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JPEG handler does not read entire file into memory anymore (+, of course, that headers change)

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git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@4980 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
This commit is contained in:
Václav Slavík 1999-12-15 22:38:18 +00:00
parent 8f49300284
commit 1aaaa7120e
1 changed files with 38 additions and 14 deletions
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52
src/common/imagjpeg.cpp
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@ -7,10 +7,9 @@
// Licence: wxWindows licence
/////////////////////////////////////////////////////////////////////////////
/*
We don't put pragma implement in this file because it is already present in
src/common/image.cpp
*/
#ifdef __GNUG__
#pragma implementation "imagjpeg.h"
#endif
// For compilers that support precompilation, includes "wx.h".
#include "wx/wxprec.h"
@ -23,7 +22,7 @@
#if wxUSE_LIBJPEG
#include "wx/image.h"
#include "wx/imagjpeg.h"
#include "wx/bitmap.h"
#include "wx/debug.h"
#include "wx/log.h"
@ -62,10 +61,13 @@ IMPLEMENT_DYNAMIC_CLASS(wxJPEGHandler,wxImageHandler)
//------------- JPEG Data Source Manager
#define JPEG_IO_BUFFER_SIZE 2048
typedef struct {
struct jpeg_source_mgr pub; /* public fields */
JOCTET* buffer; /* start of buffer */
wxInputStream *stream;
} my_source_mgr;
typedef my_source_mgr * my_src_ptr;
@ -74,24 +76,46 @@ METHODDEF(void) my_init_source ( j_decompress_ptr WXUNUSED(cinfo) )
{
}
METHODDEF(boolean) my_fill_input_buffer ( j_decompress_ptr WXUNUSED(cinfo) )
METHODDEF(boolean) my_fill_input_buffer ( j_decompress_ptr cinfo )
{
my_src_ptr src = (my_src_ptr) cinfo->src;
src->pub.next_input_byte = src->buffer;
src->pub.bytes_in_buffer = src->stream->Read(src->buffer, JPEG_IO_BUFFER_SIZE).LastRead();
if (src->pub.bytes_in_buffer == 0) // check for end-of-stream
{
// Insert a fake EOI marker
src->buffer[0] = 0xFF;
src->buffer[1] = JPEG_EOI;
src->pub.bytes_in_buffer = 2;
}
return TRUE;
}
METHODDEF(void) my_skip_input_data ( j_decompress_ptr cinfo, long num_bytes )
{
my_src_ptr src = (my_src_ptr) cinfo->src;
if (num_bytes > 0)
{
my_src_ptr src = (my_src_ptr) cinfo->src;
src->pub.next_input_byte += (size_t) num_bytes;
src->pub.bytes_in_buffer -= (size_t) num_bytes;
while (num_bytes > (long)src->pub.bytes_in_buffer)
{
num_bytes -= (long) src->pub.bytes_in_buffer;
src->pub.fill_input_buffer(cinfo);
}
src->pub.next_input_byte += (size_t) num_bytes;
src->pub.bytes_in_buffer -= (size_t) num_bytes;
}
}
METHODDEF(void) my_term_source ( j_decompress_ptr cinfo )
{
my_src_ptr src = (my_src_ptr) cinfo->src;
free (src->buffer);
if (src->pub.bytes_in_buffer > 0)
src->stream->SeekI(-src->pub.bytes_in_buffer, wxFromCurrent);
delete[] src->buffer;
}
void jpeg_wxio_src( j_decompress_ptr cinfo, wxInputStream& infile )
@ -105,10 +129,10 @@ void jpeg_wxio_src( j_decompress_ptr cinfo, wxInputStream& infile )
src = (my_src_ptr) cinfo->src;
}
src = (my_src_ptr) cinfo->src;
src->pub.bytes_in_buffer = infile.GetSize(); /* forces fill_input_buffer on first read */
src->buffer = (JOCTET *) malloc (infile.GetSize());
src->pub.next_input_byte = src->buffer; /* until buffer loaded */
infile.Read(src->buffer, infile.GetSize());
src->pub.bytes_in_buffer = 0; /* forces fill_input_buffer on first read */
src->buffer = new JOCTET[JPEG_IO_BUFFER_SIZE];
src->pub.next_input_byte = NULL; /* until buffer loaded */
src->stream = &infile;
src->pub.init_source = my_init_source;
src->pub.fill_input_buffer = my_fill_input_buffer;