/*******************************************************************************
 * Copyright (c) 2015-2018 Skymind, Inc.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Apache License, Version 2.0 which is available at
 * https://www.apache.org/licenses/LICENSE-2.0.
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations
 * under the License.
 *
 * SPDX-License-Identifier: Apache-2.0
 ******************************************************************************/

//
// Created by raver119 on 20/04/18.
//

#include <helpers/StringUtils.h>
#include <exceptions/datatype_exception.h>

namespace nd4j {
    static FORCEINLINE bool match(const uint8_t *haystack, const uint8_t *needle, uint64_t length) {
        for (int e = 0; e < length; e++)
            if (haystack[e] != needle[e])
                return false;

        return true;
    }

    uint64_t StringUtils::countSubarrays(const void *vhaystack, uint64_t haystackLength, const void *vneedle, uint64_t needleLength) {
        auto haystack = reinterpret_cast<const uint8_t*>(vhaystack);
        auto needle = reinterpret_cast<const uint8_t*>(vneedle);

        uint64_t number = 0;

        for (uint64_t e = 0; e < haystackLength - needleLength; e++) {
            if (match(&haystack[e], needle, needleLength))
                number++;
        }

        return number;
    }


    uint64_t StringUtils::byteLength(const NDArray &array) {
        if (!array.isS())
            throw nd4j::datatype_exception::build("StringUtils::byteLength expects one of String types;", array.dataType());

        uint64_t result = 0;

        // our buffer stores offsets, and the last value is basically number of bytes used
        auto buffer = array.bufferAsT<Nd4jLong>();
        result = buffer[array.lengthOf()];

        return result;
    }

    std::vector<std::string> StringUtils::split(const std::string &haystack, const std::string &delimiter) {
        std::vector<std::string> output;

        std::string::size_type prev_pos = 0, pos = 0;

        // iterating through the haystack till the end
        while((pos = haystack.find(delimiter, pos)) != std::string::npos) {
            output.emplace_back(haystack.substr(prev_pos, pos-prev_pos));
            prev_pos = ++pos;
        }

        output.emplace_back(haystack.substr(prev_pos, pos - prev_pos)); // Last word

        return output;
    }
}