J2C stream length estimation back to old

indra/llimage/llimagej2c.cpp

@@ -34,6 +34,7 @@
 #include "apr_dso.h"
 
 #include "lldir.h"
+#include "../llxml/llcontrol.h"
 #include "llimagej2c.h"
 #include "llmemtype.h"
 
@@ -382,6 +383,12 @@ S32 LLImageJ2C::calcHeaderSize()
 // to load discard_level (including header and higher discard levels)
 S32 LLImageJ2C::calcDataSize(S32 discard_level)
 {
+	static const LLCachedControl<bool> legacy_size("SianaLegacyJ2CSize", false);
+	
+	if (legacy_size) {
+		return calcDataSizeJ2C(getWidth(), getHeight(), getComponents(), discard_level, mRate);
+	}
+
 	discard_level = llclamp(discard_level, 0, MAX_DISCARD_LEVEL);
 
 	if ( mAreaUsedForDataSizeCalcs != (getHeight() * getWidth()) 

indra/newview/app_settings/settings.xml

@@ -9,6 +9,18 @@
 		<string>settings_rlv.xml</string>
 	</array>
 
+	<key>SianaLegacyJ2CSize</key>
+	<map>
+		<key>Comment</key>
+		<string>Use older JPEG2000 size estimation method</string>
+		<key>Persist</key>
+		<integer>1</integer>
+		<key>Type</key>
+		<string>Boolean</string>
+		<key>Value</key>
+		<integer>1</integer>
+	</map>
+
     <key>SpellDownloadURL</key>
     <map>
       <key>Comment</key>