Description:
------------
The inflate_add() function is available as of PHP 7.0.0 and it incrementally decompresses DEFLATE, ZLIB and GZIP compressed data passed chunk by chunk. When GZIP compressed data are feed to this function, it succeeds detecting corrupted data, but it fails to detect trunked data, as the following test script proves.

Test script:
---------------
<?php
	error_reporting(-1);
	
//	$deflateContext = deflate_init(ZLIB_ENCODING_GZIP);
//	$compressed = deflate_add($deflateContext, "Data to compress", ZLIB_NO_FLUSH);
//	$compressed .= deflate_add($deflateContext, ", more data", ZLIB_NO_FLUSH);
//	$compressed .= deflate_add($deflateContext, ", and even more data!", ZLIB_FINISH);
	
	// Creates GZIP compressed data:
	$plain = "Data to compress, more data, and even more data!";
	$compressed = gzencode($plain);
	
	echo "Compressed: ", wordwrap(bin2hex($compressed), 2, " ", TRUE), "\n";
	
	// These tests succeeded with error, as expected:
	
	// Invalid checksum:
//	$compressed[strlen($compressed)-5] = 'x';
	// --> E_WARNING: inflate_add(): data error
	
	// Invalid length:
//	$compressed[strlen($compressed)-2] = 'x';
	// --> E_WARNING: inflate_add(): data error
	
	// Corrupted compressed data:
//	$compressed[strlen($compressed)/2] = 'x';
	// --> E_WARNING: inflate_add(): data error
	
	// Following test FAILED to detect corrupted data:
	
	// Trunked lenght field:
//	$compressed = substr($compressed, 0, strlen($compressed)-4);
	// --> Data to compress, more data, and even more data!
	// NO ERROR SIGNALED
	
	// Trunked Adler32 and lenght fields:
//	$compressed = substr($compressed, 0, strlen($compressed)-8);
	// --> Data to compress, more data, and even more data!
	// NO ERROR SIGNALED
	
	// Trunked some data, Adler32 and lenght fields:
	$compressed = substr($compressed, 0, strlen($compressed)-12);
	// --> Data to compress, more data, and eve
	// TRUNKED RESULTING DATA, NO ERROR SIGNALED
	
	echo "Corrupted : ", wordwrap(bin2hex($compressed), 2, " ", TRUE), "\n";
	$inflateContext = inflate_init(ZLIB_ENCODING_GZIP);
	$uncompressed  = inflate_add($inflateContext, $compressed, ZLIB_NO_FLUSH);
	$uncompressed .= inflate_add($inflateContext, NULL, ZLIB_FINISH);
	echo $uncompressed;
?>

Expected result:
----------------
E_WARNING: inflate_add(): data error

Actual result:
--------------
Data to compress, more data, and eve


(note how the original plain string has been trunked, but no error is detected).