file_get_contents(): Add support for negative offset

ext/standard/file.c

@@ -518,7 +518,7 @@ PHP_FUNCTION(file_get_contents)
 	size_t filename_len;
 	zend_bool use_include_path = 0;
 	php_stream *stream;
-	zend_long offset = -1;
+	zend_long offset = 0;
 	zend_long maxlen = (ssize_t) PHP_STREAM_COPY_ALL;
 	zval *zcontext = NULL;
 	php_stream_context *context = NULL;
@@ -543,7 +543,7 @@ PHP_FUNCTION(file_get_contents)
 		RETURN_FALSE;
 	}
 
-	if (offset > 0 && php_stream_seek(stream, offset, SEEK_SET) < 0) {
+	if (offset != 0 && php_stream_seek(stream, offset, ((offset > 0) ? SEEK_SET : SEEK_END)) < 0) {
 		php_error_docref(NULL, E_WARNING, "Failed to seek to position " ZEND_LONG_FMT " in the stream", offset);
 		php_stream_close(stream);
 		RETURN_FALSE;

ext/standard/tests/file/bug39673.phpt

@@ -22,14 +22,14 @@ $offsets = array(
 
 foreach ($offsets as $offset) {
 	$r = file_get_contents($filename, false, null, $offset);
-	var_dump(strlen($r));
+	if ($r !== false) var_dump(strlen($r));
 }
 
 @unlink($filename);
 echo "Done\n";
 ?>
---EXPECTF--	
-int(13824)
+--EXPECTF-- 
+int(1)
 int(13824)
 int(0)
 int(1)

ext/standard/tests/file/file_get_contents_variation5_32bit.phpt

@@ -0,0 +1,236 @@
+--TEST--
+Test file_get_contents() function : usage variation 
+--CREDITS--
+Dave Kelsey <d_kelsey@uk.ibm.com>
+--SKIPIF--
+<?php if (PHP_INT_SIZE != 4) die("skip this test is for 32-bit only");
+--FILE--
+<?php
+/* Prototype  : string file_get_contents(string filename [, bool use_include_path [, resource context [, long offset [, long maxlen]]]])
+ * Description: Read the entire file into a string 
+ * Source code: ext/standard/file.c
+ * Alias to functions: 
+ */
+
+echo "*** Testing file_get_contents() : usage variation ***\n";
+
+// Define error handler
+function test_error_handler($err_no, $err_msg, $filename, $linenum, $vars) {
+	if (error_reporting() != 0) {
+		// report non-silenced errors
+		echo "Error: $err_no - $err_msg, $filename($linenum)\n";
+	}
+}
+set_error_handler('test_error_handler');
+
+// Initialise function arguments not being substituted (if any)
+$filename = 'FileGetContentsVar5.tmp';
+$absFile = dirname(__FILE__).'/'.$filename;
+$h = fopen($absFile,"w");
+fwrite($h, b"contents read");
+fclose($h);
+
+
+//get an unset variable
+$unset_var = 10;
+unset ($unset_var);
+
+// define some classes
+class classWithToString
+{
+	public function __toString() {
+		return "Class A object";
+	}
+}
+
+class classWithoutToString
+{
+}
+
+// heredoc string
+$heredoc = <<<EOT
+hello world
+EOT;
+
+// add arrays
+$index_array = array (1, 2, 3);
+$assoc_array = array ('one' => 1, 'two' => 2);
+
+//array of values to iterate over
+$inputs = array(
+
+      // int data
+      'int 0' => 0,
+      'int 1' => 1,
+      'int 12345' => 12345,
+      'int -12345' => -12345,
+	  'int -10' => -10,
+
+      // float data
+      'float 10.5' => 10.5,
+      'float -10.5' => -10.5,
+      'float -22.5' => -22.5,
+      'float 12.3456789000e10' => 12.3456789000e10,
+      'float -12.3456789000e10' => -12.3456789000e10,
+      'float .5' => .5,
+
+      // array data
+      'empty array' => array(),
+      'int indexed array' => $index_array,
+      'associative array' => $assoc_array,
+      'nested arrays' => array('foo', $index_array, $assoc_array),
+
+      // null data
+      'uppercase NULL' => NULL,
+      'lowercase null' => null,
+
+      // boolean data
+      'lowercase true' => true,
+      'lowercase false' =>false,
+      'uppercase TRUE' =>TRUE,
+      'uppercase FALSE' =>FALSE,
+
+      // empty data
+      'empty string DQ' => "",
+      'empty string SQ' => '',
+
+      // string data
+      'string DQ' => "string",
+      'string SQ' => 'string',
+      'mixed case string' => "sTrInG",
+      'heredoc' => $heredoc,
+
+      // object data
+      'instance of classWithToString' => new classWithToString(),
+      'instance of classWithoutToString' => new classWithoutToString(),
+
+      // undefined data
+      'undefined var' => @$undefined_var,
+
+      // unset data
+      'unset var' => @$unset_var,
+);
+
+// loop through each element of the array for offset
+
+foreach($inputs as $key =>$value) {
+      echo "\n--$key--\n";
+      var_dump( file_get_contents($absFile, false, null, $value) );
+};
+
+unlink($absFile);
+
+?>
+===DONE===
+--EXPECTF--
+*** Testing file_get_contents() : usage variation ***
+
+--int 0--
+string(%d) "contents read"
+
+--int 1--
+string(%d) "ontents read"
+
+--int 12345--
+string(%d) ""
+
+--int -12345--
+Error: 2 - file_get_contents(): Failed to seek to position -12345 in the stream, %s(%d)
+bool(false)
+
+--int -10--
+string(10) "tents read"
+
+--float 10.5--
+string(3) "ead"
+
+--float -10.5--
+string(10) "tents read"
+
+--float -22.5--
+Error: 2 - file_get_contents(): Failed to seek to position -22 in the stream, %s(%d)
+bool(false)
+
+--float 12.3456789000e10--
+Error: 2 - file_get_contents() expects parameter 4 to be integer, float given, %s(%d)
+NULL
+
+--float -12.3456789000e10--
+Error: 2 - file_get_contents() expects parameter 4 to be integer, float given, %s(%d)
+NULL
+
+--float .5--
+string(%d) "contents read"
+
+--empty array--
+Error: 2 - file_get_contents() expects parameter 4 to be integer, array given, %s(%d)
+NULL
+
+--int indexed array--
+Error: 2 - file_get_contents() expects parameter 4 to be integer, array given, %s(%d)
+NULL
+
+--associative array--
+Error: 2 - file_get_contents() expects parameter 4 to be integer, array given, %s(%d)
+NULL
+
+--nested arrays--
+Error: 2 - file_get_contents() expects parameter 4 to be integer, array given, %s(%d)
+NULL
+
+--uppercase NULL--
+string(%d) "contents read"
+
+--lowercase null--
+string(%d) "contents read"
+
+--lowercase true--
+string(12) "ontents read"
+
+--lowercase false--
+string(%d) "contents read"
+
+--uppercase TRUE--
+string(12) "ontents read"
+
+--uppercase FALSE--
+string(%d) "contents read"
+
+--empty string DQ--
+Error: 2 - file_get_contents() expects parameter 4 to be integer, %unicode_string_optional% given, %s(%d)
+NULL
+
+--empty string SQ--
+Error: 2 - file_get_contents() expects parameter 4 to be integer, %unicode_string_optional% given, %s(%d)
+NULL
+
+--string DQ--
+Error: 2 - file_get_contents() expects parameter 4 to be integer, %unicode_string_optional% given, %s(%d)
+NULL
+
+--string SQ--
+Error: 2 - file_get_contents() expects parameter 4 to be integer, %unicode_string_optional% given, %s(%d)
+NULL
+
+--mixed case string--
+Error: 2 - file_get_contents() expects parameter 4 to be integer, %unicode_string_optional% given, %s(%d)
+NULL
+
+--heredoc--
+Error: 2 - file_get_contents() expects parameter 4 to be integer, %unicode_string_optional% given, %s(%d)
+NULL
+
+--instance of classWithToString--
+Error: 2 - file_get_contents() expects parameter 4 to be integer, object given, %s(%d)
+NULL
+
+--instance of classWithoutToString--
+Error: 2 - file_get_contents() expects parameter 4 to be integer, object given, %s(%d)
+NULL
+
+--undefined var--
+string(%d) "contents read"
+
+--unset var--
+string(%d) "contents read"
+===DONE===

ext/standard/tests/file/file_get_contents_variation5_64bit.phpt

@@ -63,11 +63,13 @@ $inputs = array(
       'int 0' => 0,
       'int 1' => 1,
       'int 12345' => 12345,
-      'int -12345' => -2345,
+      'int -12345' => -12345,
+	  'int -10' => -10,
 
       // float data
       'float 10.5' => 10.5,
       'float -10.5' => -10.5,
+      'float -22.5' => -22.5,
       'float 12.3456789000e10' => 12.3456789000e10,
       'float -12.3456789000e10' => -12.3456789000e10,
       'float .5' => .5,
@@ -133,19 +135,28 @@ string(%d) "ontents read"
 string(%d) ""
 
 --int -12345--
-string(%d) "contents read"
+Error: 2 - file_get_contents(): Failed to seek to position -12345 in the stream, %s(%d)
+bool(false)
+
+--int -10--
+string(10) "tents read"
 
 --float 10.5--
 string(3) "ead"
 
 --float -10.5--
-string(%d) "contents read"
+string(10) "tents read"
+
+--float -22.5--
+Error: 2 - file_get_contents(): Failed to seek to position -22 in the stream, %s(%d)
+bool(false)
 
 --float 12.3456789000e10--
 string(%d) %s
 
 --float -12.3456789000e10--
-string(%d) %s
+Error: 2 - file_get_contents(): Failed to seek to position -123456789000 in the stream, %s(%d)
+bool(false)
 
 --float .5--
 string(%d) "contents read"