src/Net/URL2.php
public function resolve($reference)
    {
        if (!$reference instanceof Net_URL2) {
            $reference = new self($reference);
        }
        if (!$reference->_isFragmentOnly() && !$this->isAbsolute()) {
            throw new Exception(
                'Base-URL must be absolute if reference is not fragment-only'
            );
        }

        // A non-strict parser may ignore a scheme in the reference if it is
        // identical to the base URI's scheme.
        if (!$this->getOption(self::OPTION_STRICT)
            && $reference->_scheme == $this->_scheme
        ) {
            $reference->_scheme = false;
        }

        $target = new self('');
        if ($reference->_scheme !== false) {
            $target->_scheme = $reference->_scheme;
            $target->setAuthority($reference->getAuthority());
            $target->_path  = self::removeDotSegments($reference->_path);
            $target->_query = $reference->_query;
        } else {
            $authority = $reference->getAuthority();
            if ($authority !== false) {
                $target->setAuthority($authority);
                $target->_path  = self::removeDotSegments($reference->_path);
                $target->_query = $reference->_query;
            } else {
                if ($reference->_path == '') {
                    $target->_path = $this->_path;
                    if ($reference->_query !== false) {
                        $target->_query = $reference->_query;
                    } else {
                        $target->_query = $this->_query;
                    }
                } else {
                    if (substr($reference->_path, 0, 1) == '/') {
                        $target->_path = self::removeDotSegments($reference->_path);
                    } else {
                        // Merge paths (RFC 3986, section 5.2.3)
                        if ($this->_host !== false && $this->_path == '') {
                            $target->_path = '/' . $reference->_path;
                        } else {
                            $i = strrpos($this->_path, '/');
                            if ($i !== false) {
                                $target->_path = substr($this->_path, 0, $i + 1);
                            }
                            $target->_path .= $reference->_path;
                        }
                        $target->_path = self::removeDotSegments($target->_path);
                    }
                    $target->_query = $reference->_query;
                }
                $target->setAuthority($this->getAuthority());
            }
            $target->_scheme = $this->_scheme;
        }

        $target->_fragment = $reference->_fragment;

        return $target;
    }
public function resolve($reference)
    {
        if (!$reference instanceof Net_URL2) {
            $reference = new self($reference);
        }
        if (!$reference->_isFragmentOnly() && !$this->isAbsolute()) {
            throw new Exception(
                'Base-URL must be absolute if reference is not fragment-only'
            );
        }

        // A non-strict parser may ignore a scheme in the reference if it is
        // identical to the base URI's scheme.
        if (!$this->getOption(self::OPTION_STRICT)
            && $reference->_scheme == $this->_scheme
        ) {
            $reference->_scheme = false;
        }

        $target = new self('');
        if ($reference->_scheme !== false) {
            $target->_scheme = $reference->_scheme;
            $target->setAuthority($reference->getAuthority());
            $target->_path  = self::removeDotSegments($reference->_path);
            $target->_query = $reference->_query;
        } else {
            $authority = $reference->getAuthority();
            if ($authority !== false) {
                $target->setAuthority($authority);
                $target->_path  = self::removeDotSegments($reference->_path);
                $target->_query = $reference->_query;
            } else {
                if ($reference->_path == '') {
                    $target->_path = $this->_path;
                    if ($reference->_query !== false) {
                        $target->_query = $reference->_query;
                    } else {
                        $target->_query = $this->_query;
                    }
                } else {
                    if (substr($reference->_path, 0, 1) == '/') {
                        $target->_path = self::removeDotSegments($reference->_path);
                    } else {
                        // Merge paths (RFC 3986, section 5.2.3)
                        if ($this->_host !== false && $this->_path == '') {
                            $target->_path = '/' . $reference->_path;
                        } else {
                            $i = strrpos($this->_path, '/');
                            if ($i !== false) {
                                $target->_path = substr($this->_path, 0, $i + 1);
                            }
                            $target->_path .= $reference->_path;
                        }
                        $target->_path = self::removeDotSegments($target->_path);
                    }
                    $target->_query = $reference->_query;
                }
                $target->setAuthority($this->getAuthority());
            }
            $target->_scheme = $this->_scheme;
        }

        $target->_fragment = $reference->_fragment;

        return $target;
    }
Returns an Net_URL2 instance representing an absolute URL relative to
this URL.

@param Net_URL2|string $reference relative URL

@throws Exception
@return $this