aWord & bmask) >> bshift;
                   ptr[poffset + 2] = temp;
                   column++;
               }
               else
               {
                   unsigned char temp;
                   stream.Read( &aDword, 4 );
                   aDword = wxINT32_SWAP_ON_BE( aDword );
                   linepos += 4;
                   temp = (aDword & rmask) >> rshift;
                   ptr[poffset] = temp;
                   temp = (aDword & gmask) >> gshift;
                   ptr[poffset + 1] = temp;
                   temp = (aDword & bmask) >> bshift;
                   ptr[poffset + 2] = temp;
                   column++;
               }
          }
          while ((linepos < linesize) && (comp != 1) && (comp != 2))
          {
              stream.Read( &aByte, 1 );
              linepos += 1;
              if (stream.LastError() != wxStream_NOERROR)
                  break;
          }
     }
     if (cmap)
       free(cmap);

     image->SetMask( FALSE );

     return TRUE;
}

bool wxBMPHandler::DoCanRead( wxInputStream& stream )
{
    unsigned char hdr[2];

    stream.Read(&hdr, 2);
    stream.SeekI(-2, wxFromCurrent);
    return (hdr[0] == 'B' && hdr[1] == 'M');
}

#endif // wxUSE_STREAMS
Commit	Line	Data
	1	/////////////////////////////////////////////////////////////////////////////
	2	// Name: imagbmp.cpp
	3	// Purpose: wxImage BMP handler
	4	// Author: Robert Roebling
	5	// RCS-ID: $Id$
	6	// Copyright: (c) Robert Roebling
	7	// Licence: wxWindows licence
	8	/////////////////////////////////////////////////////////////////////////////
	9
	10	#ifdef __GNUG__
	11	#pragma implementation "imagbmp.h"
	12	#endif
	13
	14	// For compilers that support precompilation, includes "wx.h".
	15	#include "wx/wxprec.h"
	16
	17	#ifdef __BORLANDC__
	18	#pragma hdrstop
	19	#endif
	20
	21	#include "wx/imagbmp.h"
	22	#include "wx/bitmap.h"
	23	#include "wx/debug.h"
	24	#include "wx/log.h"
	25	#include "wx/app.h"
	26	#include "wx/filefn.h"
	27	#include "wx/wfstream.h"
	28	#include "wx/intl.h"
	29	#include "wx/module.h"
	30
	31	// For memcpy
	32	#include <string.h>
	33
	34	#ifdef __SALFORDC__
	35	#ifdef FAR
	36	#undef FAR
	37	#endif
	38	#endif
	39
	40	#ifdef __WXMSW__
	41	#include <windows.h>
	42	#endif
	43
	44	//-----------------------------------------------------------------------------
	45	// wxBMPHandler
	46	//-----------------------------------------------------------------------------
	47
	48	IMPLEMENT_DYNAMIC_CLASS(wxBMPHandler,wxImageHandler)
	49
	50	#if wxUSE_STREAMS
	51
	52	#ifndef BI_RGB
	53	#define BI_RGB 0
	54	#define BI_RLE8 1
	55	#define BI_RLE4 2
	56	#endif
	57
	58	#ifndef BI_BITFIELDS
	59	#define BI_BITFIELDS 3
	60	#endif
	61
	62	#define poffset (line * width * 3 + column * 3)
	63
	64	bool wxBMPHandler::LoadFile( wxImage *image, wxInputStream& stream, bool verbose, int WXUNUSED(index) )
	65	{
	66	int rshift = 0, gshift = 0, bshift = 0;
	67	wxUint8 aByte;
	68	wxUint16 aWord;
	69	wxInt32 dbuf[4], aDword,
	70	rmask = 0, gmask = 0, bmask = 0;
	71	wxInt8 bbuf[4];
	72	struct _cmap {
	73	unsigned char r, g, b;
	74	} *cmap = NULL;
	75
	76	off_t start_offset = stream.TellI();
	77
	78	image->Destroy();
	79
	80	/*
	81	* Read the BMP header
	82	*/
	83
	84	stream.Read( &bbuf, 2 );
	85	stream.Read( dbuf, 4 * 4 );
	86
	87	#if 0 // unused
	88	wxInt32 size = wxINT32_SWAP_ON_BE( dbuf[0] );
	89	#endif
	90	wxInt32 offset = wxINT32_SWAP_ON_BE( dbuf[2] );
	91
	92	stream.Read(dbuf, 4 * 2);
	93	int width = (int)wxINT32_SWAP_ON_BE( dbuf[0] );
	94	int height = (int)wxINT32_SWAP_ON_BE( dbuf[1] );
	95	if (width > 32767)
	96	{
	97	if (verbose)
	98	wxLogError( _("BMP: Image width > 32767 pixels for file.") );
	99	return FALSE;
	100	}
	101	if (height > 32767)
	102	{
	103	if (verbose)
	104	wxLogError( _("BMP: Image height > 32767 pixels for file.") );
	105	return FALSE;
	106	}
	107
	108	stream.Read( &aWord, 2 );
	109	/*
	110	TODO
	111	int planes = (int)wxUINT16_SWAP_ON_BE( aWord );
	112	*/
	113	stream.Read( &aWord, 2 );
	114	int bpp = (int)wxUINT16_SWAP_ON_BE( aWord );
	115	if (bpp != 1 && bpp != 4 && bpp != 8 && bpp != 16 && bpp != 24 && bpp != 32)
	116	{
	117	if (verbose)
	118	wxLogError( _("BMP: Unknown bitdepth in file.") );
	119	return FALSE;
	120	}
	121
	122	stream.Read( dbuf, 4 * 4 );
	123	int comp = (int)wxINT32_SWAP_ON_BE( dbuf[0] );
	124	if (comp != BI_RGB && comp != BI_RLE4 && comp != BI_RLE8 && comp != BI_BITFIELDS)
	125	{
	126	if (verbose)
	127	wxLogError( _("BMP: Unknown encoding in file.") );
	128	return FALSE;
	129	}
	130
	131	stream.Read( dbuf, 4 * 2 );
	132	int ncolors = (int)wxINT32_SWAP_ON_BE( dbuf[0] );
	133	if (ncolors == 0)
	134	ncolors = 1 << bpp;
	135	/* some more sanity checks */
	136	if (((comp == BI_RLE4) && (bpp != 4)) \|\|
	137	((comp == BI_RLE8) && (bpp != 8)) \|\|
	138	((comp == BI_BITFIELDS) && (bpp != 16 && bpp != 32)))
	139	{
	140	if (verbose)
	141	wxLogError( _("BMP: Encoding doesn't match bitdepth.") );
	142	return FALSE;
	143	}
	144	if (bpp < 16)
	145	{
	146	cmap = (struct _cmap )malloc(sizeof(struct _cmap) ncolors);
	147	if (!cmap)
	148	{
	149	if (verbose)
	150	wxLogError( _("BMP: Couldn't allocate memory.") );
	151	return FALSE;
	152	}
	153	}
	154	else
	155	cmap = NULL;
	156
	157	image->Create( width, height );
	158	unsigned char *ptr = image->GetData();
	159	if (!ptr)
	160	{
	161	if (verbose)
	162	wxLogError( _("BMP: Couldn't allocate memory.") );
	163	if (cmap)
	164	free(cmap);
	165	return FALSE;
	166	}
	167
	168	/*
	169	* Reading the palette, if it exists.
	170	*/
	171	if (bpp < 16 && ncolors != 0)
	172	{
	173	for (int j = 0; j < ncolors; j++)
	174	{
	175	stream.Read( bbuf, 4 );
	176	cmap[j].b = bbuf[0];
	177	cmap[j].g = bbuf[1];
	178	cmap[j].r = bbuf[2];
	179	}
	180	}
	181	else if (bpp == 16 \|\| bpp == 32)
	182	{
	183	if (comp == BI_BITFIELDS)
	184	{
	185	int bit = 0;
	186	stream.Read( dbuf, 4 * 3 );
	187	bmask = wxINT32_SWAP_ON_BE( dbuf[0] );
	188	gmask = wxINT32_SWAP_ON_BE( dbuf[1] );
	189	rmask = wxINT32_SWAP_ON_BE( dbuf[2] );
	190	/* find shift amount.. ugly, but i can't think of a better way */
	191	for (bit = 0; bit < bpp; bit++)
	192	{
	193	if (bmask & (1 << bit))
	194	bshift = bit;
	195	if (gmask & (1 << bit))
	196	gshift = bit;
	197	if (rmask & (1 << bit))
	198	rshift = bit;
	199	}
	200	}
	201	else if (bpp == 16)
	202	{
	203	rmask = 0x7C00;
	204	gmask = 0x03E0;
	205	bmask = 0x001F;
	206	rshift = 10;
	207	gshift = 5;
	208	bshift = 0;
	209	}
	210	else if (bpp == 32)
	211	{
	212	rmask = 0x00FF0000;
	213	gmask = 0x0000FF00;
	214	bmask = 0x000000FF;
	215	rshift = 16;
	216	gshift = 8;
	217	bshift = 0;
	218	}
	219	}
	220
	221	/*
	222	* Reading the image data
	223	*/
	224	stream.SeekI( start_offset + offset );
	225	unsigned char *data = ptr;
	226
	227	/* set the whole image to the background color */
	228	if (bpp < 16 && (comp == BI_RLE4 \|\| comp == BI_RLE8))
	229	{
	230	for (int i = 0; i < width * height; i++)
	231	{
	232	*ptr++ = cmap[0].r;
	233	*ptr++ = cmap[0].g;
	234	*ptr++ = cmap[0].b;
	235	}
	236	ptr = data;
	237	}
	238
	239	int line = 0;
	240	int column = 0;
	241	int linesize = ((width * bpp + 31) / 32) * 4;
	242
	243	/* BMPs are stored upside down */
	244	for (line = (height - 1); line >= 0; line--)
	245	{
	246	int linepos = 0;
	247	for (column = 0; column < width;)
	248	{
	249	if (bpp < 16)
	250	{
	251	int index = 0;
	252	linepos++;
	253	aByte = stream.GetC();
	254	if (bpp == 1)
	255	{
	256	int bit = 0;
	257	for (bit = 0; bit < 8; bit++)
	258	{
	259	index = ((aByte & (0x80 >> bit)) ? 1 : 0);
	260	ptr[poffset] = cmap[index].r;
	261	ptr[poffset + 1] = cmap[index].g;
	262	ptr[poffset + 2] = cmap[index].b;
	263	column++;
	264	}
	265	}
	266	else if (bpp == 4)
	267	{
	268	if (comp == BI_RLE4)
	269	{
	270	if (verbose)
	271	wxLogError( _("BMP: Cannot deal with 4bit encoded yet.") );
	272	image->Destroy();
	273	free(cmap);
	274	return FALSE;
	275	}
	276	else
	277	{
	278	int nibble = 0;
	279	for (nibble = 0; nibble < 2; nibble++)
	280	{
	281	index = ((aByte & (0xF0 >> nibble * 4)) >> (!nibble * 4));
	282	if (index >= 16)
	283	index = 15;
	284	ptr[poffset] = cmap[index].r;
	285	ptr[poffset + 1] = cmap[index].g;
	286	ptr[poffset + 2] = cmap[index].b;
	287	column++;
	288	}
	289	}
	290	}
	291	else if (bpp == 8)
	292	{
	293	if (comp == BI_RLE8)
	294	{
	295	unsigned char first;
	296	first = aByte;
	297	aByte = stream.GetC();
	298	if (first == 0)
	299	{
	300	if (aByte == 0)
	301	{
	302	/* column = width; */
	303	}
	304	else if (aByte == 1)
	305	{
	306	column = width;
	307	line = -1;
	308	}
	309	else if (aByte == 2)
	310	{
	311	aByte = stream.GetC();
	312	column += aByte;
	313	linepos = column * bpp / 8;
	314	aByte = stream.GetC();
	315	line += aByte;
	316	}
	317	else
	318	{
	319	int absolute = aByte;
	320	for (int k = 0; k < absolute; k++)
	321	{
	322	linepos++;
	323	aByte = stream.GetC();
	324	ptr[poffset ] = cmap[aByte].r;
	325	ptr[poffset + 1] = cmap[aByte].g;
	326	ptr[poffset + 2] = cmap[aByte].b;
	327	column++;
	328	}
	329	if (absolute & 0x01)
	330	aByte = stream.GetC();
	331	}
	332	}
	333	else
	334	{
	335	for (int l = 0; l < first; l++)
	336	{
	337	ptr[poffset ] = cmap[aByte].r;
	338	ptr[poffset + 1] = cmap[aByte].g;
	339	ptr[poffset + 2] = cmap[aByte].b;
	340	column++;
	341	linepos++;
	342	}
	343	}
	344	}
	345	else
	346	{
	347	ptr[poffset ] = cmap[aByte].r;
	348	ptr[poffset + 1] = cmap[aByte].g;
	349	ptr[poffset + 2] = cmap[aByte].b;
	350	column++;
	351	// linepos += size; seems to be wrong, RR
	352	}
	353	}
	354	}
	355	else if (bpp == 24)
	356	{
	357	stream.Read( &bbuf, 3 );
	358	linepos += 3;
	359	ptr[poffset ] = (unsigned char)bbuf[2];
	360	ptr[poffset + 1] = (unsigned char)bbuf[1];
	361	ptr[poffset + 2] = (unsigned char)bbuf[0];
	362	column++;
	363	}
	364	else if (bpp == 16)
	365	{
	366	unsigned char temp;
	367	stream.Read( &aWord, 2 );
	368	aWord = wxUINT16_SWAP_ON_BE( aWord );
	369	linepos += 2;
	370	temp = (aWord & rmask) >> rshift;
	371	ptr[poffset] = temp;
	372	temp = (aWord & gmask) >> gshift;
	373	ptr[poffset + 1] = temp;
	374	temp = (aWord & bmask) >> bshift;
	375	ptr[poffset + 2] = temp;
	376	column++;
	377	}
	378	else
	379	{
	380	unsigned char temp;
	381	stream.Read( &aDword, 4 );
	382	aDword = wxINT32_SWAP_ON_BE( aDword );
	383	linepos += 4;
	384	temp = (aDword & rmask) >> rshift;
	385	ptr[poffset] = temp;
	386	temp = (aDword & gmask) >> gshift;
	387	ptr[poffset + 1] = temp;
	388	temp = (aDword & bmask) >> bshift;
	389	ptr[poffset + 2] = temp;
	390	column++;
	391	}
	392	}
	393	while ((linepos < linesize) && (comp != 1) && (comp != 2))
	394	{
	395	stream.Read( &aByte, 1 );
	396	linepos += 1;
	397	if (stream.LastError() != wxStream_NOERROR)
	398	break;
	399	}
	400	}
	401	if (cmap)
	402	free(cmap);
	403
	404	image->SetMask( FALSE );
	405
	406	return TRUE;
	407	}
	408
	409	bool wxBMPHandler::DoCanRead( wxInputStream& stream )
	410	{
	411	unsigned char hdr[2];
	412
	413	stream.Read(&hdr, 2);
	414	stream.SeekI(-2, wxFromCurrent);
	415	return (hdr[0] == 'B' && hdr[1] == 'M');
	416	}
	417
	418	#endif // wxUSE_STREAMS
	419
	420