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awk: FS regex matches only non-empty separators (gawk compat)

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function                                             old     new   delta
awk_split                                            484     553     +69

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2020-12-02 19:07:31 +01:00
parent 50ead33c45
commit 665a659530
2 changed files with 32 additions and 8 deletions
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33
editors/awk.c
View File

@ -1763,6 +1763,29 @@ static void fsrealloc(int size)
nfields = size;
}
static int regexec1_nonempty(const regex_t *preg, const char *s, regmatch_t pmatch[])
{
int r = regexec(preg, s, 1, pmatch, 0);
if (r == 0 && pmatch[0].rm_eo == 0) {
/* For example, happens when FS can match
* an empty string (awk -F ' *'). Logically,
* this should split into one-char fields.
* However, gawk 5.0.1 searches for first
* _non-empty_ separator string match:
*/
size_t ofs = 0;
do {
ofs++;
if (!s[ofs])
return REG_NOMATCH;
regexec(preg, s + ofs, 1, pmatch, 0);
} while (pmatch[0].rm_eo == 0);
pmatch[0].rm_so += ofs;
pmatch[0].rm_eo += ofs;
}
return r;
}
static int awk_split(const char *s, node *spl, char **slist)
{
int n;
@ -1788,17 +1811,11 @@ static int awk_split(const char *s, node *spl, char **slist)
regmatch_t pmatch[2]; // TODO: why [2]? [1] is enough...
l = strcspn(s, c+2); /* len till next NUL or \n */
if (regexec(icase ? spl->r.ire : spl->l.re, s, 1, pmatch, 0) == 0
if (regexec1_nonempty(icase ? spl->r.ire : spl->l.re, s, pmatch) == 0
&& pmatch[0].rm_so <= l
) {
/* if (pmatch[0].rm_eo == 0) ... - impossible */
l = pmatch[0].rm_so;
if (pmatch[0].rm_eo == 0) {
/* For example, happens when FS can match
* an empthy string (awk -F ' *')
*/
l++;
pmatch[0].rm_eo++;
}
n++; /* we saw yet another delimiter */
} else {
pmatch[0].rm_eo = l;

7
testsuite/awk.tests
View File

@ -398,5 +398,12 @@ testing 'awk do not allow "str"++' \
'' \
'anything'
#gawk compat: FS regex matches only non-empty separators:
#with -*, the splitting is NOT f o o b a r, but foo bar:
testing 'awk FS regex which can match empty string' \
"awk -F '-*' '{print \$1 \"-\" \$2 \"=\" \$3 \"*\" \$4}'" \
"foo-bar=*\n" \
'' \
'foo--bar'
exit $FAILCOUNT