/////////////////////////////////////////////////////////////////////////////
-// Name: gifdecod.cpp
+// Name: src/common/gifdecod.cpp
// Purpose: wxGIFDecoder, GIF reader for wxImage and wxAnimation
// Author: Guillermo Rodriguez Garcia <guille@iies.es>
// Version: 3.04
-// RCS-ID: $Id$
// Copyright: (c) Guillermo Rodriguez Garcia
// Licence: wxWindows licence
/////////////////////////////////////////////////////////////////////////////
-#ifdef __GNUG__
-#pragma implementation "gifdecod.h"
-#endif
-
// For compilers that support precompilation, includes "wx.h".
#include "wx/wxprec.h"
#ifdef __BORLANDC__
-# pragma hdrstop
+ #pragma hdrstop
#endif
+#if wxUSE_STREAMS && wxUSE_GIF
+
#ifndef WX_PRECOMP
-# include "wx/defs.h"
+ #include "wx/palette.h"
+ #include "wx/intl.h"
+ #include "wx/log.h"
#endif
-#if wxUSE_STREAMS && wxUSE_GIF
-
#include <stdlib.h>
#include <string.h>
#include "wx/gifdecod.h"
+#include "wx/scopedptr.h"
+#include "wx/scopeguard.h"
+enum
+{
+ GIF_MARKER_EXT = '!', // 0x21
+ GIF_MARKER_SEP = ',', // 0x2C
+ GIF_MARKER_ENDOFDATA = ';', // 0x3B
+
+ GIF_MARKER_EXT_GRAPHICS_CONTROL = 0xF9,
+ GIF_MARKER_EXT_COMMENT = 0xFE,
+ GIF_MARKER_EXT_APP = 0xFF
+};
+
+#define GetFrame(n) ((GIFImage*)m_frames[n])
+
+//---------------------------------------------------------------------------
+// GIFImage
+//---------------------------------------------------------------------------
+
+// internal class for storing GIF image data
+class GIFImage
+{
+public:
+ // def ctor
+ GIFImage();
+
+ unsigned int w; // width
+ unsigned int h; // height
+ unsigned int left; // x coord (in logical screen)
+ unsigned int top; // y coord (in logical screen)
+ int transparent; // transparent color index (-1 = none)
+ wxAnimationDisposal disposal; // disposal method
+ long delay; // delay in ms (-1 = unused)
+ unsigned char *p; // bitmap
+ unsigned char *pal; // palette
+ unsigned int ncolours; // number of colours
+ wxString comment;
+
+ wxDECLARE_NO_COPY_CLASS(GIFImage);
+};
+
+wxDECLARE_SCOPED_PTR(GIFImage, GIFImagePtr)
+wxDEFINE_SCOPED_PTR(GIFImage, GIFImagePtr)
+
+
+//---------------------------------------------------------------------------
+// GIFImage constructor
+//---------------------------------------------------------------------------
+GIFImage::GIFImage()
+{
+ w = 0;
+ h = 0;
+ left = 0;
+ top = 0;
+ transparent = 0;
+ disposal = wxANIM_DONOTREMOVE;
+ delay = -1;
+ p = (unsigned char *) NULL;
+ pal = (unsigned char *) NULL;
+ ncolours = 0;
+}
//---------------------------------------------------------------------------
// wxGIFDecoder constructor and destructor
//---------------------------------------------------------------------------
-wxGIFDecoder::wxGIFDecoder(wxInputStream *s, bool anim)
+wxGIFDecoder::wxGIFDecoder()
{
- m_f = s;
- m_anim = anim;
-
- m_background = -1;
- m_screenw = 0;
- m_screenh = 0;
-
- m_pimage = NULL;
- m_pfirst = NULL;
- m_plast = NULL;
- m_image = 0;
- m_nimages = 0;
}
wxGIFDecoder::~wxGIFDecoder()
void wxGIFDecoder::Destroy()
{
- GIFImage *pimg, *paux;
-
- pimg = m_pfirst;
-
- while (pimg != NULL)
+ wxASSERT(m_nFrames==m_frames.GetCount());
+ for (unsigned int i=0; i<m_nFrames; i++)
{
- paux = pimg->next;
- free(pimg->p);
- free(pimg->pal);
- delete pimg;
- pimg = paux;
+ GIFImage *f = (GIFImage*)m_frames[i];
+ free(f->p);
+ free(f->pal);
+ delete f;
}
- m_pimage = NULL;
- m_pfirst = NULL;
- m_plast = NULL;
- m_image = 0;
- m_nimages = 0;
+ m_frames.Clear();
+ m_nFrames = 0;
}
// This function was designed by Vaclav Slavik
-bool wxGIFDecoder::ConvertToImage(wxImage *image) const
+bool wxGIFDecoder::ConvertToImage(unsigned int frame, wxImage *image) const
{
unsigned char *src, *dst, *pal;
unsigned long i;
int transparent;
- /* just in case... */
+ // just in case...
image->Destroy();
- /* create the image */
- image->Create(GetWidth(), GetHeight());
+ // create the image
+ wxSize sz = GetFrameSize(frame);
+ image->Create(sz.GetWidth(), sz.GetHeight());
+ image->SetType(wxBITMAP_TYPE_GIF);
- if (!image->Ok())
- return FALSE;
+ if (!image->IsOk())
+ return false;
- pal = GetPalette();
- src = GetData();
+ pal = GetPalette(frame);
+ src = GetData(frame);
dst = image->GetData();
- transparent = GetTransparentColour();
+ transparent = GetTransparentColourIndex(frame);
- /* set transparent colour mask */
+ // set transparent colour mask
if (transparent != -1)
{
- for (i = 0; i < 256; i++)
- {
- if ((pal[3 * i + 0] == 255) &&
- (pal[3 * i + 1] == 0) &&
- (pal[3 * i + 2] == 255))
- {
- pal[3 * i + 2] = 254;
- }
- }
-
- pal[3 * transparent + 0] = 255,
- pal[3 * transparent + 1] = 0,
- pal[3 * transparent + 2] = 255;
-
- image->SetMaskColour(255, 0, 255);
+ for (i = 0; i < GetNcolours(frame); i++)
+ {
+ if ((pal[3 * i + 0] == 255) &&
+ (pal[3 * i + 1] == 0) &&
+ (pal[3 * i + 2] == 255))
+ {
+ pal[3 * i + 2] = 254;
+ }
+ }
+
+ pal[3 * transparent + 0] = 255,
+ pal[3 * transparent + 1] = 0,
+ pal[3 * transparent + 2] = 255;
+
+ image->SetMaskColour(255, 0, 255);
}
else
- image->SetMask(FALSE);
+ image->SetMask(false);
- if (pal)
+#if wxUSE_PALETTE
+ unsigned char r[256];
+ unsigned char g[256];
+ unsigned char b[256];
+
+ for (i = 0; i < 256; i++)
{
- unsigned char* r = new unsigned char[256];
- unsigned char* g = new unsigned char[256];
- unsigned char* b = new unsigned char[256];
- for (i = 0; i < 256; i++)
- {
- r[i] = pal[3*i + 0];
- g[i] = pal[3*i + 1];
- b[i] = pal[3*i + 2];
- }
- image->SetPalette(wxPalette(256, r, g, b));
- delete[] r; delete[] g; delete[] b;
+ r[i] = pal[3*i + 0];
+ g[i] = pal[3*i + 1];
+ b[i] = pal[3*i + 2];
}
- /* copy image data */
- for (i = 0; i < (GetWidth() * GetHeight()); i++, src++)
+ image->SetPalette(wxPalette(GetNcolours(frame), r, g, b));
+#endif // wxUSE_PALETTE
+
+ // copy image data
+ unsigned long npixel = sz.GetWidth() * sz.GetHeight();
+ for (i = 0; i < npixel; i++, src++)
{
- *(dst++) = pal[3 * (*src) + 0];
- *(dst++) = pal[3 * (*src) + 1];
- *(dst++) = pal[3 * (*src) + 2];
+ *(dst++) = pal[3 * (*src) + 0];
+ *(dst++) = pal[3 * (*src) + 1];
+ *(dst++) = pal[3 * (*src) + 2];
}
- return TRUE;
+ wxString comment = GetFrame(frame)->comment;
+ if ( !comment.empty() )
+ {
+ image->SetOption(wxIMAGE_OPTION_GIF_COMMENT, comment);
+ }
+
+ return true;
}
// Get data for current frame
-int wxGIFDecoder::GetFrameIndex() const { return m_image; }
-unsigned char* wxGIFDecoder::GetData() const { return (m_pimage->p); }
-unsigned char* wxGIFDecoder::GetPalette() const { return (m_pimage->pal); }
-unsigned int wxGIFDecoder::GetWidth() const { return (m_pimage->w); }
-unsigned int wxGIFDecoder::GetHeight() const { return (m_pimage->h); }
-unsigned int wxGIFDecoder::GetTop() const { return (m_pimage->top); }
-unsigned int wxGIFDecoder::GetLeft() const { return (m_pimage->left); }
-int wxGIFDecoder::GetTransparentColour() const { return (m_pimage->transparent); }
-int wxGIFDecoder::GetDisposalMethod() const { return (m_pimage->disposal); }
-long wxGIFDecoder::GetDelay() const { return (m_pimage->delay); }
-
-// Get global data
-
-unsigned int wxGIFDecoder::GetLogicalScreenWidth() const { return m_screenw; }
-unsigned int wxGIFDecoder::GetLogicalScreenHeight() const { return m_screenh; }
-int wxGIFDecoder::GetBackgroundColour() const { return m_background; }
-int wxGIFDecoder::GetNumberOfFrames() const { return m_nimages; }
-bool wxGIFDecoder::IsAnimation() const { return (m_nimages > 1); }
-
-
-//---------------------------------------------------------------------------
-// Functions to move through the animation
-//---------------------------------------------------------------------------
-
-bool wxGIFDecoder::GoFirstFrame()
+wxSize wxGIFDecoder::GetFrameSize(unsigned int frame) const
{
- if (!IsAnimation())
- return FALSE;
-
- m_image = 1;
- m_pimage = m_pfirst;
- return TRUE;
+ return wxSize(GetFrame(frame)->w, GetFrame(frame)->h);
}
-bool wxGIFDecoder::GoLastFrame()
+wxPoint wxGIFDecoder::GetFramePosition(unsigned int frame) const
{
- if (!IsAnimation())
- return FALSE;
-
- m_image = m_nimages;
- m_pimage = m_plast;
- return TRUE;
+ return wxPoint(GetFrame(frame)->left, GetFrame(frame)->top);
}
-bool wxGIFDecoder::GoNextFrame(bool cyclic)
+wxAnimationDisposal wxGIFDecoder::GetDisposalMethod(unsigned int frame) const
{
- if (!IsAnimation())
- return FALSE;
-
- if ((m_image < m_nimages) || (cyclic))
- {
- m_pimage = m_pimage->next;
- m_image++;
-
- if (!m_pimage)
- {
- m_image = 1;
- m_pimage = m_pfirst;
- }
-
- return TRUE;
- }
- else
- return FALSE;
+ return GetFrame(frame)->disposal;
}
-bool wxGIFDecoder::GoPrevFrame(bool cyclic)
+long wxGIFDecoder::GetDelay(unsigned int frame) const
{
- if (!IsAnimation())
- return FALSE;
-
- if ((m_image > 1) || (cyclic))
- {
- m_pimage = m_pimage->prev;
- m_image--;
-
- if (!m_pimage)
- {
- m_image = m_nimages;
- m_pimage = m_plast;
- }
-
- return TRUE;
- }
- else
- return FALSE;
+ return GetFrame(frame)->delay;
}
-bool wxGIFDecoder::GoFrame(int which)
+wxColour wxGIFDecoder::GetTransparentColour(unsigned int frame) const
{
- int i;
-
- if (!IsAnimation())
- return FALSE;
-
- if ((which >= 1) && (which <= m_nimages))
- {
- m_pimage = m_pfirst;
+ unsigned char *pal = GetFrame(frame)->pal;
+ int n = GetFrame(frame)->transparent;
+ if (n == -1)
+ return wxNullColour;
+
+ return wxColour(pal[n*3 + 0],
+ pal[n*3 + 1],
+ pal[n*3 + 2]);
+}
- for (i = 1; i < which; i++)
- m_pimage = m_pimage->next;
+unsigned char* wxGIFDecoder::GetData(unsigned int frame) const { return (GetFrame(frame)->p); }
+unsigned char* wxGIFDecoder::GetPalette(unsigned int frame) const { return (GetFrame(frame)->pal); }
+unsigned int wxGIFDecoder::GetNcolours(unsigned int frame) const { return (GetFrame(frame)->ncolours); }
+int wxGIFDecoder::GetTransparentColourIndex(unsigned int frame) const { return (GetFrame(frame)->transparent); }
- return TRUE;
- }
- else
- return FALSE;
-}
//---------------------------------------------------------------------------
// getcode:
// Reads the next code from the file stream, with size 'bits'
//
-int wxGIFDecoder::getcode(int bits, int ab_fin)
+int wxGIFDecoder::getcode(wxInputStream& stream, int bits, int ab_fin)
{
- unsigned int mask; /* bit mask */
- unsigned int code; /* code (result) */
+ unsigned int mask; // bit mask
+ unsigned int code; // code (result)
-
- /* get remaining bits from last byte read */
+ // get remaining bits from last byte read
mask = (1 << bits) - 1;
code = (m_lastbyte >> (8 - m_restbits)) & mask;
- /* keep reading new bytes while needed */
+ // keep reading new bytes while needed
while (bits > m_restbits)
{
- /* if no bytes left in this block, read the next block */
- if (m_restbyte == 0)
- {
- m_restbyte = (unsigned char)m_f->GetC();
-
- /* Some encoders are a bit broken: instead of issuing
- * an end-of-image symbol (ab_fin) they come up with
- * a zero-length subblock!! We catch this here so
- * that the decoder sees an ab_fin code.
- */
- if (m_restbyte == 0)
- {
- code = ab_fin;
- break;
- }
-
- /* prefetch data */
- m_f->Read((void *) m_buffer, m_restbyte);
- m_bufp = m_buffer;
- }
-
- /* read next byte and isolate the bits we need */
- m_lastbyte = (unsigned char) (*m_bufp++);
- mask = (1 << (bits - m_restbits)) - 1;
- code = code + ((m_lastbyte & mask) << m_restbits);
- m_restbyte--;
-
- /* adjust total number of bits extracted from the buffer */
- m_restbits = m_restbits + 8;
+ // if no bytes left in this block, read the next block
+ if (m_restbyte == 0)
+ {
+ m_restbyte = stream.GetC();
+
+ /* Some encoders are a bit broken: instead of issuing
+ * an end-of-image symbol (ab_fin) they come up with
+ * a zero-length subblock!! We catch this here so
+ * that the decoder sees an ab_fin code.
+ */
+ if (m_restbyte == 0)
+ {
+ code = ab_fin;
+ break;
+ }
+
+ // prefetch data
+ stream.Read((void *) m_buffer, m_restbyte);
+ if (stream.LastRead() != m_restbyte)
+ {
+ code = ab_fin;
+ return code;
+ }
+ m_bufp = m_buffer;
+ }
+
+ // read next byte and isolate the bits we need
+ m_lastbyte = (unsigned char) (*m_bufp++);
+ mask = (1 << (bits - m_restbits)) - 1;
+ code = code + ((m_lastbyte & mask) << m_restbits);
+ m_restbyte--;
+
+ // adjust total number of bits extracted from the buffer
+ m_restbits = m_restbits + 8;
}
- /* find number of bits remaining for next code */
+ // find number of bits remaining for next code
m_restbits = (m_restbits - bits);
return code;
// dgif:
// GIF decoding function. The initial code size (aka root size)
// is 'bits'. Supports interlaced images (interl == 1).
-//
-int wxGIFDecoder::dgif(GIFImage *img, int interl, int bits)
+// Returns wxGIF_OK (== 0) on success, or an error code if something
+// fails (see header file for details)
+wxGIFErrorCode
+wxGIFDecoder::dgif(wxInputStream& stream, GIFImage *img, int interl, int bits)
{
- int *ab_prefix = new int[4096]; /* alphabet (prefixes) */
- int *ab_tail = new int[4096]; /* alphabet (tails) */
- int *stack = new int[4096]; /* decompression stack */
- int ab_clr; /* clear code */
- int ab_fin; /* end of info code */
- int ab_bits; /* actual symbol width, in bits */
- int ab_free; /* first free position in alphabet */
- int ab_max; /* last possible character in alphabet */
- int pass; /* pass number in interlaced images */
- int pos; /* index into decompresion stack */
- unsigned int x, y; /* position in image buffer */
+ static const int allocSize = 4096 + 1;
+ int *ab_prefix = new int[allocSize]; // alphabet (prefixes)
+ if (ab_prefix == NULL)
+ {
+ return wxGIF_MEMERR;
+ }
+
+ int *ab_tail = new int[allocSize]; // alphabet (tails)
+ if (ab_tail == NULL)
+ {
+ delete[] ab_prefix;
+ return wxGIF_MEMERR;
+ }
+
+ int *stack = new int[allocSize]; // decompression stack
+ if (stack == NULL)
+ {
+ delete[] ab_prefix;
+ delete[] ab_tail;
+ return wxGIF_MEMERR;
+ }
+
+ int ab_clr; // clear code
+ int ab_fin; // end of info code
+ int ab_bits; // actual symbol width, in bits
+ int ab_free; // first free position in alphabet
+ int ab_max; // last possible character in alphabet
+ int pass; // pass number in interlaced images
+ int pos; // index into decompresion stack
+ unsigned int x, y; // position in image buffer
int code, readcode, lastcode, abcabca;
- /* these won't change */
+ // these won't change
ab_clr = (1 << bits);
ab_fin = (1 << bits) + 1;
- /* these will change through the decompression proccess */
+ // these will change through the decompression process
ab_bits = bits + 1;
ab_free = (1 << bits) + 2;
ab_max = (1 << ab_bits) - 1;
pass = 1;
pos = x = y = 0;
- /* reset decoder vars */
+ // reset decoder vars
m_restbits = 0;
m_restbyte = 0;
m_lastbyte = 0;
do
{
- /* get next code */
- readcode = code = getcode(ab_bits, ab_fin);
-
- /* end of image? */
- if (code == ab_fin) break;
-
- /* reset alphabet? */
- if (code == ab_clr)
- {
- /* reset main variables */
- ab_bits = bits + 1;
- ab_free = (1 << bits) + 2;
- ab_max = (1 << ab_bits) - 1;
- lastcode = -1;
- abcabca = -1;
-
- /* skip to next code */
- continue;
- }
-
- /* unknown code: special case (like in ABCABCA) */
- if (code >= ab_free)
- {
- code = lastcode; /* take last string */
- stack[pos++] = abcabca; /* add first character */
- }
-
- /* build the string for this code in the stack */
- while (code > ab_clr)
- {
- stack[pos++] = ab_tail[code];
- code = ab_prefix[code];
- }
- stack[pos] = code; /* push last code into the stack */
- abcabca = code; /* save for special case */
-
- /* make new entry in alphabet (only if NOT just cleared) */
- if (lastcode != -1)
- {
- ab_prefix[ab_free] = lastcode;
- ab_tail[ab_free] = code;
- ab_free++;
-
- if ((ab_free > ab_max) && (ab_bits < 12))
- {
- ab_bits++;
- ab_max = (1 << ab_bits) - 1;
- }
- }
-
- /* dump stack data to the buffer */
- while (pos >= 0)
- {
- (img->p)[x + (y * (img->w))] = (char)stack[pos--];
-
- if (++x >= (img->w))
- {
- x = 0;
-
- if (interl)
- {
- /* support for interlaced images */
- switch (pass)
- {
- case 1: y += 8; break;
- case 2: y += 8; break;
- case 3: y += 4; break;
- case 4: y += 2; break;
- }
- if (y >= (img->h))
- {
- switch (++pass)
- {
- case 2: y = 4; break;
- case 3: y = 2; break;
- case 4: y = 1; break;
- }
- }
- }
- else
- {
- /* non-interlaced */
- y++;
- }
- }
- }
-
- pos = 0;
- lastcode = readcode;
+ // get next code
+ readcode = code = getcode(stream, ab_bits, ab_fin);
+
+ // end of image?
+ if (code == ab_fin) break;
+
+ // reset alphabet?
+ if (code == ab_clr)
+ {
+ // reset main variables
+ ab_bits = bits + 1;
+ ab_free = (1 << bits) + 2;
+ ab_max = (1 << ab_bits) - 1;
+ lastcode = -1;
+ abcabca = -1;
+
+ // skip to next code
+ continue;
+ }
+
+ // unknown code: special case (like in ABCABCA)
+ if (code >= ab_free)
+ {
+ code = lastcode; // take last string
+ stack[pos++] = abcabca; // add first character
+ }
+
+ // build the string for this code in the stack
+ while (code > ab_clr)
+ {
+ stack[pos++] = ab_tail[code];
+ code = ab_prefix[code];
+
+ // Don't overflow. This shouldn't happen with normal
+ // GIF files, the allocSize of 4096+1 is enough. This
+ // will only happen with badly formed GIFs.
+ if (pos >= allocSize)
+ {
+ delete[] ab_prefix;
+ delete[] ab_tail;
+ delete[] stack;
+ return wxGIF_INVFORMAT;
+ }
+ }
+
+ if (pos >= allocSize)
+ {
+ delete[] ab_prefix;
+ delete[] ab_tail;
+ delete[] stack;
+ return wxGIF_INVFORMAT;
+ }
+
+ stack[pos] = code; // push last code into the stack
+ abcabca = code; // save for special case
+
+ // make new entry in alphabet (only if NOT just cleared)
+ if (lastcode != -1)
+ {
+ // Normally, after the alphabet is full and can't grow any
+ // further (ab_free == 4096), encoder should (must?) emit CLEAR
+ // to reset it. This checks whether we really got it, otherwise
+ // the GIF is damaged.
+ if (ab_free > ab_max)
+ {
+ delete[] ab_prefix;
+ delete[] ab_tail;
+ delete[] stack;
+ return wxGIF_INVFORMAT;
+ }
+
+ // This assert seems unnecessary since the condition above
+ // eliminates the only case in which it went false. But I really
+ // don't like being forced to ask "Who in .text could have
+ // written there?!" And I wouldn't have been forced to ask if
+ // this line had already been here.
+ wxASSERT(ab_free < allocSize);
+
+ ab_prefix[ab_free] = lastcode;
+ ab_tail[ab_free] = code;
+ ab_free++;
+
+ if ((ab_free > ab_max) && (ab_bits < 12))
+ {
+ ab_bits++;
+ ab_max = (1 << ab_bits) - 1;
+ }
+ }
+
+ // dump stack data to the image buffer
+ while (pos >= 0)
+ {
+ (img->p)[x + (y * (img->w))] = (char) stack[pos];
+ pos--;
+
+ if (++x >= (img->w))
+ {
+ x = 0;
+
+ if (interl)
+ {
+ // support for interlaced images
+ switch (pass)
+ {
+ case 1: y += 8; break;
+ case 2: y += 8; break;
+ case 3: y += 4; break;
+ case 4: y += 2; break;
+ }
+
+ /* loop until a valid y coordinate has been
+ found, Or if the maximum number of passes has
+ been reached, exit the loop, and stop image
+ decoding (At this point the image is successfully
+ decoded).
+ If we don't loop, but merely set y to some other
+ value, that new value might still be invalid depending
+ on the height of the image. This would cause out of
+ bounds writing.
+ */
+ while (y >= (img->h))
+ {
+ switch (++pass)
+ {
+ case 2: y = 4; break;
+ case 3: y = 2; break;
+ case 4: y = 1; break;
+
+ default:
+ /*
+ It's possible we arrive here. For example this
+ happens when the image is interlaced, and the
+ height is 1. Looking at the above cases, the
+ lowest possible y is 1. While the only valid
+ one would be 0 for an image of height 1. So
+ 'eventually' the loop will arrive here.
+ This case makes sure this while loop is
+ exited, as well as the 2 other ones.
+ */
+
+ // Set y to a valid coordinate so the local
+ // while loop will be exited. (y = 0 always
+ // is >= img->h since if img->h == 0 the
+ // image is never decoded)
+ y = 0;
+
+ // This will exit the other outer while loop
+ pos = -1;
+
+ // This will halt image decoding.
+ code = ab_fin;
+
+ break;
+ }
+ }
+ }
+ else
+ {
+ // non-interlaced
+ y++;
+/*
+Normally image decoding is finished when an End of Information code is
+encountered (code == ab_fin) however some broken encoders write wrong
+"block byte counts" (The first byte value after the "code size" byte),
+being one value too high. It might very well be possible other variants
+of this problem occur as well. The only sensible solution seems to
+be to check for clipping.
+Example of wrong encoding:
+(1 * 1 B/W image, raster data stream follows in hex bytes)
+
+02 << B/W images have a code size of 2
+02 << Block byte count
+44 << LZW packed
+00 << Zero byte count (terminates data stream)
+
+Because the block byte count is 2, the zero byte count is used in the
+decoding process, and decoding is continued after this byte. (While it
+should signal an end of image)
+
+It should be:
+02
+02
+44
+01 << When decoded this correctly includes the End of Information code
+00
+
+Or (Worse solution):
+02
+01
+44
+00
+(The 44 doesn't include an End of Information code, but at least the
+decoder correctly skips to 00 now after decoding, and signals this
+as an End of Information itself)
+*/
+ if (y >= img->h)
+ {
+ code = ab_fin;
+ break;
+ }
+ }
+ }
+ }
+
+ pos = 0;
+ lastcode = readcode;
}
while (code != ab_fin);
delete [] ab_tail ;
delete [] stack ;
- return 0;
+ return wxGIF_OK;
}
// CanRead:
-// Returns TRUE if the file looks like a valid GIF, FALSE otherwise.
+// Returns true if the file looks like a valid GIF, false otherwise.
//
-bool wxGIFDecoder::CanRead()
+bool wxGIFDecoder::DoCanRead(wxInputStream &stream) const
{
unsigned char buf[3];
- m_f->Read(buf, 3);
- m_f->SeekI(-3, wxFromCurrent);
+ if ( !stream.Read(buf, WXSIZEOF(buf)) )
+ return false;
- return (memcmp(buf, "GIF", 3) == 0);
+ return memcmp(buf, "GIF", WXSIZEOF(buf)) == 0;
}
-// ReadGIF:
+// LoadGIF:
// Reads and decodes one or more GIF images, depending on whether
// animated GIF support is enabled. Can read GIFs with any bit
// size (color depth), but the output images are always expanded
// (== 0) on success, or an error code if something fails (see
// header file for details)
//
-int wxGIFDecoder::ReadGIF()
+wxGIFErrorCode wxGIFDecoder::LoadGIF(wxInputStream& stream)
{
- int ncolors, bits, interl, transparent, disposal, i;
+ unsigned int global_ncolors = 0;
+ int bits, interl, i;
+ wxAnimationDisposal disposal;
long size;
long delay;
unsigned char type = 0;
unsigned char pal[768];
unsigned char buf[16];
- GIFImage **ppimg;
- GIFImage *pimg, *pprev;
+ bool anim = true;
- /* check GIF signature */
- if (!CanRead())
- return wxGIF_INVFORMAT;
+ // check GIF signature
+ if (!CanRead(stream))
+ return wxGIF_INVFORMAT;
- /* check for animated GIF support (ver. >= 89a) */
- m_f->Read(buf, 6);
+ // check for animated GIF support (ver. >= 89a)
+
+ static const unsigned int headerSize = (3 + 3);
+ stream.Read(buf, headerSize);
+ if (stream.LastRead() != headerSize)
+ {
+ return wxGIF_INVFORMAT;
+ }
if (memcmp(buf + 3, "89a", 3) < 0)
- m_anim = FALSE;
+ {
+ anim = false;
+ }
- /* read logical screen descriptor block (LSDB) */
- m_f->Read(buf, 7);
- m_screenw = buf[0] + 256 * buf[1];
- m_screenh = buf[2] + 256 * buf[3];
+ // read logical screen descriptor block (LSDB)
+ static const unsigned int lsdbSize = (2 + 2 + 1 + 1 + 1);
+ stream.Read(buf, lsdbSize);
+ if (stream.LastRead() != lsdbSize)
+ {
+ return wxGIF_INVFORMAT;
+ }
- /* load global color map if available */
- if ((buf[4] & 0x80) == 0x80)
+ m_szAnimation.SetWidth( buf[0] + 256 * buf[1] );
+ m_szAnimation.SetHeight( buf[2] + 256 * buf[3] );
+
+ if (anim && ((m_szAnimation.GetWidth() == 0) || (m_szAnimation.GetHeight() == 0)))
{
- m_background = buf[5];
+ return wxGIF_INVFORMAT;
+ }
- ncolors = 2 << (buf[4] & 0x07);
- m_f->Read(pal, 3 * ncolors);
+ // load global color map if available
+ if ((buf[4] & 0x80) == 0x80)
+ {
+ int backgroundColIndex = buf[5];
+
+ global_ncolors = 2 << (buf[4] & 0x07);
+ unsigned int numBytes = 3 * global_ncolors;
+ stream.Read(pal, numBytes);
+ if (stream.LastRead() != numBytes)
+ {
+ return wxGIF_INVFORMAT;
+ }
+
+ m_background.Set(pal[backgroundColIndex*3 + 0],
+ pal[backgroundColIndex*3 + 1],
+ pal[backgroundColIndex*3 + 2]);
}
- /* transparent colour, disposal method and delay default to unused */
- transparent = -1;
- disposal = -1;
+ // transparent colour, disposal method and delay default to unused
+ int transparent = -1;
+ disposal = wxANIM_UNSPECIFIED;
delay = -1;
+ wxString comment;
- /* read images */
- ppimg = &m_pfirst;
- pprev = NULL;
- pimg = NULL;
-
- bool done = FALSE;
-
- while(!done)
+ bool done = false;
+ while (!done)
{
- type = (unsigned char)m_f->GetC();
-
- /* end of data? */
- if (type == 0x3B)
- {
- done = TRUE;
- }
- else
- /* extension block? */
- if (type == 0x21)
- {
- if (((unsigned char)m_f->GetC()) == 0xF9)
- /* graphics control extension, parse it */
- {
- m_f->Read(buf, 6);
-
- /* read delay and convert from 1/100 of a second to ms */
- delay = 10 * (buf[2] + 256 * buf[3]);
-
- /* read transparent colour index, if used */
- if (buf[1] & 0x01)
- transparent = buf[4];
-
- /* read disposal method */
- disposal = (buf[1] & 0x1C) - 1;
- }
- else
- /* other extension, skip */
- {
- while ((i = (unsigned char)m_f->GetC()) != 0)
- {
- m_f->SeekI(i, wxFromCurrent);
- }
- }
- }
- else
- /* image descriptor block? */
- if (type == 0x2C)
- {
- /* allocate memory for IMAGEN struct */
- pimg = (*ppimg) = new GIFImage();
-
- if (pimg == NULL)
- {
- Destroy();
- return wxGIF_MEMERR;
- }
-
- /* fill in the data */
- m_f->Read(buf, 9);
- pimg->left = buf[0] + 256 * buf[1];
- pimg->top = buf[2] + 256 * buf[3];
-/*
- pimg->left = buf[4] + 256 * buf[5];
- pimg->top = buf[4] + 256 * buf[5];
-*/
- pimg->w = buf[4] + 256 * buf[5];
- pimg->h = buf[6] + 256 * buf[7];
- interl = ((buf[8] & 0x40)? 1 : 0);
- size = pimg->w * pimg->h;
-
- pimg->transparent = transparent;
- pimg->disposal = disposal;
- pimg->delay = delay;
- pimg->next = NULL;
- pimg->prev = pprev;
- pprev = pimg;
- ppimg = &pimg->next;
-
- /* allocate memory for image and palette */
- pimg->p = (unsigned char *) malloc((size_t)size);
- pimg->pal = (unsigned char *) malloc(768);
-
- if ((!pimg->p) || (!pimg->pal))
- {
- Destroy();
- return wxGIF_MEMERR;
- }
-
- /* load local color map if available, else use global map */
- if ((buf[8] & 0x80) == 0x80)
- {
- ncolors = 2 << (buf[8] & 0x07);
- m_f->Read(pimg->pal, 3 * ncolors);
- }
- else
- memcpy(pimg->pal, pal, 768);
-
- /* get initial code size from first byte in raster data */
- bits = (unsigned char)m_f->GetC();
-
- /* decode image */
- dgif(pimg, interl, bits);
- m_nimages++;
-
- /* if this is not an animated GIF, exit after first image */
- if (!m_anim)
- done = TRUE;
- }
+ type = stream.GetC();
+
+ /*
+ If the end of file has been reached (or an error) and a ";"
+ (GIF_MARKER_ENDOFDATA) hasn't been encountered yet, exit the loop. (Without this
+ check the while loop would loop endlessly.) Later on, in the next while
+ loop, the file will be treated as being truncated (But still
+ be decoded as far as possible). returning wxGIF_TRUNCATED is not
+ possible here since some init code is done after this loop.
+ */
+ if (stream.Eof())// || !stream.IsOk())
+ {
+ /*
+ type is set to some bogus value, so there's no
+ need to continue evaluating it.
+ */
+ break; // Alternative : "return wxGIF_INVFORMAT;"
+ }
+
+ switch (type)
+ {
+ case GIF_MARKER_ENDOFDATA:
+ done = true;
+ break;
+ case GIF_MARKER_EXT:
+ switch (stream.GetC())
+ {
+ case GIF_MARKER_EXT_GRAPHICS_CONTROL:
+ {
+ // graphics control extension, parse it
+
+ static const unsigned int gceSize = 6;
+ stream.Read(buf, gceSize);
+ if (stream.LastRead() != gceSize)
+ {
+ Destroy();
+ return wxGIF_INVFORMAT;
+ }
+
+ // read delay and convert from 1/100 of a second to ms
+ delay = 10 * (buf[2] + 256 * buf[3]);
+
+ // read transparent colour index, if used
+ transparent = buf[1] & 0x01 ? buf[4] : -1;
+
+ // read disposal method
+ disposal = (wxAnimationDisposal)(((buf[1] & 0x1C) >> 2) - 1);
+ break;
+ }
+ case GIF_MARKER_EXT_COMMENT:
+ {
+ int len = stream.GetC();
+ while (len)
+ {
+ if ( stream.Eof() )
+ {
+ done = true;
+ break;
+ }
+
+ wxCharBuffer charbuf(len);
+ stream.Read(charbuf.data(), len);
+ if ( (int) stream.LastRead() != len )
+ {
+ done = true;
+ break;
+ }
+
+ comment += wxConvertMB2WX(charbuf.data());
+
+ len = stream.GetC();
+ }
+
+ break;
+ }
+ default:
+ // other extension, skip
+ while ((i = stream.GetC()) != 0)
+ {
+ if (stream.Eof() || (stream.LastRead() == 0) ||
+ stream.SeekI(i, wxFromCurrent) == wxInvalidOffset)
+ {
+ done = true;
+ break;
+ }
+ }
+ break;
+ }
+ break;
+ case GIF_MARKER_SEP:
+ {
+ // allocate memory for IMAGEN struct
+ GIFImagePtr pimg(new GIFImage());
+
+ wxScopeGuard guardDestroy = wxMakeObjGuard(*this, &wxGIFDecoder::Destroy);
+
+ if ( !pimg.get() )
+ return wxGIF_MEMERR;
+
+ // fill in the data
+ static const unsigned int idbSize = (2 + 2 + 2 + 2 + 1);
+ stream.Read(buf, idbSize);
+ if (stream.LastRead() != idbSize)
+ return wxGIF_INVFORMAT;
+
+ pimg->comment = comment;
+ comment.clear();
+ pimg->left = buf[0] + 256 * buf[1];
+ pimg->top = buf[2] + 256 * buf[3];
+ /*
+ pimg->left = buf[4] + 256 * buf[5];
+ pimg->top = buf[4] + 256 * buf[5];
+ */
+ pimg->w = buf[4] + 256 * buf[5];
+ pimg->h = buf[6] + 256 * buf[7];
+
+ if ( anim )
+ {
+ // some GIF images specify incorrect animation size but we can
+ // still open them if we fix up the animation size, see #9465
+ if ( m_nFrames == 0 )
+ {
+ if ( pimg->w > (unsigned)m_szAnimation.x )
+ m_szAnimation.x = pimg->w;
+ if ( pimg->h > (unsigned)m_szAnimation.y )
+ m_szAnimation.y = pimg->h;
+ }
+ else // subsequent frames
+ {
+ // check that we have valid size
+ if ( (!pimg->w || pimg->w > (unsigned)m_szAnimation.x) ||
+ (!pimg->h || pimg->h > (unsigned)m_szAnimation.y) )
+ {
+ wxLogError(_("Incorrect GIF frame size (%u, %d) for "
+ "the frame #%u"),
+ pimg->w, pimg->h, m_nFrames);
+ return wxGIF_INVFORMAT;
+ }
+ }
+ }
+
+ interl = ((buf[8] & 0x40)? 1 : 0);
+ size = pimg->w * pimg->h;
+
+ pimg->transparent = transparent;
+ pimg->disposal = disposal;
+ pimg->delay = delay;
+
+ // allocate memory for image and palette
+ pimg->p = (unsigned char *) malloc((unsigned int)size);
+ pimg->pal = (unsigned char *) malloc(768);
+
+ if ((!pimg->p) || (!pimg->pal))
+ return wxGIF_MEMERR;
+
+ // load local color map if available, else use global map
+ if ((buf[8] & 0x80) == 0x80)
+ {
+ unsigned int local_ncolors = 2 << (buf[8] & 0x07);
+ unsigned int numBytes = 3 * local_ncolors;
+ stream.Read(pimg->pal, numBytes);
+ pimg->ncolours = local_ncolors;
+ if (stream.LastRead() != numBytes)
+ return wxGIF_INVFORMAT;
+ }
+ else
+ {
+ memcpy(pimg->pal, pal, 768);
+ pimg->ncolours = global_ncolors;
+ }
+
+ // get initial code size from first byte in raster data
+ bits = stream.GetC();
+ if (bits == 0)
+ return wxGIF_INVFORMAT;
+
+ // decode image
+ wxGIFErrorCode result = dgif(stream, pimg.get(), interl, bits);
+ if (result != wxGIF_OK)
+ return result;
+
+ guardDestroy.Dismiss();
+
+ // add the image to our frame array
+ m_frames.Add(pimg.release());
+ m_nFrames++;
+
+ // if this is not an animated GIF, exit after first image
+ if (!anim)
+ done = true;
+ break;
+ }
+ }
}
- /* setup image pointers */
- if (m_nimages != 0)
+ if (m_nFrames <= 0)
{
- m_image = 1;
- m_plast = pimg;
- m_pimage = m_pfirst;
+ Destroy();
+ return wxGIF_INVFORMAT;
}
- /* try to read to the end of the stream */
- while (type != 0x3B)
+ // try to read to the end of the stream
+ while (type != GIF_MARKER_ENDOFDATA)
{
- type = (unsigned char)m_f->GetC();
-
- if (type == 0x21)
- {
- /* extension type */
- (void) m_f->GetC();
-
- /* skip all data */
- while ((i = (unsigned char)m_f->GetC()) != 0)
- {
- m_f->SeekI(i, wxFromCurrent);
- }
- }
- else if (type == 0x2C)
- {
- /* image descriptor block */
- m_f->Read(buf, 9);
-
- /* local color map */
- if ((buf[8] & 0x80) == 0x80)
- {
- ncolors = 2 << (buf[8] & 0x07);
- m_f->SeekI(3 * ncolors, wxFromCurrent);
- }
-
- /* initial code size */
- (void) m_f->GetC();
-
- /* skip all data */
- while ((i = (unsigned char)m_f->GetC()) != 0)
- {
- m_f->SeekI(i, wxFromCurrent);
- }
- }
- else if ((type != 0x3B) && (type != 00)) /* testing */
- {
- /* images are OK, but couldn't read to the end of the stream */
- return wxGIF_TRUNCATED;
- }
+ if (!stream.IsOk())
+ return wxGIF_TRUNCATED;
+
+ type = stream.GetC();
+
+ switch (type)
+ {
+ case GIF_MARKER_EXT:
+ // extension type
+ (void) stream.GetC();
+
+ // skip all data
+ while ((i = stream.GetC()) != 0)
+ {
+ if (stream.Eof() || (stream.LastRead() == 0) ||
+ stream.SeekI(i, wxFromCurrent) == wxInvalidOffset)
+ {
+ Destroy();
+ return wxGIF_INVFORMAT;
+ }
+ }
+ break;
+ case GIF_MARKER_SEP:
+ {
+ // image descriptor block
+ static const unsigned int idbSize = (2 + 2 + 2 + 2 + 1);
+ stream.Read(buf, idbSize);
+ if (stream.LastRead() != idbSize)
+ {
+ Destroy();
+ return wxGIF_INVFORMAT;
+ }
+
+ // local color map
+ if ((buf[8] & 0x80) == 0x80)
+ {
+ unsigned int local_ncolors = 2 << (buf[8] & 0x07);
+ wxFileOffset numBytes = 3 * local_ncolors;
+ if (stream.SeekI(numBytes, wxFromCurrent) == wxInvalidOffset)
+ {
+ Destroy();
+ return wxGIF_INVFORMAT;
+ }
+ }
+
+ // initial code size
+ (void) stream.GetC();
+ if (stream.Eof() || (stream.LastRead() == 0))
+ {
+ Destroy();
+ return wxGIF_INVFORMAT;
+ }
+
+ // skip all data
+ while ((i = stream.GetC()) != 0)
+ {
+ if (stream.Eof() || (stream.LastRead() == 0) ||
+ stream.SeekI(i, wxFromCurrent) == wxInvalidOffset)
+ {
+ Destroy();
+ return wxGIF_INVFORMAT;
+ }
+ }
+ break;
+ }
+ default:
+ if ((type != GIF_MARKER_ENDOFDATA) && (type != 00)) // testing
+ {
+ // images are OK, but couldn't read to the end of the stream
+ return wxGIF_TRUNCATED;
+ }
+ break;
+ }
}
return wxGIF_OK;
projects / wxWidgets.git / blobdiff