From 59bcaeac168dd56bbc9dbe8e987603c1852ce198 Mon Sep 17 00:00:00 2001
From: jrobinso <933148+jrobinso@users.noreply.github.com>
Date: Tue, 10 Jan 2023 22:56:56 -0800
Subject: [PATCH] Fix block cache for small bam edge case

---
 js/bam/bgzBlockLoader.js | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/js/bam/bgzBlockLoader.js b/js/bam/bgzBlockLoader.js
index 85838efb4..9deac70d6 100644
--- a/js/bam/bgzBlockLoader.js
+++ b/js/bam/bgzBlockLoader.js
@@ -69,8 +69,10 @@ class BGZBlockLoader {
         } else {
 
             const c = this.cache
-            if (c && (c.startBlock <= startBlock && c.endBlock >= endBlock)) {
-                //console.log("Complete overlap")
+            if (c &&
+                c.startBlock <= startBlock &&
+                (c.endBlock >= endBlock || skipEnd && c.nextEndBlock === endBlock)) {
+                console.log("Complete overlap")
                 const startOffset = startBlock - c.startBlock
                 const endOffset = endBlock - c.startBlock
                 return inflateBlocks(c.buffer, startOffset, endOffset)
@@ -127,12 +129,13 @@ class BGZBlockLoader {
                 }
 
                 // If skipEnd === true we need to find boundary of last block in cache
+                let nextEndBlock = endBlock
                 if(skipEnd) {
                     const boundaries = findBlockBoundaries(buffer)
                     endBlock = boundaries[boundaries.length - 1]
                 }
 
-                this.cache = {startBlock, endBlock, buffer}
+                this.cache = {startBlock, endBlock, nextEndBlock, buffer}
                 return inflateBlocks(buffer)
             }
         }