665a65953
Denys Vlasenko
2020-12-02
Subject
awk: FS regex matches only non-empty separators (gawk compat)
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editors/awk.c+25 -8
| @@ -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; | |
testsuite/awk.tests+7 -0
| @@ -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 | |