ptlis\SemanticVersion\Parse\VersionTokenizer

Complexity

Total Complexity

31

Size/Duplication

Total Lines	243
Duplicated Lines	0 %

Coupling/Cohesion

Dependencies

1

Test Coverage

Coverage

100%

Importance

Changes

0

8 Methods

Rating	Name	Duplication	Size	Complexity
A	isPossibleLogicalOperator()	0	4	2
D	tokenize()	0	87	14
A	addImplicitAnd()	0	11	3
A	getComparatorToken()	0	19	3
A	getSimpleToken()	0	9	2
A	conditionallyAddToken()	0	11	2
A	isPrefixedV()	0	8	3
A	getCharacter()	0	9	2

<?php

/**
 * @copyright   (c) 2014-2017 brian ridley
 * @author      brian ridley <ptlis@ptlis.net>
 * @license     http://opensource.org/licenses/MIT MIT
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

namespace ptlis\SemanticVersion\Parse;

/**
 * Tokenizer for version numbers.
 */
final class VersionTokenizer
{
    /** @var array Array mapping strings to comparator types */
    private $comparatorMap = [
        '>' => Token::GREATER_THAN,
        '>=' => Token::GREATER_THAN_EQUAL,
        '<' => Token::LESS_THAN,
        '<=' => Token::LESS_THAN_EQUAL,
        '=' => Token::EQUAL_TO
    ];

    /** @var array Array mapping strings to simple token types */
    private $simpleTokenMap = [
        '-' => Token::DASH_SEPARATOR,
        '.' => Token::DOT_SEPARATOR,
        '~' => Token::TILDE_RANGE,
        '^' => Token::CARET_RANGE,
        '*' => Token::WILDCARD_DIGITS,
        'x' => Token::WILDCARD_DIGITS
    ];

    /**
     * Accepts a version string & returns an array of tokenized values.
     *
     * @param string $versionString
     *
     * @return Token[]
     */
    public function tokenize($versionString)
    {
        /** @var Token[] $tokenList */
        $tokenList = [];
        $digitAccumulator = '';
        $stringAccumulator = '';

        // Iterate through string, character-by-character
        for ($i = 0; $i < strlen($versionString); $i++) {
            $chr = $this->getCharacter($i, $versionString);

            switch (true) {
                // Simple token types - separators and range indicators
                case !is_null($this->getSimpleToken($chr)):
                    // Handle preceding digits or labels
                    $this->conditionallyAddToken(Token::DIGITS, $digitAccumulator, $tokenList);
                    $this->conditionallyAddToken(Token::LABEL_STRING, $stringAccumulator, $tokenList);

                    $tokenList[] = $this->getSimpleToken($chr);
                    break;

                // Comparator token types
                case !is_null($token = $this->getComparatorToken($i, $versionString)):
                    // Handle preceding digits or labels
                    $this->conditionallyAddToken(Token::DIGITS, $digitAccumulator, $tokenList);
                    $this->conditionallyAddToken(Token::LABEL_STRING, $stringAccumulator, $tokenList);

                    $this->addImplicitAnd($tokenList);

                    $tokenList[] = $token;
                    break;

                // Skip the 'v' character if immediately preceding a digit
                case $this->isPrefixedV($i, $versionString):
                    // Do nothing
                    break;

                // Spaces, pipes, ampersands and commas may contextually be logical AND/OR
                case $this->isPossibleLogicalOperator($chr):
                    // Handle preceding digits or labels
                    $this->conditionallyAddToken(Token::DIGITS, $digitAccumulator, $tokenList);
                    $this->conditionallyAddToken(Token::LABEL_STRING, $stringAccumulator, $tokenList);

                    // No previous tokens, or previous token was not a comparator
                    if (
                        !count($tokenList)
                        || !in_array($tokenList[count($tokenList)-1]->getType(), $this->comparatorMap)
                    ) {
                        $possibleOperator = trim($chr);

                        for ($j = $i + 1; $j < strlen($versionString); $j++) {
                            $operatorChr = $this->getCharacter($j, $versionString);

                            if ($this->isPossibleLogicalOperator($operatorChr)) {
                                $possibleOperator .= trim($operatorChr);
                            } else {
                                if (!strlen($possibleOperator) || ',' === $possibleOperator) {
                                    $tokenList[] = new Token(Token::LOGICAL_AND, $possibleOperator);
                                } else {
                                    $tokenList[] = new Token(Token::LOGICAL_OR, $possibleOperator);
                                }
                                $i = $j - 1;
                                break;
                            }
                        }
                    }

                    break;

                // Start accumulating on the first non-digit & continue until we reach a separator
                case !is_numeric($chr) || strlen($stringAccumulator):
                    $stringAccumulator .= $chr;
                    break;

                // Simple digits
                default:
                    $digitAccumulator .= $chr;
                    break;
            }
        }

        // Handle any remaining digits or labels
        $this->conditionallyAddToken(Token::DIGITS, $digitAccumulator, $tokenList);
        $this->conditionallyAddToken(Token::LABEL_STRING, $stringAccumulator, $tokenList);

        return $tokenList;
    }

    /**
     * Add an implicit AND between a version & the comparator of a subsequent version.
     *
     * @param Token[] $tokenList
     */
    private function addImplicitAnd(array &$tokenList)
    {
        $digitTokenList = [
            Token::DIGITS,
            Token::WILDCARD_DIGITS
        ];

        if (count($tokenList) && in_array($tokenList[count($tokenList) -1]->getType(), $digitTokenList)) {
            $tokenList[] = new Token(Token::LOGICAL_AND, '');
        }
    }

    /**
     * Returns true if the character is an AND comparator
     *
     * @param string $chr
     *
     * @return bool
     */
    private function isPossibleLogicalOperator($chr)
    {
        return in_array($chr, array(',', '|')) || ctype_space($chr);
    }

    /**
     * Tries to find a comparator token beginning at the specified index.
     *
     * @param int $index
     * @param string $versionString
     *
     * @return Token|null
     */
    private function getComparatorToken(&$index, $versionString)
    {
        $token = null;

        // See if the first character matches a token
        $comparator = substr($versionString, $index, 1);
        if (array_key_exists($comparator, $this->comparatorMap)) {
            // Check for second character in comparator ('<=' or '=>')
            $nextChr = $this->getCharacter($index + 1, $versionString);
            if (array_key_exists($comparator . $nextChr, $this->comparatorMap)) {
                $comparator .= $nextChr;
                $index++;
            }

            $token = new Token($this->comparatorMap[$comparator], $comparator);
        }

        return $token;
    }

    /**
     * Get a token from a single-character.
     *
     * @param string $chr
     *
     * @return Token|null
     */
    private function getSimpleToken($chr)
    {
        $token = null;
        if (array_key_exists($chr, $this->simpleTokenMap)) {
            $token = new Token($this->simpleTokenMap[$chr], $chr);
        }

        return $token;
    }

    /**
     * Add a token to the list if the string length is greater than 0, empties string.
     *
     * @param string $type One of Token class constants
     * @param string $value
     * @param Token[] $tokenList
     */
    public function conditionallyAddToken($type, &$value, &$tokenList)
    {
        if (strlen($value)) {
            $tokenList[] = new Token(
                $type,
                $value
            );

            $value = '';
        }
    }

    /**
     * Returns true if the character is a 'v' prefix to a version number (e.g. v1.0.7).
     *
     * @param int $index
     * @param string $versionString
     *
     * @return bool
     */
    private function isPrefixedV($index, $versionString)
    {
        $chr = $this->getCharacter($index, $versionString);

        return 'v' === $chr
            && $index + 1 < strlen($versionString)
            && is_numeric($this->getCharacter($index + 1, $versionString));
    }

    /**
     * Get the next character after the specified index or an empty string if not present.
     *
     * @param int $index
     * @param string $versionString
     * @return string
     */
    private function getCharacter($index, $versionString)
    {
        $chr = '';
        if ($index < strlen($versionString)) {
            $chr = substr($versionString, $index, 1);
        }

        return $chr;
    }
}