Factor out std/bzip2/decode_flush_slow.wuffs
diff --git a/std/bzip2/decode_bzip2.wuffs b/std/bzip2/decode_bzip2.wuffs
index 177f281..64350c6 100644
--- a/std/bzip2/decode_bzip2.wuffs
+++ b/std/bzip2/decode_bzip2.wuffs
@@ -698,69 +698,6 @@
} endwhile
}
-pri func decoder.flush_block?(dst: base.io_writer) {
- var i : base.u32[..= 1_048575]
- var n : base.u32
- var entry : base.u32
- var repeat_count : base.u32[..= 255]
- var block_checksum_have : base.u32
- var prev : base.u8
- var curr : base.u8
-
- if this.original_pointer >= this.block_size {
- return "#bad block length"
- }
- assert this.original_pointer < 900000 via "a < b: a < c; c <= b"(c: this.block_size)
- i = this.bwt[this.original_pointer] >> 12
-
- block_checksum_have = 0xFFFF_FFFF
-
- n = 0
- while n < this.block_size {
- assert n < 900000 via "a < b: a < c; c <= b"(c: this.block_size)
- entry = this.bwt[i]
- curr = (entry & 0xFF) as base.u8
- i = entry >> 12
-
- if repeat_count >= 4 {
- repeat_count = curr as base.u32
- while repeat_count > 0,
- inv n < 900000,
- {
- block_checksum_have =
- REV_CRC32_TABLE[((block_checksum_have >> 24) as base.u8) ^ prev] ^
- (block_checksum_have ~mod<< 8)
- args.dst.write_u8?(a: prev)
- repeat_count -= 1
- } endwhile
- repeat_count = 0
- } else if curr <> prev {
- repeat_count = 1
- block_checksum_have =
- REV_CRC32_TABLE[((block_checksum_have >> 24) as base.u8) ^ curr] ^
- (block_checksum_have ~mod<< 8)
- args.dst.write_u8?(a: curr)
- } else {
- repeat_count += 1
- block_checksum_have =
- REV_CRC32_TABLE[((block_checksum_have >> 24) as base.u8) ^ curr] ^
- (block_checksum_have ~mod<< 8)
- args.dst.write_u8?(a: curr)
- }
-
- prev = curr
- n += 1
- } endwhile
-
- block_checksum_have ^= 0xFFFF_FFFF
- if block_checksum_have <> this.block_checksum_want {
- return "#bad checksum"
- }
- this.final_checksum_have = block_checksum_have ^ (
- (this.final_checksum_have >> 31) |
- (this.final_checksum_have ~mod<< 1))
-}
-
// The table below was created by script/print-crc32-magic-numbers.go with the
// -reverse flag set.
diff --git a/std/bzip2/decode_flush_slow.wuffs b/std/bzip2/decode_flush_slow.wuffs
new file mode 100644
index 0000000..33b21d2
--- /dev/null
+++ b/std/bzip2/decode_flush_slow.wuffs
@@ -0,0 +1,76 @@
+// Copyright 2022 The Wuffs Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+pri func decoder.flush_block?(dst: base.io_writer) {
+ var i : base.u32[..= 1_048575]
+ var n : base.u32
+ var entry : base.u32
+ var repeat_count : base.u32[..= 255]
+ var block_checksum_have : base.u32
+ var prev : base.u8
+ var curr : base.u8
+
+ if this.original_pointer >= this.block_size {
+ return "#bad block length"
+ }
+ assert this.original_pointer < 900000 via "a < b: a < c; c <= b"(c: this.block_size)
+ i = this.bwt[this.original_pointer] >> 12
+
+ block_checksum_have = 0xFFFF_FFFF
+
+ n = 0
+ while n < this.block_size {
+ assert n < 900000 via "a < b: a < c; c <= b"(c: this.block_size)
+ entry = this.bwt[i]
+ curr = (entry & 0xFF) as base.u8
+ i = entry >> 12
+
+ if repeat_count >= 4 {
+ repeat_count = curr as base.u32
+ while repeat_count > 0,
+ inv n < 900000,
+ {
+ block_checksum_have =
+ REV_CRC32_TABLE[((block_checksum_have >> 24) as base.u8) ^ prev] ^
+ (block_checksum_have ~mod<< 8)
+ args.dst.write_u8?(a: prev)
+ repeat_count -= 1
+ } endwhile
+ repeat_count = 0
+ } else if curr <> prev {
+ repeat_count = 1
+ block_checksum_have =
+ REV_CRC32_TABLE[((block_checksum_have >> 24) as base.u8) ^ curr] ^
+ (block_checksum_have ~mod<< 8)
+ args.dst.write_u8?(a: curr)
+ } else {
+ repeat_count += 1
+ block_checksum_have =
+ REV_CRC32_TABLE[((block_checksum_have >> 24) as base.u8) ^ curr] ^
+ (block_checksum_have ~mod<< 8)
+ args.dst.write_u8?(a: curr)
+ }
+
+ prev = curr
+ n += 1
+ } endwhile
+
+ block_checksum_have ^= 0xFFFF_FFFF
+ if block_checksum_have <> this.block_checksum_want {
+ return "#bad checksum"
+ }
+ this.final_checksum_have = block_checksum_have ^ (
+ (this.final_checksum_have >> 31) |
+ (this.final_checksum_have ~mod<< 1))
+}
