From 659f6c14a976759941eba715d5d8ce6699abde23 Mon Sep 17 00:00:00 2001
From: Emmanuel Marty <emmanuel@fgl.com>
Date: Sat, 8 Jun 2019 16:18:36 +0200
Subject: [PATCH] Small improvement over 6502 LZSA2 depacker

---
 asm/6502/decompress_v2.asm | 10 ++++++----
 src/expand_streaming.c     |  5 +++--
 2 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/asm/6502/decompress_v2.asm b/asm/6502/decompress_v2.asm
index 3bd3093..0b94e8b 100755
--- a/asm/6502/decompress_v2.asm
+++ b/asm/6502/decompress_v2.asm
@@ -56,8 +56,9 @@ DECODE_TOKEN
    BNE PREPARE_COPY_LITERALS            ; if less, literals count is complete
 
    JSR GETSRC                           ; get extra byte of variable literals count
-   CLC
-   ADC #$12                             ; overflow?
+                                        ; the carry is always set by the CMP above
+                                        ; GETSRC doesn't change it
+   SBC #$EE                             ; overflow?
    BCC PREPARE_COPY_LITERALS            ; if not, literals count is complete
 
                                         ; handle 16 bits literals count
@@ -155,8 +156,9 @@ REP_MATCH
    BNE PREPARE_COPY_MATCH               ; if less, match length is complete
 
    JSR GETSRC                           ; get extra byte of variable match length
-   CLC
-   ADC #$18                             ; overflow?
+                                        ; the carry is always set by the CMP above
+                                        ; GETSRC doesn't change it
+   SBC #$E8                             ; overflow?
    BCC PREPARE_COPY_MATCH               ; if not, the match length is complete
    BEQ DECOMPRESSION_DONE               ; if EOD code, bail
 
diff --git a/src/expand_streaming.c b/src/expand_streaming.c
index f96755b..215c265 100644
--- a/src/expand_streaming.c
+++ b/src/expand_streaming.c
@@ -185,8 +185,9 @@ lzsa_status_t lzsa_decompress_stream(lzsa_stream_t *pInStream, lzsa_stream_t *pO
          }
          size_t nReadBytes = pInStream->read(pInStream, pInBlock, nBlockSize);
          if (nFlags & LZSA_FLAG_RAW_BLOCK) {
-            if (nReadBytes > 2)
-               nReadBytes -= 2;
+            size_t nEODBytes = (nFormatVersion == 2) ? 2 : 4;
+            if (nReadBytes > nEODBytes)
+               nReadBytes -= nEODBytes;
             else
                nReadBytes = 0;
             nBlockSize = (unsigned int)nReadBytes;