[git commit master] awk: don't append bogus data after NUL in sub(); shrink
Denys Vlasenko
vda.linux at googlemail.com
Sat Apr 3 23:17:30 UTC 2010
commit: http://git.busybox.net/busybox/commit/?id=fab288cf0b31ff64a562cc496b20add822a6abbd
branch: http://git.busybox.net/busybox/commit/?id=refs/heads/master
also renamed variables to more sensible names
function old new delta
mk_re_node 56 49 -7
awk_sub 601 591 -10
Signed-off-by: Denys Vlasenko <vda.linux at googlemail.com>
---
editors/awk.c | 120 +++++++++++++++++++++++++++++++++------------------------
1 files changed, 69 insertions(+), 51 deletions(-)
diff --git a/editors/awk.c b/editors/awk.c
index 30c6b88..3ba1a42 100644
--- a/editors/awk.c
+++ b/editors/awk.c
@@ -1134,15 +1134,13 @@ static node *new_node(uint32_t info)
return n;
}
-static node *mk_re_node(const char *s, node *n, regex_t *re)
+static void mk_re_node(const char *s, node *n, regex_t *re)
{
n->info = OC_REGEXP;
n->l.re = re;
n->r.ire = re + 1;
xregcomp(re, s, REG_EXTENDED);
xregcomp(re + 1, s, REG_EXTENDED | REG_ICASE);
-
- return n;
}
static node *condition(void)
@@ -1541,7 +1539,10 @@ static regex_t *as_regex(node *op, regex_t *preg)
return preg;
}
-/* gradually increasing buffer */
+/* gradually increasing buffer.
+ * note that we reallocate even if n == old_size,
+ * and thus there is at least one extra allocated byte.
+ */
static char* qrealloc(char *b, int n, int *size)
{
if (!b || n >= *size) {
@@ -1983,83 +1984,100 @@ static char *awk_printf(node *n)
return b;
}
-/* common substitution routine
- * replace (nm) substring of (src) that match (n) with (repl), store
- * result into (dest), return number of substitutions. If nm=0, replace
- * all matches. If src or dst is NULL, use $0. If ex=TRUE, enable
- * subexpression matching (\1-\9)
+/* Common substitution routine.
+ * Replace (nm)'th substring of (src) that matches (rn) with (repl),
+ * store result into (dest), return number of substitutions.
+ * If nm = 0, replace all matches.
+ * If src or dst is NULL, use $0.
+ * If subexp != 0, enable subexpression matching (\1-\9).
*/
-static int awk_sub(node *rn, const char *repl, int nm, var *src, var *dest, int ex)
+static int awk_sub(node *rn, const char *repl, int nm, var *src, var *dest, int subexp)
{
- char *ds = NULL;
- const char *s;
+ char *resbuf;
const char *sp;
- int c, i, j, di, rl, so, eo, nbs, n, dssize;
+ int match_no, residx, replen, resbufsize;
+ int regexec_flags;
regmatch_t pmatch[10];
- regex_t sreg, *re;
+ regex_t sreg, *regex;
+
+ resbuf = NULL;
+ residx = 0;
+ match_no = 0;
+ regexec_flags = 0;
+ regex = as_regex(rn, &sreg);
+ sp = getvar_s(src ? src : intvar[F0]);
+ replen = strlen(repl);
+ while (regexec(regex, sp, 10, pmatch, regexec_flags) == 0) {
+ int so = pmatch[0].rm_so;
+ int eo = pmatch[0].rm_eo;
+
+ //bb_error_msg("match %u: [%u,%u] '%s'%p", match_no+1, so, eo, sp,sp);
+ resbuf = qrealloc(resbuf, residx + eo + replen, &resbufsize);
+ memcpy(resbuf + residx, sp, eo);
+ residx += eo;
+ if (++match_no >= nm) {
+ const char *s;
+ int nbs;
- re = as_regex(rn, &sreg);
- if (!src)
- src = intvar[F0];
- if (!dest)
- dest = intvar[F0];
-
- i = di = 0;
- sp = getvar_s(src);
- rl = strlen(repl);
- while (regexec(re, sp, 10, pmatch, sp==getvar_s(src) ? 0 : REG_NOTBOL) == 0) {
- so = pmatch[0].rm_so;
- eo = pmatch[0].rm_eo;
-
- ds = qrealloc(ds, di + eo + rl, &dssize);
- memcpy(ds + di, sp, eo);
- di += eo;
- if (++i >= nm) {
/* replace */
- di -= (eo - so);
+ residx -= (eo - so);
nbs = 0;
for (s = repl; *s; s++) {
- ds[di++] = c = *s;
+ char c = resbuf[residx++] = *s;
if (c == '\\') {
nbs++;
continue;
}
- if (c == '&' || (ex && c >= '0' && c <= '9')) {
- di -= ((nbs + 3) >> 1);
+ if (c == '&' || (subexp && c >= '0' && c <= '9')) {
+ int j;
+ residx -= ((nbs + 3) >> 1);
j = 0;
if (c != '&') {
j = c - '0';
nbs++;
}
if (nbs % 2) {
- ds[di++] = c;
+ resbuf[residx++] = c;
} else {
- n = pmatch[j].rm_eo - pmatch[j].rm_so;
- ds = qrealloc(ds, di + rl + n, &dssize);
- memcpy(ds + di, sp + pmatch[j].rm_so, n);
- di += n;
+ int n = pmatch[j].rm_eo - pmatch[j].rm_so;
+ resbuf = qrealloc(resbuf, residx + replen + n, &resbufsize);
+ memcpy(resbuf + residx, sp + pmatch[j].rm_so, n);
+ residx += n;
}
}
nbs = 0;
}
}
+ regexec_flags = REG_NOTBOL;
sp += eo;
- if (i == nm)
+ if (match_no == nm)
break;
if (eo == so) {
- ds[di] = *sp++;
- if (!ds[di++])
- break;
+ /* Empty match (e.g. "b*" will match anywhere).
+ * Advance by one char. */
+//BUG (bug 1333):
+//gsub(/\<b*/,"") on "abc" will reach this point, advance to "bc"
+//... and will erroneously match "b" even though it is NOT at the word start.
+//we need REG_NOTBOW but it does not exist...
+ /* Subtle: this is safe only because
+ * qrealloc allocated at least one extra byte */
+ resbuf[residx] = *sp;
+ if (*sp == '\0')
+ goto ret;
+ sp++;
+ residx++;
}
}
- ds = qrealloc(ds, di + strlen(sp), &dssize);
- strcpy(ds + di, sp);
- setvar_p(dest, ds);
- if (re == &sreg)
- regfree(re);
- return i;
+ resbuf = qrealloc(resbuf, residx + strlen(sp), &resbufsize);
+ strcpy(resbuf + residx, sp);
+ ret:
+ //bb_error_msg("end sp:'%s'%p", sp,sp);
+ setvar_p(dest ? dest : intvar[F0], resbuf);
+ if (regex == &sreg)
+ regfree(regex);
+ return match_no;
}
static NOINLINE int do_mktime(const char *ds)
--
1.6.3.3
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