src/PEAR/PackageFile/v2.php
function isSubpackage($p)
    {
        $sub = array();
        if (isset($this->_packageInfo['dependencies']['required']['subpackage'])) {
            $sub = $this->_packageInfo['dependencies']['required']['subpackage'];
            if (!isset($sub[0])) {
                $sub = array($sub);
            }
        }
        if (isset($this->_packageInfo['dependencies']['optional']['subpackage'])) {
            $sub1 = $this->_packageInfo['dependencies']['optional']['subpackage'];
            if (!isset($sub1[0])) {
                $sub1 = array($sub1);
            }
            $sub = array_merge($sub, $sub1);
        }
        if (isset($this->_packageInfo['dependencies']['group'])) {
            $group = $this->_packageInfo['dependencies']['group'];
            if (!isset($group[0])) {
                $group = array($group);
            }
            foreach ($group as $deps) {
                if (isset($deps['subpackage'])) {
                    $sub2 = $deps['subpackage'];
                    if (!isset($sub2[0])) {
                        $sub2 = array($sub2);
                    }
                    $sub = array_merge($sub, $sub2);
                }
            }
        }
        foreach ($sub as $dep) {
            if (strtolower($dep['name']) == strtolower($p->getPackage())) {
                if (isset($dep['channel'])) {
                    if (strtolower($dep['channel']) == strtolower($p->getChannel())) {
                        return true;
                    }
                } else {
                    if ($dep['uri'] == $p->getURI()) {
                        return true;
                    }
                }
            }
        }
        return false;
    }
function isSubpackage($p)
    {
        $sub = array();
        if (isset($this->_packageInfo['dependencies']['required']['subpackage'])) {
            $sub = $this->_packageInfo['dependencies']['required']['subpackage'];
            if (!isset($sub[0])) {
                $sub = array($sub);
            }
        }
        if (isset($this->_packageInfo['dependencies']['optional']['subpackage'])) {
            $sub1 = $this->_packageInfo['dependencies']['optional']['subpackage'];
            if (!isset($sub1[0])) {
                $sub1 = array($sub1);
            }
            $sub = array_merge($sub, $sub1);
        }
        if (isset($this->_packageInfo['dependencies']['group'])) {
            $group = $this->_packageInfo['dependencies']['group'];
            if (!isset($group[0])) {
                $group = array($group);
            }
            foreach ($group as $deps) {
                if (isset($deps['subpackage'])) {
                    $sub2 = $deps['subpackage'];
                    if (!isset($sub2[0])) {
                        $sub2 = array($sub2);
                    }
                    $sub = array_merge($sub, $sub2);
                }
            }
        }
        foreach ($sub as $dep) {
            if (strtolower($dep['name']) == strtolower($p->getPackage())) {
                if (isset($dep['channel'])) {
                    if (strtolower($dep['channel']) == strtolower($p->getChannel())) {
                        return true;
                    }
                } else {
                    if ($dep['uri'] == $p->getURI()) {
                        return true;
                    }
                }
            }
        }
        return false;
    }
Determines whether the passed in package is a subpackage of this package.

No version checking is done, only name verification.
@param PEAR_PackageFile_v1|PEAR_PackageFile_v2
@return bool