Attachment 133545 Details for Bug 25625 – extract inline images v2

[patch] extract inline images v2

0001-pdfimages-support-listing-extracting-inline-images.patch (text/plain), 10.56 KB, created by Adrian Johnson on 2017-08-16 11:33:41 UTC

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Creator: Adrian Johnson

Created: 2017-08-16 11:33:41 UTC

Size: 10.56 KB

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obsolete

>From 0e0804cf6ca707189282b3dbe0753f631c556d8b Mon Sep 17 00:00:00 2001
>From: Adrian Johnson <ajohnson@redneon.com>
>Date: Wed, 16 Aug 2017 21:01:07 +0930
>Subject: [PATCH] pdfimages: support listing/extracting inline images
>
>The difficulty with extracting inline images is that inline images do
>not provide any way of determining the length or end of image data
>without decoding the image. We can get the length by using ImageStream
>to decode the data then check the stream position. But then we are
>still unable to extract the undecoded image data because embedded
>streams can only be read once.
>
>Since inline images tend to be small the solution implemented is to
>modify EmbedStream to keep a copy of the data read from it in memory
>and then allow the data to be read again.
>
>Two new functions have been added to EmbedStream. rewind() will cause
>EmbedStream.getChar() to stop recording data and switch to replaying
>the saved data, returning EOF when the end of the saved data is
>reached. The restore() function will make getChar() switch back to
>reading from the parent stream.
>
>ImageOutputDev can now extract or get the image size by first using
>ImageStream to read data from the embedded stream. After calling
>rewind() the undecoded image data can be read from the embedded stream
>until EOF is returned. Then restore() is called so that Gfx can read
>the 'EI' from the end of the embedded stream.
>---
> poppler/Gfx.cc          |  2 +-
> poppler/Stream.cc       | 96 +++++++++++++++++++++++++++++++++++++++++++------
> poppler/Stream.h        | 14 ++++++--
> utils/ImageOutputDev.cc | 67 ++++++++++++++++++++++++++++++----
> utils/ImageOutputDev.h  |  1 +
> 5 files changed, 159 insertions(+), 21 deletions(-)
>
>diff --git a/poppler/Gfx.cc b/poppler/Gfx.cc
>index be9810e1..2bfc1ecd 100644
>--- a/poppler/Gfx.cc
>+++ b/poppler/Gfx.cc
>@@ -4901,7 +4901,7 @@ Stream *Gfx::buildImageStream() {
> 
>   // make stream
>   if (parser->getStream()) {
>-    str = new EmbedStream(parser->getStream(), std::move(dict), gFalse, 0);
>+    str = new EmbedStream(parser->getStream(), std::move(dict), gFalse, 0, gTrue);
>     str = str->addFilters(str->getDict());
>   } else {
>     str = NULL;
>diff --git a/poppler/Stream.cc b/poppler/Stream.cc
>index df767652..9cb48abc 100644
>--- a/poppler/Stream.cc
>+++ b/poppler/Stream.cc
>@@ -1033,14 +1033,25 @@ void MemStream::moveStart(Goffset delta) {
> //------------------------------------------------------------------------
> 
> EmbedStream::EmbedStream(Stream *strA, Object &&dictA,
>-			 GBool limitedA, Goffset lengthA):
>+			 GBool limitedA, Goffset lengthA, GBool reusableA):
>     BaseStream(std::move(dictA), lengthA) {
>   str = strA;
>   limited = limitedA;
>   length = lengthA;
>+  reusable = reusableA;
>+  record = gFalse;
>+  replay = gFalse;
>+  if (reusable) {
>+    bufData = (unsigned char*)gmalloc(16384);
>+    bufMax = 16384;
>+    bufLen = 0;
>+    record = gTrue;
>+  }
> }
> 
> EmbedStream::~EmbedStream() {
>+  if (reusable)
>+    gfree(bufData);
> }
> 
> BaseStream *EmbedStream::copy() {
>@@ -1054,31 +1065,94 @@ Stream *EmbedStream::makeSubStream(Goffset start, GBool limitedA,
>   return NULL;
> }
> 
>+void EmbedStream::rewind() {
>+  record = gFalse;
>+  replay = gTrue;
>+  bufPos = 0;
>+}
>+
>+void EmbedStream::restore() {
>+  replay = gFalse;
>+}
>+
>+Goffset EmbedStream::getPos() {
>+  if (replay)
>+    return bufPos;
>+  else
>+    return str->getPos();
>+}
>+
> int EmbedStream::getChar() {
>-  if (limited && !length) {
>-    return EOF;
>+  if (replay) {
>+    if (bufPos < bufLen)
>+      return bufData[bufPos++];
>+    else
>+      return EOF;
>+  } else {
>+    if (limited && !length) {
>+      return EOF;
>+    }
>+    int c = str->getChar();
>+    --length;
>+    if (record) {
>+      bufData[bufLen] = c;
>+      bufLen++;
>+      if (bufLen >= bufMax) {
>+        bufMax *= 2;
>+        bufData = (unsigned char *)grealloc(bufData, bufMax);
>+      }
>+    }
>+    return c;
>   }
>-  --length;
>-  return str->getChar();
> }
> 
> int EmbedStream::lookChar() {
>-  if (limited && !length) {
>-    return EOF;
>+  if (replay) {
>+    if (bufPos < bufLen)
>+      return bufData[bufPos];
>+    else
>+      return EOF;
>+  } else {
>+    if (limited && !length) {
>+      return EOF;
>+    }
>+    return str->lookChar();
>   }
>-  return str->lookChar();
> }
> 
> int EmbedStream::getChars(int nChars, Guchar *buffer) {
>+  int len;
>+
>   if (nChars <= 0) {
>     return 0;
>   }
>-  if (limited && length < nChars) {
>-    nChars = length;
>+  if (replay) {
>+    if (bufPos >= bufLen)
>+      return EOF;
>+    len = bufLen - bufPos;
>+    if (nChars > len)
>+      nChars = len;
>+    memcpy(buffer, bufData, len);
>+    return len;
>+  } else {
>+    if (limited && length < nChars) {
>+      nChars = length;
>+    }
>+    len = str->doGetChars(nChars, buffer);
>+    if (record) {
>+      if (bufLen + len >= bufMax) {
>+        while (bufLen + len >= bufMax)
>+          bufMax *= 2;
>+        bufData = (unsigned char *)grealloc(bufData, bufMax);
>+      }
>+      memcpy(bufData+bufLen, buffer, len);
>+      bufLen += len;
>+    }
>   }
>-  return str->doGetChars(nChars, buffer);
>+  return len;
> }
> 
>+
> void EmbedStream::setPos(Goffset pos, int dir) {
>   error(errInternal, -1, "Internal: called setPos() on EmbedStream");
> }
>diff --git a/poppler/Stream.h b/poppler/Stream.h
>index 2317080e..7e67697c 100644
>--- a/poppler/Stream.h
>+++ b/poppler/Stream.h
>@@ -607,7 +607,7 @@ private:
> class EmbedStream: public BaseStream {
> public:
> 
>-  EmbedStream(Stream *strA, Object &&dictA, GBool limitedA, Goffset lengthA);
>+  EmbedStream(Stream *strA, Object &&dictA, GBool limitedA, Goffset lengthA, GBool reusableA = gFalse);
>   ~EmbedStream();
>   BaseStream *copy() override;
>   Stream *makeSubStream(Goffset start, GBool limitedA,
>@@ -616,7 +616,7 @@ public:
>   void reset() override {}
>   int getChar() override;
>   int lookChar() override;
>-  Goffset getPos() override { return str->getPos(); }
>+  Goffset getPos() override;
>   void setPos(Goffset pos, int dir = 0) override;
>   Goffset getStart() override;
>   void moveStart(Goffset delta) override;
>@@ -624,6 +624,8 @@ public:
>   int getUnfilteredChar () override { return str->getUnfilteredChar(); }
>   void unfilteredReset () override { str->unfilteredReset(); }
> 
>+  void rewind();
>+  void restore();
> 
> private:
> 
>@@ -632,6 +634,14 @@ private:
> 
>   Stream *str;
>   GBool limited;
>+  GBool reusable;
>+  GBool record;
>+  GBool replay;
>+  unsigned char *bufData;
>+  long bufMax;
>+  long bufLen;
>+  long bufPos;
>+
> };
> 
> //------------------------------------------------------------------------
>diff --git a/utils/ImageOutputDev.cc b/utils/ImageOutputDev.cc
>index f6fb35dd..33cbb714 100644
>--- a/utils/ImageOutputDev.cc
>+++ b/utils/ImageOutputDev.cc
>@@ -246,7 +246,9 @@ void ImageOutputDev::listImage(GfxState *state, Object *ref, Stream *str,
>     printf("%5.0f ", yppi);
> 
>   Goffset embedSize = -1;
>-  if (!inlineImg)
>+  if (inlineImg)
>+    embedSize = getInlineImageLength(str, width, height, colorMap);
>+  else
>     embedSize = str->getBaseStream()->getLength();
> 
>   long long imageSize = 0;
>@@ -311,6 +313,43 @@ void ImageOutputDev::listImage(GfxState *state, Object *ref, Stream *str,
>   }
> }
> 
>+long ImageOutputDev::getInlineImageLength(Stream *str, int width, int height,
>+                                          GfxImageColorMap *colorMap) {
>+  long len;
>+
>+  if (colorMap) {
>+    ImageStream *imgStr = new ImageStream(str, width, colorMap->getNumPixelComps(),
>+                                          colorMap->getBits());
>+    imgStr->reset();
>+    for (int y = 0; y < height; y++)
>+      imgStr->getLine();
>+
>+    imgStr->close();
>+    delete imgStr;
>+  } else {
>+    str->reset();
>+    for (int y = 0; y < height; y++) {
>+      int size = (width + 7)/8;
>+      for (int x = 0; x < size; x++)
>+        str->getChar();
>+    }
>+  }
>+
>+  EmbedStream *embedStr = (EmbedStream *) (str->getBaseStream());
>+  embedStr->rewind();
>+  if (str->getKind() == strDCT || str->getKind() == strCCITTFax)
>+    str = str->getNextStream();
>+  len = 0;
>+  str->reset();
>+  while (str->getChar() != EOF)
>+    len++;
>+
>+  embedStr->restore();
>+
>+
>+  return len;
>+}
>+
> void ImageOutputDev::writeRawImage(Stream *str, const char *ext) {
>   FILE *f;
>   int c;
>@@ -498,15 +537,21 @@ void ImageOutputDev::writeImage(GfxState *state, Object *ref, Stream *str,
> 				int width, int height,
> 				GfxImageColorMap *colorMap, GBool inlineImg) {
>   ImageFormat format;
>+  EmbedStream *embedStr;
> 
>-  if (dumpJPEG && str->getKind() == strDCT &&
>-      (colorMap->getNumPixelComps() == 1 ||
>-       colorMap->getNumPixelComps() == 3) &&
>-      !inlineImg) {
>+  if (dumpJPEG && str->getKind() == strDCT) {
>+    if (inlineImg) {
>+      embedStr = (EmbedStream *) (str->getBaseStream());
>+      getInlineImageLength(str, width, height, colorMap); // record the strean
>+      embedStr->rewind();
>+    }
> 
>     // dump JPEG file
>     writeRawImage(str, "jpg");
> 
>+    if (inlineImg)
>+      embedStr->restore();
>+
>   } else if (dumpJP2 && str->getKind() == strJPX && !inlineImg) {
>     // dump JPEG2000 file
>     writeRawImage(str, "jp2");
>@@ -535,7 +580,7 @@ void ImageOutputDev::writeImage(GfxState *state, Object *ref, Stream *str,
>     // dump JBIG2 embedded file
>     writeRawImage(str, "jb2e");
> 
>-  } else if (dumpCCITT && str->getKind() == strCCITTFax && !inlineImg) {
>+  } else if (dumpCCITT && str->getKind() == strCCITTFax) {
>     // write CCITT parameters
>     CCITTFaxStream *ccittStr = static_cast<CCITTFaxStream *>(str);
>     FILE *f;
>@@ -567,14 +612,22 @@ void ImageOutputDev::writeImage(GfxState *state, Object *ref, Stream *str,
> 
>     fclose(f);
> 
>+    if (inlineImg) {
>+      embedStr = (EmbedStream *) (str->getBaseStream());
>+      getInlineImageLength(str, width, height, colorMap); // record the strean
>+      embedStr->rewind();
>+    }
>+
>     // dump CCITT file
>     writeRawImage(str, "ccitt");
> 
>+    if (inlineImg)
>+      embedStr->restore();
>+
>   } else if (outputPNG && !(outputTiff && colorMap &&
>                             (colorMap->getColorSpace()->getMode() == csDeviceCMYK ||
>                              (colorMap->getColorSpace()->getMode() == csICCBased &&
>                               colorMap->getNumPixelComps() == 4)))) {
>-
>     // output in PNG format
> 
> #if ENABLE_LIBPNG
>diff --git a/utils/ImageOutputDev.h b/utils/ImageOutputDev.h
>index 22954cf0..baccd8ef 100644
>--- a/utils/ImageOutputDev.h
>+++ b/utils/ImageOutputDev.h
>@@ -160,6 +160,7 @@ private:
>   void writeRawImage(Stream *str, const char *ext);
>   void writeImageFile(ImgWriter *writer, ImageFormat format, const char *ext,
>                       Stream *str, int width, int height, GfxImageColorMap *colorMap);
>+  long getInlineImageLength(Stream *str, int width, int height, GfxImageColorMap *colorMap);
> 
>   char *fileRoot;		// root of output file names
>   char *fileName;		// buffer for output file names
>-- 
>2.11.0
>

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Attachments on bug 25625: 32076 | 84828 | 133545

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