Fix #76859 stream_get_line skips data if used with data-generating filter

stream_get-line repeatedly calls php_stream_fill_read_buffer until
enough data is accumulated in buffer. However, when stream contains
filters attached to it, then each call to fill buffer essentially
resets buffer read/write pointers and new data is written over old.
This causes stream_get_line to skip parts of data from stream
This patch fixes such behavior, so fill buffer call will append.

2 files changed, 36 insertions, 0 deletions

diff --git a/ext/standard/tests/streams/bug46147.phpt b/ext/standard/tests/streams/bug46147.phpt
new file mode 100644
index 0000000000..bed2ee5472
--- /dev/null
+++ b/ext/standard/tests/streams/bug46147.phpt
@@ -0,0 +1,14 @@
+--TEST--
+Bug #46147 (after stream seek, appending stream filter reads incorrect data)
+--FILE--
+<?php
+$fp = tmpfile();
+fwrite($fp, "this is a lowercase string.\n");
+fseek($fp, 5);
+stream_filter_append($fp, "string.toupper");
+while (!feof($fp)) {
+    echo fread($fp, 5);
+}
+
+--EXPECT--
+IS A LOWERCASE STRING.
diff --git a/ext/standard/tests/streams/bug76859.phpt b/ext/standard/tests/streams/bug76859.phpt
new file mode 100644
index 0000000000..268b06a01b
--- /dev/null
+++ b/ext/standard/tests/streams/bug76859.phpt
@@ -0,0 +1,22 @@
+--TEST--
+Bug #76859 (stream_get_line skips data if used with filters)
+--FILE--
+<?php
+
+$data = '123';
+
+$fh = fopen('php://memory', 'r+b');
+fwrite($fh, $data);
+rewind($fh);
+stream_filter_append($fh, 'string.rot13', STREAM_FILTER_READ);
+
+$out = '';
+while (!feof($fh)) {
+    $out .= stream_get_line($fh, 1024);
+}
+
+fclose($fh);
+
+echo strlen($out) . "\n";
+--EXPECT--
+3