feat: finish string strip (maybe)
- add Trie Tree for string strip op. - finish string strip but it may still buggy (though i have tested it)
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@ -1,4 +1,7 @@
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#include "op.hpp"
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#include <map>
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#include <memory>
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#include <iterator>
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#include <type_traits>
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#include <algorithm>
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#include <stdexcept>
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@ -172,7 +175,7 @@ namespace yycc::string::op {
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class CodePointIterator {
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public:
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using iterator_category = std::forward_iterator_tag;
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using iterator_category = std::input_iterator_tag;
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using value_type = std::u8string_view;
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using difference_type = std::ptrdiff_t;
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using pointer = const std::u8string_view*;
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@ -274,39 +277,149 @@ namespace yycc::string::op {
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}
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};
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#pragma endregion
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#pragma region Trie Tree Node
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struct TrieTreeNode {
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TrieTreeNode() : is_end(false), children() {}
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bool is_end; ///< Whether this node is a viable end.
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std::map<char8_t, std::unique_ptr<TrieTreeNode>> children; ///< The children node.
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};
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#pragma endregion
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#pragma region Trie Tree
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class TrieTree {
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private:
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std::unique_ptr<TrieTreeNode> root;
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public:
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TrieTree() : root(std::make_unique<TrieTreeNode>()) {
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// Do not accept root element always (no empty string).
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root->is_end = false;
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}
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/**
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* @brief Insert new words in trie tree.
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* @details
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* The reason why use iterator, rather than string view, is that in strip function, we may need insert a string backwardly,
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* so using string view reverse iterator and iterator argument can easily achieve this goal without any more burden.
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* @tparam InputIt The iterator following input iterator name convention.
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* @param[in] first The head of iterator.
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* @param[in] last The tail of iterator.
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*/
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template<std::input_iterator InputIt>
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requires std::is_same_v<std::iter_value_t<InputIt>, char8_t>
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void insert(InputIt first, InputIt last) {
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// prevent empty string
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if (first == last) return;
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// insert item
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TrieTreeNode* node = root.get();
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for (auto it = first; it != last; ++it) {
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char8_t c = *it;
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if (node->children.find(c) == node->children.end()) {
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node->children[c] = std::make_unique<TrieTreeNode>();
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}
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node = node->children[c].get();
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}
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node->is_end = true;
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}
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/**
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* @brief Check whether given words has prefix stored in this trie tree.
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* @details Same reason for using iterator as function argument.
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* @tparam InputIt The iterator following input iterator name convention.
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* @param[in] first The head of iterator.
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* @param[in] last The tail of iterator.
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* @return \c std::nullopt if there is no match, otherwise the length of matched prefix.
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*/
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template<std::input_iterator InputIt>
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requires std::is_same_v<std::iter_value_t<InputIt>, char8_t>
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std::optional<size_t> search(InputIt first, InputIt last) {
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TrieTreeNode* node = root.get();
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size_t cnt = 0;
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for (auto it = first; it != last; ++it) {
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char8_t c = *it;
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auto finder = node->children.find(c);
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if (finder == node->children.end()) {
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// There is no more matching, break the while.
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break;
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} else {
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// There are more matching item, find next one.
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node = finder->second.get();
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++cnt;
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}
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}
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// YYC MARK:
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// There is a fatal bug for Trie Tree, but it doesn't matter with our usage scenario.
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//
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// Assume there is two string "ab" and "abcd". If user give "abc",
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// we should match it with "ab" prefix, but this function will return there is no match.
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// However, this is impossible for UTF8 sequence.
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// There is no possibility that two UTF8 sequence, indicating two different Unicode code point respectively,
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// has the same prefix and different length. Because their first byte must be different,
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// the first byte indicate the length of sequence.
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//
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// This result also can be proven for suffix,
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// because first byte must not be equal to any other continuation bytes.
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// It is impossible that they have same "ab".
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//
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// So it is safe for our usage scenario although this bug is presented.
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// check whether current is valid end.
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// if it is, return the count of prefix, otherwise return nothing.
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if (node->is_end) {
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return cnt;
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} else {
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return std::nullopt;
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}
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}
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};
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#pragma endregion
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template<bool bDoLeft, bool bDoRight>
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void internal_strip(std::u8string& strl, const std::u8string_view& words) {
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std::u8string_view internal_strip(const std::u8string_view& strl, const std::u8string_view& words) {
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std::optional<TrieTree> prefix, suffix;
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if constexpr (bDoLeft) prefix = TrieTree();
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if constexpr (bDoRight) suffix = TrieTree();
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CodePoint code_point(words);
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for (const auto& seq : code_point) {
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if (prefix.has_value()) prefix.value().insert(seq.begin(), seq.end());
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if (suffix.has_value()) suffix.value().insert(seq.rbegin(), seq.rend());
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}
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std::u8string_view striped = strl;
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if constexpr (bDoLeft) {
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while (auto cnt = prefix.value().search(striped.begin(), striped.end())) {
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striped = striped.substr(cnt.value());
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}
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}
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if constexpr (bDoRight) {
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while (auto cnt = suffix.value().search(striped.rbegin(), striped.rend())) {
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striped = striped.substr(0, striped.size() - cnt.value());
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}
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}
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return striped;
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}
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void strip(std::u8string& strl, const std::u8string_view& words) {}
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std::u8string to_strip(const std::u8string_view& strl, const std::u8string_view& words) {
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std::u8string rv(strl);
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strip(rv, words);
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return rv;
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std::u8string_view strip(const std::u8string_view& strl, const std::u8string_view& words) {
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return internal_strip<true, true>(strl, words);
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}
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void lstrip(std::u8string& strl, const std::u8string_view& words) {}
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std::u8string to_lstrip(const std::u8string_view& strl, const std::u8string_view& words) {
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std::u8string rv(strl);
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lstrip(rv, words);
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return rv;
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std::u8string_view lstrip(const std::u8string_view& strl, const std::u8string_view& words) {
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return internal_strip<true, false>(strl, words);
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}
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void rstrip(std::u8string& strl, const std::u8string_view& words) {}
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std::u8string to_rstrip(const std::u8string_view& strl, const std::u8string_view& words) {
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std::u8string rv(strl);
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rstrip(rv, words);
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return rv;
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std::u8string_view rstrip(const std::u8string_view& strl, const std::u8string_view& words) {
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return internal_strip<false, true>(strl, words);
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}
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#pragma endregion
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@ -145,46 +145,25 @@ namespace yycc::string::op {
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* @brief Remove leading and trailing whitespace from the string.
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* @param[in,out] strl The string to be stripped.
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* @param[in] words The characters to be stripped.
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* @return The string view with leading and trailing whitespace removed.
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*/
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void strip(std::u8string& strl, const std::u8string_view& words);
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/**
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* @brief Return a copy of the string with leading and trailing whitespace removed.
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* @param[in] strl The string to be stripped.
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* @param[in] words The characters to be stripped.
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* @return The copy of the string with leading and trailing whitespace removed.
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*/
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std::u8string to_strip(const std::u8string_view& strl, const std::u8string_view& words);
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std::u8string_view strip(const std::u8string_view& strl, const std::u8string_view& words);
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/**
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* @brief Remove leading whitespace from the string.
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* @param[in,out] strl The string to be stripped.
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* @param[in] words The characters to be stripped.
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* @return The string view with leading whitespace removed.
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*/
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void lstrip(std::u8string& strl, const std::u8string_view& words);
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/**
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* @brief Return a copy of the string with leading whitespace removed.
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* @param[in] strl The string to be stripped.
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* @param[in] words The characters to be stripped.
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* @return The copy of the string with leading whitespace removed.
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*/
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std::u8string to_lstrip(const std::u8string_view& strl, const std::u8string_view& words);
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std::u8string_view lstrip(const std::u8string_view& strl, const std::u8string_view& words);
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/**
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* @brief Remove trailing whitespace from the string.
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* @param[in,out] strl The string to be stripped.
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* @param[in] words The characters to be stripped.
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* @return The string view with trailing whitespace removed.
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*/
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void rstrip(std::u8string& strl, const std::u8string_view& words);
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/**
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* @brief Return a copy of the string with trailing whitespace removed.
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* @param[in] strl The string to be stripped.
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* @param[in] words The characters to be stripped.
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* @return The copy of the string with trailing whitespace removed.
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*/
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std::u8string to_rstrip(const std::u8string_view& strl, const std::u8string_view& words);
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std::u8string_view rstrip(const std::u8string_view& strl, const std::u8string_view& words);
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#pragma endregion
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@ -195,7 +174,7 @@ namespace yycc::string::op {
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*/
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class LazySplitIterator {
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public:
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using iterator_category = std::forward_iterator_tag;
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using iterator_category = std::input_iterator_tag;
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using value_type = std::u8string_view;
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using difference_type = std::ptrdiff_t;
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using pointer = const std::u8string_view*;
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@ -74,22 +74,39 @@ namespace yycctest::string::op {
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TEST(StringOp, Strip) {
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// Normal strip
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{
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auto rv = OP::to_strip(u8" \taaa\n", u8" \t\r\n");
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auto rv = OP::strip(u8" \taaa\n", u8" \t\r\n");
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EXPECT_EQ(rv, u8"aaa");
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}
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{
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auto rv = OP::lstrip(u8" \taaa\n", u8" \t\r\n");
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EXPECT_EQ(rv, u8"aaa\n");
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}
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{
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auto rv = OP::rstrip(u8" \taaa\n", u8" \t\r\n");
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EXPECT_EQ(rv, u8" \taaa");
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}
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// Special strip
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{
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auto rv = OP::to_strip(u8"<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>aaa<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>", u8"<EFBFBD><EFBFBD><EFBFBD><EFBFBD>");
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auto rv = OP::strip(u8"啊啊啊aaaあああ", u8"啊あ");
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EXPECT_EQ(rv, u8"aaa");
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}
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{
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auto rv = OP::to_strip(u8"<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>aaa<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>", u8"<EFBFBD><EFBFBD>");
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EXPECT_EQ(rv, u8"aaa<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>");
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auto rv = OP::strip(u8"啊啊啊aaaあああ", u8"啊");
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EXPECT_EQ(rv, u8"aaaあああ");
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}
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{
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auto rv = OP::to_strip(u8"<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>aaa<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>", u8"<EFBFBD><EFBFBD>");
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EXPECT_EQ(rv, u8"<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>aaa");
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auto rv = OP::strip(u8"啊啊啊aaaあああ", u8"あ");
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EXPECT_EQ(rv, u8"啊啊啊aaa");
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}
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// Possible buggy strip.
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// We use 2 UTF8 code points introduced following:
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// U+00AA (UTF-8: C2 AA)
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// U+1002A (UTF-8 : F0 90 80 AA)
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{
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auto rv = OP::rstrip(u8"aaa\u00AA", u8"\u00AA\U0001002A");
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EXPECT_EQ(rv, u8"aaa");
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}
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}
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