HTTP_Encoder now tests decompression and allows compressed content to be within 100 bytes of target size.

web/test/test_HTTP_Encoder.php

@@ -72,9 +72,9 @@ function test_HTTP_Encoder()
     $variedLength = strlen($variedContent);
     
     $encodingTests = array(
-        array('method' => 'deflate', 'exp' => 32157)
-        ,array('method' => 'gzip', 'exp' => 32175)
-        ,array('method' => 'compress', 'exp' => 32211)
+        array('method' => 'deflate', 'inv' => 'gzinflate', 'exp' => 32157)
+        ,array('method' => 'gzip', 'inv' => '_gzdecode', 'exp' => 32175)
+        ,array('method' => 'compress', 'inv' => 'gzuncompress', 'exp' => 32211)
     );
     
     foreach ($encodingTests as $test) {
@@ -85,16 +85,140 @@ function test_HTTP_Encoder()
         $e->encode(9);
         $ret = strlen($e->getContent());
         
-        $desc = "HTTP_Encoder : {$test['method']} -> "
-            . sprintf('%d(%4.2f%%)', $ret, $ret/$variedLength*100);
-        
-        $passed = assertTrue($ret == $test['exp'], $desc);
+        // test uncompression
+        $roundTrip = @call_user_func($test['inv'], $e->getContent());
+        $desc = "HTTP_Encoder : {$test['method']} : uncompress possible";
+        $passed = assertTrue($variedContent == $roundTrip, $desc);
         
+        // test expected compressed size
+        $desc = "HTTP_Encoder : {$test['method']} : compressed to "
+            . sprintf('%4.2f%% of original', $ret/$variedLength*100);
+        $passed = assertTrue(abs($ret - $test['exp']) < 100, $desc);
         if (__FILE__ === realpath($_SERVER['SCRIPT_FILENAME'])) {
             echo "\n--- {$test['method']}: expected bytes: "
-                , "{$test['exp']}. Returned: {$ret}\n\n";
+                , "{$test['exp']}. Returned: {$ret} "
+                , "(off by ". abs($ret - $test['exp']) . " bytes)\n\n";
         }
     }
 }
 
 test_HTTP_Encoder();
+
+function _gzdecode($data)
+{
+    $filename = $error = '';
+    return _phpman_gzdecode($data, $filename, $error);
+}
+
+// http://www.php.net/manual/en/function.gzdecode.php#82930
+function _phpman_gzdecode($data, &$filename='', &$error='', $maxlength=null)
+{
+    $len = strlen($data);
+    if ($len < 18 || strcmp(substr($data,0,2),"\x1f\x8b")) {
+        $error = "Not in GZIP format.";
+        return null;  // Not GZIP format (See RFC 1952)
+    }
+    $method = ord(substr($data,2,1));  // Compression method
+    $flags  = ord(substr($data,3,1));  // Flags
+    if ($flags & 31 != $flags) {
+        $error = "Reserved bits not allowed.";
+        return null;
+    }
+    // NOTE: $mtime may be negative (PHP integer limitations)
+    $mtime = unpack("V", substr($data,4,4));
+    $mtime = $mtime[1];
+    $xfl   = substr($data,8,1);
+    $os    = substr($data,8,1);
+    $headerlen = 10;
+    $extralen  = 0;
+    $extra     = "";
+    if ($flags & 4) {
+        // 2-byte length prefixed EXTRA data in header
+        if ($len - $headerlen - 2 < 8) {
+            return false;  // invalid
+        }
+        $extralen = unpack("v",substr($data,8,2));
+        $extralen = $extralen[1];
+        if ($len - $headerlen - 2 - $extralen < 8) {
+            return false;  // invalid
+        }
+        $extra = substr($data,10,$extralen);
+        $headerlen += 2 + $extralen;
+    }
+    $filenamelen = 0;
+    $filename = "";
+    if ($flags & 8) {
+        // C-style string
+        if ($len - $headerlen - 1 < 8) {
+            return false; // invalid
+        }
+        $filenamelen = strpos(substr($data,$headerlen),chr(0));
+        if ($filenamelen === false || $len - $headerlen - $filenamelen - 1 < 8) {
+            return false; // invalid
+        }
+        $filename = substr($data,$headerlen,$filenamelen);
+        $headerlen += $filenamelen + 1;
+    }
+    $commentlen = 0;
+    $comment = "";
+    if ($flags & 16) {
+        // C-style string COMMENT data in header
+        if ($len - $headerlen - 1 < 8) {
+            return false;    // invalid
+        }
+        $commentlen = strpos(substr($data,$headerlen),chr(0));
+        if ($commentlen === false || $len - $headerlen - $commentlen - 1 < 8) {
+            return false;    // Invalid header format
+        }
+        $comment = substr($data,$headerlen,$commentlen);
+        $headerlen += $commentlen + 1;
+    }
+    $headercrc = "";
+    if ($flags & 2) {
+        // 2-bytes (lowest order) of CRC32 on header present
+        if ($len - $headerlen - 2 < 8) {
+            return false;    // invalid
+        }
+        $calccrc = crc32(substr($data,0,$headerlen)) & 0xffff;
+        $headercrc = unpack("v", substr($data,$headerlen,2));
+        $headercrc = $headercrc[1];
+        if ($headercrc != $calccrc) {
+            $error = "Header checksum failed.";
+            return false;    // Bad header CRC
+        }
+        $headerlen += 2;
+    }
+    // GZIP FOOTER
+    $datacrc = unpack("V",substr($data,-8,4));
+    $datacrc = sprintf('%u',$datacrc[1] & 0xFFFFFFFF);
+    $isize = unpack("V",substr($data,-4));
+    $isize = $isize[1];
+    // decompression:
+    $bodylen = $len-$headerlen-8;
+    if ($bodylen < 1) {
+        // IMPLEMENTATION BUG!
+        return null;
+    }
+    $body = substr($data,$headerlen,$bodylen);
+    $data = "";
+    if ($bodylen > 0) {
+        switch ($method) {
+        case 8:
+            // Currently the only supported compression method:
+            $data = gzinflate($body,$maxlength);
+            break;
+        default:
+            $error = "Unknown compression method.";
+            return false;
+        }
+    }  // zero-byte body content is allowed
+    // Verifiy CRC32
+    $crc   = sprintf("%u",crc32($data));
+    $crcOK = $crc == $datacrc;
+    $lenOK = $isize == strlen($data);
+    if (!$lenOK || !$crcOK) {
+        $error = ( $lenOK ? '' : 'Length check FAILED. ') . ( $crcOK ? '' : 'Checksum FAILED.');
+        return false;
+    }
+    return $data;
+}