From 721c25d85b39a7b013a182cb0f60e159bfc28807 Mon Sep 17 00:00:00 2001
From: thickbrick
Date: Tue, 21 Sep 2010 23:55:50 +0200
Subject: More sanity checks in OpenJPEG decodes for #355 Patch by Carjay
 McGinnis from VWR-1815. This fixes decoding lossless and small textures where
 the viewer's assumption about compressed size breaks (i.e. discard level only
 half there), and also encoding small lossy textures.

This relys on a patched OpenJPEG to work
(see openjpeg_top_corner_fix.diff from VWR-1815.)
---
 linden/indra/llimagej2coj/llimagej2coj.cpp | 45 +++++++++++++++++++++++-------
 1 file changed, 35 insertions(+), 10 deletions(-)

(limited to 'linden')

diff --git a/linden/indra/llimagej2coj/llimagej2coj.cpp b/linden/indra/llimagej2coj/llimagej2coj.cpp
index b7a1b82..829dceb 100644
--- a/linden/indra/llimagej2coj/llimagej2coj.cpp
+++ b/linden/indra/llimagej2coj/llimagej2coj.cpp
@@ -152,8 +152,13 @@ BOOL LLImageJ2COJ::decodeImpl(LLImageJ2C &base, LLImageRaw &raw_image, F32 decod
 	/* open a byte stream */
 	cio = opj_cio_open((opj_common_ptr)dinfo, base.getData(), base.getDataSize());
 
-	/* decode the stream and fill the image structure */
-	image = opj_decode(dinfo, cio);
+	/* decode the stream and fill the image structure, also fill in an additional
+	   structure to get the decoding result. This structure is a bit unusual in that
+	   it is not received through opj, but still has some dynamically allocated fields
+	   that need to be cleared up at the end by calling a destroy function. */
+	opj_codestream_info_t cinfo;
+	memset(&cinfo, 0, sizeof(opj_codestream_info_t));
+	image = opj_decode_with_info(dinfo, cio, &cinfo);
 
 	/* close the byte stream */
 	opj_cio_close(cio);
@@ -180,6 +185,7 @@ BOOL LLImageJ2COJ::decodeImpl(LLImageJ2C &base, LLImageRaw &raw_image, F32 decod
 		LL_DEBUGS("Openjpeg") << "ERROR -> decodeImpl: failed to decode image wrong number of components: " << img_components << LL_ENDL;
 		if (image)
 		{
+			opj_destroy_cstr_info(&cinfo);
 			opj_image_destroy(image);
 		}
 
@@ -187,23 +193,40 @@ BOOL LLImageJ2COJ::decodeImpl(LLImageJ2C &base, LLImageRaw &raw_image, F32 decod
 	}
 
 	// sometimes we get bad data out of the cache - check to see if the decode succeeded
-	for (S32 i = 0; i < img_components; i++)
+	int decompdifference = 0;
+	if (cinfo.numdecompos) // sanity
 	{
-		if (image->comps[i].factor != base.getRawDiscardLevel())
+		for (int comp = 0; comp < image->numcomps; comp++)
+		{	/* get maximum decomposition level difference, first field is from the COD header and the second
+			   is what is actually met in the codestream, NB: if everything was ok, this calculation will
+			   return what was set in the cp_reduce value! */
+			decompdifference = std::max(decompdifference, cinfo.numdecompos[comp] - image->comps[comp].resno_decoded);
+		}
+		if (decompdifference < 0) // sanity
 		{
-			// if we didn't get the discard level we're expecting, fail
-			if (image) //anyway somthing odd with the image, better check than crash
-				opj_image_destroy(image);
-			base.mDecoding = FALSE;
-			return TRUE;
+			decompdifference = 0;
 		}
 	}
 	
+
+	/* if OpenJPEG failed to decode all requested decomposition levels
+	   the difference will be greater than this level */
+	if (decompdifference > base.getRawDiscardLevel())
+	{
+		llwarns << "not enough data for requested discard level, setting mDecoding to FALSE, difference: " << (decompdifference - base.getRawDiscardLevel()) << llendl;
+		opj_destroy_cstr_info(&cinfo);
+		opj_image_destroy(image);
+		base.mDecoding = FALSE;
+		return TRUE;
+	}
+
 	if(img_components <= first_channel)
 	{
+		// sanity
 		LL_DEBUGS("Openjpeg") << "trying to decode more channels than are present in image: numcomps: " << img_components << " first_channel: " << first_channel << LL_ENDL;
 		if (image)
 		{
+			opj_destroy_cstr_info(&cinfo);
 			opj_image_destroy(image);
 		}
 			
@@ -252,15 +275,17 @@ BOOL LLImageJ2COJ::decodeImpl(LLImageJ2C &base, LLImageRaw &raw_image, F32 decod
 		else // Some rare OpenJPEG versions have this bug.
 		{
 			llwarns << "ERROR -> decodeImpl: failed to decode image! (NULL comp data - OpenJPEG bug)" << llendl;
+			opj_destroy_cstr_info(&cinfo);
 			opj_image_destroy(image);
 
 			return TRUE; // done
 		}
 	}
 
-	/* free image data structure */
+	/* free opj data structures */
 	if (image)
 	{
+		opj_destroy_cstr_info(&cinfo);
 		opj_image_destroy(image);
 	}
 
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