gzip: flush output buffer after stored blocks, they are not 32-bit aligned

function                                             old     new   delta
flush_block                                          665     671      +6

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 20 insertions, 15 deletions

diff --git a/archival/gzip.c b/archival/gzip.c
index 6083cde88..7df38c2bc 100644
--- a/archival/gzip.c
+++ b/archival/gzip.c
@@ -486,19 +486,26 @@ static void put_16bit(ush w)
 #define OPTIMIZED_PUT_32BIT (CONFIG_GZIP_FAST > 0 && BB_UNALIGNED_MEMACCESS_OK && BB_LITTLE_ENDIAN)
 static void put_32bit(ulg n)
 {
-#if OPTIMIZED_PUT_32BIT
-        unsigned outcnt = G1.outcnt;
-        if (outcnt < OUTBUFSIZ-4) {
-                /* Common case */
-                ulg *dst32 = (void*) &G1.outbuf[outcnt];
-                *dst32 = n; /* unaligned LSB 32-bit store */
-                G1.outcnt = outcnt + 4;
-                return;
+        if (OPTIMIZED_PUT_32BIT) {
+                unsigned outcnt = G1.outcnt;
+                if (outcnt < OUTBUFSIZ-4) {
+                        /* Common case */
+                        ulg *dst32 = (void*) &G1.outbuf[outcnt];
+                        *dst32 = n; /* unaligned LSB 32-bit store */
+                        //bb_error_msg("%p", dst32); // store alignment debugging
+                        G1.outcnt = outcnt + 4;
+                        return;
+                }
         }
-#endif
         put_16bit(n);
         put_16bit(n >> 16);
 }
+static ALWAYS_INLINE void flush_outbuf_if_32bit_optimized(void)
+{
+        /* If put_32bit() performs 32bit stores && it is used in send_bits() */
+        if (OPTIMIZED_PUT_32BIT && BUF_SIZE > 16)
+                flush_outbuf();
+}
 
 /* ===========================================================================
  * Run a set of bytes through the crc shift register.  If s is a NULL
@@ -626,6 +633,8 @@ static void copy_block(char *buf, unsigned len, int header)
         while (len--) {
                 put_8bit(*buf++);
         }
+        /* The above can 32-bit misalign outbuf */
+        flush_outbuf_if_32bit_optimized();
 }
 
 
@@ -2110,12 +2119,8 @@ static void zip(void)
 
         put_16bit(deflate_flags | 0x300); /* extra flags. OS id = 3 (Unix) */
 
-#if OPTIMIZED_PUT_32BIT
-        /* put_32bit() performs 32bit stores. If we use it in send_bits()... */
-        if (BUF_SIZE > 16)
-                /* then all stores are misaligned, unless we flush the buffer now */
-                flush_outbuf();
-#endif
+        /* The above 32-bit misaligns outbuf (10 bytes are stored), flush it */
+        flush_outbuf_if_32bit_optimized();
 
         deflate();