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+<?php
+/**
+ * Parse and evaluate a plural rule.
+ *
+ * http://unicode.org/reports/tr35/#Language_Plural_Rules
+ *
+ * @author Niklas Laxstrom, Tim Starling
+ *
+ * @copyright Copyright © 2010-2012, Niklas Laxström
+ * @license http://www.gnu.org/copyleft/gpl.html GNU General Public License 2.0 or later
+ * @file
+ * @since 1.20
+ */
+
+class CLDRPluralRuleEvaluator {
+ /**
+ * Evaluate a number against a set of plural rules. If a rule passes,
+ * return the index of plural rule.
+ *
+ * @param int The number to be evaluated against the rules
+ * @param array The associative array of plural rules in pluralform => rule format.
+ * @return int The index of the plural form which passed the evaluation
+ */
+ public static function evaluate( $number, array $rules ) {
+ $rules = self::compile( $rules );
+ return self::evaluateCompiled( $number, $rules );
+ }
+
+ /**
+ * Convert a set of rules to a compiled form which is optimised for
+ * fast evaluation. The result will be an array of strings, and may be cached.
+ *
+ * @param $rules The rules to compile
+ * @return An array of compile rules.
+ */
+ public static function compile( array $rules ) {
+ // We can't use array_map() for this because it generates a warning if
+ // there is an exception.
+ foreach ( $rules as &$rule ) {
+ $rule = CLDRPluralRuleConverter::convert( $rule );
+ }
+ return $rules;
+ }
+
+ /**
+ * Evaluate a compiled set of rules returned by compile(). Do not allow
+ * the user to edit the compiled form, or else PHP errors may result.
+ */
+ public static function evaluateCompiled( $number, array $rules ) {
+ // The compiled form is RPN, with tokens strictly delimited by
+ // spaces, so this is a simple RPN evaluator.
+ foreach ( $rules as $i => $rule ) {
+ $stack = array();
+ $zero = ord( '0' );
+ $nine = ord( '9' );
+ foreach ( StringUtils::explode( ' ', $rule ) as $token ) {
+ $ord = ord( $token );
+ if ( $token === 'n' ) {
+ $stack[] = $number;
+ } elseif ( $ord >= $zero && $ord <= $nine ) {
+ $stack[] = intval( $token );
+ } else {
+ $right = array_pop( $stack );
+ $left = array_pop( $stack );
+ $result = self::doOperation( $token, $left, $right );
+ $stack[] = $result;
+ }
+ }
+ if ( $stack[0] ) {
+ return $i;
+ }
+ }
+ // None of the provided rules match. The number belongs to caregory
+ // 'other' which comes last.
+ return count( $rules );
+ }
+
+ /**
+ * Do a single operation
+ *
+ * @param $token string The token string
+ * @param $left The left operand. If it is an object, its state may be destroyed.
+ * @param $right The right operand
+ * @return mixed
+ */
+ private static function doOperation( $token, $left, $right ) {
+ if ( in_array( $token, array( 'in', 'not-in', 'within', 'not-within' ) ) ) {
+ if ( !($right instanceof CLDRPluralRuleEvaluator_Range ) ) {
+ $right = new CLDRPluralRuleEvaluator_Range( $right );
+ }
+ }
+ switch ( $token ) {
+ case 'or':
+ return $left || $right;
+ case 'and':
+ return $left && $right;
+ case 'is':
+ return $left == $right;
+ case 'is-not':
+ return $left != $right;
+ case 'in':
+ return $right->isNumberIn( $left );
+ case 'not-in':
+ return !$right->isNumberIn( $left );
+ case 'within':
+ return $right->isNumberWithin( $left );
+ case 'not-within':
+ return !$right->isNumberWithin( $left );
+ case 'mod':
+ if ( is_int( $left ) ) {
+ return (int) fmod( $left, $right );
+ }
+ return fmod( $left, $right );
+ case ',':
+ if ( $left instanceof CLDRPluralRuleEvaluator_Range ) {
+ $range = $left;
+ } else {
+ $range = new CLDRPluralRuleEvaluator_Range( $left );
+ }
+ $range->add( $right );
+ return $range;
+ case '..':
+ return new CLDRPluralRuleEvaluator_Range( $left, $right );
+ default:
+ throw new CLDRPluralRuleError( "Invalid RPN token" );
+ }
+ }
+}
+
+/**
+ * Evaluator helper class representing a range list.
+ */
+class CLDRPluralRuleEvaluator_Range {
+ var $parts = array();
+
+ function __construct( $start, $end = false ) {
+ if ( $end === false ) {
+ $this->parts[] = $start;
+ } else {
+ $this->parts[] = array( $start, $end );
+ }
+ }
+
+ /**
+ * Determine if the given number is inside the range. If $integerConstraint
+ * is true, the number must additionally be an integer if it is to match
+ * any interval part.
+ */
+ function isNumberIn( $number, $integerConstraint = true ) {
+ foreach ( $this->parts as $part ) {
+ if ( is_array( $part ) ) {
+ if ( ( !$integerConstraint || floor( $number ) === (float)$number )
+ && $number >= $part[0] && $number <= $part[1] )
+ {
+ return true;
+ }
+ } else {
+ if ( $number == $part ) {
+ return true;
+ }
+ }
+ }
+ return false;
+ }
+
+ /**
+ * Readable alias for isNumberIn( $number, false ), and the implementation
+ * of the "within" operator.
+ */
+ function isNumberWithin( $number ) {
+ return $this->isNumberIn( $number, false );
+ }
+
+ /**
+ * Add another part to this range. The supplied new part may either be a
+ * range object itself, or a single number.
+ */
+ function add( $other ) {
+ if ( $other instanceof self ) {
+ $this->parts = array_merge( $this->parts, $other->parts );
+ } else {
+ $this->parts[] = $other;
+ }
+ }
+
+ /**
+ * For debugging
+ */
+ function __toString() {
+ $s = 'Range(';
+ foreach ( $this->parts as $i => $part ) {
+ if ( $i ) {
+ $s .= ', ';
+ }
+ if ( is_array( $part ) ) {
+ $s .= $part[0] . '..' . $part[1];
+ } else {
+ $s .= $part;
+ }
+ }
+ $s .= ')';
+ return $s;
+ }
+
+}
+
+/**
+ * Helper class for converting rules to reverse polish notation (RPN).
+ */
+class CLDRPluralRuleConverter {
+ var $rule, $pos, $end;
+ var $operators = array();
+ var $operands = array();
+
+ /**
+ * Precedence levels. Note that there's no need to worry about associativity
+ * for the level 4 operators, since they return boolean and don't accept
+ * boolean inputs.
+ */
+ static $precedence = array(
+ 'or' => 2,
+ 'and' => 3,
+ 'is' => 4,
+ 'is-not' => 4,
+ 'in' => 4,
+ 'not-in' => 4,
+ 'within' => 4,
+ 'not-within' => 4,
+ 'mod' => 5,
+ ',' => 6,
+ '..' => 7,
+ );
+
+ /**
+ * A character list defining whitespace, for use in strspn() etc.
+ */
+ const WHITESPACE_CLASS = " \t\r\n";
+
+ /**
+ * Same for digits. Note that the grammar given in UTS #35 doesn't allow
+ * negative numbers or decimals.
+ */
+ const NUMBER_CLASS = '0123456789';
+
+ /**
+ * An anchored regular expression which matches a word at the current offset.
+ */
+ const WORD_REGEX = '/[a-zA-Z]+/A';
+
+ /**
+ * Convert a rule to RPN. This is the only public entry point.
+ */
+ public static function convert( $rule ) {
+ $parser = new self( $rule );
+ return $parser->doConvert();
+ }
+
+ /**
+ * Private constructor.
+ */
+ protected function __construct( $rule ) {
+ $this->rule = $rule;
+ $this->pos = 0;
+ $this->end = strlen( $rule );
+ }
+
+ /**
+ * Do the operation.
+ */
+ protected function doConvert() {
+ $expectOperator = true;
+
+ // Iterate through all tokens, saving the operators and operands to a
+ // stack per Dijkstra's shunting yard algorithm.
+ while ( false !== ( $token = $this->nextToken() ) ) {
+ // In this grammar, there are only binary operators, so every valid
+ // rule string will alternate between operator and operand tokens.
+ $expectOperator = !$expectOperator;
+
+ if ( $token instanceof CLDRPluralRuleConverter_Expression ) {
+ // Operand
+ if ( $expectOperator ) {
+ $token->error( 'unexpected operand' );
+ }
+ $this->operands[] = $token;
+ continue;
+ } else {
+ // Operator
+ if ( !$expectOperator ) {
+ $token->error( 'unexpected operator' );
+ }
+ // Resolve higher precedence levels
+ $lastOp = end( $this->operators );
+ while ( $lastOp && self::$precedence[$token->name] <= self::$precedence[$lastOp->name] ) {
+ $this->doOperation( $lastOp, $this->operands );
+ array_pop( $this->operators );
+ $lastOp = end( $this->operators );
+ }
+ $this->operators[] = $token;
+ }
+ }
+
+ // Finish off the stack
+ while ( $op = array_pop( $this->operators ) ) {
+ $this->doOperation( $op, $this->operands );
+ }
+
+ // Make sure the result is sane. The first case is possible for an empty
+ // string input, the second should be unreachable.
+ if ( !count( $this->operands ) ) {
+ $this->error( 'condition expected' );
+ } elseif ( count( $this->operands ) > 1 ) {
+ $this->error( 'missing operator or too many operands' );
+ }
+
+ $value = $this->operands[0];
+ if ( $value->type !== 'boolean' ) {
+ $this->error( 'the result must have a boolean type' );
+ }
+
+ return $this->operands[0]->rpn;
+ }
+
+ /**
+ * Fetch the next token from the input string. Return it as a
+ * CLDRPluralRuleConverter_Fragment object.
+ */
+ protected function nextToken() {
+ if ( $this->pos >= $this->end ) {
+ return false;
+ }
+
+ // Whitespace
+ $length = strspn( $this->rule, self::WHITESPACE_CLASS, $this->pos );
+ $this->pos += $length;
+
+ if ( $this->pos >= $this->end ) {
+ return false;
+ }
+
+ // Number
+ $length = strspn( $this->rule, self::NUMBER_CLASS, $this->pos );
+ if ( $length !== 0 ) {
+ $token = $this->newNumber( substr( $this->rule, $this->pos, $length ), $this->pos );
+ $this->pos += $length;
+ return $token;
+ }
+
+ // Comma
+ if ( $this->rule[$this->pos] === ',' ) {
+ $token = $this->newOperator( ',', $this->pos, 1 );
+ $this->pos ++;
+ return $token;
+ }
+
+ // Dot dot
+ if ( substr( $this->rule, $this->pos, 2 ) === '..' ) {
+ $token = $this->newOperator( '..', $this->pos, 2 );
+ $this->pos += 2;
+ return $token;
+ }
+
+ // Word
+ if ( !preg_match( self::WORD_REGEX, $this->rule, $m, 0, $this->pos ) ) {
+ $this->error( 'unexpected character "' . $this->rule[$this->pos] . '"' );
+ }
+ $word1 = strtolower( $m[0] );
+ $word2 = '';
+ $nextTokenPos = $this->pos + strlen( $word1 );
+ if ( $word1 === 'not' || $word1 === 'is' ) {
+ // Look ahead one word
+ $nextTokenPos += strspn( $this->rule, self::WHITESPACE_CLASS, $nextTokenPos );
+ if ( $nextTokenPos < $this->end
+ && preg_match( self::WORD_REGEX, $this->rule, $m, 0, $nextTokenPos ) )
+ {
+ $word2 = strtolower( $m[0] );
+ $nextTokenPos += strlen( $word2 );
+ }
+ }
+
+ // Two-word operators like "is not" take precedence over single-word operators like "is"
+ if ( $word2 !== '' ) {
+ $bothWords = "{$word1}-{$word2}";
+ if ( isset( self::$precedence[$bothWords] ) ) {
+ $token = $this->newOperator( $bothWords, $this->pos, $nextTokenPos - $this->pos );
+ $this->pos = $nextTokenPos;
+ return $token;
+ }
+ }
+
+ // Single-word operators
+ if ( isset( self::$precedence[$word1] ) ) {
+ $token = $this->newOperator( $word1, $this->pos, strlen( $word1 ) );
+ $this->pos += strlen( $word1 );
+ return $token;
+ }
+
+ // The special numerical keyword "n"
+ if ( $word1 === 'n' ) {
+ $token = $this->newNumber( 'n', $this->pos );
+ $this->pos ++;
+ return $token;
+ }
+
+ $this->error( 'unrecognised word' );
+ }
+
+ /**
+ * For the binary operator $op, pop its operands off the stack and push
+ * a fragment with rpn and type members describing the result of that
+ * operation.
+ */
+ protected function doOperation( $op ) {
+ if ( count( $this->operands ) < 2 ) {
+ $op->error( 'missing operand' );
+ }
+ $right = array_pop( $this->operands );
+ $left = array_pop( $this->operands );
+ $result = $op->operate( $left, $right );
+ $this->operands[] = $result;
+ }
+
+ /**
+ * Create a numerical expression object
+ */
+ protected function newNumber( $text, $pos ) {
+ return new CLDRPluralRuleConverter_Expression( $this, 'number', $text, $pos, strlen( $text ) );
+ }
+
+ /**
+ * Create a binary operator
+ */
+ protected function newOperator( $type, $pos, $length ) {
+ return new CLDRPluralRuleConverter_Operator( $this, $type, $pos, $length );
+ }
+
+ /**
+ * Throw an error
+ */
+ protected function error( $message ) {
+ throw new CLDRPluralRuleError( $message );
+ }
+}
+
+/**
+ * Helper for CLDRPluralRuleConverter.
+ * The base class for operators and expressions, describing a region of the input string.
+ */
+class CLDRPluralRuleConverter_Fragment {
+ var $parser, $pos, $length, $end;
+
+ function __construct( $parser, $pos, $length ) {
+ $this->parser = $parser;
+ $this->pos = $pos;
+ $this->length = $length;
+ $this->end = $pos + $length;
+ }
+
+ public function error( $message ) {
+ $text = $this->getText();
+ throw new CLDRPluralRuleError( "$message at position " . ( $this->pos + 1 ) . ": \"$text\"" );
+ }
+
+ public function getText() {
+ return substr( $this->parser->rule, $this->pos, $this->length );
+ }
+}
+
+/**
+ * Helper for CLDRPluralRuleConverter.
+ * An expression object, representing a region of the input string (for error
+ * messages), the RPN notation used to evaluate it, and the result type for
+ * validation.
+ */
+class CLDRPluralRuleConverter_Expression extends CLDRPluralRuleConverter_Fragment {
+ var $type, $rpn;
+
+ function __construct( $parser, $type, $rpn, $pos, $length ) {
+ parent::__construct( $parser, $pos, $length );
+ $this->type = $type;
+ $this->rpn = $rpn;
+ }
+
+ public function isType( $type ) {
+ if ( $type === 'range' && ( $this->type === 'range' || $this->type === 'number' ) ) {
+ return true;
+ }
+ if ( $type === $this->type ) {
+ return true;
+ }
+ return false;
+ }
+}
+
+/**
+ * Helper for CLDRPluralRuleConverter.
+ * An operator object, representing a region of the input string (for error
+ * messages), and the binary operator at that location.
+ */
+class CLDRPluralRuleConverter_Operator extends CLDRPluralRuleConverter_Fragment {
+ var $name;
+
+ /**
+ * Each op type has three characters: left operand type, right operand type and result type
+ *
+ * b = boolean
+ * n = number
+ * r = range
+ *
+ * A number is a kind of range.
+ */
+ static $opTypes = array(
+ 'or' => 'bbb',
+ 'and' => 'bbb',
+ 'is' => 'nnb',
+ 'is-not' => 'nnb',
+ 'in' => 'nrb',
+ 'not-in' => 'nrb',
+ 'within' => 'nrb',
+ 'not-within' => 'nrb',
+ 'mod' => 'nnn',
+ ',' => 'rrr',
+ '..' => 'nnr',
+ );
+
+ /**
+ * Map converting from the abbrevation to the full form.
+ */
+ static $typeSpecMap = array(
+ 'b' => 'boolean',
+ 'n' => 'number',
+ 'r' => 'range',
+ );
+
+ function __construct( $parser, $name, $pos, $length ) {
+ parent::__construct( $parser, $pos, $length );
+ $this->name = $name;
+ }
+
+ public function operate( $left, $right ) {
+ $typeSpec = self::$opTypes[$this->name];
+
+ $leftType = self::$typeSpecMap[$typeSpec[0]];
+ $rightType = self::$typeSpecMap[$typeSpec[1]];
+ $resultType = self::$typeSpecMap[$typeSpec[2]];
+
+ $start = min( $this->pos, $left->pos, $right->pos );
+ $end = max( $this->end, $left->end, $right->end );
+ $length = $end - $start;
+
+ $newExpr = new CLDRPluralRuleConverter_Expression( $this->parser, $resultType,
+ "{$left->rpn} {$right->rpn} {$this->name}",
+ $start, $length );
+
+ if ( !$left->isType( $leftType ) ) {
+ $newExpr->error( "invalid type for left operand: expected $leftType, got {$left->type}" );
+ }
+
+ if ( !$right->isType( $rightType ) ) {
+ $newExpr->error( "invalid type for right operand: expected $rightType, got {$right->type}" );
+ }
+ return $newExpr;
+ }
+}
+
+/**
+ * The exception class for all the classes in this file. This will be thrown
+ * back to the caller if there is any validation error.
+ */
+class CLDRPluralRuleError extends MWException {
+ function __construct( $message ) {
+ parent::__construct( 'CLDR plural rule error: ' . $message );
+ }
+}
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