forked from Public-Mirror/Textractor
98 lines
4.5 KiB
C++
98 lines
4.5 KiB
C++
#include "extension.h"
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std::vector<int> GenerateSuffixArray(const std::wstring& text)
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{
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std::vector<int> suffixArray(text.size());
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for (int i = 0; i < text.size(); ++i) suffixArray[i] = i;
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// The below code is a more efficient way of doing this:
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// std::sort(suffixArray.begin(), suffixArray.end(), [&](int a, int b) { return wcscmp(text.c_str() + a, text.c_str() + b) > 0; });
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std::stable_sort(suffixArray.begin(), suffixArray.end(), [&](int a, int b) { return text[a] > text[b]; });
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std::vector<int> eqClasses(text.begin(), text.end());
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std::vector<int> count(text.size());
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for (int length = 1; length < text.size(); length *= 2)
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{
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// Determine equivalence class up to length, by checking length / 2 equivalence of suffixes and their following length / 2 suffixes
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std::vector<int> prevEqClasses = eqClasses;
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eqClasses[suffixArray[0]] = 0;
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for (int i = 1; i < text.size(); ++i)
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{
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int currentSuffix = suffixArray[i], lastSuffix = suffixArray[i - 1];
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if (currentSuffix + length < text.size() && prevEqClasses[currentSuffix] == prevEqClasses[lastSuffix] &&
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prevEqClasses[currentSuffix + length / 2] == prevEqClasses[lastSuffix + length / 2]
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)
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eqClasses[currentSuffix] = eqClasses[lastSuffix];
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else eqClasses[currentSuffix] = i;
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}
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// Sort within equivalence class based on order of following suffix after length (orders up to length * 2)
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for (int i = 0; i < text.size(); ++i) count[i] = i;
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for (auto suffix : std::vector(suffixArray))
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{
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int precedingSuffix = suffix - length;
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if (precedingSuffix >= 0) suffixArray[count[eqClasses[precedingSuffix]]++] = precedingSuffix;
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}
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}
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for (int i = 0; i + 1 < text.size(); ++i)
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assert(wcscmp(text.c_str() + suffixArray[i], text.c_str() + suffixArray[i + 1]) > 0);
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return suffixArray;
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}
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constexpr wchar_t ERASED = 0xf246; // inside Unicode private use area
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bool ProcessSentence(std::wstring& sentence, SentenceInfo sentenceInfo)
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{
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if (sentenceInfo["text number"] == 0) return false;
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// This algorithm looks for repeating substrings (in other words, common prefixes among the set of suffixes) of the sentence with length > 6
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// It then looks for any regions of characters at least twice as long as the substring made up only of characters in the substring, and erases them
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// If this results in the substring being completely erased from the string, the substring is copied to the last location where it was located in the original string
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auto timeout = GetTickCount64() + 30'000; // give up if taking over 30 seconds
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std::vector<int> suffixArray = GenerateSuffixArray(sentence);
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for (int i = 0; i + 1 < sentence.size() && GetTickCount64() < timeout; ++i)
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{
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int commonPrefixLength = 0;
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for (int j = suffixArray[i], k = suffixArray[i + 1]; j < sentence.size() && k < sentence.size(); ++j, ++k)
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if (sentence[j] != ERASED && sentence[j] == sentence[k]) commonPrefixLength += 1;
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else break;
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if (commonPrefixLength > 6)
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{
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std::wstring substring(sentence, suffixArray[i], commonPrefixLength);
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bool substringCharMap[0x10000] = {};
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for (auto ch : substring) substringCharMap[ch] = true;
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for (int regionSize = 0, j = 0; j <= sentence.size(); ++j)
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if (substringCharMap[sentence[j]]) regionSize += 1;
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else if (regionSize >= commonPrefixLength * 2)
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while (regionSize > 0) sentence[j - regionSize--] = ERASED;
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else regionSize = 0;
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if (!wcsstr(sentence.c_str(), substring.c_str())) std::copy(substring.begin(), substring.end(), sentence.begin() + max(suffixArray[i], suffixArray[i + 1]));
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}
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}
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sentence.erase(std::remove(sentence.begin(), sentence.end(), ERASED), sentence.end());
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return true;
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}
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TEST(
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{
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InfoForExtension nonConsole[] = { { "text number", 1 }, {} };
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std::wstring cyclicRepeats = L"Name: '_abcdefg_abcdefg_abcdefg_abcdefg_abcdefg'";
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std::wstring buildupRepeats = L"Name: '__a_ab_abc_abcd_abcde_abcdef_abcdefg'";
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std::wstring breakdownRepeats = L"Name: '_abcdefg_abcdef_abcde_abcd_abc_ab_a_'";
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ProcessSentence(cyclicRepeats, { nonConsole });
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ProcessSentence(buildupRepeats, { nonConsole });
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ProcessSentence(breakdownRepeats, { nonConsole });
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assert(cyclicRepeats == L"Name: '_abcdefg'");
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assert(buildupRepeats == L"Name: '_abcdefg'");
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assert(breakdownRepeats == L"Name: '_abcdefg'");
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std::wstring empty = L"", one = L" ", normal = L"This is a normal sentence. はい";
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ProcessSentence(empty, { nonConsole });
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ProcessSentence(one, { nonConsole });
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ProcessSentence(normal, { nonConsole });
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assert(empty == L"" && one == L" " && normal == L"This is a normal sentence. はい");
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}
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);
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