Author: sobomax
Date: Mon Dec 17 15:19:48 2018
New Revision: 342167
URL: https://svnweb.freebsd.org/changeset/base/342167
Log:
MFC r341257: improve speed of empty block detection.
Modified:
stable/11/bin/dd/dd.c
stable/11/bin/dd/dd.h
Directory Properties:
stable/11/ (props changed)
Modified: stable/11/bin/dd/dd.c
==============================================================================
--- stable/11/bin/dd/dd.c Mon Dec 17 15:17:09 2018 (r342166)
+++ stable/11/bin/dd/dd.c Mon Dec 17 15:19:48 2018 (r342167)
@@ -474,7 +474,7 @@ void
dd_out(int force)
{
u_char *outp;
- size_t cnt, i, n;
+ size_t cnt, n;
ssize_t nw;
static int warned;
int sparse;
@@ -507,12 +507,8 @@ dd_out(int force)
do {
sparse = 0;
if (ddflags & C_SPARSE) {
- sparse = 1; /* Is buffer sparse? */
- for (i = 0; i < cnt; i++)
- if (outp[i] != 0) {
- sparse = 0;
- break;
- }
+ /* Is buffer sparse? */
+ sparse = BISZERO(outp, cnt);
}
if (sparse && !force) {
pending += cnt;
Modified: stable/11/bin/dd/dd.h
==============================================================================
--- stable/11/bin/dd/dd.h Mon Dec 17 15:17:09 2018 (r342166)
+++ stable/11/bin/dd/dd.h Mon Dec 17 15:19:48 2018 (r342167)
@@ -102,3 +102,7 @@ typedef struct {
#define C_PROGRESS 0x40000000
#define C_PARITY (C_PAREVEN | C_PARODD | C_PARNONE | C_PARSET)
+
+#define BISZERO(p, s) ((s) > 0 && *((const char *)p) == 0 && !memcmp(
\
+ (const void *)(p), (const void *) \
+ ((const char *)p + 1), (s) - 1))
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