vi: allow regular expressions in ':s' commands
BusyBox vi has never supported the use of regular expressions in
search/replace (':s') commands. Implement this using GNU regex
when VI_REGEX_SEARCH is enabled.
The implementation:
- uses basic regular expressions, to match those used in the search
command;
- only supports substitution of back references ('\0' - '\9') in the
replacement string. Any other character following a backslash is
treated as that literal character.
VI_REGEX_SEARCH isn't enabled in the default build. In that case:
function old new delta
colon 4036 4033 -3
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-3) Total: -3 bytes
When VI_REGEX_SEARCH is enabled:
function old new delta
colon 4036 4378 +342
.rodata 108207 108229 +22
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 2/0 up/down: 364/0) Total: 364 bytes
v2: Rebase. Code shrink. Ensure empty replacement string is null terminated.
Signed-off-by: Andrey Dobrovolsky <andrey.dobrovolsky.odessa@gmail.com>
Signed-off-by: Ron Yorston <rmy@pobox.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko
parent
c76c78740a
commit
95ac4a48f1
119
editors/vi.c
119
editors/vi.c
@ -2677,6 +2677,59 @@ static char *expand_args(char *args)
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# endif
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#endif /* FEATURE_VI_COLON */
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#if ENABLE_FEATURE_VI_REGEX_SEARCH
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# define MAX_SUBPATTERN 10 // subpatterns \0 .. \9
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// If the return value is not NULL the caller should free R
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static char *regex_search(char *q, regex_t *preg, const char *Rorig,
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size_t *len_F, size_t *len_R, char **R)
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{
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regmatch_t regmatch[MAX_SUBPATTERN], *cur_match;
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char *found = NULL;
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const char *t;
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char *r;
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regmatch[0].rm_so = 0;
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regmatch[0].rm_eo = end_line(q) - q;
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if (regexec(preg, q, MAX_SUBPATTERN, regmatch, REG_STARTEND) != 0)
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return found;
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found = q + regmatch[0].rm_so;
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*len_F = regmatch[0].rm_eo - regmatch[0].rm_so;
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*R = NULL;
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fill_result:
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// first pass calculates len_R, second fills R
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*len_R = 0;
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for (t = Rorig, r = *R; *t; t++) {
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size_t len = 1; // default is to copy one char from replace pattern
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const char *from = t;
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if (*t == '\\') {
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from = ++t; // skip backslash
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if (*t >= '0' && *t < '0' + MAX_SUBPATTERN) {
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cur_match = regmatch + (*t - '0');
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if (cur_match->rm_so >= 0) {
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len = cur_match->rm_eo - cur_match->rm_so;
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from = q + cur_match->rm_so;
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}
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}
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}
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*len_R += len;
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if (*R) {
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memcpy(r, from, len);
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r += len;
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/* *r = '\0'; - xzalloc did it */
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}
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}
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if (*R == NULL) {
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*R = xzalloc(*len_R + 1);
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goto fill_result;
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}
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return found;
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}
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#endif /* ENABLE_FEATURE_VI_REGEX_SEARCH */
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// buf must be no longer than MAX_INPUT_LEN!
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static void colon(char *buf)
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{
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@ -3083,6 +3136,14 @@ static void colon(char *buf)
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int subs = 0; // number of substitutions
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# if ENABLE_FEATURE_VI_VERBOSE_STATUS
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int last_line = 0, lines = 0;
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# endif
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# if ENABLE_FEATURE_VI_REGEX_SEARCH
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regex_t preg;
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int cflags;
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char *Rorig;
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# if ENABLE_FEATURE_VI_UNDO
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int undo = 0;
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# endif
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# endif
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// F points to the "find" pattern
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@ -3100,7 +3161,6 @@ static void colon(char *buf)
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*flags++ = '\0'; // terminate "replace"
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gflag = *flags;
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}
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len_R = strlen(R);
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if (len_F) { // save "find" as last search pattern
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free(last_search_pattern);
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@ -3122,18 +3182,60 @@ static void colon(char *buf)
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b = e;
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}
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# if ENABLE_FEATURE_VI_REGEX_SEARCH
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Rorig = R;
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cflags = 0;
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if (ignorecase)
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cflags = REG_ICASE;
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memset(&preg, 0, sizeof(preg));
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if (regcomp(&preg, F, cflags) != 0) {
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status_line(":s bad search pattern");
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goto regex_search_end;
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}
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# else
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len_R = strlen(R);
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# endif
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for (i = b; i <= e; i++) { // so, :20,23 s \0 find \0 replace \0
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char *ls = q; // orig line start
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char *found;
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vc4:
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# if ENABLE_FEATURE_VI_REGEX_SEARCH
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found = regex_search(q, &preg, Rorig, &len_F, &len_R, &R);
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# else
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found = char_search(q, F, (FORWARD << 1) | LIMITED); // search cur line only for "find"
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# endif
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if (found) {
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uintptr_t bias;
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// we found the "find" pattern - delete it
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// For undo support, the first item should not be chained
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// This needs to be handled differently depending on
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// whether or not regex support is enabled.
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# if ENABLE_FEATURE_VI_REGEX_SEARCH
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# define TEST_LEN_F len_F // len_F may be zero
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# define TEST_UNDO1 undo++
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# define TEST_UNDO2 undo++
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# else
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# define TEST_LEN_F 1 // len_F is never zero
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# define TEST_UNDO1 subs
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# define TEST_UNDO2 1
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# endif
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if (TEST_LEN_F) // match can be empty, no delete needed
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text_hole_delete(found, found + len_F - 1,
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subs ? ALLOW_UNDO_CHAIN: ALLOW_UNDO);
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// can't do this above, no undo => no third argument
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TEST_UNDO1 ? ALLOW_UNDO_CHAIN: ALLOW_UNDO);
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if (len_R) { // insert the "replace" pattern, if required
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bias = string_insert(found, R,
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TEST_UNDO2 ? ALLOW_UNDO_CHAIN: ALLOW_UNDO);
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found += bias;
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ls += bias;
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dot = ls;
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//q += bias; - recalculated anyway
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}
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# if ENABLE_FEATURE_VI_REGEX_SEARCH
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free(R);
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# endif
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if (TEST_LEN_F || len_R) {
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dot = ls;
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subs++;
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# if ENABLE_FEATURE_VI_VERBOSE_STATUS
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if (last_line != i) {
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@ -3141,12 +3243,7 @@ static void colon(char *buf)
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++lines;
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}
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# endif
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// insert the "replace" patern
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bias = string_insert(found, R, ALLOW_UNDO_CHAIN);
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found += bias;
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ls += bias;
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dot = ls;
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//q += bias; - recalculated anyway
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}
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// check for "global" :s/foo/bar/g
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if (gflag == 'g') {
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if ((found + len_R) < end_line(ls)) {
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@ -3166,6 +3263,10 @@ static void colon(char *buf)
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status_line("%d substitutions on %d lines", subs, lines);
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# endif
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}
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# if ENABLE_FEATURE_VI_REGEX_SEARCH
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regex_search_end:
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regfree(&preg);
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# endif
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# endif /* FEATURE_VI_SEARCH */
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} else if (strncmp(cmd, "version", i) == 0) { // show software version
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status_line(BB_VER);
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