protected DiffEngine::_shift_boundaries($lines, &$changed, $other_changed)
Adjust inserts/deletes of identical lines to join changes as much as possible.
We do something when a run of changed lines include a line at one end and has an excluded, identical line at the other. We are free to choose which identical line is included. `compareseq' usually chooses the one at the beginning, but usually it is cleaner to consider the following identical line to be the "change".
This is extracted verbatim from analyze.c (GNU diffutils-2.7).
File
- core/lib/Drupal/Component/Diff/Engine/DiffEngine.php, line 343
Class
- DiffEngine
- Class used internally by Diff to actually compute the diffs.
Namespace
Drupal\Component\Diff\Engine
Code
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 | protected function _shift_boundaries($lines, &$changed, $other_changed) { $i = 0; $j = 0; $this::USE_ASSERTS && assert('sizeof($lines) == sizeof($changed)'); $len = sizeof($lines); $other_len = sizeof($other_changed); while (1) { /* * Scan forwards to find beginning of another run of changes. * Also keep track of the corresponding point in the other file. * * Throughout this code, $i and $j are adjusted together so that * the first $i elements of $changed and the first $j elements * of $other_changed both contain the same number of zeros * (unchanged lines). * Furthermore, $j is always kept so that $j == $other_len or * $other_changed[$j] == FALSE. */ while ($j < $other_len && $other_changed[$j]) { $j++; } while ($i < $len && !$changed[$i]) { $this::USE_ASSERTS && assert('$j < $other_len && ! $other_changed[$j]'); $i++; $j++; while ($j < $other_len && $other_changed[$j]) { $j++; } } if ($i == $len) { break; } $start = $i; // Find the end of this run of changes. while (++$i < $len && $changed[$i]) { continue; } do { /* * Record the length of this run of changes, so that * we can later determine whether the run has grown. */ $runlength = $i - $start; /* * Move the changed region back, so long as the * previous unchanged line matches the last changed one. * This merges with previous changed regions. */ while ($start > 0 && $lines[$start - 1] == $lines[$i - 1]) { $changed[--$start] = 1; $changed[--$i] = FALSE; while ($start > 0 && $changed[$start - 1]) { $start--; } $this::USE_ASSERTS && assert('$j > 0'); while ($other_changed[--$j]) { continue; } $this::USE_ASSERTS && assert('$j >= 0 && !$other_changed[$j]'); } /* * Set CORRESPONDING to the end of the changed run, at the last * point where it corresponds to a changed run in the other file. * CORRESPONDING == LEN means no such point has been found. */ $corresponding = $j < $other_len ? $i : $len; /* * Move the changed region forward, so long as the * first changed line matches the following unchanged one. * This merges with following changed regions. * Do this second, so that if there are no merges, * the changed region is moved forward as far as possible. */ while ($i < $len && $lines[$start] == $lines[$i]) { $changed[$start++] = FALSE; $changed[$i++] = 1; while ($i < $len && $changed[$i]) { $i++; } $this::USE_ASSERTS && assert('$j < $other_len && ! $other_changed[$j]'); $j++; if ($j < $other_len && $other_changed[$j]) { $corresponding = $i; while ($j < $other_len && $other_changed[$j]) { $j++; } } } } while ($runlength != $i - $start); /* * If possible, move the fully-merged run of changes * back to a corresponding run in the other file. */ while ($corresponding < $i) { $changed[--$start] = 1; $changed[--$i] = 0; $this::USE_ASSERTS && assert('$j > 0'); while ($other_changed[--$j]) { continue; } $this::USE_ASSERTS && assert('$j >= 0 && !$other_changed[$j]'); } }} |
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