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uniq: optimization: reuse the prevline buffer

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don't strdup for each prevline, try to reuse the allocated buffer and if needed
increase it's size.
This commit is contained in:
Hiltjo Posthuma 2015-03-08 14:41:05 +01:00
parent 603499b674
commit 78187474cf
1 changed files with 23 additions and 18 deletions
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35
uniq.c
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@ -15,11 +15,12 @@ static int sskip = 0;
static char *prevline = NULL; static char *prevline = NULL;
static char *prevoffset = NULL; static char *prevoffset = NULL;
static long prevlinecount = 0; static long prevlinecount = 0;
static size_t prevlinesiz = 0;
static char * static const char *
uniqskip(char *l) uniqskip(const char *l)
{ {
char *lo = l; const char *lo = l;
int f = fskip, s = sskip; int f = fskip, s = sskip;
for (; f; --f) { for (; f; --f) {
@ -33,32 +34,35 @@ uniqskip(char *l)
} }
static void static void
uniqline(FILE *ofp, char *l) uniqline(FILE *ofp, const char *l, size_t len)
{ {
char *loffset = l ? uniqskip(l) : l; const char *loffset = l ? uniqskip(l) : l;
int linesequel = (!l || !prevline) int linesequel = l && prevoffset &&
? l == prevline !strcmp(loffset, prevoffset);
: !strcmp(loffset, prevoffset);
if (linesequel) { if (linesequel) {
++prevlinecount; ++prevlinecount;
return; return;
} }
if (prevline) { if (prevoffset) {
if ((prevlinecount == 1 && !dflag) || if ((prevlinecount == 1 && !dflag) ||
(prevlinecount != 1 && !uflag)) { (prevlinecount != 1 && !uflag)) {
if (*countfmt) if (*countfmt)
fprintf(ofp, countfmt, prevlinecount); fprintf(ofp, countfmt, prevlinecount);
fputs(prevline, ofp); fputs(prevline, ofp);
} }
free(prevline); prevoffset = NULL;
prevline = prevoffset = NULL;
} }
if (l) { if (l) {
prevline = estrdup(l); if (!prevline || len >= prevlinesiz) {
prevlinesiz = len + 1;
prevline = erealloc(prevline, prevlinesiz);
}
memcpy(prevline, l, len);
prevline[len] = '\0';
prevoffset = prevline + (loffset - l); prevoffset = prevline + (loffset - l);
} }
prevlinecount = 1; prevlinecount = 1;
@ -69,15 +73,16 @@ uniq(FILE *fp, FILE *ofp)
{ {
char *buf = NULL; char *buf = NULL;
size_t size = 0; size_t size = 0;
ssize_t len;
while (getline(&buf, &size, fp) != -1) while ((len = getline(&buf, &size, fp)) != -1)
uniqline(ofp, buf); uniqline(ofp, buf, (size_t)len);
} }
static void static void
uniqfinish(FILE *ofp) uniqfinish(FILE *ofp)
{ {
uniqline(ofp, NULL); uniqline(ofp, NULL, 0);
} }
static void static void