stringi/src/stri_search_fixed_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_bytesearch.h"
#include <deque>
#include <utility>
using namespace std;


/**
 * Extract first or last occurrences of pattern in a string [exact byte search]
 *
 * @param str character vector
 * @param pattern character vector
 * @param first looking for first or last match?
 * @return character vector
 *
 * @version 0.1-?? (Marek Gagolewski, 2013-06-24)
 *
 * @version 0.2-3 (Marek Gagolewski, 2014-05-08)
 *          stri_extract_fixed now uses byte search only
 *
 * @version 0.4-1 (Marek Gagolewski, 2014-12-08)
 *          new args: opts_fixed
 *
 * @version 0.5-1 (Marek Gagolewski, 2015-02-14)
 *    use StriByteSearchMatcher
 */
SEXP stri__extract_firstlast_fixed(SEXP str, SEXP pattern, SEXP opts_fixed, bool first)
{
    uint32_t pattern_flags = StriContainerByteSearch::getByteSearchFlags(opts_fixed);
    PROTECT(str = stri__prepare_arg_string(str, "str")); // prepare string argument
    PROTECT(pattern = stri__prepare_arg_string(pattern, "pattern")); // prepare string argument

    STRI__ERROR_HANDLER_BEGIN(2)
    int vectorize_length = stri__recycling_rule(true, 2, LENGTH(str), LENGTH(pattern));
    StriContainerUTF8 str_cont(str, vectorize_length);
    StriContainerByteSearch pattern_cont(pattern, vectorize_length, pattern_flags);

    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_STR_PATTERN(str_cont, pattern_cont,
                SET_STRING_ELT(ret, i, NA_STRING);, SET_STRING_ELT(ret, i, NA_STRING);)

        StriByteSearchMatcher* matcher = pattern_cont.getMatcher(i);
        matcher->reset(str_cont.get(i).c_str(), str_cont.get(i).length());
        int start, len;
        if (first) {
            start = matcher->findFirst();
        } else {
            start = matcher->findLast();
        }
        if (start == USEARCH_DONE) {
            SET_STRING_ELT(ret, i, NA_STRING);
            continue;
        }

        len = matcher->getMatchedLength();

        SET_STRING_ELT(ret, i, Rf_mkCharLenCE(str_cont.get(i).c_str()+start, len, CE_UTF8));
    }

    STRI__UNPROTECT_ALL
    return ret;
    STRI__ERROR_HANDLER_END({ /* no-op */ })
}


/**
 * Extract first occurrence of a fixed pattern in each string
 *
 * @param str character vector
 * @param pattern character vector
 * @return character vector
 *
 * @version 0.1-?? (Marek Gagolewski, 2013-06-24)
 *
 * @version 0.2-3 (Marek Gagolewski, 2014-05-08)
 *          stri_extract_fixed now uses byte search only
 *
 * @version 0.4-1 (Marek Gagolewski, 2014-12-08)
 *          new args: opts_fixed
 */
SEXP stri_extract_first_fixed(SEXP str, SEXP pattern, SEXP opts_fixed)
{
    return stri__extract_firstlast_fixed(str, pattern, opts_fixed, true);
}


/**
 * Extract last occurrence of a fixed pattern in each string
 *
 * @param str character vector
 * @param pattern character vector
 * @return character vector
 *
 * @version 0.1-?? (Marek Gagolewski, 2013-06-24)
 *
 * @version 0.2-3 (Marek Gagolewski, 2014-05-08)
 *          stri_extract_fixed now uses byte search only
 *
 * @version 0.4-1 (Marek Gagolewski, 2014-12-08)
 *          new args: opts_fixed
 */
SEXP stri_extract_last_fixed(SEXP str, SEXP pattern, SEXP opts_fixed)
{
    return stri__extract_firstlast_fixed(str, pattern, opts_fixed, false);
}


/**
 * Extract all occurrences of pattern in a string [exact byte search]
 *
 * @param str character vector
 * @param pattern character vector
 * @return character vector
 *
 * @version 0.1-?? (Marek Gagolewski, 2013-06-24)
 *
 * @version 0.2-3 (Marek Gagolewski, 2014-05-08)
 *          stri_extract_fixed now uses byte search only
 *
 * @version 0.4-1 (Marek Gagolewski, 2014-12-08)
 *          new args: opts_fixed, omit_no_match, simplify
 *
 * @version 0.5-1 (Marek Gagolewski, 2015-02-14)
 *    use StriByteSearchMatcher
 */
SEXP stri_extract_all_fixed(SEXP str, SEXP pattern, SEXP simplify, SEXP omit_no_match, SEXP opts_fixed)
{
    uint32_t pattern_flags = StriContainerByteSearch::getByteSearchFlags(opts_fixed, /*allow_overlap*/true);
    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

    STRI__ERROR_HANDLER_BEGIN(3)
    R_len_t vectorize_length = stri__recycling_rule(true, 2, LENGTH(str), LENGTH(pattern));
    StriContainerUTF8 str_cont(str, vectorize_length);
    StriContainerByteSearch pattern_cont(pattern, vectorize_length, pattern_flags);

    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_STR_PATTERN(str_cont, pattern_cont,
                SET_VECTOR_ELT(ret, i, stri__vector_NA_strings(1));,
                SET_VECTOR_ELT(ret, i, stri__vector_NA_strings(omit_no_match1?0:1));)

        StriByteSearchMatcher* matcher = pattern_cont.getMatcher(i);
        matcher->reset(str_cont.get(i).c_str(), str_cont.get(i).length());

        int start = matcher->findFirst();
        deque< pair<R_len_t, R_len_t> > occurrences;
        while (start != USEARCH_DONE) {
            occurrences.push_back(pair<R_len_t, R_len_t>(start, start+matcher->getMatchedLength()));
            start = matcher->findNext();
        }

        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 (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({/* no-op */})
}