stringi/src/stri_search_regex_extract.cpp

/* This file is part of the 'stringi' project.
 * Copyright (c) 2013-2021, Marek Gagolewski <https://www.gagolewski.com>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 * this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 *
 * 3. Neither the name of the copyright holder nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING,
 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
 * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */


#include "stri_stringi.h"
#include "stri_container_utf8.h"
#include "stri_container_regex.h"
#include <deque>
#include <utility>
using namespace std;


/**
 * Extract first 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?
 * @return character vector
 *
 * @version 0.1-?? (Marek Gagolewski, 2013-06-20)
 *
 * @version 0.3-1 (Marek Gagolewski, 2014-11-05)
 *    Issue #112: str_prepare_arg* retvals were not PROTECTed from gc
 *
 * @version 1.0-2 (Marek Gagolewski, 2016-01-29)
 *    Issue #214: allow a regex pattern like `.*`  to match an empty string
 *
 * @version 1.4.7 (Marek Gagolewski, 2020-08-24)
 *    Use StriContainerRegexPattern::getRegexOptions
 */
SEXP stri__extract_firstlast_regex(SEXP str, SEXP pattern, SEXP opts_regex, bool first)
{
    PROTECT(str = stri__prepare_arg_string(str, "str")); // prepare string argument
    PROTECT(pattern = stri__prepare_arg_string(pattern, "pattern")); // prepare string argument
    R_len_t vectorize_length = stri__recycling_rule(true, 2, LENGTH(str), LENGTH(pattern));

    StriRegexMatcherOptions pattern_opts =
        StriContainerRegexPattern::getRegexOptions(opts_regex);

    UText* str_text = NULL; // may potentially be slower, but definitely is more convenient!
    STRI__ERROR_HANDLER_BEGIN(2)
    StriContainerUTF8 str_cont(str, vectorize_length);
    StriContainerRegexPattern pattern_cont(pattern, vectorize_length, pattern_opts);

    SEXP ret;
    STRI__PROTECT(ret = Rf_allocVector(STRSXP, vectorize_length));

    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,
                                              SET_STRING_ELT(ret, i, NA_STRING);)

        UErrorCode status = U_ZERO_ERROR;
        RegexMatcher *matcher = pattern_cont.getMatcher(i); // will be deleted automatically
        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 */})

        int m_start = -1;
        int m_end = -1;
        int m_res;
        matcher->reset(str_text);
        m_res = (int)matcher->find(status);
        STRI__CHECKICUSTATUS_THROW(status, {/* do nothing special on err */})
        if (m_res) { // find first match
            m_start = (int)matcher->start(status); // The **native** position in the input string :-)
            STRI__CHECKICUSTATUS_THROW(status, {/* do nothing special on err */})
            m_end   = (int)matcher->end(status);
            STRI__CHECKICUSTATUS_THROW(status, {/* do nothing special on err */})
        }
        else {
            SET_STRING_ELT(ret, i, NA_STRING);
            continue;
        }

        if (!first) { // continue searching
            while (1) {
                m_res = (int)matcher->find(status);
                STRI__CHECKICUSTATUS_THROW(status, {/* do nothing special on err */})
                if (!m_res) break;
                m_start = (int)matcher->start(status);
                m_end   = (int)matcher->end(status);
                STRI__CHECKICUSTATUS_THROW(status, {/* do nothing special on err */})
            }
        }

        SET_STRING_ELT(ret, i, Rf_mkCharLenCE(str_cont.get(i).c_str()+m_start, m_end-m_start, CE_UTF8));
    }

    if (str_text) {
        utext_close(str_text);
        str_text = NULL;
    }
    STRI__UNPROTECT_ALL
    return ret;
    STRI__ERROR_HANDLER_END(if (str_text) utext_close(str_text);)
    }


/**
 * Extract first occurrence of a regex pattern in each string
 *
 * @param str character vector
 * @param pattern character vector
 * @param opts_regex list
 * @return character vector
 *
 * @version 0.1-?? (Marek Gagolewski, 2013-06-20)
 */
SEXP stri_extract_first_regex(SEXP str, SEXP pattern, SEXP opts_regex)
{
    return stri__extract_firstlast_regex(str, pattern, opts_regex, true);
}


/**
 * Extract last occurrence of a regex pattern in each string
 *
 * @param str character vector
 * @param pattern character vector
 * @param opts_regex list
 * @return character vector
 *
 * @version 0.1-?? (Marek Gagolewski, 2013-06-20)
 */
SEXP stri_extract_last_regex(SEXP str, SEXP pattern, SEXP opts_regex)
{
    return stri__extract_firstlast_regex(str, pattern, opts_regex, false);
}


/**
 * Extract all occurrences of a regex pattern in each string
 *
 * @param str character vector
 * @param pattern character vector
 * @param opts_regex list
 * @param simplify single logical value
 *
 * @return list of character vectors  or character matrix
 *
 * @version 0.1-?? (Marek Gagolewski, 2013-06-20)
 *
 * @version 0.3-1 (Marek Gagolewski, 2014-10-24)
 *          added simplify param
 *
 * @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, 2014-11-27)
 *    FR #117: omit_no_match arg added
 *
 * @version 0.4-1 (Marek Gagolewski, 2014-12-04)
 *    allow `simplify=NA`
 *
 * @version 1.0-2 (Marek Gagolewski, 2016-01-29)
 *    Issue #214: allow a regex pattern like `.*`  to match an empty string
 */
SEXP stri_extract_all_regex(SEXP str, SEXP pattern, SEXP simplify, SEXP omit_no_match, SEXP opts_regex)
{
    StriRegexMatcherOptions pattern_opts =
        StriContainerRegexPattern::getRegexOptions(opts_regex);
    bool omit_no_match1 = stri__prepare_arg_logical_1_notNA(omit_no_match, "omit_no_match");
    PROTECT(simplify = stri__prepare_arg_logical_1(simplify, "simplify"));
    PROTECT(str = stri__prepare_arg_string(str, "str")); // prepare string argument
    PROTECT(pattern = stri__prepare_arg_string(pattern, "pattern")); // prepare string argument
    R_len_t vectorize_length = stri__recycling_rule(true, 2, LENGTH(str), LENGTH(pattern));

    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_opts);

    SEXP ret;
    STRI__PROTECT(ret = Rf_allocVector(VECSXP, vectorize_length));

    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,
                                              SET_VECTOR_ELT(ret, i, stri__vector_NA_strings(1));)

        UErrorCode status = U_ZERO_ERROR;
        RegexMatcher *matcher = pattern_cont.getMatcher(i); // will be deleted automatically
        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 */})

        matcher->reset(str_text);

        deque< pair<R_len_t, R_len_t> > occurrences;
        int m_res;
        while (1) {
            m_res = (int)matcher->find(status);
            STRI__CHECKICUSTATUS_THROW(status, {/* do nothing special on err */})
            if (!m_res) break;

            occurrences.push_back(pair<R_len_t, R_len_t>(
                                      (R_len_t)matcher->start(status), (R_len_t)matcher->end(status)
                                  ));
            STRI__CHECKICUSTATUS_THROW(status, {/* do nothing special on err */})
        }

        R_len_t noccurrences = (R_len_t)occurrences.size();
        if (noccurrences <= 0) {
            SET_VECTOR_ELT(ret, i, stri__vector_NA_strings(omit_no_match1?0:1));
            continue;
        }

        const char* str_cur_s = str_cont.get(i).c_str();
        SEXP cur_res;
        STRI__PROTECT(cur_res = Rf_allocVector(STRSXP, noccurrences));
        deque< pair<R_len_t, R_len_t> >::iterator iter = occurrences.begin();
        for (R_len_t j = 0; iter != occurrences.end(); ++iter, ++j) {
            pair<R_len_t, R_len_t> curo = *iter;
            SET_STRING_ELT(cur_res, j,
                           Rf_mkCharLenCE(str_cur_s+curo.first, curo.second-curo.first, CE_UTF8));
        }
        SET_VECTOR_ELT(ret, i, cur_res);
        STRI__UNPROTECT(1);
    }

    if (str_text) {
        utext_close(str_text);
        str_text = NULL;
    }

    if (LOGICAL(simplify)[0] == NA_LOGICAL || LOGICAL(simplify)[0]) {
        SEXP robj_TRUE, robj_zero, robj_na_strings, robj_empty_strings;
        STRI__PROTECT(robj_TRUE = Rf_ScalarLogical(TRUE));
        STRI__PROTECT(robj_zero = Rf_ScalarInteger(0));
        STRI__PROTECT(robj_na_strings = stri__vector_NA_strings(1));
        STRI__PROTECT(robj_empty_strings = stri__vector_empty_strings(1));
        STRI__PROTECT(ret = stri_list2matrix(ret, robj_TRUE,
                                             (LOGICAL(simplify)[0] == NA_LOGICAL)?robj_na_strings
                                             :robj_empty_strings,
                                             robj_zero));
    }

    STRI__UNPROTECT_ALL
    return ret;
    STRI__ERROR_HANDLER_END(if (str_text) utext_close(str_text);)
    }