/**
* Extract all capture groups of the first/last occurrence
* of a regex pattern in each string
*
* @param str character vector
* @param pattern character vector
* @param opts_regex list
* @param first logical - search for the first or the last occurrence?
* @param cg_missing single string
* @return character matrix
*
* @version 0.1-??? (Marek Gagolewski, 2013-06-22)
*
* @version 0.3-1 (Marek Gagolewski, 2014-11-05)
* Issue #112: str_prepare_arg* retvals were not PROTECTed from gc
*
* @version 0.4-1 (Marek Gagolewski, 2014-12-06)
* new arg: cg_missing
*
* @version 1.0-2 (Marek Gagolewski, 2016-01-29)
* Issue #214: allow a regex pattern like `.*` to match an empty string
*/
SEXP stri__match_firstlast_regex(SEXP str, SEXP pattern, SEXP cg_missing, SEXP opts_regex, bool first)
{
// @TODO: capture_groups arg (integer vector/set - which capture groups to extract)
PROTECT(str = stri_prepare_arg_string(str, "str")); // prepare string argument
PROTECT(pattern = stri_prepare_arg_string(pattern, "pattern")); // prepare string argument
PROTECT(cg_missing = stri_prepare_arg_string_1(cg_missing, "cg_missing"));
R_len_t vectorize_length = stri__recycling_rule(true, 2, LENGTH(str), LENGTH(pattern));
uint32_t pattern_flags = StriContainerRegexPattern::getRegexFlags(opts_regex);
UText* str_text = NULL; // may potentially be slower, but definitely is more convenient!
STRI__ERROR_HANDLER_BEGIN(3)
StriContainerUTF8 str_cont(str, vectorize_length);
StriContainerRegexPattern pattern_cont(pattern, vectorize_length, pattern_flags);
StriContainerUTF8 cg_missing_cont(cg_missing, 1);
STRI__PROTECT(cg_missing = STRING_ELT(cg_missing, 0));
// we don't know how many capture groups are there:
vector< vector< pair<const char*, const char*> > > occurrences(vectorize_length);
R_len_t occurrences_max = 1;
for (R_len_t i = pattern_cont.vectorize_init();
i != pattern_cont.vectorize_end();
i = pattern_cont.vectorize_next(i))
{
STRI__CONTINUE_ON_EMPTY_OR_NA_PATTERN(str_cont, pattern_cont,
/*do nothing*/; )
UErrorCode status = U_ZERO_ERROR;
RegexMatcher *matcher = pattern_cont.getMatcher(i); // will be deleted automatically
int pattern_cur_groups = matcher->groupCount();
if (occurrences_max < pattern_cur_groups+1) occurrences_max=pattern_cur_groups+1;
str_text = utext_openUTF8(str_text, str_cont.get(i).c_str(), str_cont.get(i).length(), &status);
STRI__CHECKICUSTATUS_THROW(status, {/* do nothing special on err */})
