From 6dfb6a30165d258e636f8048edfc5e9001d60f90 Mon Sep 17 00:00:00 2001
From: Alexander Alekhin <alexander.a.alekhin@gmail.com>
Date: Sun, 31 Mar 2019 10:16:49 +0000
Subject: [PATCH] imgcodecs: fix RBaseStream::setPos() outside of current block

Seeking outside of the current block doesn't update actual data,
so getByte()/etc will get wrong data from stalled buffer.
---
 modules/imgcodecs/src/bitstrm.cpp | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/modules/imgcodecs/src/bitstrm.cpp b/modules/imgcodecs/src/bitstrm.cpp
index 2f5b44dfeb..97df645a6d 100644
--- a/modules/imgcodecs/src/bitstrm.cpp
+++ b/modules/imgcodecs/src/bitstrm.cpp
@@ -175,8 +175,11 @@ void  RBaseStream::setPos( int pos )
     }
 
     int offset = pos % m_block_size;
+    int old_block_pos = m_block_pos;
     m_block_pos = pos - offset;
     m_current = m_start + offset;
+    if (old_block_pos != m_block_pos)
+        readBlock();
 }