HTTP/2 Frame Iterater

client.php

<?php

require 'H2FrameIter.php';
require 'h2testdata.php';

$chunk = h2_server_frame();
$iter = H2FrameIter($chunk);
$current = 0;

foreach ($iter as $index => $next) {
    var_dump([
        'index' => $inex,
        'current' => $current,
        'next' => $next,
        'isEndStream' => isEndStream($chunk, $current)
    ]);

    $current = $next;
}

H2FrameIter.php

<?php

function H2FrameIter(string $chunk): Generator {
    $chunk_size = strlen($chunk);
    $index = 0;
    $next = 0;

    while (true) {
        if ($next > $chunk_size || $next + 3 > $chunk_size) {
            break;
        }

        $size = hexdec(bin2hex(substr($chunk, $next, 3))) + 9;
        $next += $size;

        yield $index => $next;
        ++$index;
    }
}

function isEndStream(string $chunk, int $current): bool {
    $chunk_size = strlen($chunk);

    if ($current + 4 > $chunk_size) {
        return false;
    }

    $type = ord(substr($chunk, $current + 3, 1));
    $flag = ord(substr($chunk, $current + 4, 1));

    return $type === 0x00 && $flag === 0x01 ?: false;
}

function isDataFrame(string $chunk, int $current): bool {
    $chunk_size = strlen($chunk);

    if ($current + 4 > $chunk_size) {
        return false;
    }

    $type = ord(substr($chunk, $current + 3, 1));

    return $type === 0x00;
}

function getPayload(string $chunk, $current): string {
    $chunk_size = strlen($chunk);

    if ($current + 3 > $chunk_size) {
        return "";
    }

    $length = hexdec(bin2hex(substr($chunk, $current, 3)));

    if ($current + 9 + $length > $chunk_size) {
        return "";
    }

    return substr($chunk, $current + 9, $length);
}

h2testdata.php

function h2_client_frame($name = null) {
    $ret = [
      'pri' => "PRI * HTTP/2.0\r\n\r\nSM\r\n\r\n",
      'settings' => "\x00\x00\x0C".
                    "\x04".
                    "\x00".
                    "\x00\x00\x00\x00".
                    "\x00\x02\x00\x00\x00\x00".
                    "\x00\x03\x00\x00\x00\x64",
    'ack' => "\x00\x00\x00".
             "\x04".
             "\x01".
             "\x00\x00\x00\x00",
   'headers' => "\x00\x00\x3a".
                "\x01".
                "\x05".
                "\x00\x00\x00\x01".
                "\x00".
                "\x07:method".                                  // 7 :method
                "\x03\x47\x45\x54".                             // 3 GET
                "\x00".
                "\x05\x3a\x70\x61\x74\x68".                     // 5 :path
                "\x01\x2f".                                     // 1 /
                "\x00".
                "\x07\x3a\x73\x63\x68\x65\x6d\x65".             // 7 :scheme
                "\x04http".                                     // 4 http
                "\x00".
                "\x0a\x3a\x61\x75\x74\x68\x6f\x72\x69\x74\x79". // 10 :authority
                "\x09localhost"                                // 9 localhost
    ];

    return $name === null ? implode($ret) : $ret[$name];
}

function h2_server_frame() {
    $ret = [
        'settings' => "\x00\x00\x06".
                      "\x04".
                      "\x00".
                      "\x00\x00\x00\x00".
                      "\x00\x03\x00\x00\x00\x64",
        'ack' => "\x00\x00\x00".
                 "\x04".
                 "\x01".
                 "\x00\x00\x00\x00",
        'headers' => "\x00\x00\x5c".
                     "\x01".
                     "\x04".
                     "\x00\x00\x00\x01".
                     "\x88\x76\x90\xaa\x69\xd2\x9a\xe4\x52\xa9\xa7".
                     "\x4a\x6b\x13\x01\x5d\xb1\x2e\x0f\x58\x89\xa4".
                     "\x7e\x56\x1c\xc5\x81\x97\x00\x0f\x61\x97\xdf".
                     "\x3d\xbf\x4a\x05\xe5\x32\xdb\x42\x82\x00\x9a".
                     "\x50\x22\xb8\xcb\xb7\x1b\x6d\x4c\x5a\x37\xff".
                     "\x0f\x0d\x01\x36\x6c\x96\xdc\x34\xfd\x28\x07".
                     "\x14\xcb\x6d\x0a\x08\x02\x69\x40\xbf\x70\x2f".
                     "\xdc\x6d\xb5\x31\x68\xdf\x5f\x87\x49\x7c\xa5".
                     "\x89\xd3\x4d\x1f",
    'data' => "\x00\x00\x06".
              "\x00".
              "\x01".
              "\x00\x00\x00\x01".
              "\x48\x65\x6c\x6c\x6f\x0a"
    ];

    return implode($ret);
}