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document that CanRead() and GetImageCount() functions of wxImageHandlers do NOT modify the current stream position and that they require seekable streams; rename current GetImageCount() functions to DoGetImageCount() and put save-and-restore stream position logic in GetImageCount(); add comments in the various DoCanRead() and in DoGetImageCount() where the stream position is modified; remove unneeded SeekI(0) calls from DoCanRead() and DoGetImageCount() functions: they didn't allow to load images from non-seekable streams; implement forward-seeking in wxInputStream::SeekI() also for non-seekable streams

Browse Source 
git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@60852 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
This commit is contained in:
Francesco Montorsi
2009-06-01 11:43:36 +00:00
parent 1f51673bb8
commit 8faef7ccbc
25 changed files with 236 additions and 93 deletions
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64
src/common/imagbmp.cpp
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@@ -641,7 +641,9 @@ bool wxBMPHandler::DoLoadDib(wxImage * image, int width, int height,
*/
if ( IsBmp )
{
if (stream.SeekI(bmpOffset) == wxInvalidOffset)
// NOTE: seeking a positive amount in wxFromCurrent mode allows us to
// load even non-seekable streams (see wxInputStream::SeekI docs)!
if (stream.SeekI(bmpOffset, wxFromCurrent) == wxInvalidOffset)
return false;
//else: icon, just carry on
}
@@ -899,15 +901,9 @@ bool wxBMPHandler::LoadDib(wxImage *image, wxInputStream& stream,
wxInt32 dbuf[4];
wxInt8 bbuf[4];
wxFileOffset offset = 0; // keep gcc quiet
if ( IsBmp )
{
// read the header off the .BMP format file
offset = stream.TellI();
if (offset == wxInvalidOffset)
offset = 0;
stream.Read(bbuf, 2);
stream.Read(dbuf, 16);
}
@@ -918,7 +914,7 @@ bool wxBMPHandler::LoadDib(wxImage *image, wxInputStream& stream,
#if 0 // unused
wxInt32 size = wxINT32_SWAP_ON_BE(dbuf[0]);
#endif
offset = offset + wxINT32_SWAP_ON_BE(dbuf[2]);
wxFileOffset offset = wxINT32_SWAP_ON_BE(dbuf[2]);
stream.Read(dbuf, 4 * 2);
int width = wxINT32_SWAP_ON_BE((int)dbuf[0]);
@@ -1021,7 +1017,7 @@ bool wxBMPHandler::DoCanRead(wxInputStream& stream)
{
unsigned char hdr[2];
if ( !stream.Read(hdr, WXSIZEOF(hdr)) )
if ( !stream.Read(hdr, WXSIZEOF(hdr)) ) // it's ok to modify the stream position here
return false;
// do we have the BMP file signature?
@@ -1259,8 +1255,6 @@ bool wxICOHandler::SaveFile(wxImage *image,
bool wxICOHandler::LoadFile(wxImage *image, wxInputStream& stream,
bool verbose, int index)
{
if (stream.SeekI(0) == wxInvalidOffset)
return false;
return DoLoadFile(image, stream, verbose, index);
}
@@ -1272,9 +1266,9 @@ bool wxICOHandler::DoLoadFile(wxImage *image, wxInputStream& stream,
ICONDIR IconDir;
wxFileOffset iPos = stream.TellI();
stream.Read(&IconDir, sizeof(IconDir));
wxUint16 nIcons = wxUINT16_SWAP_ON_BE(IconDir.idCount);
// nType is 1 for Icons, 2 for Cursors:
wxUint16 nType = wxUINT16_SWAP_ON_BE(IconDir.idType);
@@ -1285,9 +1279,13 @@ bool wxICOHandler::DoLoadFile(wxImage *image, wxInputStream& stream,
int colmax = 0;
int iSel = wxNOT_FOUND;
for (int i = 0; i < nIcons; i++ )
// remember how many bytes we read from the stream:
wxFileOffset offset = sizeof(IconDir);
for (unsigned int i = 0; i < nIcons; i++ )
{
stream.Read(pCurrentEntry, sizeof(ICONDIRENTRY));
offset += stream.Read(pCurrentEntry, sizeof(ICONDIRENTRY)).LastRead();
// bHeight and bColorCount are wxUint8
if ( pCurrentEntry->bWidth >= wMax )
{
@@ -1301,6 +1299,7 @@ bool wxICOHandler::DoLoadFile(wxImage *image, wxInputStream& stream,
colmax = pCurrentEntry->bColorCount;
}
}
pCurrentEntry++;
}
@@ -1320,8 +1319,13 @@ bool wxICOHandler::DoLoadFile(wxImage *image, wxInputStream& stream,
{
// seek to selected icon:
pCurrentEntry = pIconDirEntry + iSel;
if (stream.SeekI(iPos + wxUINT32_SWAP_ON_BE(pCurrentEntry->dwImageOffset), wxFromStart) == wxInvalidOffset)
// NOTE: seeking a positive amount in wxFromCurrent mode allows us to
// load even non-seekable streams (see wxInputStream::SeekI docs)!
if (stream.SeekI(wxUINT32_SWAP_ON_BE(pCurrentEntry->dwImageOffset) - offset,
wxFromCurrent) == wxInvalidOffset)
return false;
bResult = LoadDib(image, stream, true, IsBmp);
bool bIsCursorType = (this->GetType() == wxBITMAP_TYPE_CUR) || (this->GetType() == wxBITMAP_TYPE_ANI);
if ( bResult && bIsCursorType && nType == 2 )
@@ -1331,30 +1335,27 @@ bool wxICOHandler::DoLoadFile(wxImage *image, wxInputStream& stream,
image->SetOption(wxIMAGE_OPTION_CUR_HOTSPOT_Y, wxUINT16_SWAP_ON_BE(pCurrentEntry->wBitCount));
}
}
delete[] pIconDirEntry;
delete [] pIconDirEntry;
return bResult;
}
int wxICOHandler::GetImageCount(wxInputStream& stream)
int wxICOHandler::DoGetImageCount(wxInputStream& stream)
{
ICONDIR IconDir;
wxFileOffset iPos = stream.TellI();
if (stream.SeekI(0) == wxInvalidOffset)
return 0;
if (stream.Read(&IconDir, sizeof(IconDir)).LastRead() != sizeof(IconDir))
// it's ok to modify the stream position here
return 0;
wxUint16 nIcons = wxUINT16_SWAP_ON_BE(IconDir.idCount);
if (stream.SeekI(iPos) == wxInvalidOffset)
return 0;
return (int)nIcons;
return (int)wxUINT16_SWAP_ON_BE(IconDir.idCount);
}
bool wxICOHandler::DoCanRead(wxInputStream& stream)
{
if (stream.SeekI(0) == wxInvalidOffset)
return false;
unsigned char hdr[4];
if ( !stream.Read(hdr, WXSIZEOF(hdr)) )
if ( !stream.Read(hdr, WXSIZEOF(hdr)) ) // it's ok to modify the stream position here
return false;
// hdr[2] is one for an icon and two for a cursor
@@ -1374,10 +1375,8 @@ IMPLEMENT_DYNAMIC_CLASS(wxCURHandler, wxICOHandler)
bool wxCURHandler::DoCanRead(wxInputStream& stream)
{
if (stream.SeekI(0) == wxInvalidOffset)
return false;
unsigned char hdr[4];
if ( !stream.Read(hdr, WXSIZEOF(hdr)) )
if ( !stream.Read(hdr, WXSIZEOF(hdr)) ) // it's ok to modify the stream position here
return false;
// hdr[2] is one for an icon and two for a cursor
@@ -1408,12 +1407,13 @@ bool wxANIHandler::DoCanRead(wxInputStream& stream)
{
wxANIDecoder decod;
return decod.CanRead(stream);
// it's ok to modify the stream position here
}
int wxANIHandler::GetImageCount(wxInputStream& stream)
int wxANIHandler::DoGetImageCount(wxInputStream& stream)
{
wxANIDecoder decoder;
if (!decoder.Load(stream))
if (!decoder.Load(stream)) // it's ok to modify the stream position here
return wxNOT_FOUND;
return decoder.GetFrameCount();