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

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function                                             old     new   delta
flush_block                                          665     671      +6

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2018-01-31 17:19:59 +01:00
parent ba63d70e2d
commit f21ebeece5
1 changed files with 20 additions and 15 deletions
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35
archival/gzip.c
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@ -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) #define OPTIMIZED_PUT_32BIT (CONFIG_GZIP_FAST > 0 && BB_UNALIGNED_MEMACCESS_OK && BB_LITTLE_ENDIAN)
static void put_32bit(ulg n) static void put_32bit(ulg n)
{ {
#if OPTIMIZED_PUT_32BIT if (OPTIMIZED_PUT_32BIT) {
unsigned outcnt = G1.outcnt; unsigned outcnt = G1.outcnt;
if (outcnt < OUTBUFSIZ-4) { if (outcnt < OUTBUFSIZ-4) {
/* Common case */ /* Common case */
ulg *dst32 = (void*) &G1.outbuf[outcnt]; ulg *dst32 = (void*) &G1.outbuf[outcnt];
*dst32 = n; /* unaligned LSB 32-bit store */ *dst32 = n; /* unaligned LSB 32-bit store */
G1.outcnt = outcnt + 4; //bb_error_msg("%p", dst32); // store alignment debugging
return; G1.outcnt = outcnt + 4;
return;
}
} }
#endif
put_16bit(n); put_16bit(n);
put_16bit(n >> 16); 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 * 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--) { while (len--) {
put_8bit(*buf++); 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) */ put_16bit(deflate_flags | 0x300); /* extra flags. OS id = 3 (Unix) */
#if OPTIMIZED_PUT_32BIT /* The above 32-bit misaligns outbuf (10 bytes are stored), flush it */
/* put_32bit() performs 32bit stores. If we use it in send_bits()... */ flush_outbuf_if_32bit_optimized();
if (BUF_SIZE > 16)
/* then all stores are misaligned, unless we flush the buffer now */
flush_outbuf();
#endif
deflate(); deflate();