Stream filter seeking

ext/bz2/bz2_filter.c

@@ -42,6 +42,10 @@ typedef struct _php_bz2_filter_data {
 	unsigned int is_flushed : 1;          /* only for compression */
 
 	int persistent;
+
+	/* Configuration for reset - immutable */
+	int blockSize100k;  /* compress only */
+	int workFactor;     /* compress only */
 } php_bz2_filter_data;
 
 /* }}} */
@@ -178,6 +182,36 @@ static php_stream_filter_status_t php_bz2_decompress_filter(
 	return exit_status;
 }
 
+static zend_result php_bz2_decompress_seek(
+	php_stream *stream,
+	php_stream_filter *thisfilter,
+	zend_off_t offset,
+	int whence
+	)
+{
+	if (!Z_PTR(thisfilter->abstract)) {
+		return FAILURE;
+	}
+
+	php_bz2_filter_data *data = Z_PTR(thisfilter->abstract);
+
+	/* End current decompression if running */
+	if (data->status == PHP_BZ2_RUNNING) {
+		BZ2_bzDecompressEnd(&(data->strm));
+	}
+
+	/* Reset stream state */
+	data->strm.next_in = data->inbuf;
+	data->strm.avail_in = 0;
+	data->strm.next_out = data->outbuf;
+	data->strm.avail_out = data->outbuf_len;
+	data->status = PHP_BZ2_UNINITIALIZED;
+
+	/* Note: We don't reinitialize here - it will be done on first use in the filter function */
+
+	return SUCCESS;
+}
+
 static void php_bz2_decompress_dtor(php_stream_filter *thisfilter)
 {
 	if (thisfilter && Z_PTR(thisfilter->abstract)) {
@@ -193,6 +227,7 @@ static void php_bz2_decompress_dtor(php_stream_filter *thisfilter)
 
 static const php_stream_filter_ops php_bz2_decompress_ops = {
 	php_bz2_decompress_filter,
+	php_bz2_decompress_seek,
 	php_bz2_decompress_dtor,
 	"bzip2.decompress"
 };
@@ -288,6 +323,41 @@ static php_stream_filter_status_t php_bz2_compress_filter(
 	return exit_status;
 }
 
+static zend_result php_bz2_compress_seek(
+	php_stream *stream,
+	php_stream_filter *thisfilter,
+	zend_off_t offset,
+	int whence
+	)
+{
+	int status;
+
+	if (!Z_PTR(thisfilter->abstract)) {
+		return FAILURE;
+	}
+
+	php_bz2_filter_data *data = Z_PTR(thisfilter->abstract);
+
+	/* End current compression */
+	BZ2_bzCompressEnd(&(data->strm));
+
+	/* Reset stream state */
+	data->strm.next_in = data->inbuf;
+	data->strm.avail_in = 0;
+	data->strm.next_out = data->outbuf;
+	data->strm.avail_out = data->outbuf_len;
+	data->is_flushed = 1;
+
+	/* Reinitialize compression with saved configuration */
+	status = BZ2_bzCompressInit(&(data->strm), data->blockSize100k, 0, data->workFactor);
+	if (status != BZ_OK) {
+		php_error_docref(NULL, E_WARNING, "bzip2.compress: failed to reset compression state");
+		return FAILURE;
+	}
+
+	return SUCCESS;
+}
+
 static void php_bz2_compress_dtor(php_stream_filter *thisfilter)
 {
 	if (Z_PTR(thisfilter->abstract)) {
@@ -301,6 +371,7 @@ static void php_bz2_compress_dtor(php_stream_filter *thisfilter)
 
 static const php_stream_filter_ops php_bz2_compress_ops = {
 	php_bz2_compress_filter,
+	php_bz2_compress_seek,
 	php_bz2_compress_dtor,
 	"bzip2.compress"
 };
@@ -309,7 +380,7 @@ static const php_stream_filter_ops php_bz2_compress_ops = {
 
 /* {{{ bzip2.* common factory */
 
-static php_stream_filter *php_bz2_filter_create(const char *filtername, zval *filterparams, uint8_t persistent)
+static php_stream_filter *php_bz2_filter_create(const char *filtername, zval *filterparams, bool persistent)
 {
 	const php_stream_filter_ops *fops = NULL;
 	php_bz2_filter_data *data;
@@ -388,6 +459,10 @@ static php_stream_filter *php_bz2_filter_create(const char *filtername, zval *fi
 			}
 		}
 
+		/* Save configuration for reset */
+		data->blockSize100k = blockSize100k;
+		data->workFactor = workFactor;
+
 		status = BZ2_bzCompressInit(&(data->strm), blockSize100k, 0, workFactor);
 		data->is_flushed = 1;
 		fops = &php_bz2_compress_ops;
@@ -403,7 +478,7 @@ static php_stream_filter *php_bz2_filter_create(const char *filtername, zval *fi
 		return NULL;
 	}
 
-	return php_stream_filter_alloc(fops, data, persistent);
+	return php_stream_filter_alloc(fops, data, persistent, PSFS_SEEKABLE_START);
 }
 
 const php_stream_filter_factory php_bz2_filter_factory = {

ext/bz2/tests/bz2_filter_seek_compress.phpt

@@ -0,0 +1,55 @@
+--TEST--
+bzip2.compress filter with seek to start
+--EXTENSIONS--
+bz2
+--FILE--
+<?php
+$file = __DIR__ . '/bz2_filter_seek_compress.bz2';
+
+$text1 = 'Short text.';
+$text2 = 'This is a much longer text that will completely overwrite the previous compressed data in the file.';
+
+$fp = fopen($file, 'w+');
+stream_filter_append($fp, 'bzip2.compress', STREAM_FILTER_WRITE);
+
+fwrite($fp, $text1);
+fflush($fp);
+
+$size1 = ftell($fp);
+echo "Size after first write: $size1\n";
+
+$result = fseek($fp, 0, SEEK_SET);
+echo "Seek to start: " . ($result === 0 ? "SUCCESS" : "FAILURE") . "\n";
+
+fwrite($fp, $text2);
+fflush($fp);
+
+$size2 = ftell($fp);
+echo "Size after second write: $size2\n";
+echo "Second write is larger: " . ($size2 > $size1 ? "YES" : "NO") . "\n";
+
+$result = fseek($fp, 50, SEEK_SET);
+echo "Seek to middle: " . ($result === 0 ? "SUCCESS" : "FAILURE") . "\n";
+
+fclose($fp);
+
+$fp = fopen($file, 'r');
+stream_filter_append($fp, 'bzip2.decompress', STREAM_FILTER_READ);
+$content = stream_get_contents($fp);
+fclose($fp);
+
+echo "Decompressed content matches text2: " . ($content === $text2 ? "YES" : "NO") . "\n";
+?>
+--CLEAN--
+<?php
+@unlink(__DIR__ . '/bz2_filter_seek_compress.bz2');
+?>
+--EXPECTF--
+Size after first write: 40
+Seek to start: SUCCESS
+Size after second write: 98
+Second write is larger: YES
+
+Warning: fseek(): Stream filter bzip2.compress is seekable only to start position in %s on line %d
+Seek to middle: FAILURE
+Decompressed content matches text2: YES

ext/bz2/tests/bz2_filter_seek_decompress.phpt

@@ -0,0 +1,43 @@
+--TEST--
+bzip2.decompress filter with seek to start
+--EXTENSIONS--
+bz2
+--FILE--
+<?php
+$file = __DIR__ . '/bz2_filter_seek_decompress.bz2';
+
+$text = 'I am the very model of a modern major general, I\'ve information vegetable, animal, and mineral.';
+
+$fp = fopen($file, 'w');
+stream_filter_append($fp, 'bzip2.compress', STREAM_FILTER_WRITE);
+fwrite($fp, $text);
+fclose($fp);
+
+$fp = fopen($file, 'r');
+stream_filter_append($fp, 'bzip2.decompress', STREAM_FILTER_READ);
+
+$partial = fread($fp, 20);
+echo "First read (20 bytes): " . $partial . "\n";
+
+$result = fseek($fp, 0, SEEK_SET);
+echo "Seek to start: " . ($result === 0 ? "SUCCESS" : "FAILURE") . "\n";
+
+$full = stream_get_contents($fp);
+echo "Content after seek matches: " . ($full === $text ? "YES" : "NO") . "\n";
+
+$result = fseek($fp, 50, SEEK_SET);
+echo "Seek to middle: " . ($result === 0 ? "SUCCESS" : "FAILURE") . "\n";
+
+fclose($fp);
+?>
+--CLEAN--
+<?php
+@unlink(__DIR__ . '/bz2_filter_seek_decompress.bz2');
+?>
+--EXPECTF--
+First read (20 bytes): I am the very model 
+Seek to start: SUCCESS
+Content after seek matches: YES
+
+Warning: fseek(): Stream filter bzip2.decompress is seekable only to start position in %s on line %d
+Seek to middle: FAILURE

ext/gd/tests/bug79945.phpt

@@ -9,17 +9,17 @@ if (!(imagetypes() & IMG_PNG)) {
 }
 set_error_handler(function($errno, $errstr) {
     if (str_contains($errstr, 'Cannot cast a filtered stream on this system')) {
-        die('skip: fopencookie not support on this system');
+        die('skip: fopencookie not supported on this system');
     }
 });
-imagecreatefrompng('php://filter/read=convert.base64-encode/resource=' . __DIR__ . '/test.png');
+imagecreatefrompng('php://filter/read=string.rot13/resource=' . __DIR__ . '/test.png');
 restore_error_handler();
 ?>
 --FILE--
 <?php
-imagecreatefrompng('php://filter/read=convert.base64-encode/resource=' . __DIR__ . '/test.png');
+imagecreatefrompng('php://filter/read=string.rot13/resource=' . __DIR__ . '/test.png');
 ?>
 --CLEAN--
 --EXPECTF--
 
-Warning: imagecreatefrompng(): "php://filter/read=convert.base64-encode/resource=%s" is not a valid PNG file in %s on line %d
+Warning: imagecreatefrompng(): "php://filter/read=string.rot13/resource=%s" is not a valid PNG file in %s on line %d

ext/iconv/iconv.c

@@ -2554,6 +2554,33 @@ static php_stream_filter_status_t php_iconv_stream_filter_do_filter(
 }
 /* }}} */
 
+/* {{{ php_iconv_stream_filter_seek */
+static zend_result php_iconv_stream_filter_seek(
+		php_stream *stream,
+		php_stream_filter *filter,
+		zend_off_t offset,
+		int whence)
+{
+	php_iconv_stream_filter *self = (php_iconv_stream_filter *)Z_PTR(filter->abstract);
+
+	/* Reset stub buffer */
+	self->stub_len = 0;
+
+	/* Reset iconv conversion state by closing and reopening the converter */
+	iconv_close(self->cd);
+
+	self->cd = iconv_open(self->to_charset, self->from_charset);
+	if ((iconv_t)-1 == self->cd) {
+		php_error_docref(NULL, E_WARNING,
+				"iconv stream filter (\"%s\"=>\"%s\"): failed to reset conversion state",
+				self->from_charset, self->to_charset);
+		return FAILURE;
+	}
+
+	return SUCCESS;
+}
+/* }}} */
+
 /* {{{ php_iconv_stream_filter_cleanup */
 static void php_iconv_stream_filter_cleanup(php_stream_filter *filter)
 {
@@ -2564,12 +2591,13 @@ static void php_iconv_stream_filter_cleanup(php_stream_filter *filter)
 
 static const php_stream_filter_ops php_iconv_stream_filter_ops = {
 	php_iconv_stream_filter_do_filter,
+	php_iconv_stream_filter_seek,
 	php_iconv_stream_filter_cleanup,
 	"convert.iconv.*"
 };
 
 /* {{{ php_iconv_stream_filter_create */
-static php_stream_filter *php_iconv_stream_filter_factory_create(const char *name, zval *params, uint8_t persistent)
+static php_stream_filter *php_iconv_stream_filter_factory_create(const char *name, zval *params, bool persistent)
 {
 	php_iconv_stream_filter *inst;
 	const char *from_charset = NULL, *to_charset = NULL;
@@ -2601,7 +2629,8 @@ static php_stream_filter *php_iconv_stream_filter_factory_create(const char *nam
 		return NULL;
 	}
 
-	return php_stream_filter_alloc(&php_iconv_stream_filter_ops, inst, persistent);
+	return php_stream_filter_alloc(&php_iconv_stream_filter_ops, inst, persistent,
+			PSFS_SEEKABLE_START);
 }
 /* }}} */
 

ext/iconv/tests/iconv_stream_filter_seek.phpt

@@ -0,0 +1,43 @@
+--TEST--
+iconv stream filter with seek to start
+--EXTENSIONS--
+iconv
+--FILE--
+<?php
+$file = __DIR__ . '/iconv_stream_filter_seek.txt';
+
+$text = 'Hello, this is a test for iconv stream filter seeking functionality.';
+
+$fp = fopen($file, 'w');
+stream_filter_append($fp, 'convert.iconv.ISO-2022-JP/UTF-8');
+fwrite($fp, $text);
+fclose($fp);
+
+$fp = fopen($file, 'r');
+stream_filter_append($fp, 'convert.iconv.UTF-8/ISO-2022-JP');
+
+$partial = fread($fp, 20);
+echo "First read (20 bytes): " . $partial . "\n";
+
+$result = fseek($fp, 0, SEEK_SET);
+echo "Seek to start: " . ($result === 0 ? "SUCCESS" : "FAILURE") . "\n";
+
+$full = fread($fp, strlen($text));
+echo "Content after seek matches: " . ($full === $text ? "YES" : "NO") . "\n";
+
+$result = fseek($fp, 50, SEEK_SET);
+echo "Seek to middle: " . ($result === 0 ? "SUCCESS" : "FAILURE") . "\n";
+
+fclose($fp);
+?>
+--CLEAN--
+<?php
+@unlink(__DIR__ . '/iconv_stream_filter_seek.txt');
+?>
+--EXPECTF--
+First read (20 bytes): Hello, this is a tes
+Seek to start: SUCCESS
+Content after seek matches: YES
+
+Warning: fseek(): Stream filter convert.iconv.* is seekable only to start position in %s on line %d
+Seek to middle: FAILURE