Complex classes like AbstractCsv often do a lot of different things. To break such a class down, we need to identify a cohesive component within that class. A common approach to find such a component is to look for fields/methods that share the same prefixes, or suffixes. You can also have a look at the cohesion graph to spot any un-connected, or weakly-connected components.
Once you have determined the fields that belong together, you can apply the Extract Class refactoring. If the component makes sense as a sub-class, Extract Subclass is also a candidate, and is often faster.
While breaking up the class, it is a good idea to analyze how other classes use AbstractCsv, and based on these observations, apply Extract Interface, too.
| 1 | <?php  | 
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| 36 | abstract class AbstractCsv implements ByteSequence  | 
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| 37 | { | 
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| 38 | /**  | 
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| 39 | * The stream filter mode (read or write).  | 
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| 40 | *  | 
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| 41 | * @var int  | 
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| 42 | */  | 
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| 43 | protected $stream_filter_mode;  | 
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| 44 | |||
| 45 | /**  | 
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| 46 | * collection of stream filters.  | 
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| 47 | *  | 
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| 48 | * @var bool[]  | 
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| 49 | */  | 
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| 50 | protected $stream_filters = [];  | 
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| 51 | |||
| 52 | /**  | 
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| 53 | * The CSV document BOM sequence.  | 
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| 54 | *  | 
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| 55 | * @var string|null  | 
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| 56 | */  | 
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| 57 | protected $input_bom = null;  | 
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| 58 | |||
| 59 | /**  | 
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| 60 | * The Output file BOM character.  | 
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| 61 | *  | 
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| 62 | * @var string  | 
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| 63 | */  | 
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| 64 | protected $output_bom = '';  | 
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| 65 | |||
| 66 | /**  | 
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| 67 | * the field delimiter (one character only).  | 
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| 68 | *  | 
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| 69 | * @var string  | 
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| 70 | */  | 
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| 71 | protected $delimiter = ',';  | 
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| 72 | |||
| 73 | /**  | 
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| 74 | * the field enclosure character (one character only).  | 
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| 75 | *  | 
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| 76 | * @var string  | 
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| 77 | */  | 
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| 78 | protected $enclosure = '"';  | 
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| 79 | |||
| 80 | /**  | 
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| 81 | * the field escape character (one character only).  | 
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| 82 | *  | 
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| 83 | * @var string  | 
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| 84 | */  | 
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| 85 | protected $escape = '\\';  | 
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| 86 | |||
| 87 | /**  | 
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| 88 | * The CSV document.  | 
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| 89 | *  | 
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| 90 | * @var SplFileObject|Stream  | 
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| 91 | */  | 
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| 92 | protected $document;  | 
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| 93 | |||
| 94 | /**  | 
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| 95 | * New instance.  | 
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| 96 | *  | 
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| 97 | * @param SplFileObject|Stream $document The CSV Object instance  | 
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| 98 | */  | 
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| 99 | 36 | protected function __construct($document)  | 
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| 100 |     { | 
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| 101 | 36 | $this->document = $document;  | 
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| 102 | 36 | list($this->delimiter, $this->enclosure, $this->escape) = $this->document->getCsvControl();  | 
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| 103 | 36 | $this->resetProperties();  | 
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| 104 | 36 | }  | 
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| 105 | |||
| 106 | /**  | 
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| 107 | * Reset dynamic object properties to improve performance.  | 
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| 108 | */  | 
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| 109 | 33 | protected function resetProperties()  | 
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| 110 |     { | 
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| 111 | 33 | }  | 
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| 112 | |||
| 113 | /**  | 
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| 114 |      * {@inheritdoc} | 
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| 115 | */  | 
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| 116 | 36 | public function __destruct()  | 
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| 120 | |||
| 121 | /**  | 
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| 122 |      * {@inheritdoc} | 
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| 123 | */  | 
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| 124 | 3 | public function __clone()  | 
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| 128 | |||
| 129 | /**  | 
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| 130 | * Return a new instance from a SplFileObject.  | 
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| 131 | *  | 
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| 132 | * @return static  | 
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| 133 | */  | 
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| 134 | 36 | public static function createFromFileObject(SplFileObject $file)  | 
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| 138 | |||
| 139 | /**  | 
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| 140 | * Return a new instance from a PHP resource stream.  | 
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| 141 | *  | 
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| 142 | * @param resource $stream  | 
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| 143 | *  | 
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| 144 | * @return static  | 
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| 145 | */  | 
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| 146 | 3 | public static function createFromStream($stream)  | 
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| 150 | |||
| 151 | /**  | 
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| 152 | * Return a new instance from a string.  | 
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| 153 | *  | 
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| 154 | * @return static  | 
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| 155 | */  | 
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| 156 | 6 | public static function createFromString(string $content = '')  | 
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| 160 | |||
| 161 | /**  | 
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| 162 | * Return a new instance from a file path.  | 
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| 163 | *  | 
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| 164 | * @param resource|null $context the resource context  | 
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| 165 | *  | 
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| 166 | * @return static  | 
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| 167 | */  | 
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| 168 | 6 | public static function createFromPath(string $path, string $open_mode = 'r+', $context = null)  | 
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| 172 | |||
| 173 | /**  | 
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| 174 | * Returns the current field delimiter.  | 
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| 175 | */  | 
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| 176 | 15 | public function getDelimiter(): string  | 
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| 180 | |||
| 181 | /**  | 
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| 182 | * Returns the current field enclosure.  | 
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| 183 | */  | 
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| 184 | 3 | public function getEnclosure(): string  | 
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| 188 | |||
| 189 | /**  | 
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| 190 | * Returns the pathname of the underlying document.  | 
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| 191 | */  | 
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| 192 | 12 | public function getPathname(): string  | 
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| 196 | |||
| 197 | /**  | 
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| 198 | * Returns the current field escape character.  | 
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| 199 | */  | 
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| 200 | 3 | public function getEscape(): string  | 
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| 204 | |||
| 205 | /**  | 
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| 206 | * Returns the BOM sequence in use on Output methods.  | 
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| 207 | */  | 
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| 208 | 3 | public function getOutputBOM(): string  | 
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| 212 | |||
| 213 | /**  | 
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| 214 | * Returns the BOM sequence of the given CSV.  | 
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| 215 | */  | 
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| 216 | 54 | public function getInputBOM(): string  | 
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| 228 | |||
| 229 | /**  | 
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| 230 | * Returns the stream filter mode.  | 
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| 231 | */  | 
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| 232 | 3 | public function getStreamFilterMode(): int  | 
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| 236 | |||
| 237 | /**  | 
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| 238 | * Tells whether the stream filter capabilities can be used.  | 
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| 239 | */  | 
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| 240 | 6 | public function supportsStreamFilter(): bool  | 
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| 244 | |||
| 245 | /**  | 
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| 246 | * Tell whether the specify stream filter is attach to the current stream.  | 
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| 247 | */  | 
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| 248 | 3 | public function hasStreamFilter(string $filtername): bool  | 
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| 252 | |||
| 253 | /**  | 
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| 254 | * Retuns the CSV document as a Generator of string chunk.  | 
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| 255 | *  | 
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| 256 | * @param int $length number of bytes read  | 
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| 257 | *  | 
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| 258 | * @throws Exception if the number of bytes is lesser than 1  | 
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| 259 | */  | 
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| 260 | 15 | public function chunk(int $length): Generator  | 
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| 277 | |||
| 278 | /**  | 
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| 279 | * DEPRECATION WARNING! This method will be removed in the next major point release.  | 
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| 280 | *  | 
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| 281 | * @deprecated deprecated since version 9.1.0  | 
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| 282 | * @see AbstractCsv::getContent  | 
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| 283 | *  | 
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| 284 | * Retrieves the CSV content  | 
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| 285 | */  | 
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| 286 | 3 | public function __toString(): string  | 
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| 290 | |||
| 291 | /**  | 
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| 292 | * Retrieves the CSV content.  | 
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| 293 | */  | 
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| 294 | 18 | public function getContent(): string  | 
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| 303 | |||
| 304 | /**  | 
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| 305 | * Outputs all data on the CSV file.  | 
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| 306 | *  | 
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| 307 | * @return int Returns the number of characters read from the handle  | 
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| 308 | * and passed through to the output.  | 
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| 309 | */  | 
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| 310 | 9 | public function output(string $filename = null): int  | 
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| 322 | |||
| 323 | /**  | 
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| 324 | * Send the CSV headers.  | 
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| 325 | *  | 
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| 326 | * Adapted from Symfony\Component\HttpFoundation\ResponseHeaderBag::makeDisposition  | 
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| 327 | *  | 
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| 328 | * @throws Exception if the submitted header is invalid according to RFC 6266  | 
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| 329 | *  | 
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| 330 | * @see https://tools.ietf.org/html/rfc6266#section-4.3  | 
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| 331 | */  | 
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| 332 | 9 | protected function sendHeaders(string $filename)  | 
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| 355 | |||
| 356 | /**  | 
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| 357 | * Sets the field delimiter.  | 
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| 358 | *  | 
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| 359 | * @throws Exception If the Csv control character is not one character only.  | 
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| 360 | *  | 
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| 361 | * @return static  | 
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| 362 | */  | 
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| 363 | 18 | public function setDelimiter(string $delimiter): self  | 
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| 378 | |||
| 379 | /**  | 
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| 380 | * Sets the field enclosure.  | 
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| 381 | *  | 
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| 382 | * @throws Exception If the Csv control character is not one character only.  | 
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| 383 | *  | 
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| 384 | * @return static  | 
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| 385 | */  | 
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| 386 | 3 | public function setEnclosure(string $enclosure): self  | 
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| 401 | |||
| 402 | /**  | 
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| 403 | * Sets the field escape character.  | 
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| 404 | *  | 
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| 405 | * @throws Exception If the Csv control character is not one character only.  | 
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| 406 | *  | 
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| 407 | * @return static  | 
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| 408 | */  | 
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| 409 | 3 | public function setEscape(string $escape): self  | 
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| 424 | |||
| 425 | /**  | 
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| 426 | * Sets the BOM sequence to prepend the CSV on output.  | 
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| 427 | *  | 
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| 428 | * @return static  | 
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| 429 | */  | 
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| 430 | 9 | public function setOutputBOM(string $str): self  | 
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| 436 | |||
| 437 | /**  | 
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| 438 | * append a stream filter.  | 
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| 439 | *  | 
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| 440 | * @param null|mixed $params  | 
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| 441 | *  | 
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| 442 | * @throws Exception If the stream filter API can not be used  | 
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| 443 | *  | 
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| 444 | * @return static  | 
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| 445 | */  | 
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| 446 | 15 | public function addStreamFilter(string $filtername, $params = null): self  | 
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| 459 | }  | 
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| 460 |