| /* |
| * Copyright 2008 Google Inc. All Rights Reserved. |
| * Author: fraser@google.com (Neil Fraser) |
| * Author: mikeslemmer@gmail.com (Mike Slemmer) |
| * Author: snhere@gmail.com (Sergey Nozhenko) |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://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. |
| * |
| * Diff Match and Patch |
| * http://code.google.com/p/google-diff-match-patch/ |
| */ |
| |
| #ifndef DIFF_MATCH_PATCH_H |
| #define DIFF_MATCH_PATCH_H |
| |
| #include <limits> |
| #include <list> |
| #include <map> |
| #include <string> |
| #include <vector> |
| #include <algorithm> |
| #include <cstdlib> |
| #include <cwchar> |
| #include <time.h> |
| |
| #include "llvm/Support/ErrorHandling.h" |
| |
| /* |
| * Functions for diff, match and patch. |
| * Computes the difference between two texts to create a patch. |
| * Applies the patch onto another text, allowing for errors. |
| * |
| * @author fraser@google.com (Neil Fraser) |
| * |
| * Qt/C++ port by mikeslemmer@gmail.com (Mike Slemmer) |
| * |
| * STL-only port by snhere@gmail.com (Sergey Nozhenko) |
| * and some tweaks for std::string by leutloff@sundancer.oche.de (Christian Leutloff) |
| * |
| * Here is a trivial sample program: |
| * |
| |
| #include "diff_match_patch.h" |
| #include <string> |
| using namespace std; |
| int main(int argc, char **argv) { |
| diff_match_patch<wstring> dmp; |
| wstring str1 = L"First string in diff"; |
| wstring str2 = L"Second string in diff"; |
| |
| wstring strPatch = dmp.patch_toText(dmp.patch_make(str1, str2)); |
| pair<wstring, vector<bool> > out |
| = dmp.patch_apply(dmp.patch_fromText(strPatch), str1); |
| wstring strResult = out.first; |
| |
| // here, strResult will equal str2 above. |
| return 0; |
| } |
| |
| */ |
| |
| // Character type dependencies |
| template <class char_t> struct diff_match_patch_traits {}; |
| |
| /** |
| * Class containing the diff, match and patch methods. |
| * Also contains the behaviour settings. |
| */ |
| template <class stringT, class traits = diff_match_patch_traits<typename stringT::value_type> > |
| class diff_match_patch { |
| public: |
| /** |
| * String and character types |
| */ |
| typedef stringT string_t; |
| typedef typename string_t::value_type char_t; |
| |
| /**- |
| * The data structure representing a diff is a Linked list of Diff objects: |
| * {Diff(Operation.DELETE, "Hello"), Diff(Operation.INSERT, "Goodbye"), |
| * Diff(Operation.EQUAL, " world.")} |
| * which means: delete "Hello", add "Goodbye" and keep " world." |
| */ |
| enum Operation { |
| DELETE, INSERT, EQUAL |
| }; |
| |
| /** |
| * Class representing one diff operation. |
| */ |
| class Diff { |
| public: |
| Operation operation; |
| // One of: INSERT, DELETE or EQUAL. |
| |
| string_t text; |
| // The text associated with this diff operation. |
| |
| /** |
| * Constructor. Initializes the diff with the provided values. |
| * @param _operation One of INSERT, DELETE or EQUAL. |
| * @param _text The text being applied. |
| */ |
| Diff(Operation _operation, const string_t &_text) : operation(_operation), text(_text) {} |
| Diff() {} |
| |
| /** |
| * Display a human-readable version of this Diff. |
| * @return text version. |
| */ |
| string_t toString() const { |
| string_t prettyText = text; |
| // Replace linebreaks with Pilcrow signs. |
| for (typename string_t::iterator i = prettyText.begin(); i != prettyText.end(); ++i) |
| if (traits::to_wchar(*i) == L'\n') *i = traits::from_wchar(L'\u00b6'); |
| return traits::cs(L"Diff(") + strOperation(operation) + traits::cs(L",\"") + prettyText + traits::cs(L"\")"); |
| } |
| |
| /** |
| * Is this Diff equivalent to another Diff? |
| * @param d Another Diff to compare against |
| * @return true or false |
| */ |
| bool operator==(const Diff &d) const { |
| return (d.operation == this->operation) && (d.text == this->text); |
| } |
| bool operator!=(const Diff &d) const { return !(operator == (d)); } |
| |
| static string_t strOperation(Operation op) { |
| switch (op) { |
| case INSERT: |
| return traits::cs(L"INSERT"); |
| case DELETE: |
| return traits::cs(L"DELETE"); |
| case EQUAL: |
| return traits::cs(L"EQUAL"); |
| } |
| llvm_unreachable("Invalid operation."); |
| } |
| }; |
| |
| typedef std::list<Diff> Diffs; |
| |
| |
| /** |
| * Class representing one patch operation. |
| */ |
| class Patch { |
| public: |
| Diffs diffs; |
| int start1; |
| int start2; |
| int length1; |
| int length2; |
| |
| /** |
| * Constructor. Initializes with an empty list of diffs. |
| */ |
| Patch() : start1(0), start2(0), length1(0), length2(0) {} |
| |
| bool isNull() const { |
| return start1 == 0 && start2 == 0 && length1 == 0 && length2 == 0 && diffs.empty(); |
| } |
| |
| /** |
| * Emulate GNU diff's format. |
| * Header: @@ -382,8 +481,9 @@ |
| * Indices are printed as 1-based, not 0-based. |
| * @return The GNU diff string |
| */ |
| string_t toString() const { |
| string_t coords1, coords2; |
| if (length1 == 0) { |
| coords1 = to_string(start1) + traits::cs(L",0"); |
| } else if (length1 == 1) { |
| coords1 = to_string(start1 + 1); |
| } else { |
| coords1 = to_string(start1 + 1) + traits::from_wchar(L',') + to_string(length1); |
| } |
| if (length2 == 0) { |
| coords2 = to_string(start2) + traits::cs(L",0"); |
| } else if (length2 == 1) { |
| coords2 = to_string(start2 + 1); |
| } else { |
| coords2 = to_string(start2 + 1) + traits::from_wchar(L',') + to_string(length2); |
| } |
| string_t text(traits::cs(L"@@ -") + coords1 + traits::cs(L" +") + coords2 + traits::cs(L" @@\n")); |
| // Escape the body of the patch with %xx notation. |
| for (typename Diffs::const_iterator cur_diff = diffs.begin(); cur_diff != diffs.end(); ++cur_diff) { |
| switch ((*cur_diff).operation) { |
| case INSERT: |
| text += traits::from_wchar(L'+'); |
| break; |
| case DELETE: |
| text += traits::from_wchar(L'-'); |
| break; |
| case EQUAL: |
| text += traits::from_wchar(L' '); |
| break; |
| } |
| append_percent_encoded(text, (*cur_diff).text); |
| text += traits::from_wchar(L'\n'); |
| } |
| |
| return text; |
| } |
| }; |
| |
| typedef std::list<Patch> Patches; |
| |
| friend class diff_match_patch_test; |
| |
| public: |
| // Defaults. |
| // Set these on your diff_match_patch instance to override the defaults. |
| |
| // Number of seconds to map a diff before giving up (0 for infinity). |
| float Diff_Timeout; |
| // Cost of an empty edit operation in terms of edit characters. |
| short Diff_EditCost; |
| // At what point is no match declared (0.0 = perfection, 1.0 = very loose). |
| float Match_Threshold; |
| // How far to search for a match (0 = exact location, 1000+ = broad match). |
| // A match this many characters away from the expected location will add |
| // 1.0 to the score (0.0 is a perfect match). |
| int Match_Distance; |
| // When deleting a large block of text (over ~64 characters), how close does |
| // the contents have to match the expected contents. (0.0 = perfection, |
| // 1.0 = very loose). Note that Match_Threshold controls how closely the |
| // end points of a delete need to match. |
| float Patch_DeleteThreshold; |
| // Chunk size for context length. |
| short Patch_Margin; |
| |
| // The number of bits in an int. |
| short Match_MaxBits; |
| |
| |
| public: |
| |
| diff_match_patch() : |
| Diff_Timeout(1.0f), |
| Diff_EditCost(4), |
| Match_Threshold(0.5f), |
| Match_Distance(1000), |
| Patch_DeleteThreshold(0.5f), |
| Patch_Margin(4), |
| Match_MaxBits(32) { |
| } |
| |
| // DIFF FUNCTIONS |
| |
| /** |
| * Find the differences between two texts. |
| * @param text1 Old string to be diffed. |
| * @param text2 New string to be diffed. |
| * @param checklines Speedup flag. If false, then don't run a |
| * line-level diff first to identify the changed areas. |
| * If true, then run a faster slightly less optimal diff. |
| * Most of the time checklines is wanted, so default to true. |
| * @return Linked List of Diff objects. |
| */ |
| Diffs diff_main(const string_t &text1, const string_t &text2, bool checklines = true) const { |
| // Set a deadline by which time the diff must be complete. |
| clock_t deadline; |
| if (Diff_Timeout <= 0) { |
| deadline = std::numeric_limits<clock_t>::max(); |
| } else { |
| deadline = clock() + (clock_t)(Diff_Timeout * CLOCKS_PER_SEC); |
| } |
| Diffs diffs; |
| diff_main(text1, text2, checklines, deadline, diffs); |
| return diffs; |
| } |
| |
| /** |
| * Find the differences between two texts. Simplifies the problem by |
| * stripping any common prefix or suffix off the texts before diffing. |
| * @param text1 Old string to be diffed. |
| * @param text2 New string to be diffed. |
| * @param checklines Speedup flag. If false, then don't run a |
| * line-level diff first to identify the changed areas. |
| * If true, then run a faster slightly less optimal diff. |
| * @param deadline Time when the diff should be complete by. Used |
| * internally for recursive calls. Users should set DiffTimeout instead. |
| * @param diffs Linked List of Diff objects. |
| */ |
| private: |
| static void diff_main(const string_t &text1, const string_t &text2, bool checklines, clock_t deadline, Diffs& diffs) { |
| diffs.clear(); |
| |
| // Check for equality (speedup). |
| if (text1 == text2) { |
| if (!text1.empty()) { |
| diffs.push_back(Diff(EQUAL, text1)); |
| } |
| } |
| else { |
| // Trim off common prefix (speedup). |
| int commonlength = diff_commonPrefix(text1, text2); |
| const string_t &commonprefix = text1.substr(0, commonlength); |
| string_t textChopped1 = text1.substr(commonlength); |
| string_t textChopped2 = text2.substr(commonlength); |
| |
| // Trim off common suffix (speedup). |
| commonlength = diff_commonSuffix(textChopped1, textChopped2); |
| const string_t &commonsuffix = right(textChopped1, commonlength); |
| textChopped1 = textChopped1.substr(0, textChopped1.length() - commonlength); |
| textChopped2 = textChopped2.substr(0, textChopped2.length() - commonlength); |
| |
| // Compute the diff on the middle block. |
| diff_compute(textChopped1, textChopped2, checklines, deadline, diffs); |
| |
| // Restore the prefix and suffix. |
| if (!commonprefix.empty()) { |
| diffs.push_front(Diff(EQUAL, commonprefix)); |
| } |
| if (!commonsuffix.empty()) { |
| diffs.push_back(Diff(EQUAL, commonsuffix)); |
| } |
| |
| diff_cleanupMerge(diffs); |
| } |
| } |
| |
| /** |
| * Find the differences between two texts. Assumes that the texts do not |
| * have any common prefix or suffix. |
| * @param text1 Old string to be diffed. |
| * @param text2 New string to be diffed. |
| * @param checklines Speedup flag. If false, then don't run a |
| * line-level diff first to identify the changed areas. |
| * If true, then run a faster slightly less optimal diff. |
| * @param deadline Time when the diff should be complete by. |
| * @param diffs Linked List of Diff objects. |
| */ |
| private: |
| static void diff_compute(string_t text1, string_t text2, bool checklines, clock_t deadline, Diffs& diffs) { |
| if (text1.empty()) { |
| // Just add some text (speedup). |
| diffs.push_back(Diff(INSERT, text2)); |
| return; |
| } |
| |
| if (text2.empty()) { |
| // Just delete some text (speedup). |
| diffs.push_back(Diff(DELETE, text1)); |
| return; |
| } |
| |
| { |
| const string_t& longtext = text1.length() > text2.length() ? text1 : text2; |
| const string_t& shorttext = text1.length() > text2.length() ? text2 : text1; |
| const size_t i = longtext.find(shorttext); |
| if (i != string_t::npos) { |
| // Shorter text is inside the longer text (speedup). |
| const Operation op = (text1.length() > text2.length()) ? DELETE : INSERT; |
| diffs.push_back(Diff(op, longtext.substr(0, i))); |
| diffs.push_back(Diff(EQUAL, shorttext)); |
| diffs.push_back(Diff(op, safeMid(longtext, i + shorttext.length()))); |
| return; |
| } |
| |
| if (shorttext.length() == 1) { |
| // Single character string. |
| // After the previous speedup, the character can't be an equality. |
| diffs.push_back(Diff(DELETE, text1)); |
| diffs.push_back(Diff(INSERT, text2)); |
| return; |
| } |
| // Garbage collect longtext and shorttext by scoping out. |
| } |
| |
| // Don't risk returning a non-optimal diff if we have unlimited time. |
| if (deadline != std::numeric_limits<clock_t>::max()) { |
| // Check to see if the problem can be split in two. |
| HalfMatchResult hm; |
| if (diff_halfMatch(text1, text2, hm)) { |
| // A half-match was found, sort out the return data. |
| // Send both pairs off for separate processing. |
| diff_main(hm.text1_a, hm.text2_a, checklines, deadline, diffs); |
| diffs.push_back(Diff(EQUAL, hm.mid_common)); |
| Diffs diffs_b; |
| diff_main(hm.text1_b, hm.text2_b, checklines, deadline, diffs_b); |
| diffs.splice(diffs.end(), diffs_b); |
| return; |
| } |
| } |
| |
| // Perform a real diff. |
| if (checklines && text1.length() > 100 && text2.length() > 100) { |
| diff_lineMode(text1, text2, deadline, diffs); |
| return; |
| } |
| |
| diff_bisect(text1, text2, deadline, diffs); |
| } |
| |
| /** |
| * Do a quick line-level diff on both strings, then rediff the parts for |
| * greater accuracy. |
| * This speedup can produce non-minimal diffs. |
| * @param text1 Old string to be diffed. |
| * @param text2 New string to be diffed. |
| * @param deadline Time when the diff should be complete by. |
| * @param diffs Linked List of Diff objects. |
| */ |
| private: |
| static void diff_lineMode(string_t text1, string_t text2, clock_t deadline, Diffs& diffs) { |
| // Scan the text on a line-by-line basis first. |
| Lines linearray; |
| diff_linesToChars(text1, text2, linearray); |
| |
| diff_main(text1, text2, false, deadline, diffs); |
| |
| // Convert the diff back to original text. |
| diff_charsToLines(diffs, linearray); |
| // Eliminate freak matches (e.g. blank lines) |
| diff_cleanupSemantic(diffs); |
| |
| // Rediff any replacement blocks, this time character-by-character. |
| // Add a dummy entry at the end. |
| diffs.push_back(Diff(EQUAL, string_t())); |
| int count_delete = 0; |
| int count_insert = 0; |
| string_t text_delete; |
| string_t text_insert; |
| |
| for (typename Diffs::iterator cur_diff = diffs.begin(); cur_diff != diffs.end(); ++cur_diff) { |
| switch ((*cur_diff).operation) { |
| case INSERT: |
| count_insert++; |
| text_insert += (*cur_diff).text; |
| break; |
| case DELETE: |
| count_delete++; |
| text_delete += (*cur_diff).text; |
| break; |
| case EQUAL: |
| // Upon reaching an equality, check for prior redundancies. |
| if (count_delete >= 1 && count_insert >= 1) { |
| // Delete the offending records and add the merged ones. |
| typename Diffs::iterator last = cur_diff; |
| std::advance(cur_diff, -(count_delete + count_insert)); |
| cur_diff = diffs.erase(cur_diff, last); |
| |
| Diffs new_diffs; |
| diff_main(text_delete, text_insert, false, deadline, new_diffs); |
| diffs.splice(cur_diff++, new_diffs); |
| --cur_diff; |
| } |
| count_insert = 0; |
| count_delete = 0; |
| text_delete.clear(); |
| text_insert.clear(); |
| break; |
| } |
| } |
| diffs.pop_back(); // Remove the dummy entry at the end. |
| } |
| |
| /** |
| * Find the 'middle snake' of a diff, split the problem in two |
| * and return the recursively constructed diff. |
| * See Myers 1986 paper: An O(ND) Difference Algorithm and Its Variations. |
| * @param text1 Old string to be diffed. |
| * @param text2 New string to be diffed. |
| * @return Linked List of Diff objects. |
| */ |
| protected: |
| static Diffs diff_bisect(const string_t &text1, const string_t &text2, clock_t deadline) { |
| Diffs diffs; |
| diff_bisect(text1, text2, deadline, diffs); |
| return diffs; |
| } |
| private: |
| static void diff_bisect(const string_t &text1, const string_t &text2, clock_t deadline, Diffs& diffs) { |
| // Cache the text lengths to prevent multiple calls. |
| const int text1_length = text1.length(); |
| const int text2_length = text2.length(); |
| const int max_d = (text1_length + text2_length + 1) / 2; |
| const int v_offset = max_d; |
| const int v_length = 2 * max_d; |
| std::vector<int> v1(v_length, -1), |
| v2(v_length, -1); |
| v1[v_offset + 1] = 0; |
| v2[v_offset + 1] = 0; |
| const int delta = text1_length - text2_length; |
| // If the total number of characters is odd, then the front path will |
| // collide with the reverse path. |
| const bool front = (delta % 2 != 0); |
| // Offsets for start and end of k loop. |
| // Prevents mapping of space beyond the grid. |
| int k1start = 0; |
| int k1end = 0; |
| int k2start = 0; |
| int k2end = 0; |
| for (int d = 0; d < max_d; d++) { |
| // Bail out if deadline is reached. |
| if (clock() > deadline) { |
| break; |
| } |
| |
| // Walk the front path one step. |
| for (int k1 = -d + k1start; k1 <= d - k1end; k1 += 2) { |
| const int k1_offset = v_offset + k1; |
| int x1; |
| if (k1 == -d || (k1 != d && v1[k1_offset - 1] < v1[k1_offset + 1])) { |
| x1 = v1[k1_offset + 1]; |
| } else { |
| x1 = v1[k1_offset - 1] + 1; |
| } |
| int y1 = x1 - k1; |
| while (x1 < text1_length && y1 < text2_length |
| && text1[x1] == text2[y1]) { |
| x1++; |
| y1++; |
| } |
| v1[k1_offset] = x1; |
| if (x1 > text1_length) { |
| // Ran off the right of the graph. |
| k1end += 2; |
| } else if (y1 > text2_length) { |
| // Ran off the bottom of the graph. |
| k1start += 2; |
| } else if (front) { |
| int k2_offset = v_offset + delta - k1; |
| if (k2_offset >= 0 && k2_offset < v_length && v2[k2_offset] != -1) { |
| // Mirror x2 onto top-left coordinate system. |
| int x2 = text1_length - v2[k2_offset]; |
| if (x1 >= x2) { |
| // Overlap detected. |
| diff_bisectSplit(text1, text2, x1, y1, deadline, diffs); |
| return; |
| } |
| } |
| } |
| } |
| |
| // Walk the reverse path one step. |
| for (int k2 = -d + k2start; k2 <= d - k2end; k2 += 2) { |
| const int k2_offset = v_offset + k2; |
| int x2; |
| if (k2 == -d || (k2 != d && v2[k2_offset - 1] < v2[k2_offset + 1])) { |
| x2 = v2[k2_offset + 1]; |
| } else { |
| x2 = v2[k2_offset - 1] + 1; |
| } |
| int y2 = x2 - k2; |
| while (x2 < text1_length && y2 < text2_length |
| && text1[text1_length - x2 - 1] == text2[text2_length - y2 - 1]) { |
| x2++; |
| y2++; |
| } |
| v2[k2_offset] = x2; |
| if (x2 > text1_length) { |
| // Ran off the left of the graph. |
| k2end += 2; |
| } else if (y2 > text2_length) { |
| // Ran off the top of the graph. |
| k2start += 2; |
| } else if (!front) { |
| int k1_offset = v_offset + delta - k2; |
| if (k1_offset >= 0 && k1_offset < v_length && v1[k1_offset] != -1) { |
| int x1 = v1[k1_offset]; |
| int y1 = v_offset + x1 - k1_offset; |
| // Mirror x2 onto top-left coordinate system. |
| x2 = text1_length - x2; |
| if (x1 >= x2) { |
| // Overlap detected. |
| diff_bisectSplit(text1, text2, x1, y1, deadline, diffs); |
| return; |
| } |
| } |
| } |
| } |
| } |
| // Diff took too long and hit the deadline or |
| // number of diffs equals number of characters, no commonality at all. |
| diffs.clear(); |
| diffs.push_back(Diff(DELETE, text1)); |
| diffs.push_back(Diff(INSERT, text2)); |
| } |
| |
| /** |
| * Given the location of the 'middle snake', split the diff in two parts |
| * and recurse. |
| * @param text1 Old string to be diffed. |
| * @param text2 New string to be diffed. |
| * @param x Index of split point in text1. |
| * @param y Index of split point in text2. |
| * @param deadline Time at which to bail if not yet complete. |
| * @param diffs LinkedList of Diff objects. |
| */ |
| private: |
| static void diff_bisectSplit(const string_t &text1, const string_t &text2, int x, int y, clock_t deadline, Diffs& diffs) { |
| string_t text1a = text1.substr(0, x); |
| string_t text2a = text2.substr(0, y); |
| string_t text1b = safeMid(text1, x); |
| string_t text2b = safeMid(text2, y); |
| |
| // Compute both diffs serially. |
| diff_main(text1a, text2a, false, deadline, diffs); |
| Diffs diffs_b; |
| diff_main(text1b, text2b, false, deadline, diffs_b); |
| diffs.splice(diffs.end(), diffs_b); |
| } |
| |
| protected: |
| struct LinePtr : std::pair<typename string_t::const_pointer, size_t> { |
| LinePtr() {} |
| LinePtr(typename string_t::const_pointer p, size_t n) : std::pair<typename string_t::const_pointer, size_t>(p, n) {} |
| bool operator<(const LinePtr& p) const |
| { return this->second < p.second? true : this->second > p.second? false : string_t::traits_type::compare(this->first, p.first, this->second) < 0; } |
| }; |
| struct Lines : std::vector<LinePtr> { string_t text1, text2; }; |
| |
| /** |
| * Split two texts into a list of strings. Reduce the texts to a string of |
| * hashes where each Unicode character represents one line. |
| * @param text1 First string. |
| * @param text2 Second string. |
| * @param lineArray Lines object, containing the encoded text1, the |
| * encoded text2 and the List of pointers to unique strings. The zeroth element |
| * of the List of unique strings is intentionally blank. |
| */ |
| static void diff_linesToChars(string_t &text1, string_t &text2, Lines& lineArray) { |
| std::map<LinePtr, size_t> lineHash; |
| lineArray.text1.swap(text1), lineArray.text2.swap(text2); |
| // e.g. linearray[4] == "Hello\n" |
| // e.g. linehash.get("Hello\n") == 4 |
| |
| // "\x00" is a valid character, but various debuggers don't like it. |
| // So we'll insert a junk entry to avoid generating a null character. |
| |
| text1 = diff_linesToCharsMunge(lineArray.text1, lineHash); |
| text2 = diff_linesToCharsMunge(lineArray.text2, lineHash); |
| |
| lineArray.resize(lineHash.size() + 1); |
| for (typename std::map<LinePtr, size_t>::const_iterator i = lineHash.begin(); i != lineHash.end(); ++i) |
| lineArray[(*i).second] = (*i).first; |
| } |
| |
| /** |
| * Split a text into a list of pointers to strings. Reduce the texts to a string of |
| * hashes where each Unicode character represents one line. |
| * @param text String to encode. |
| * @param lineHash Map of string pointers to indices. |
| * @return Encoded string. |
| */ |
| private: |
| static string_t diff_linesToCharsMunge(const string_t &text, std::map<LinePtr, size_t> &lineHash) { |
| string_t chars; |
| // Walk the text, pulling out a substring for each line. |
| // text.split('\n') would would temporarily double our memory footprint. |
| // Modifying text would create many large strings to garbage collect. |
| typename string_t::size_type lineLen; |
| for (typename string_t::const_pointer lineStart = text.c_str(), textEnd = lineStart + text.size(); lineStart < textEnd; lineStart += lineLen + 1) { |
| lineLen = next_token(text, traits::from_wchar(L'\n'), lineStart); |
| if (lineStart + lineLen == textEnd) --lineLen; |
| chars += (char_t)(*lineHash.insert(std::make_pair(LinePtr(lineStart, lineLen + 1), lineHash.size() + 1)).first).second; |
| } |
| return chars; |
| } |
| |
| /** |
| * Rehydrate the text in a diff from a string of line hashes to real lines of |
| * text. |
| * @param diffs LinkedList of Diff objects. |
| * @param lineArray List of pointers to unique strings. |
| */ |
| private: |
| static void diff_charsToLines(Diffs &diffs, const Lines& lineArray) { |
| for (typename Diffs::iterator cur_diff = diffs.begin(); cur_diff != diffs.end(); ++cur_diff) { |
| string_t text; |
| for (int y = 0; y < (int)(*cur_diff).text.length(); y++) { |
| const LinePtr& lp = lineArray[static_cast<size_t>((*cur_diff).text[y])]; |
| text.append(lp.first, lp.second); |
| } |
| (*cur_diff).text.swap(text); |
| } |
| } |
| |
| /** |
| * Determine the common prefix of two strings. |
| * @param text1 First string. |
| * @param text2 Second string. |
| * @return The number of characters common to the start of each string. |
| */ |
| public: |
| static int diff_commonPrefix(const string_t &text1, const string_t &text2) { |
| // Performance analysis: http://neil.fraser.name/news/2007/10/09/ |
| const int n = std::min(text1.length(), text2.length()); |
| for (int i = 0; i < n; i++) { |
| if (text1[i] != text2[i]) { |
| return i; |
| } |
| } |
| return n; |
| } |
| |
| /** |
| * Determine the common suffix of two strings. |
| * @param text1 First string. |
| * @param text2 Second string. |
| * @return The number of characters common to the end of each string. |
| */ |
| public: |
| static int diff_commonSuffix(const string_t &text1, const string_t &text2) { |
| // Performance analysis: http://neil.fraser.name/news/2007/10/09/ |
| const int text1_length = text1.length(); |
| const int text2_length = text2.length(); |
| const int n = std::min(text1_length, text2_length); |
| for (int i = 1; i <= n; i++) { |
| if (text1[text1_length - i] != text2[text2_length - i]) { |
| return i - 1; |
| } |
| } |
| return n; |
| } |
| |
| /** |
| * Determine if the suffix of one string is the prefix of another. |
| * @param text1 First string. |
| * @param text2 Second string. |
| * @return The number of characters common to the end of the first |
| * string and the start of the second string. |
| */ |
| protected: |
| static int diff_commonOverlap(const string_t &text1, const string_t &text2) { |
| // Cache the text lengths to prevent multiple calls. |
| const int text1_length = text1.length(); |
| const int text2_length = text2.length(); |
| // Eliminate the null case. |
| if (text1_length == 0 || text2_length == 0) { |
| return 0; |
| } |
| // Truncate the longer string. |
| string_t text1_trunc = text1; |
| string_t text2_trunc = text2; |
| if (text1_length > text2_length) { |
| text1_trunc = right(text1, text2_length); |
| } else if (text1_length < text2_length) { |
| text2_trunc = text2.substr(0, text1_length); |
| } |
| const int text_length = std::min(text1_length, text2_length); |
| // Quick check for the worst case. |
| if (text1_trunc == text2_trunc) { |
| return text_length; |
| } |
| |
| // Start by looking for a single character match |
| // and increase length until no match is found. |
| // Performance analysis: http://neil.fraser.name/news/2010/11/04/ |
| int best = 0; |
| int length = 1; |
| while (true) { |
| string_t pattern = right(text1_trunc, length); |
| size_t found = text2_trunc.find(pattern); |
| if (found == string_t::npos) { |
| return best; |
| } |
| length += found; |
| if (found == 0 || right(text1_trunc, length) == text2_trunc.substr(0, length)) { |
| best = length; |
| length++; |
| } |
| } |
| } |
| |
| protected: |
| struct HalfMatchResult { |
| string_t text1_a, text1_b, text2_a, text2_b, mid_common; |
| void swap(HalfMatchResult& hm) { |
| text1_a.swap(hm.text1_a), text1_b.swap(hm.text1_b), text2_a.swap(hm.text2_a), text2_b.swap(hm.text2_b), mid_common.swap(hm.mid_common); |
| } |
| }; |
| |
| /** |
| * Do the two texts share a substring which is at least half the length of |
| * the longer text? |
| * This speedup can produce non-minimal diffs. |
| * @param text1 First string. |
| * @param text2 Second string. |
| * @param hm HalfMatchResult object, containing the prefix of text1, the |
| * suffix of text1, the prefix of text2, the suffix of text2 and the |
| * common middle. |
| * @return Boolean true if there was a match, false otherwise. |
| */ |
| static bool diff_halfMatch(const string_t &text1, const string_t &text2, HalfMatchResult& hm) { |
| const string_t longtext = text1.length() > text2.length() ? text1 : text2; |
| const string_t shorttext = text1.length() > text2.length() ? text2 : text1; |
| if (longtext.length() < 4 || shorttext.length() * 2 < longtext.length()) { |
| return false; // Pointless. |
| } |
| |
| HalfMatchResult res1, res2; |
| // First check if the second quarter is the seed for a half-match. |
| bool hm1 = diff_halfMatchI(longtext, shorttext, |
| (longtext.length() + 3) / 4, res1); |
| // Check again based on the third quarter. |
| bool hm2 = diff_halfMatchI(longtext, shorttext, |
| (longtext.length() + 1) / 2, res2); |
| if (!hm1 && !hm2) { |
| return false; |
| } else if (!hm2) { |
| hm.swap(res1); |
| } else if (!hm1) { |
| hm.swap(res2); |
| } else { |
| // Both matched. Select the longest. |
| hm.swap(res1.mid_common.length() > res2.mid_common.length() ? res1 : res2); |
| } |
| |
| // A half-match was found, sort out the return data. |
| if (text1.length() <= text2.length()) { |
| hm.text1_a.swap(hm.text2_a); |
| hm.text1_b.swap(hm.text2_b); |
| } |
| return true; |
| } |
| |
| /** |
| * Does a substring of shorttext exist within longtext such that the |
| * substring is at least half the length of longtext? |
| * @param longtext Longer string. |
| * @param shorttext Shorter string. |
| * @param i Start index of quarter length substring within longtext. |
| * @param best HalfMatchResult object, containing the prefix of longtext, the |
| * suffix of longtext, the prefix of shorttext, the suffix of shorttext |
| * and the common middle. |
| * @return Boolean true if there was a match, false otherwise. |
| */ |
| private: |
| static bool diff_halfMatchI(const string_t &longtext, const string_t &shorttext, int i, HalfMatchResult& best) { |
| // Start with a 1/4 length substring at position i as a seed. |
| const string_t seed = safeMid(longtext, i, longtext.length() / 4); |
| size_t j = string_t::npos; |
| while ((j = shorttext.find(seed, j + 1)) != string_t::npos) { |
| const int prefixLength = diff_commonPrefix(safeMid(longtext, i), |
| safeMid(shorttext, j)); |
| const int suffixLength = diff_commonSuffix(longtext.substr(0, i), |
| shorttext.substr(0, j)); |
| if ((int)best.mid_common.length() < suffixLength + prefixLength) { |
| best.mid_common = safeMid(shorttext, j - suffixLength, suffixLength) |
| + safeMid(shorttext, j, prefixLength); |
| best.text1_a = longtext.substr(0, i - suffixLength); |
| best.text1_b = safeMid(longtext, i + prefixLength); |
| best.text2_a = shorttext.substr(0, j - suffixLength); |
| best.text2_b = safeMid(shorttext, j + prefixLength); |
| } |
| } |
| return best.mid_common.length() * 2 >= longtext.length(); |
| } |
| |
| /** |
| * Reduce the number of edits by eliminating semantically trivial equalities. |
| * @param diffs LinkedList of Diff objects. |
| */ |
| public: |
| static void diff_cleanupSemantic(Diffs &diffs) { |
| if (diffs.empty()) { |
| return; |
| } |
| bool changes = false; |
| std::vector<typename Diffs::iterator> equalities; // Stack of equalities. |
| string_t lastequality; // Always equal to equalities.lastElement().text |
| typename Diffs::iterator cur_diff; |
| // Number of characters that changed prior to the equality. |
| int length_insertions1 = 0; |
| int length_deletions1 = 0; |
| // Number of characters that changed after the equality. |
| int length_insertions2 = 0; |
| int length_deletions2 = 0; |
| for (cur_diff = diffs.begin(); cur_diff != diffs.end();) { |
| if ((*cur_diff).operation == EQUAL) { |
| // Equality found. |
| equalities.push_back(cur_diff); |
| length_insertions1 = length_insertions2; |
| length_deletions1 = length_deletions2; |
| length_insertions2 = 0; |
| length_deletions2 = 0; |
| lastequality = (*cur_diff).text; |
| } else { |
| // An insertion or deletion. |
| if ((*cur_diff).operation == INSERT) { |
| length_insertions2 += (*cur_diff).text.length(); |
| } else { |
| length_deletions2 += (*cur_diff).text.length(); |
| } |
| // Eliminate an equality that is smaller or equal to the edits on both |
| // sides of it. |
| if (!lastequality.empty() |
| && ((int)lastequality.length() |
| <= std::max(length_insertions1, length_deletions1)) |
| && ((int)lastequality.length() |
| <= std::max(length_insertions2, length_deletions2))) { |
| // printf("Splitting: '%s'\n", qPrintable(lastequality)); |
| // Walk back to offending equality. |
| // Change second copy to insert. |
| (*(cur_diff = equalities.back())).operation = INSERT; |
| // Duplicate record. |
| diffs.insert(cur_diff, Diff(DELETE, lastequality)); |
| equalities.pop_back(); // Throw away the equality we just deleted. |
| if (!equalities.empty()) { |
| // Throw away the previous equality (it needs to be reevaluated). |
| equalities.pop_back(); |
| } |
| length_insertions1 = 0; // Reset the counters. |
| length_deletions1 = 0; |
| length_insertions2 = 0; |
| length_deletions2 = 0; |
| lastequality = string_t(); |
| changes = true; |
| |
| if (!equalities.empty()) |
| // There is a safe equality we can fall back to. |
| cur_diff = equalities.back(); |
| else |
| { |
| // There are no previous equalities, walk back to the start. |
| cur_diff = diffs.begin(); |
| continue; |
| } |
| } |
| } |
| ++cur_diff; |
| } |
| |
| // Normalize the diff. |
| if (changes) { |
| diff_cleanupMerge(diffs); |
| } |
| diff_cleanupSemanticLossless(diffs); |
| |
| // Find any overlaps between deletions and insertions. |
| // e.g: <del>abcxxx</del><ins>xxxdef</ins> |
| // -> <del>abc</del>xxx<ins>def</ins> |
| // e.g: <del>xxxabc</del><ins>defxxx</ins> |
| // -> <ins>def</ins>xxx<del>abc</del> |
| // Only extract an overlap if it is as big as the edit ahead or behind it. |
| if ((cur_diff = diffs.begin()) != diffs.end()) { |
| for (typename Diffs::iterator prev_diff = cur_diff; ++cur_diff != diffs.end(); prev_diff = cur_diff) { |
| if ((*prev_diff).operation == DELETE && |
| (*cur_diff).operation == INSERT) { |
| string_t deletion = (*prev_diff).text; |
| string_t insertion = (*cur_diff).text; |
| int overlap_length1 = diff_commonOverlap(deletion, insertion); |
| int overlap_length2 = diff_commonOverlap(insertion, deletion); |
| if (overlap_length1 >= overlap_length2) { |
| if (overlap_length1 >= deletion.size() / 2.0 || |
| overlap_length1 >= insertion.size() / 2.0) { |
| // Overlap found. Insert an equality and trim the surrounding edits. |
| diffs.insert(cur_diff, Diff(EQUAL, insertion.substr(0, overlap_length1))); |
| prev_diff->text = |
| deletion.substr(0, deletion.length() - overlap_length1); |
| cur_diff->text = safeMid(insertion, overlap_length1); |
| // diffs.insert inserts the element before the cursor, so there is |
| // no need to step past the new element. |
| } |
| } else { |
| if (overlap_length2 >= deletion.length() / 2.0 || |
| overlap_length2 >= insertion.length() / 2.0) { |
| // Reverse overlap found. |
| // Insert an equality and swap and trim the surrounding edits. |
| diffs.insert(cur_diff, Diff(EQUAL, deletion.substr(0, overlap_length2))); |
| prev_diff->operation = INSERT; |
| prev_diff->text = |
| insertion.substr(0, insertion.length() - overlap_length2); |
| cur_diff->operation = DELETE; |
| cur_diff->text = safeMid(deletion, overlap_length2); |
| // diffs.insert inserts the element before the cursor, so there is |
| // no need to step past the new element. |
| } |
| } |
| if (++cur_diff == diffs.end()) break; |
| } |
| } |
| } |
| } |
| |
| /** |
| * Look for single edits surrounded on both sides by equalities |
| * which can be shifted sideways to align the edit to a word boundary. |
| * e.g: The c<ins>at c</ins>ame. -> The <ins>cat </ins>came. |
| * @param diffs LinkedList of Diff objects. |
| */ |
| public: |
| static void diff_cleanupSemanticLossless(Diffs &diffs) { |
| string_t equality1, edit, equality2; |
| string_t commonString; |
| int commonOffset; |
| int score, bestScore; |
| string_t bestEquality1, bestEdit, bestEquality2; |
| // Create a new iterator at the start. |
| typename Diffs::iterator prev_diff = diffs.begin(), cur_diff = prev_diff; |
| if (prev_diff == diffs.end() || ++cur_diff == diffs.end()) return; |
| |
| // Intentionally ignore the first and last element (don't need checking). |
| for (typename Diffs::iterator next_diff = cur_diff; ++next_diff != diffs.end(); prev_diff = cur_diff, cur_diff = next_diff) { |
| if ((*prev_diff).operation == EQUAL && |
| (*next_diff).operation == EQUAL) { |
| // This is a single edit surrounded by equalities. |
| equality1 = (*prev_diff).text; |
| edit = (*cur_diff).text; |
| equality2 = (*next_diff).text; |
| |
| // First, shift the edit as far left as possible. |
| commonOffset = diff_commonSuffix(equality1, edit); |
| if (commonOffset != 0) { |
| commonString = safeMid(edit, edit.length() - commonOffset); |
| equality1 = equality1.substr(0, equality1.length() - commonOffset); |
| edit = commonString + edit.substr(0, edit.length() - commonOffset); |
| equality2 = commonString + equality2; |
| } |
| |
| // Second, step character by character right, looking for the best fit. |
| bestEquality1 = equality1; |
| bestEdit = edit; |
| bestEquality2 = equality2; |
| bestScore = diff_cleanupSemanticScore(equality1, edit) |
| + diff_cleanupSemanticScore(edit, equality2); |
| while (!edit.empty() && !equality2.empty() |
| && edit[0] == equality2[0]) { |
| equality1 += edit[0]; |
| edit = safeMid(edit, 1) + equality2[0]; |
| equality2 = safeMid(equality2, 1); |
| score = diff_cleanupSemanticScore(equality1, edit) |
| + diff_cleanupSemanticScore(edit, equality2); |
| // The >= encourages trailing rather than leading whitespace on edits. |
| if (score >= bestScore) { |
| bestScore = score; |
| bestEquality1 = equality1; |
| bestEdit = edit; |
| bestEquality2 = equality2; |
| } |
| } |
| |
| if ((*prev_diff).text != bestEquality1) { |
| // We have an improvement, save it back to the diff. |
| if (!bestEquality1.empty()) { |
| (*prev_diff).text = bestEquality1; |
| } else { |
| diffs.erase(prev_diff); |
| } |
| (*cur_diff).text = bestEdit; |
| if (!bestEquality2.empty()) { |
| (*next_diff).text = bestEquality2; |
| } else { |
| diffs.erase(next_diff); // Delete nextDiff. |
| next_diff = cur_diff; |
| cur_diff = prev_diff; |
| } |
| } |
| } |
| } |
| } |
| |
| /** |
| * Given two strings, compute a score representing whether the internal |
| * boundary falls on logical boundaries. |
| * Scores range from 6 (best) to 0 (worst). |
| * @param one First string. |
| * @param two Second string. |
| * @return The score. |
| */ |
| private: |
| static int diff_cleanupSemanticScore(const string_t &one, const string_t &two) { |
| if (one.empty() || two.empty()) { |
| // Edges are the best. |
| return 6; |
| } |
| |
| // Each port of this function behaves slightly differently due to |
| // subtle differences in each language's definition of things like |
| // 'whitespace'. Since this function's purpose is largely cosmetic, |
| // the choice has been made to use each language's native features |
| // rather than force total conformity. |
| char_t char1 = one[one.length() - 1]; |
| char_t char2 = two[0]; |
| bool nonAlphaNumeric1 = !traits::is_alnum(char1); |
| bool nonAlphaNumeric2 = !traits::is_alnum(char2); |
| bool whitespace1 = nonAlphaNumeric1 && traits::is_space(char1); |
| bool whitespace2 = nonAlphaNumeric2 && traits::is_space(char2); |
| bool lineBreak1 = whitespace1 && is_control(char1); |
| bool lineBreak2 = whitespace2 && is_control(char2); |
| bool blankLine1 = false; |
| if (lineBreak1) { |
| typename string_t::const_reverse_iterator p1 = one.rbegin(), p2 = one.rend(); |
| if (traits::to_wchar(*p1) == L'\n' && ++p1 != p2) { |
| if (traits::to_wchar(*p1) == L'\r') |
| ++p1; |
| blankLine1 = p1 != p2 && traits::to_wchar(*p1) == L'\n'; |
| } |
| } |
| bool blankLine2 = false; |
| if (lineBreak2) { |
| typename string_t::const_iterator p1 = two.end(), p2 = two.begin(); |
| if (traits::to_wchar(*p2) == L'\r') |
| ++p2; |
| if (p2 != p1 && traits::to_wchar(*p2) == L'\n') { |
| if (++p2 != p1 && traits::to_wchar(*p2) == L'\r') |
| ++p2; |
| if (p2 != p1 && traits::to_wchar(*p2) == L'\n') |
| blankLine2 = true; |
| } |
| } |
| |
| if (blankLine1 || blankLine2) { |
| // Five points for blank lines. |
| return 5; |
| } else if (lineBreak1 || lineBreak2) { |
| // Four points for line breaks. |
| return 4; |
| } else if (nonAlphaNumeric1 && !whitespace1 && whitespace2) { |
| // Three points for end of sentences. |
| return 3; |
| } else if (whitespace1 || whitespace2) { |
| // Two points for whitespace. |
| return 2; |
| } else if (nonAlphaNumeric1 || nonAlphaNumeric2) { |
| // One point for non-alphanumeric. |
| return 1; |
| } |
| return 0; |
| } |
| /** |
| * Reduce the number of edits by eliminating operationally trivial equalities. |
| * @param diffs LinkedList of Diff objects. |
| */ |
| public: |
| void diff_cleanupEfficiency(Diffs &diffs) const { |
| if (diffs.empty()) { |
| return; |
| } |
| bool changes = false; |
| std::vector<typename Diffs::iterator> equalities; // Stack of equalities. |
| string_t lastequality; // Always equal to equalities.lastElement().text |
| // Is there an insertion operation before the last equality. |
| bool pre_ins = false; |
| // Is there a deletion operation before the last equality. |
| bool pre_del = false; |
| // Is there an insertion operation after the last equality. |
| bool post_ins = false; |
| // Is there a deletion operation after the last equality. |
| bool post_del = false; |
| |
| for (typename Diffs::iterator cur_diff = diffs.begin(); cur_diff != diffs.end();) { |
| if ((*cur_diff).operation == EQUAL) { |
| // Equality found. |
| if ((int)(*cur_diff).text.length() < Diff_EditCost && (post_ins || post_del)) { |
| // Candidate found. |
| equalities.push_back(cur_diff); |
| pre_ins = post_ins; |
| pre_del = post_del; |
| lastequality = (*cur_diff).text; |
| } else { |
| // Not a candidate, and can never become one. |
| equalities.clear(); |
| lastequality.clear(); |
| } |
| post_ins = post_del = false; |
| } else { |
| // An insertion or deletion. |
| if ((*cur_diff).operation == DELETE) { |
| post_del = true; |
| } else { |
| post_ins = true; |
| } |
| /* |
| * Five types to be split: |
| * <ins>A</ins><del>B</del>XY<ins>C</ins><del>D</del> |
| * <ins>A</ins>X<ins>C</ins><del>D</del> |
| * <ins>A</ins><del>B</del>X<ins>C</ins> |
| * <ins>A</del>X<ins>C</ins><del>D</del> |
| * <ins>A</ins><del>B</del>X<del>C</del> |
| */ |
| if (!lastequality.empty() |
| && ((pre_ins && pre_del && post_ins && post_del) |
| || (((int)lastequality.length() < Diff_EditCost / 2) |
| && ((pre_ins ? 1 : 0) + (pre_del ? 1 : 0) |
| + (post_ins ? 1 : 0) + (post_del ? 1 : 0)) == 3))) { |
| // printf("Splitting: '%s'\n", qPrintable(lastequality)); |
| // Walk back to offending equality. |
| // Change second copy to insert. |
| (*(cur_diff = equalities.back())).operation = INSERT; |
| // Duplicate record. |
| diffs.insert(cur_diff, Diff(DELETE, lastequality)); |
| equalities.pop_back(); // Throw away the equality we just deleted. |
| lastequality.clear(); |
| changes = true; |
| if (pre_ins && pre_del) { |
| // No changes made which could affect previous entry, keep going. |
| post_ins = post_del = true; |
| equalities.clear(); |
| } else { |
| if (!equalities.empty()) { |
| // Throw away the previous equality (it needs to be reevaluated). |
| equalities.pop_back(); |
| } |
| post_ins = post_del = false; |
| if (!equalities.empty()) |
| // There is a safe equality we can fall back to. |
| cur_diff = equalities.back(); |
| else |
| { |
| // There are no previous equalities, walk back to the start. |
| cur_diff = diffs.begin(); |
| continue; |
| } |
| } |
| } |
| } |
| ++cur_diff; |
| } |
| |
| if (changes) { |
| diff_cleanupMerge(diffs); |
| } |
| } |
| |
| /** |
| * Reorder and merge like edit sections. Merge equalities. |
| * Any edit section can move as long as it doesn't cross an equality. |
| * @param diffs LinkedList of Diff objects. |
| */ |
| public: |
| static void diff_cleanupMerge(Diffs &diffs) { |
| diffs.push_back(Diff(EQUAL, string_t())); // Add a dummy entry at the end. |
| typename Diffs::iterator prev_diff, cur_diff; |
| int count_delete = 0; |
| int count_insert = 0; |
| string_t text_delete; |
| string_t text_insert; |
| Diff *prevEqual = NULL; |
| int commonlength; |
| for (cur_diff = diffs.begin(); cur_diff != diffs.end(); ++cur_diff) { |
| switch ((*cur_diff).operation) { |
| case INSERT: |
| count_insert++; |
| text_insert += (*cur_diff).text; |
| prevEqual = NULL; |
| break; |
| case DELETE: |
| count_delete++; |
| text_delete += (*cur_diff).text; |
| prevEqual = NULL; |
| break; |
| case EQUAL: |
| if (count_delete + count_insert > 1) { |
| // Delete the offending records. |
| prev_diff = cur_diff; |
| std::advance(prev_diff, -(count_delete + count_insert)); |
| diffs.erase(prev_diff, cur_diff); |
| if (count_delete != 0 && count_insert != 0) { |
| // Factor out any common prefixes. |
| commonlength = diff_commonPrefix(text_insert, text_delete); |
| if (commonlength != 0) { |
| if (cur_diff != diffs.begin()) { |
| prev_diff = cur_diff; |
| if ((*--prev_diff).operation != EQUAL) { |
| llvm_unreachable("Previous diff should have been an equality."); |
| } |
| (*prev_diff).text += text_insert.substr(0, commonlength); |
| } else { |
| diffs.insert(cur_diff, Diff(EQUAL, text_insert.substr(0, commonlength))); |
| } |
| text_insert = safeMid(text_insert, commonlength); |
| text_delete = safeMid(text_delete, commonlength); |
| } |
| // Factor out any common suffixes. |
| commonlength = diff_commonSuffix(text_insert, text_delete); |
| if (commonlength != 0) { |
| (*cur_diff).text = safeMid(text_insert, text_insert.length() |
| - commonlength) + (*cur_diff).text; |
| text_insert = text_insert.substr(0, text_insert.length() |
| - commonlength); |
| text_delete = text_delete.substr(0, text_delete.length() |
| - commonlength); |
| } |
| } |
| // Insert the merged records. |
| if (!text_delete.empty()) { |
| diffs.insert(cur_diff, Diff(DELETE, text_delete)); |
| } |
| if (!text_insert.empty()) { |
| diffs.insert(cur_diff, Diff(INSERT, text_insert)); |
| } |
| } else if (prevEqual != NULL) { |
| // Merge this equality with the previous one. |
| prevEqual->text += (*cur_diff).text; |
| diffs.erase(cur_diff--); |
| } |
| |
| count_insert = 0; |
| count_delete = 0; |
| text_delete.clear(); |
| text_insert.clear(); |
| prevEqual = &*cur_diff; |
| break; |
| } |
| |
| } |
| if (diffs.back().text.empty()) { |
| diffs.pop_back(); // Remove the dummy entry at the end. |
| } |
| |
| /* |
| * Second pass: look for single edits surrounded on both sides by equalities |
| * which can be shifted sideways to eliminate an equality. |
| * e.g: A<ins>BA</ins>C -> <ins>AB</ins>AC |
| */ |
| bool changes = false; |
| // Create a new iterator at the start. |
| // (As opposed to walking the current one back.) |
| prev_diff = cur_diff = diffs.begin(); |
| if (prev_diff != diffs.end() && ++cur_diff != diffs.end()) { |
| // Intentionally ignore the first and last element (don't need checking). |
| for (typename Diffs::iterator next_diff = cur_diff; ++next_diff != diffs.end(); prev_diff = cur_diff, cur_diff = next_diff) { |
| if ((*prev_diff).operation == EQUAL && |
| (*next_diff).operation == EQUAL) { |
| // This is a single edit surrounded by equalities. |
| if ((*cur_diff).text.size() >= (*prev_diff).text.size() && |
| (*cur_diff).text.compare((*cur_diff).text.size() - (*prev_diff).text.size(), (*prev_diff).text.size(), (*prev_diff).text) == 0) { |
| // Shift the edit over the previous equality. |
| (*cur_diff).text = (*prev_diff).text |
| + (*cur_diff).text.substr(0, (*cur_diff).text.length() |
| - (*prev_diff).text.length()); |
| (*next_diff).text = (*prev_diff).text + (*next_diff).text; |
| diffs.erase(prev_diff); |
| cur_diff = next_diff; |
| changes = true; |
| if (++next_diff == diffs.end()) break; |
| } else if ((*cur_diff).text.size() >= (*next_diff).text.size() && (*cur_diff).text.compare(0, (*next_diff).text.size(), (*next_diff).text) == 0) { |
| // Shift the edit over the next equality. |
| (*prev_diff).text += (*next_diff).text; |
| (*cur_diff).text = safeMid((*cur_diff).text, (*next_diff).text.length()) |
| + (*next_diff).text; |
| next_diff = diffs.erase(next_diff); // Delete nextDiff. |
| changes = true; |
| if (next_diff == diffs.end()) break; |
| } |
| } |
| } |
| } |
| // If shifts were made, the diff needs reordering and another shift sweep. |
| if (changes) { |
| diff_cleanupMerge(diffs); |
| } |
| } |
| |
| /** |
| * loc is a location in text1, compute and return the equivalent location in |
| * text2. |
| * e.g. "The cat" vs "The big cat", 1->1, 5->8 |
| * @param diffs LinkedList of Diff objects. |
| * @param loc Location within text1. |
| * @return Location within text2. |
| */ |
| public: |
| static int diff_xIndex(const Diffs &diffs, int loc) { |
| int chars1 = 0; |
| int chars2 = 0; |
| int last_chars1 = 0; |
| int last_chars2 = 0; |
| typename Diffs::const_iterator last_diff = diffs.end(), cur_diff; |
| for (cur_diff = diffs.begin(); cur_diff != diffs.end(); ++cur_diff) { |
| if ((*cur_diff).operation != INSERT) { |
| // Equality or deletion. |
| chars1 += (*cur_diff).text.length(); |
| } |
| if ((*cur_diff).operation != DELETE) { |
| // Equality or insertion. |
| chars2 += (*cur_diff).text.length(); |
| } |
| if (chars1 > loc) { |
| // Overshot the location. |
| last_diff = cur_diff; |
| break; |
| } |
| last_chars1 = chars1; |
| last_chars2 = chars2; |
| } |
| if (last_diff != diffs.end() && (*last_diff).operation == DELETE) { |
| // The location was deleted. |
| return last_chars2; |
| } |
| // Add the remaining character length. |
| return last_chars2 + (loc - last_chars1); |
| } |
| |
| /** |
| * Convert a Diff list into a pretty HTML report. |
| * @param diffs LinkedList of Diff objects. |
| * @return HTML representation. |
| */ |
| public: |
| static string_t diff_prettyHtml(const Diffs &diffs) { |
| string_t html; |
| string_t text; |
| for (typename Diffs::const_iterator cur_diff = diffs.begin(); cur_diff != diffs.end(); ++cur_diff) { |
| typename string_t::size_type n = (*cur_diff).text.size(); |
| typename string_t::const_pointer p, end; |
| for (p = (*cur_diff).text.c_str(), end = p + n; p != end; ++p) |
| switch (traits::to_wchar(*p)) { |
| case L'&': n += 4; break; |
| case L'<': |
| case L'>': n += 3; break; |
| case L'\n': n += 9; break; |
| } |
| if (n == (*cur_diff).text.size()) |
| text = (*cur_diff).text; |
| else { |
| text.clear(); |
| text.reserve(n); |
| for (p = (*cur_diff).text.c_str(); p != end; ++p) |
| switch (traits::to_wchar(*p)) { |
| case L'&': text += traits::cs(L"&"); break; |
| case L'<': text += traits::cs(L"<"); break; |
| case L'>': text += traits::cs(L">"); break; |
| case L'\n': text += traits::cs(L"¶<br>"); break; |
| default: text += *p; |
| } |
| } |
| switch ((*cur_diff).operation) { |
| case INSERT: |
| html += traits::cs(L"<ins style=\"background:#e6ffe6;\">") + text + traits::cs(L"</ins>"); |
| break; |
| case DELETE: |
| html += traits::cs(L"<del style=\"background:#ffe6e6;\">") + text + traits::cs(L"</del>"); |
| break; |
| case EQUAL: |
| html += traits::cs(L"<span>") + text + traits::cs(L"</span>"); |
| break; |
| } |
| } |
| return html; |
| } |
| |
| /** |
| * Compute and return the source text (all equalities and deletions). |
| * @param diffs LinkedList of Diff objects. |
| * @return Source text. |
| */ |
| public: |
| static string_t diff_text1(const Diffs &diffs) { |
| string_t text; |
| for (typename Diffs::const_iterator cur_diff = diffs.begin(); cur_diff != diffs.end(); ++cur_diff) { |
| if ((*cur_diff).operation != INSERT) { |
| text += (*cur_diff).text; |
| } |
| } |
| return text; |
| } |
| |
| /** |
| * Compute and return the destination text (all equalities and insertions). |
| * @param diffs LinkedList of Diff objects. |
| * @return Destination text. |
| */ |
| public: |
| static string_t diff_text2(const Diffs &diffs) { |
| string_t text; |
| for (typename Diffs::const_iterator cur_diff = diffs.begin(); cur_diff != diffs.end(); ++cur_diff) { |
| if ((*cur_diff).operation != DELETE) { |
| text += (*cur_diff).text; |
| } |
| } |
| return text; |
| } |
| |
| /** |
| * Compute the Levenshtein distance; the number of inserted, deleted or |
| * substituted characters. |
| * @param diffs LinkedList of Diff objects. |
| * @return Number of changes. |
| */ |
| public: |
| static int diff_levenshtein(const Diffs &diffs) { |
| int levenshtein = 0; |
| int insertions = 0; |
| int deletions = 0; |
| for (typename Diffs::const_iterator cur_diff = diffs.begin(); cur_diff != diffs.end(); ++cur_diff) { |
| switch ((*cur_diff).operation) { |
| case INSERT: |
| insertions += (*cur_diff).text.length(); |
| break; |
| case DELETE: |
| deletions += (*cur_diff).text.length(); |
| break; |
| case EQUAL: |
| // A deletion and an insertion is one substitution. |
| levenshtein += std::max(insertions, deletions); |
| insertions = 0; |
| deletions = 0; |
| break; |
| } |
| } |
| levenshtein += std::max(insertions, deletions); |
| return levenshtein; |
| } |
| |
| /** |
| * Crush the diff into an encoded string which describes the operations |
| * required to transform text1 into text2. |
| * E.g. =3\t-2\t+ing -> Keep 3 chars, delete 2 chars, insert 'ing'. |
| * Operations are tab-separated. Inserted text is escaped using %xx notation. |
| * @param diffs Array of diff tuples. |
| * @return Delta text. |
| */ |
| public: |
| static string_t diff_toDelta(const Diffs &diffs) { |
| string_t text; |
| for (typename Diffs::const_iterator cur_diff = diffs.begin(); cur_diff != diffs.end(); ++cur_diff) { |
| switch ((*cur_diff).operation) { |
| case INSERT: { |
| text += traits::from_wchar(L'+'); |
| append_percent_encoded(text, (*cur_diff).text); |
| text += traits::from_wchar(L'\t'); |
| break; |
| } |
| case DELETE: |
| text += traits::from_wchar(L'-') + to_string((*cur_diff).text.length()) + traits::from_wchar(L'\t'); |
| break; |
| case EQUAL: |
| text += traits::from_wchar(L'=') + to_string((*cur_diff).text.length()) + traits::from_wchar(L'\t'); |
| break; |
| } |
| } |
| if (!text.empty()) { |
| // Strip off trailing tab character. |
| text = text.substr(0, text.length() - 1); |
| } |
| return text; |
| } |
| |
| /** |
| * Given the original text1, and an encoded string which describes the |
| * operations required to transform text1 into text2, compute the full diff. |
| * @param text1 Source string for the diff. |
| * @param delta Delta text. |
| * @return Array of diff tuples or null if invalid. |
| * @throws string_t If invalid input. |
| */ |
| public: |
| static Diffs diff_fromDelta(const string_t &text1, const string_t &delta) { |
| Diffs diffs; |
| int pointer = 0; // Cursor in text1 |
| typename string_t::size_type token_len; |
| for (typename string_t::const_pointer token = delta.c_str(); token - delta.c_str() < (int)delta.length(); token += token_len + 1) { |
| token_len = next_token(delta, traits::from_wchar(L'\t'), token); |
| if (token_len == 0) { |
| // Blank tokens are ok (from a trailing \t). |
| continue; |
| } |
| // Each token begins with a one character parameter which specifies the |
| // operation of this token (delete, insert, equality). |
| string_t param(token + 1, token_len - 1); |
| switch (traits::to_wchar(*token)) { |
| case L'+': |
| percent_decode(param); |
| diffs.push_back(Diff(INSERT, param)); |
| break; |
| case L'-': |
| // Fall through. |
| case L'=': { |
| int n; |
| n = to_int(param); |
| if (n < 0) { |
| llvm_unreachable("Negative number in diff_fromDelta: " + param); |
| } |
| string_t text; |
| text = safeMid(text1, pointer, n); |
| pointer += n; |
| if (traits::to_wchar(*token) == L'=') { |
| diffs.push_back(Diff(EQUAL, text)); |
| } else { |
| diffs.push_back(Diff(DELETE, text)); |
| } |
| break; |
| } |
| default: |
| llvm_unreachable(traits::cs(L"Invalid diff operation in diff_fromDelta: " + *token)); |
| } |
| } |
| if (pointer != text1.length()) { |
| llvm_unreachable(traits::cs(L"Delta length (") + to_string(pointer) |
| + traits::cs(L") smaller than source text length (") |
| + to_string(text1.length()) + traits::from_wchar(L')')); |
| } |
| return diffs; |
| } |
| |
| |
| // MATCH FUNCTIONS |
| |
| |
| /** |
| * Locate the best instance of 'pattern' in 'text' near 'loc'. |
| * Returns -1 if no match found. |
| * @param text The text to search. |
| * @param pattern The pattern to search for. |
| * @param loc The location to search around. |
| * @return Best match index or -1. |
| */ |
| public: |
| int match_main(const string_t &text, const string_t &pattern, int loc) const { |
| loc = std::max(0, std::min(loc, (int)text.length())); |
| if (text == pattern) { |
| // Shortcut (potentially not guaranteed by the algorithm) |
| return 0; |
| } else if (text.empty()) { |
| // Nothing to match. |
| return -1; |
| } else if (loc + pattern.length() <= text.length() |
| && safeMid(text, loc, pattern.length()) == pattern) { |
| // Perfect match at the perfect spot! (Includes case of null pattern) |
| return loc; |
| } else { |
| // Do a fuzzy compare. |
| return match_bitap(text, pattern, loc); |
| } |
| } |
| |
| /** |
| * Locate the best instance of 'pattern' in 'text' near 'loc' using the |
| * Bitap algorithm. Returns -1 if no match found. |
| * @param text The text to search. |
| * @param pattern The pattern to search for. |
| * @param loc The location to search around. |
| * @return Best match index or -1. |
| */ |
| protected: |
| int match_bitap(const string_t &text, const string_t &pattern, int loc) const { |
| if (!(Match_MaxBits == 0 || (int)pattern.length() <= Match_MaxBits)) { |
| llvm_unreachable("Pattern too long for this application."); |
| } |
| |
| // Initialise the alphabet. |
| std::map<char_t, int> s; |
| match_alphabet(pattern, s); |
| |
| // Highest score beyond which we give up. |
| double score_threshold = Match_Threshold; |
| // Is there a nearby exact match? (speedup) |
| size_t best_loc = text.find(pattern, loc); |
| if (best_loc != string_t::npos) { |
| score_threshold = std::min(match_bitapScore(0, best_loc, loc, pattern), |
| score_threshold); |
| // What about in the other direction? (speedup) |
| best_loc = text.rfind(pattern, loc + pattern.length()); |
| if (best_loc != string_t::npos) { |
| score_threshold = std::min(match_bitapScore(0, best_loc, loc, pattern), |
| score_threshold); |
| } |
| } |
| |
| // Initialise the bit arrays. |
| int matchmask = 1 << (pattern.length() - 1); |
| best_loc = -1; |
| |
| int bin_min, bin_mid; |
| int bin_max = pattern.length() + text.length(); |
| int *rd; |
| int *last_rd = NULL; |
| for (int d = 0; d < (int)pattern.length(); d++) { |
| // Scan for the best match; each iteration allows for one more error. |
| // Run a binary search to determine how far from 'loc' we can stray at |
| // this error level. |
| bin_min = 0; |
| bin_mid = bin_max; |
| while (bin_min < bin_mid) { |
| if (match_bitapScore(d, loc + bin_mid, loc, pattern) |
| <= score_threshold) { |
| bin_min = bin_mid; |
| } else { |
| bin_max = bin_mid; |
| } |
| bin_mid = (bin_max - bin_min) / 2 + bin_min; |
| } |
| // Use the result from this iteration as the maximum for the next. |
| bin_max = bin_mid; |
| int start = std::max(1, loc - bin_mid + 1); |
| int finish = std::min(loc + bin_mid, (int)text.length()) + pattern.length(); |
| |
| rd = new int[finish + 2]; |
| rd[finish + 1] = (1 << d) - 1; |
| for (int j = finish; j >= start; j--) { |
| int charMatch; |
| if ((int)text.length() <= j - 1) { |
| // Out of range. |
| charMatch = 0; |
| } else { |
| charMatch = s[text[j - 1]]; |
| } |
| if (d == 0) { |
| // First pass: exact match. |
| rd[j] = ((rd[j + 1] << 1) | 1) & charMatch; |
| } else { |
| // Subsequent passes: fuzzy match. |
| rd[j] = (((rd[j + 1] << 1) | 1) & charMatch) |
| | (((last_rd[j + 1] | last_rd[j]) << 1) | 1) |
| | last_rd[j + 1]; |
| } |
| if ((rd[j] & matchmask) != 0) { |
| double score = match_bitapScore(d, j - 1, loc, pattern); |
| // This match will almost certainly be better than any existing |
| // match. But check anyway. |
| if (score <= score_threshold) { |
| // Told you so. |
| score_threshold = score; |
| best_loc = j - 1; |
| if (best_loc > loc) { |
| // When passing loc, don't exceed our current distance from loc. |
| start = std::max(1, 2 * loc - (int)best_loc); |
| } else { |
| // Already passed loc, downhill from here on in. |
| break; |
| } |
| } |
| } |
| } |
| if (match_bitapScore(d + 1, loc, loc, pattern) > score_threshold) { |
| // No hope for a (better) match at greater error levels. |
| break; |
| } |
| delete [] last_rd; |
| last_rd = rd; |
| } |
| delete [] last_rd; |
| delete [] rd; |
| return best_loc; |
| } |
| |
| /** |
| * Compute and return the score for a match with e errors and x location. |
| * @param e Number of errors in match. |
| * @param x Location of match. |
| * @param loc Expected location of match. |
| * @param pattern Pattern being sought. |
| * @return Overall score for match (0.0 = good, 1.0 = bad). |
| */ |
| private: |
| double match_bitapScore(int e, int x, int loc, const string_t &pattern) const { |
| const float accuracy = static_cast<float> (e) / pattern.length(); |
| const int proximity = (loc - x < 0)? (x - loc) : (loc - x); |
| if (Match_Distance == 0) { |
| // Dodge divide by zero error. |
| return proximity == 0 ? accuracy : 1.0; |
| } |
| return accuracy + (proximity / static_cast<float> (Match_Distance)); |
| } |
| |
| /** |
| * Initialise the alphabet for the Bitap algorithm. |
| * @param pattern The text to encode. |
| * @param s Hash of character locations. |
| */ |
| protected: |
| static void match_alphabet(const string_t &pattern, std::map<char_t, int>& s) { |
| // There is no need to initialize map values, since they are zero-initialized by default |
| for (size_t i = 0; i < pattern.length(); i++) |
| s[pattern[i]] |= (1 << (pattern.length() - i - 1)); |
| } |
| |
| |
| // PATCH FUNCTIONS |
| |
| |
| /** |
| * Increase the context until it is unique, |
| * but don't let the pattern expand beyond Match_MaxBits. |
| * @param patch The patch to grow. |
| * @param text Source text. |
| */ |
| protected: |
| void patch_addContext(Patch &patch, const string_t &text) const { |
| if (text.empty()) { |
| return; |
| } |
| string_t pattern = safeMid(text, patch.start2, patch.length1); |
| int padding = 0; |
| |
| // Look for the first and last matches of pattern in text. If two different |
| // matches are found, increase the pattern length. |
| while (text.find(pattern) != text.rfind(pattern) |
| && (int)pattern.length() < Match_MaxBits - Patch_Margin - Patch_Margin) { |
| padding += Patch_Margin; |
| pattern = safeMid(text, std::max(0, patch.start2 - padding), |
| std::min((int)text.length(), patch.start2 + patch.length1 + padding) |
| - std::max(0, patch.start2 - padding)); |
| } |
| // Add one chunk for good luck. |
| padding += Patch_Margin; |
| |
| // Add the prefix. |
| string_t prefix = safeMid(text, std::max(0, patch.start2 - padding), |
| patch.start2 - std::max(0, patch.start2 - padding)); |
| if (!prefix.empty()) { |
| patch.diffs.push_front(Diff(EQUAL, prefix)); |
| } |
| // Add the suffix. |
| string_t suffix = safeMid(text, patch.start2 + patch.length1, |
| std::min((int)text.length(), patch.start2 + patch.length1 + padding) |
| - (patch.start2 + patch.length1)); |
| if (!suffix.empty()) { |
| patch.diffs.push_back(Diff(EQUAL, suffix)); |
| } |
| |
| // Roll back the start points. |
| patch.start1 -= prefix.length(); |
| patch.start2 -= prefix.length(); |
| // Extend the lengths. |
| patch.length1 += prefix.length() + suffix.length(); |
| patch.length2 += prefix.length() + suffix.length(); |
| } |
| |
| /** |
| * Compute a list of patches to turn text1 into text2. |
| * A set of diffs will be computed. |
| * @param text1 Old text. |
| * @param text2 New text. |
| * @return LinkedList of Patch objects. |
| */ |
| public: |
| Patches patch_make(const string_t &text1, const string_t &text2) const { |
| // No diffs provided, compute our own. |
| Diffs diffs = diff_main(text1, text2, true); |
| if (diffs.size() > 2) { |
| diff_cleanupSemantic(diffs); |
| diff_cleanupEfficiency(diffs); |
| } |
| |
| return patch_make(text1, diffs); |
| } |
| |
| /** |
| * Compute a list of patches to turn text1 into text2. |
| * text1 will be derived from the provided diffs. |
| * @param diffs Array of diff tuples for text1 to text2. |
| * @return LinkedList of Patch objects. |
| */ |
| public: |
| Patches patch_make(const Diffs &diffs) const { |
| // No origin string provided, compute our own. |
| return patch_make(diff_text1(diffs), diffs); |
| } |
| |
| /** |
| * Compute a list of patches to turn text1 into text2. |
| * text2 is ignored, diffs are the delta between text1 and text2. |
| * @param text1 Old text. |
| * @param text2 Ignored. |
| * @param diffs Array of diff tuples for text1 to text2. |
| * @return LinkedList of Patch objects. |
| * @note Prefer patch_make(const string_t &text1, const Diffs &diffs). |
| */ |
| public: |
| Patches patch_make(const string_t &text1, const string_t &text2, const Diffs &diffs) const { |
| return patch_make(text1, diffs); // text2 is entirely unused. |
| } |
| |
| /** |
| * Compute a list of patches to turn text1 into text2. |
| * text2 is not provided, diffs are the delta between text1 and text2. |
| * @param text1 Old text. |
| * @param diffs Array of diff tuples for text1 to text2. |
| * @return LinkedList of Patch objects. |
| */ |
| public: |
| Patches patch_make(const string_t &text1, const Diffs &diffs) const { |
| Patches patches; |
| if (!diffs.empty()) { // Get rid of the null case. |
| Patch patch; |
| int char_count1 = 0; // Number of characters into the text1 string. |
| int char_count2 = 0; // Number of characters into the text2 string. |
| // Start with text1 (prepatch_text) and apply the diffs until we arrive at |
| // text2 (postpatch_text). We recreate the patches one by one to determine |
| // context info. |
| string_t prepatch_text = text1; |
| string_t postpatch_text = text1; |
| for (typename Diffs::const_iterator cur_diff = diffs.begin(); cur_diff != diffs.end(); ++cur_diff) { |
| if (patch.diffs.empty() && (*cur_diff).operation != EQUAL) { |
| // A new patch starts here. |
| patch.start1 = char_count1; |
| patch.start2 = char_count2; |
| } |
| |
| switch ((*cur_diff).operation) { |
| case INSERT: |
| patch.diffs.push_back(*cur_diff); |
| patch.length2 += (*cur_diff).text.length(); |
| postpatch_text = postpatch_text.substr(0, char_count2) |
| + (*cur_diff).text + safeMid(postpatch_text, char_count2); |
| break; |
| case DELETE: |
| patch.length1 += (*cur_diff).text.length(); |
| patch.diffs.push_back(*cur_diff); |
| postpatch_text = postpatch_text.substr(0, char_count2) |
| + safeMid(postpatch_text, char_count2 + (*cur_diff).text.length()); |
| break; |
| case EQUAL: |
| if ((int)(*cur_diff).text.length() <= 2 * Patch_Margin |
| && !patch.diffs.empty() && !(*cur_diff == diffs.back())) { |
| // Small equality inside a patch. |
| patch.diffs.push_back(*cur_diff); |
| patch.length1 += (*cur_diff).text.length(); |
| patch.length2 += (*cur_diff).text.length(); |
| } |
| |
| if ((int)(*cur_diff).text.length() >= 2 * Patch_Margin) { |
| // Time for a new patch. |
| if (!patch.diffs.empty()) { |
| patch_addContext(patch, prepatch_text); |
| patches.push_back(patch); |
| patch = Patch(); |
| // Unlike Unidiff, our patch lists have a rolling context. |
| // http://code.google.com/p/google-diff-match-patch/wiki/Unidiff |
| // Update prepatch text & pos to reflect the application of the |
| // just completed patch. |
| prepatch_text = postpatch_text; |
| char_count1 = char_count2; |
| } |
| } |
| break; |
| } |
| |
| // Update the current character count. |
| if ((*cur_diff).operation != INSERT) { |
| char_count1 += (*cur_diff).text.length(); |
| } |
| if ((*cur_diff).operation != DELETE) { |
| char_count2 += (*cur_diff).text.length(); |
| } |
| } |
| // Pick up the leftover patch if not empty. |
| if (!patch.diffs.empty()) { |
| patch_addContext(patch, prepatch_text); |
| patches.push_back(patch); |
| } |
| } |
| return patches; |
| } |
| |
| /** |
| * Given an array of patches, return another array that is identical. |
| * @param patches Array of patch objects. |
| * @return Array of patch objects. |
| */ |
| public: |
| Patches patch_deepCopy(const Patches &patches) const { return patches; } |
| |
| /** |
| * Merge a set of patches onto the text. Return a patched text, as well |
| * as an array of true/false values indicating which patches were applied. |
| * @param patches Array of patch objects. |
| * @param text Old text. |
| * @return Two element Object array, containing the new text and an array of |
| * boolean values. |
| */ |
| public: |
| std::pair<string_t, std::vector<bool> > patch_apply(const Patches &patches, const string_t &text) const |
| { std::pair<string_t, std::vector<bool> > res; patch_apply(patches, text, res); return res; } |
| void patch_apply(const Patches &patches, const string_t &sourceText, std::pair<string_t, std::vector<bool> >& res) const { |
| if (patches.empty()) { |
| res.first = sourceText; |
| res.second.clear(); |
| return; |
| } |
| string_t text = sourceText; // Copy to preserve original. |
| |
| // Deep copy the patches so that no changes are made to originals. |
| // Patches patchesCopy = patch_deepCopy(patches); |
| Patches patchesCopy(patches); // Default copy constructor will do it just fine |
| |
| string_t nullPadding = patch_addPadding(patchesCopy); |
| text = nullPadding + text + nullPadding; |
| patch_splitMax(patchesCopy); |
| |
| int x = 0; |
| // delta keeps track of the offset between the expected and actual location |
| // of the previous patch. If there are patches expected at positions 10 and |
| // 20, but the first patch was found at 12, delta is 2 and the second patch |
| // has an effective expected position of 22. |
| int delta = 0; |
| std::vector<bool>& results = res.second; |
| results.resize(patchesCopy.size()); |
| string_t text1, text2; |
| for (typename Patches::const_iterator cur_patch = patchesCopy.begin(); cur_patch != patchesCopy.end(); ++cur_patch) { |
| int expected_loc = (*cur_patch).start2 + delta; |
| text1 = diff_text1((*cur_patch).diffs); |
| int start_loc; |
| int end_loc = -1; |
| if ((int)text1.length() > Match_MaxBits) { |
| // patch_splitMax will only provide an oversized pattern in the case of |
| // a monster delete. |
| start_loc = match_main(text, text1.substr(0, Match_MaxBits), expected_loc); |
| if (start_loc != -1) { |
| end_loc = match_main(text, right(text1, Match_MaxBits), |
| expected_loc + text1.length() - Match_MaxBits); |
| if (end_loc == -1 || start_loc >= end_loc) { |
| // Can't find valid trailing context. Drop this patch. |
| start_loc = -1; |
| } |
| } |
| } else { |
| start_loc = match_main(text, text1, expected_loc); |
| } |
| if (start_loc == -1) { |
| // No match found. :( |
| results[x] = false; |
| // Subtract the delta for this failed patch from subsequent patches. |
| delta -= (*cur_patch).length2 - (*cur_patch).length1; |
| } else { |
| // Found a match. :) |
| results[x] = true; |
| delta = start_loc - expected_loc; |
| if (end_loc == -1) { |
| text2 = safeMid(text, start_loc, text1.length()); |
| } else { |
| text2 = safeMid(text, start_loc, end_loc + Match_MaxBits - start_loc); |
| } |
| if (text1 == text2) { |
| // Perfect match, just shove the replacement text in. |
| text = text.substr(0, start_loc) + diff_text2((*cur_patch).diffs) + safeMid(text, start_loc + text1.length()); |
| } else { |
| // Imperfect match. Run a diff to get a framework of equivalent |
| // indices. |
| Diffs diffs = diff_main(text1, text2, false); |
| if ((int)text1.length() > Match_MaxBits |
| && diff_levenshtein(diffs) / static_cast<float> (text1.length()) |
| > Patch_DeleteThreshold) { |
| // The end points match, but the content is unacceptably bad. |
| results[x] = false; |
| } else { |
| diff_cleanupSemanticLossless(diffs); |
| int index1 = 0; |
| for (typename Diffs::const_iterator cur_diff = (*cur_patch).diffs.begin(); cur_diff != (*cur_patch).diffs.end(); ++cur_diff) { |
| if ((*cur_diff).operation != EQUAL) { |
| int index2 = diff_xIndex(diffs, index1); |
| if ((*cur_diff).operation == INSERT) { |
| // Insertion |
| text = text.substr(0, start_loc + index2) + (*cur_diff).text |
| + safeMid(text, start_loc + index2); |
| } else if ((*cur_diff).operation == DELETE) { |
| // Deletion |
| text = text.substr(0, start_loc + index2) |
| + safeMid(text, start_loc + diff_xIndex(diffs, |
| index1 + (*cur_diff).text.length())); |
| } |
| } |
| if ((*cur_diff).operation != DELETE) { |
| index1 += (*cur_diff).text.length(); |
| } |
| } |
| } |
| } |
| } |
| x++; |
| } |
| // Strip the padding off. |
| res.first = safeMid(text, nullPadding.length(), text.length() - 2 * nullPadding.length()); |
| } |
| |
| /** |
| * Add some padding on text start and end so that edges can match something. |
| * Intended to be called only from within patch_apply. |
| * @param patches Array of patch objects. |
| * @return The padding string added to each side. |
| */ |
| public: |
| string_t patch_addPadding(Patches &patches) const { |
| short paddingLength = Patch_Margin; |
| string_t nullPadding; |
| for (short x = 1; x <= paddingLength; x++) { |
| nullPadding += (char_t)x; |
| } |
| |
| // Bump all the patches forward. |
| for (typename Patches::iterator cur_patch = patches.begin(); cur_patch != patches.end(); ++cur_patch) { |
| (*cur_patch).start1 += paddingLength; |
| (*cur_patch).start2 += paddingLength; |
| } |
| |
| // Add some padding on start of first diff. |
| Patch &firstPatch = patches.front(); |
| Diffs &firstPatchDiffs = firstPatch.diffs; |
| if (firstPatchDiffs.empty() || firstPatchDiffs.front().operation != EQUAL) { |
| // Add nullPadding equality. |
| firstPatchDiffs.push_front(Diff(EQUAL, nullPadding)); |
| firstPatch.start1 -= paddingLength; // Should be 0. |
| firstPatch.start2 -= paddingLength; // Should be 0. |
| firstPatch.length1 += paddingLength; |
| firstPatch.length2 += paddingLength; |
| } else if (paddingLength > (int)firstPatchDiffs.front().text.length()) { |
| // Grow first equality. |
| Diff &firstDiff = firstPatchDiffs.front(); |
| int extraLength = paddingLength - firstDiff.text.length(); |
| firstDiff.text = safeMid(nullPadding, firstDiff.text.length(), |
| paddingLength - firstDiff.text.length()) + firstDiff.text; |
| firstPatch.start1 -= extraLength; |
| firstPatch.start2 -= extraLength; |
| firstPatch.length1 += extraLength; |
| firstPatch.length2 += extraLength; |
| } |
| |
| // Add some padding on end of last diff. |
| Patch &lastPatch = patches.front(); |
| Diffs &lastPatchDiffs = lastPatch.diffs; |
| if (lastPatchDiffs.empty() || lastPatchDiffs.back().operation != EQUAL) { |
| // Add nullPadding equality. |
| lastPatchDiffs.push_back(Diff(EQUAL, nullPadding)); |
| lastPatch.length1 += paddingLength; |
| lastPatch.length2 += paddingLength; |
| } else if (paddingLength > (int)lastPatchDiffs.back().text.length()) { |
| // Grow last equality. |
| Diff &lastDiff = lastPatchDiffs.back(); |
| int extraLength = paddingLength - lastDiff.text.length(); |
| lastDiff.text += nullPadding.substr(0, extraLength); |
| lastPatch.length1 += extraLength; |
| lastPatch.length2 += extraLength; |
| } |
| |
| return nullPadding; |
| } |
| |
| /** |
| * Look through the patches and break up any which are longer than the |
| * maximum limit of the match algorithm. |
| * Intended to be called only from within patch_apply. |
| * @param patches LinkedList of Patch objects. |
| */ |
| public: |
| void patch_splitMax(Patches &patches) const { |
| short patch_size = Match_MaxBits; |
| string_t precontext, postcontext; |
| Patch patch; |
| int start1, start2; |
| bool empty; |
| Operation diff_type; |
| string_t diff_text; |
| Patch bigpatch; |
| |
| for (typename Patches::iterator cur_patch = patches.begin(); cur_patch != patches.end();) { |
| if ((*cur_patch).length1 <= patch_size) { ++cur_patch; continue; } |
| bigpatch = *cur_patch; |
| // Remove the big old patch. |
| cur_patch = patches.erase(cur_patch); |
| start1 = bigpatch.start1; |
| start2 = bigpatch.start2; |
| precontext.clear(); |
| while (!bigpatch.diffs.empty()) { |
| // Create one of several smaller patches. |
| patch = Patch(); |
| empty = true; |
| patch.start1 = start1 - precontext.length(); |
| patch.start2 = start2 - precontext.length(); |
| if (!precontext.empty()) { |
| patch.length1 = patch.length2 = precontext.length(); |
| patch.diffs.push_back(Diff(EQUAL, precontext)); |
| } |
| while (!bigpatch.diffs.empty() |
| && patch.length1 < patch_size - Patch_Margin) { |
| diff_type = bigpatch.diffs.front().operation; |
| diff_text = bigpatch.diffs.front().text; |
| if (diff_type == INSERT) { |
| // Insertions are harmless. |
| patch.length2 += diff_text.length(); |
| start2 += diff_text.length(); |
| patch.diffs.push_back(bigpatch.diffs.front()); |
| bigpatch.diffs.pop_front(); |
| empty = false; |
| } else if (diff_type == DELETE && patch.diffs.size() == 1 |
| && patch.diffs.front().operation == EQUAL |
| && (int)diff_text.length() > 2 * patch_size) { |
| // This is a large deletion. Let it pass in one chunk. |
| patch.length1 += diff_text.length(); |
| start1 += diff_text.length(); |
| empty = false; |
| patch.diffs.push_back(Diff(diff_type, diff_text)); |
| bigpatch.diffs.pop_front(); |
| } else { |
| // Deletion or equality. Only take as much as we can stomach. |
| diff_text = diff_text.substr(0, std::min((int)diff_text.length(), |
| patch_size - patch.length1 - Patch_Margin)); |
| patch.length1 += diff_text.length(); |
| start1 += diff_text.length(); |
| if (diff_type == EQUAL) { |
| patch.length2 += diff_text.length(); |
| start2 += diff_text.length(); |
| } else { |
| empty = false; |
| } |
| patch.diffs.push_back(Diff(diff_type, diff_text)); |
| if (diff_text == bigpatch.diffs.front().text) { |
| bigpatch.diffs.pop_front(); |
| } else { |
| bigpatch.diffs.front().text = safeMid(bigpatch.diffs.front().text, diff_text.length()); |
| } |
| } |
| } |
| // Compute the head context for the next patch. |
| precontext = safeMid(diff_text2(patch.diffs), std::max(0, (int)precontext.length() - Patch_Margin)); |
| // Append the end context for this patch. |
| postcontext = diff_text1(bigpatch.diffs); |
| if ((int)postcontext.length() > Patch_Margin) { |
| postcontext = postcontext.substr(0, Patch_Margin); |
| } |
| if (!postcontext.empty()) { |
| patch.length1 += postcontext.length(); |
| patch.length2 += postcontext.length(); |
| if (!patch.diffs.empty() |
| && patch.diffs.back().operation == EQUAL) { |
| patch.diffs.back().text += postcontext; |
| } else { |
| patch.diffs.push_back(Diff(EQUAL, postcontext)); |
| } |
| } |
| if (!empty) { |
| patches.insert(cur_patch, patch); |
| } |
| } |
| } |
| } |
| |
| /** |
| * Take a list of patches and return a textual representation. |
| * @param patches List of Patch objects. |
| * @return Text representation of patches. |
| */ |
| public: |
| static string_t patch_toText(const Patches &patches) { |
| string_t text; |
| for (typename Patches::const_iterator cur_patch = patches.begin(); cur_patch != patches.end(); ++cur_patch) { |
| text += (*cur_patch).toString(); |
| } |
| return text; |
| } |
| |
| /** |
| * Parse a textual representation of patches and return a List of Patch |
| * objects. |
| * @param textline Text representation of patches. |
| * @return List of Patch objects. |
| * @throws string_t If invalid input. |
| */ |
| public: |
| Patches patch_fromText(const string_t &textline) const { |
| Patches patches; |
| if (!textline.empty()) { |
| char_t sign; |
| string_t line; |
| typename string_t::const_pointer text = textline.c_str(); |
| typename string_t::size_type text_len, l; |
| while (text - textline.c_str() < (int)textline.length()) { |
| if ((text_len = next_token(textline, traits::from_wchar(L'\n'), text)) == 0) { ++text; continue; } |
| |
| // A replacement for the regexp "^@@ -(\\d+),?(\\d*) \\+(\\d+),?(\\d*) @@$" exact match |
| string_t start1, length1, start2, length2; |
| do { |
| typename string_t::const_pointer t = text; |
| l = text_len; |
| if ((l -= 9) > 0 && traits::to_wchar(*t) == L'@' && traits::to_wchar(*++t) == L'@' |
| && traits::to_wchar(*++t) == L' ' && traits::to_wchar(*++t) == L'-' && traits::is_digit(*++t)) { |
| do { start1 += *t; } while (--l > 0 && traits::is_digit(*++t)); |
| if (l > 0 && traits::to_wchar(*t) == L',') ++t, --l; |
| while (l > 0 && traits::is_digit(*t)) --l, length1 += *t++; |
| if (l > 0 && traits::to_wchar(*t++) == L' ' && traits::to_wchar(*t++) == L'+' && traits::is_digit(*t)) { |
| do { start2 += *t; --l; } while (traits::is_digit(*++t)); |
| if (l > 0 && traits::to_wchar(*t) == L',') ++t, --l; |
| while (l > 0 && traits::is_digit(*t)) --l, length2 += *t++; |
| if (l == 0 && traits::to_wchar(*t++) == L' ' && traits::to_wchar(*t++) == L'@' && traits::to_wchar(*t) == L'@') break; // Success |
| } |
| } |
| llvm_unreachable(traits::cs(L"Invalid patch string: ") + string_t(text, text_len)); |
| } while (false); |
| |
| Patch patch; |
| patch.start1 = to_int(start1); |
| if (length1.empty()) { |
| patch.start1--; |
| patch.length1 = 1; |
| } else if (length1.size() == 1 && traits::to_wchar(length1[0]) == L'0') { |
| patch.length1 = 0; |
| } else { |
| patch.start1--; |
| patch.length1 = to_int(length1); |
| } |
| |
| patch.start2 = to_int(start2); |
| if (length2.empty()) { |
| patch.start2--; |
| patch.length2 = 1; |
| } else if (length2.size() == 1 && traits::to_wchar(length2[0]) == L'0') { |
| patch.length2 = 0; |
| } else { |
| patch.start2--; |
| patch.length2 = to_int(length2); |
| } |
| |
| for (text += text_len + 1; text - textline.c_str() < (int)textline.length(); text += text_len + 1) { |
| if ((text_len = next_token(textline, traits::from_wchar(L'\n'), text)) == 0) continue; |
| |
| sign = *text; |
| line.assign(text + 1, text_len - 1); |
| percent_decode(line); |
| switch (traits::to_wchar(sign)) { |
| case L'-': |
| // Deletion. |
| patch.diffs.push_back(Diff(DELETE, line)); |
| continue; |
| case L'+': |
| // Insertion. |
| patch.diffs.push_back(Diff(INSERT, line)); |
| continue; |
| case L' ': |
| // Minor equality. |
| patch.diffs.push_back(Diff(EQUAL, line)); |
| continue; |
| case L'@': |
| // Start of next patch. |
| break; |
| default: |
| // WTF? |
| llvm_unreachable(traits::cs(L"Invalid patch mode '") + (sign + (traits::cs(L"' in: ") + line))); |
| } |
| break; |
| } |
| |
| patches.push_back(patch); |
| } |
| } |
| return patches; |
| } |
| |
| /** |
| * A safer version of string_t.mid(pos). This one returns "" instead of |
| * null when the position equals the string length. |
| * @param str String to take a substring from. |
| * @param pos Position to start the substring from. |
| * @return Substring. |
| */ |
| private: |
| static inline string_t safeMid(const string_t &str, size_t pos) { |
| return (pos == str.length()) ? string_t() : str.substr(pos); |
| } |
| |
| /** |
| * A safer version of string_t.mid(pos, len). This one returns "" instead of |
| * null when the position equals the string length. |
| * @param str String to take a substring from. |
| * @param pos Position to start the substring from. |
| * @param len Length of substring. |
| * @return Substring. |
| */ |
| private: |
| static inline string_t safeMid(const string_t &str, size_t pos, size_t len) { |
| return (pos == str.length()) ? string_t() : str.substr(pos, len); |
| } |
| |
| /** |
| * Utility functions |
| */ |
| private: |
| static string_t to_string(int n) { |
| string_t str; |
| bool negative = false; |
| size_t l = 0; |
| if (n < 0) n = -n, ++l, negative = true; |
| int n_ = n; do { ++l; } while ((n_ /= 10) > 0); |
| str.resize(l); |
| typename string_t::iterator s = str.end(); |
| const wchar_t digits[] = L"0123456789"; |
| do { *--s = traits::from_wchar(digits[n % 10]); } while ((n /= 10) > 0); |
| if (negative) *--s = traits::from_wchar(L'-'); |
| return str; |
| } |
| |
| static int to_int(const string_t& str) { return traits::to_int(str.c_str()); } |
| |
| static bool is_control(char_t c) { switch (traits::to_wchar(c)) { case L'\n': case L'\r': return true; } return false; } |
| |
| static typename string_t::size_type next_token(const string_t& str, char_t delim, typename string_t::const_pointer off) { |
| typename string_t::const_pointer p = off, end = str.c_str() + str.length(); |
| for (; p != end; ++p) if (*p == delim) break; |
| return p - off; |
| } |
| |
| static void append_percent_encoded(string_t& s1, const string_t& s2) { |
| const wchar_t safe_chars[] = L"0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz-_.~ !*'();/?:@&=+$,#"; |
| |
| size_t safe[0x100], i; |
| for (i = 0; i < 0x100; ++i) safe[i] = 0; |
| for (i = 0; i < sizeof(safe_chars) / sizeof(wchar_t); ++i) safe[safe_chars[i]] = i + 1; |
| |
| int n = 0; |
| typename traits::utf32_t u; |
| typename string_t::const_pointer c = s2.c_str(), end = c + s2.length(); |
| while (c != end) { |
| c = traits::to_utf32(c, end, u); |
| n += u >= 0x10000? 12 : u >= 0x800? 9 : u >= 0x80? 6 : safe[static_cast<unsigned char>(u)]? 1 : 3; |
| } |
| if (n == int(s2.length())) |
| s1.append(s2); |
| else { |
| s1.reserve(s1.size() + n); |
| // Encode as UTF-8, then escape unsafe characters |
| unsigned char utf8[4]; |
| for (c = s2.c_str(); c != end;) { |
| c = traits::to_utf32(c, end, u); |
| unsigned char* pt = utf8; |
| if (u < 0x80) |
| *pt++ = (unsigned char)u; |
| else if (u < 0x800) { |
| *pt++ = (unsigned char)((u >> 6) | 0xC0); |
| *pt++ = (unsigned char)((u & 0x3F) | 0x80); |
| } |
| else if (u < 0x10000) { |
| *pt++ = (unsigned char)((u >> 12) | 0xE0); |
| *pt++ = (unsigned char)(((u >> 6) & 0x3F) | 0x80); |
| *pt++ = (unsigned char)((u & 0x3F) | 0x80); |
| } |
| else { |
| *pt++ = (unsigned char)((u >> 18) | 0xF0); |
| *pt++ = (unsigned char)(((u >> 12) & 0x3F) | 0x80); |
| *pt++ = (unsigned char)(((u >> 6) & 0x3F) | 0x80); |
| *pt++ = (unsigned char)((u & 0x3F) | 0x80); |
| } |
| |
| for (const unsigned char* p = utf8; p < pt; ++p) |
| if (safe[*p]) |
| s1 += traits::from_wchar(safe_chars[safe[*p] - 1]); |
| else { |
| s1 += traits::from_wchar(L'%'); |
| s1 += traits::from_wchar(safe_chars[(*p & 0xF0) >> 4]); |
| s1 += traits::from_wchar(safe_chars[*p & 0xF]); |
| } |
| } |
| } |
| } |
| |
| static unsigned hex_digit_value(char_t c) { |
| switch (traits::to_wchar(c)) |
| { |
| case L'0': return 0; |
| case L'1': return 1; |
| case L'2': return 2; |
| case L'3': return 3; |
| case L'4': return 4; |
| case L'5': return 5; |
| case L'6': return 6; |
| case L'7': return 7; |
| case L'8': return 8; |
| case L'9': return 9; |
| case L'A': case L'a': return 0xA; |
| case L'B': case L'b': return 0xB; |
| case L'C': case L'c': return 0xC; |
| case L'D': case L'd': return 0xD; |
| case L'E': case L'e': return 0xE; |
| case L'F': case L'f': return 0xF; |
| } |
| llvm_unreachable(string_t(traits::cs(L"Invalid character: ")) + c); |
| } |
| |
| static void percent_decode(string_t& str) { |
| typename string_t::iterator s2 = str.begin(), s3 = s2, s4 = s2; |
| for (typename string_t::const_pointer s1 = str.c_str(), end = s1 + str.size(); s1 != end; ++s1, ++s2) |
| if (traits::to_wchar(*s1) != L'%') |
| *s2 = *s1; |
| else { |
| char_t d1 = *++s1; |
| *s2 = char_t((hex_digit_value(d1) << 4) + hex_digit_value(*++s1)); |
| } |
| // Decode UTF-8 string in-place |
| while (s3 != s2) { |
| unsigned u = *s3; |
| if (u < 0x80) |
| ; |
| else if ((u >> 5) == 6) { |
| if (++s3 == s2 || (*s3 & 0xC0) != 0x80) continue; |
| u = ((u & 0x1F) << 6) + (*s3 & 0x3F); |
| } |
| else if ((u >> 4) == 0xE) { |
| if (++s3 == s2 || (*s3 & 0xC0) != 0x80) continue; |
| u = ((u & 0xF) << 12) + ((*s3 & 0x3F) << 6); |
| if (++s3 == s2 || (*s3 & 0xC0) != 0x80) continue; |
| u += *s3 & 0x3F; |
| } |
| else if ((u >> 3) == 0x1E) { |
| if (++s3 == s2 || (*s3 & 0xC0) != 0x80) continue; |
| u = ((u & 7) << 18) + ((*s3 & 0x3F) << 12); |
| if (++s3 == s2 || (*s3 & 0xC0) != 0x80) continue; |
| u += (*s3 & 0x3F) << 6; |
| if (++s3 == s2 || (*s3 & 0xC0) != 0x80) continue; |
| u += *s3 & 0x3F; |
| } |
| else { |
| ++s3; |
| continue; |
| } |
| s4 = traits::from_utf32(u, s4); |
| ++s3; |
| } |
| if (s4 != str.end()) str.resize(s4 - str.begin()); |
| } |
| |
| static string_t right(const string_t& str, typename string_t::size_type n) { return str.substr(str.size() - n); } |
| }; |
| |
| |
| /** |
| * Functions dependent on character type |
| */ |
| |
| // Unicode helpers |
| template <class char_t, class utf32_type = unsigned> |
| struct diff_match_patch_utf32_direct { |
| typedef utf32_type utf32_t; |
| template <class iterator> static iterator to_utf32(iterator i, iterator /*end*/, utf32_t& u) |
| { |
| u = *i++; |
| return i; |
| } |
| template <class iterator> static iterator from_utf32(utf32_t u, iterator o) |
| { |
| *o++ = static_cast<char_t>(u); |
| return o; |
| } |
| }; |
| |
| template <class char_t, class utf32_type = unsigned> |
| struct diff_match_patch_utf32_from_utf16 { |
| typedef utf32_type utf32_t; |
| static const unsigned UTF16_SURROGATE_MIN = 0xD800u; |
| static const unsigned UTF16_SURROGATE_MAX = 0xDFFFu; |
| static const unsigned UTF16_HIGH_SURROGATE_MAX = 0xDBFFu; |
| static const unsigned UTF16_LOW_SURROGATE_MIN = 0xDC00u; |
| static const unsigned UTF16_SURROGATE_OFFSET = (UTF16_SURROGATE_MIN << 10) + UTF16_HIGH_SURROGATE_MAX - 0xFFFFu; |
| template <class iterator> static iterator to_utf32(iterator i, iterator end, utf32_t& u) |
| { |
| u = *i++; |
| if (UTF16_SURROGATE_MIN <= u && u <= UTF16_HIGH_SURROGATE_MAX && i != end) |
| u = (u << 10) + *i++ - UTF16_SURROGATE_OFFSET; // Assume it is a UTF-16 surrogate pair |
| return i; |
| } |
| template <class iterator> static iterator from_utf32(utf32_t u, iterator o) |
| { |
| if (u > 0xFFFF) { // Encode code points that do not fit in char_t as UTF-16 surrogate pairs |
| *o++ = static_cast<char_t>((u >> 10) + UTF16_SURROGATE_MIN - (0x10000 >> 10)); |
| *o++ = static_cast<char_t>((u & 0x3FF) + UTF16_LOW_SURROGATE_MIN); |
| } |
| else |
| *o++ = static_cast<char_t>(u); |
| return o; |
| } |
| }; |
| |
| // Specialization of the traits for wchar_t |
| #include <cwctype> |
| template <> struct diff_match_patch_traits<wchar_t> : diff_match_patch_utf32_from_utf16<wchar_t> { |
| static bool is_alnum(wchar_t c) { return std::iswalnum(c)? true : false; } |
| static bool is_digit(wchar_t c) { return std::iswdigit(c)? true : false; } |
| static bool is_space(wchar_t c) { return std::iswspace(c)? true : false; } |
| static int to_int(const wchar_t* s) { return static_cast<int>(std::wcstol(s, NULL, 10)); } |
| static wchar_t from_wchar(wchar_t c) { return c; } |
| static wchar_t to_wchar(wchar_t c) { return c; } |
| static const wchar_t* cs(const wchar_t* s) { return s; } |
| static const wchar_t eol = L'\n'; |
| static const wchar_t tab = L'\t'; |
| }; |
| |
| // Possible specialization of the traits for char |
| #include <cctype> |
| template <> struct diff_match_patch_traits<char> : diff_match_patch_utf32_direct<char> |
| { |
| static bool is_alnum(char c) { return std::isalnum(c)? true : false; } |
| static bool is_digit(char c) { return std::isdigit(c)? true : false; } |
| static bool is_space(char c) { return std::isspace(c)? true : false; } |
| static int to_int(const char* s) { return std::atoi(s); } |
| static char from_wchar(wchar_t c) { return static_cast<char>(c); } |
| static wchar_t to_wchar(char c) { return static_cast<wchar_t>(c); } |
| static std::string cs(const wchar_t* s) { return std::string(s, s + wcslen(s)); } |
| static const char eol = '\n'; |
| static const char tab = '\t'; |
| }; |
| |
| |
| #endif // DIFF_MATCH_PATCH_H |