don't emit empty penultimate metadata block unless needed

ryancdotorg · ryancdotorg · commit 68e6634f5874 · 2020-11-22T16:44:33.000Z
diff --git a/src/enc/encode.rs b/src/enc/encode.rs
@@ -2020,7 +2020,8 @@ fn WriteMetaBlockInternal<Alloc: BrotliAlloc,
                                      false,
                                      cb);
     if actual_is_last != is_last {
-      if params.byte_align {
+      // insert empty block for byte alignment if required
+      if params.byte_align && ((*storage_ix & 7u32 as (usize)) != 0) {
         BrotliStoreSyncMetaBlock(storage_ix, storage);
       }
       BrotliWriteEmptyLastMetaBlock(storage_ix, storage)
@@ -2163,7 +2164,8 @@ fn WriteMetaBlockInternal<Alloc: BrotliAlloc,
                                        cb);
   }
   if actual_is_last != is_last {
-    if params.byte_align {
+    // insert empty block for byte alignment if required
+    if params.byte_align && ((*storage_ix & 7u32 as (usize)) != 0) {
       BrotliStoreSyncMetaBlock(storage_ix, storage);
     }
     BrotliWriteEmptyLastMetaBlock(storage_ix, storage)

Original file line number	Diff line number	Diff line change
`@@ -2020,7 +2020,8 @@ fn WriteMetaBlockInternal<Alloc: BrotliAlloc,`
`2020`	`2020`	`false,`
`2021`	`2021`	`cb);`
`2022`	`2022`	`if actual_is_last != is_last {`
`2023`		`- if params.byte_align {`
	`2023`	`+ // insert empty block for byte alignment if required`
	`2024`	`+ if params.byte_align && ((*storage_ix & 7u32 as (usize)) != 0) {`
`2024`	`2025`	`BrotliStoreSyncMetaBlock(storage_ix, storage);`
`2025`	`2026`	`}`
`2026`	`2027`	`BrotliWriteEmptyLastMetaBlock(storage_ix, storage)`
`@@ -2163,7 +2164,8 @@ fn WriteMetaBlockInternal<Alloc: BrotliAlloc,`
`2163`	`2164`	`cb);`
`2164`	`2165`	`}`
`2165`	`2166`	`if actual_is_last != is_last {`
`2166`		`- if params.byte_align {`
	`2167`	`+ // insert empty block for byte alignment if required`
	`2168`	`+ if params.byte_align && ((*storage_ix & 7u32 as (usize)) != 0) {`
`2167`	`2169`	`BrotliStoreSyncMetaBlock(storage_ix, storage);`
`2168`	`2170`	`}`
`2169`	`2171`	`BrotliWriteEmptyLastMetaBlock(storage_ix, storage)`