2006-09-06 Jeff Muizelaar <jeff@infidigm.net>

	* configure.ac:
	* poppler/FlateStream.cc:
	* poppler/FlateStream.h: Fix FlateStream to not read more than it
	needs. This has a performance impact because our input buffer is now
	only 1 byte large, however correctness is better than performance.
	This should fix #3948.

4 files changed, 37 insertions, 12 deletions

diff --git a/ChangeLog b/ChangeLog
index f643e843..9d4d4d05 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,12 @@
+2006-09-06  Jeff Muizelaar  <jeff@infidigm.net>
+
+	* configure.ac:
+	* poppler/FlateStream.cc:
+	* poppler/FlateStream.h: Fix FlateStream to not read more than it
+	needs. This has a performance impact because our input buffer is now
+	only 1 byte large, however correctness is better than performance.
+	This should fix #3948.
+
 2006-09-04  Jeff Muizelaar  <jeff@infidigm.net>
 
 	* poppler/CairoOutputDev.cc: Initialize currentFont to NULL before
diff --git a/configure.ac b/configure.ac
index c57daeed..de197b70 100644
--- a/configure.ac
+++ b/configure.ac
@@ -82,7 +82,7 @@ fi
 dnl Test for zlib
 AC_ARG_ENABLE(zlib,
 	      AC_HELP_STRING([--disable-zlib],
-	                     [Don't build against zlib. This is the default value as the zlib code is known to fail in some cases.]),
+	                     [Don't build against zlib.]),
               enable_zlib=$enableval,
               enable_zlib="no")
 if test x$enable_zlib = xyes; then
diff --git a/poppler/FlateStream.cc b/poppler/FlateStream.cc
index 67fa6c3c..da17c685 100644
--- a/poppler/FlateStream.cc
+++ b/poppler/FlateStream.cc
@@ -16,6 +16,7 @@ FlateStream::FlateStream(Stream *strA, int predictor, int columns, int colors, i
   }
   out_pos = 0;
   memset(&d_stream, 0, sizeof(d_stream));
+  inflateInit(&d_stream);
 }
 
 FlateStream::~FlateStream() {
@@ -27,9 +28,13 @@ FlateStream::~FlateStream() {
 void FlateStream::reset() {
   //FIXME: what are the semantics of reset?
   //i.e. how much intialization has to happen in the constructor?
-  str->reset();
+
+  /* reinitialize zlib */
+  inflateEnd(&d_stream);
   memset(&d_stream, 0, sizeof(d_stream));
   inflateInit(&d_stream);
+
+  str->reset();
   d_stream.avail_in = 0;
   status = Z_OK;
   out_pos = 0;
@@ -61,25 +66,35 @@ int FlateStream::lookChar() {
 }
 
 int FlateStream::fill_buffer() {
+  /* only fill the buffer if it has all been used */
   if (out_pos >= out_buf_len) {
+    /* check if the flatestream has been exhausted */
     if (status == Z_STREAM_END) {
       return -1;
     }
+
+    /* set to the begining of out_buf */
     d_stream.avail_out = sizeof(out_buf);
     d_stream.next_out = out_buf;
     out_pos = 0;
-    /* buffer is empty so we need to fill it */
-    if (d_stream.avail_in == 0) {
-      int c;
-      /* read from the source stream */
-      while (d_stream.avail_in < sizeof(in_buf) && (c = str->getChar()) != EOF) {
-	in_buf[d_stream.avail_in++] = c;
+
+    while (1) {
+      /* buffer is empty so we need to fill it */
+      if (d_stream.avail_in == 0) {
+	int c;
+	/* read from the source stream */
+	while (d_stream.avail_in < sizeof(in_buf) && (c = str->getChar()) != EOF) {
+	  in_buf[d_stream.avail_in++] = c;
+	}
+	d_stream.next_in = in_buf;
       }
-      d_stream.next_in = in_buf;
-    }
-    while (d_stream.avail_out && d_stream.avail_in && (status == Z_OK || status == Z_BUF_ERROR)) {
+
+      /* keep decompressing until we can't anymore */
+      if (d_stream.avail_out == 0 || d_stream.avail_in == 0 || (status != Z_OK && status != Z_BUF_ERROR))
+	break;
       status = inflate(&d_stream, Z_SYNC_FLUSH);
     }
+
     out_buf_len = sizeof(out_buf) - d_stream.avail_out;
     if (status != Z_OK && status != Z_STREAM_END)
       return -1;
diff --git a/poppler/FlateStream.h b/poppler/FlateStream.h
index 82021341..812c6292 100644
--- a/poppler/FlateStream.h
+++ b/poppler/FlateStream.h
@@ -57,7 +57,8 @@ private:
   z_stream d_stream;
   StreamPredictor *pred;
   int status;
-  unsigned char in_buf[4096];
+  /* in_buf currently needs to be 1 or we over read from EmbedStreams */
+  unsigned char in_buf[1];
   unsigned char out_buf[4096];
   int out_pos;
   int out_buf_len;