string.php 8.16 KB
Newer Older
imac's avatar
imac committed
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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248
<?php
/**
 * Parses unified or context diffs output from eg. the diff utility.
 *
 * Example:
 * <code>
 * $patch = file_get_contents('example.patch');
 * $diff = new Text_Diff('string', array($patch));
 * $renderer = new Text_Diff_Renderer_inline();
 * echo $renderer->render($diff);
 * </code>
 *
 * Copyright 2005 Örjan Persson <o@42mm.org>
 * Copyright 2005-2010 The Horde Project (http://www.horde.org/)
 *
 * See the enclosed file COPYING for license information (LGPL). If you did
 * not receive this file, see http://opensource.org/licenses/lgpl-license.php.
 *
 * @author  Örjan Persson <o@42mm.org>
 * @package Text_Diff
 * @since   0.2.0
 */
class Text_Diff_Engine_string {

    /**
     * Parses a unified or context diff.
     *
     * First param contains the whole diff and the second can be used to force
     * a specific diff type. If the second parameter is 'autodetect', the
     * diff will be examined to find out which type of diff this is.
     *
     * @param string $diff  The diff content.
     * @param string $mode  The diff mode of the content in $diff. One of
     *                      'context', 'unified', or 'autodetect'.
     *
     * @return array  List of all diff operations.
     */
    function diff($diff, $mode = 'autodetect')
    {
        // Detect line breaks.
        $lnbr = "\n";
        if (strpos($diff, "\r\n") !== false) {
            $lnbr = "\r\n";
        } elseif (strpos($diff, "\r") !== false) {
            $lnbr = "\r";
        }

        // Make sure we have a line break at the EOF.
        if (substr($diff, -strlen($lnbr)) != $lnbr) {
            $diff .= $lnbr;
        }

        if ($mode != 'autodetect' && $mode != 'context' && $mode != 'unified') {
            return PEAR::raiseError('Type of diff is unsupported');
        }

        if ($mode == 'autodetect') {
            $context = strpos($diff, '***');
            $unified = strpos($diff, '---');
            if ($context === $unified) {
                return PEAR::raiseError('Type of diff could not be detected');
            } elseif ($context === false || $unified === false) {
                $mode = $context !== false ? 'context' : 'unified';
            } else {
                $mode = $context < $unified ? 'context' : 'unified';
            }
        }

        // Split by new line and remove the diff header, if there is one.
        $diff = explode($lnbr, $diff);
        if (($mode == 'context' && strpos($diff[0], '***') === 0) ||
            ($mode == 'unified' && strpos($diff[0], '---') === 0)) {
            array_shift($diff);
            array_shift($diff);
        }

        if ($mode == 'context') {
            return $this->parseContextDiff($diff);
        } else {
            return $this->parseUnifiedDiff($diff);
        }
    }

    /**
     * Parses an array containing the unified diff.
     *
     * @param array $diff  Array of lines.
     *
     * @return array  List of all diff operations.
     */
    function parseUnifiedDiff($diff)
    {
        $edits = array();
        $end = count($diff) - 1;
        for ($i = 0; $i < $end;) {
            $diff1 = array();
            switch (substr($diff[$i], 0, 1)) {
            case ' ':
                do {
                    $diff1[] = substr($diff[$i], 1);
                } while (++$i < $end && substr($diff[$i], 0, 1) == ' ');
                $edits[] = new Text_Diff_Op_copy($diff1);
                break;

            case '+':
                // get all new lines
                do {
                    $diff1[] = substr($diff[$i], 1);
                } while (++$i < $end && substr($diff[$i], 0, 1) == '+');
                $edits[] = new Text_Diff_Op_add($diff1);
                break;

            case '-':
                // get changed or removed lines
                $diff2 = array();
                do {
                    $diff1[] = substr($diff[$i], 1);
                } while (++$i < $end && substr($diff[$i], 0, 1) == '-');

                while ($i < $end && substr($diff[$i], 0, 1) == '+') {
                    $diff2[] = substr($diff[$i++], 1);
                }
                if (count($diff2) == 0) {
                    $edits[] = new Text_Diff_Op_delete($diff1);
                } else {
                    $edits[] = new Text_Diff_Op_change($diff1, $diff2);
                }
                break;

            default:
                $i++;
                break;
            }
        }

        return $edits;
    }

    /**
     * Parses an array containing the context diff.
     *
     * @param array $diff  Array of lines.
     *
     * @return array  List of all diff operations.
     */
    function parseContextDiff(&$diff)
    {
        $edits = array();
        $i = $max_i = $j = $max_j = 0;
        $end = count($diff) - 1;
        while ($i < $end && $j < $end) {
            while ($i >= $max_i && $j >= $max_j) {
                // Find the boundaries of the diff output of the two files
                for ($i = $j;
                     $i < $end && substr($diff[$i], 0, 3) == '***';
                     $i++);
                for ($max_i = $i;
                     $max_i < $end && substr($diff[$max_i], 0, 3) != '---';
                     $max_i++);
                for ($j = $max_i;
                     $j < $end && substr($diff[$j], 0, 3) == '---';
                     $j++);
                for ($max_j = $j;
                     $max_j < $end && substr($diff[$max_j], 0, 3) != '***';
                     $max_j++);
            }

            // find what hasn't been changed
            $array = array();
            while ($i < $max_i &&
                   $j < $max_j &&
                   strcmp($diff[$i], $diff[$j]) == 0) {
                $array[] = substr($diff[$i], 2);
                $i++;
                $j++;
            }

            while ($i < $max_i && ($max_j-$j) <= 1) {
                if ($diff[$i] != '' && substr($diff[$i], 0, 1) != ' ') {
                    break;
                }
                $array[] = substr($diff[$i++], 2);
            }

            while ($j < $max_j && ($max_i-$i) <= 1) {
                if ($diff[$j] != '' && substr($diff[$j], 0, 1) != ' ') {
                    break;
                }
                $array[] = substr($diff[$j++], 2);
            }
            if (count($array) > 0) {
                $edits[] = new Text_Diff_Op_copy($array);
            }

            if ($i < $max_i) {
                $diff1 = array();
                switch (substr($diff[$i], 0, 1)) {
                case '!':
                    $diff2 = array();
                    do {
                        $diff1[] = substr($diff[$i], 2);
                        if ($j < $max_j && substr($diff[$j], 0, 1) == '!') {
                            $diff2[] = substr($diff[$j++], 2);
                        }
                    } while (++$i < $max_i && substr($diff[$i], 0, 1) == '!');
                    $edits[] = new Text_Diff_Op_change($diff1, $diff2);
                    break;

                case '+':
                    do {
                        $diff1[] = substr($diff[$i], 2);
                    } while (++$i < $max_i && substr($diff[$i], 0, 1) == '+');
                    $edits[] = new Text_Diff_Op_add($diff1);
                    break;

                case '-':
                    do {
                        $diff1[] = substr($diff[$i], 2);
                    } while (++$i < $max_i && substr($diff[$i], 0, 1) == '-');
                    $edits[] = new Text_Diff_Op_delete($diff1);
                    break;
                }
            }

            if ($j < $max_j) {
                $diff2 = array();
                switch (substr($diff[$j], 0, 1)) {
                case '+':
                    do {
                        $diff2[] = substr($diff[$j++], 2);
                    } while ($j < $max_j && substr($diff[$j], 0, 1) == '+');
                    $edits[] = new Text_Diff_Op_add($diff2);
                    break;

                case '-':
                    do {
                        $diff2[] = substr($diff[$j++], 2);
                    } while ($j < $max_j && substr($diff[$j], 0, 1) == '-');
                    $edits[] = new Text_Diff_Op_delete($diff2);
                    break;
                }
            }
        }

        return $edits;
    }

}