Move sqfs_istream_t & sqfs_ostream_t into libsquashfs

For now, only the interfaces and helper functions are moved, the
concrete implementations remain in libio.

Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>

39 files changed, 243 insertions, 244 deletions

diff --git a/bin/tar2sqfs/src/process_tarball.c b/bin/tar2sqfs/src/process_tarball.c
index 5e7f030..639adf8 100644
--- a/bin/tar2sqfs/src/process_tarball.c
+++ b/bin/tar2sqfs/src/process_tarball.c
@@ -28,7 +28,7 @@ static int write_file(sqfs_writer_t *sqfs, dir_iterator_t *it,
 	}
 
 	do {
-		ret = istream_splice(in, out, cfg.block_size);
+		ret = sqfs_istream_splice(in, out, cfg.block_size);
 	} while (ret > 0);
 
 	out->flush(out);
diff --git a/include/common.h b/include/common.h
index c289458..d2e3f73 100644
--- a/include/common.h
+++ b/include/common.h
@@ -17,10 +17,10 @@
 #include "sqfs/block.h"
 #include "sqfs/xattr.h"
 #include "sqfs/dir.h"
+#include "sqfs/io.h"
 
 #include "simple_writer.h"
 #include "compress_cli.h"
-#include "io/ostream.h"
 #include "io/file.h"
 #include "io/std.h"
 #include "compat.h"
diff --git a/include/io/file.h b/include/io/file.h
index 1072b6a..fa0abc0 100644
--- a/include/io/file.h
+++ b/include/io/file.h
@@ -8,7 +8,6 @@
 #define IO_FILE_H
 
 #include "io/istream.h"
-#include "io/ostream.h"
 
 #if defined(_WIN32) || defined(__WINDOWS__)
 #include <handleapi.h>
diff --git a/include/io/istream.h b/include/io/istream.h
index f4ffcb2..f41be2e 100644
--- a/include/io/istream.h
+++ b/include/io/istream.h
@@ -8,66 +8,6 @@
 #define IO_ISTREAM_H
 
 #include "sqfs/predef.h"
-#include "io/ostream.h"
-
-typedef struct sqfs_istream_t sqfs_istream_t;
-
-/**
- * @interface sqfs_istream_t
- *
- * @extends sqfs_object_t
- *
- * @brief A sequential, read-only data stream.
- */
-struct sqfs_istream_t {
-	sqfs_object_t base;
-
-	/**
-	 * @brief Peek into the data buffered in an istream
-	 *
-	 * If the internal buffer is empty, the function tries to fetch more,
-	 * which can block. It returns a positive return code if there is no
-	 * more data to be read, a negative error code if reading failed. Since
-	 * this and other functions can alter the buffer pointer and contents,
-	 * do not store the pointers returned here across function calls.
-	 *
-	 * Higher level functions like @ref istream_read (providing a
-	 * Unix read() style API) are built on top of this primitive.
-	 *
-	 * @param strm A pointer to an sqfs_istream_t implementation.
-	 * @param out Returns a pointer into an internal buffer on success.
-	 * @param size Returns the number of bytes available in the buffer.
-	 * @param want A number of bytes that the reader would like to have.
-	 *             If there is less than this available, the implementation
-	 *             can choose to do a blocking precache.
-	 *
-	 * @return Zero on success, a negative error code on failure,
-	 *         a postive number on EOF.
-	 */
-	int (*get_buffered_data)(sqfs_istream_t *strm, const sqfs_u8 **out,
-				 size_t *size, size_t want);
-
-	/**
-	 * @brief Mark a section of the internal buffer of an istream as used
-	 *
-	 * This marks the first `count` bytes of the internal buffer as used,
-	 * forcing get_buffered_data to return data afterwards and potentially
-	 * try to load more data.
-	 *
-	 * @param strm A pointer to an sqfs_istream_t implementation.
-	 * @param count The number of bytes used up.
-	 */
-	void (*advance_buffer)(sqfs_istream_t *strm, size_t count);
-
-	/**
-	 * @brief Get the underlying filename of an input stream.
-	 *
-	 * @param strm The input stream to get the filename from.
-	 *
-	 * @return A string holding the underlying filename.
-	 */
-	const char *(*get_filename)(sqfs_istream_t *strm);
-};
 
 enum {
 	ISTREAM_LINE_LTRIM = 0x01,
@@ -108,48 +48,6 @@ extern "C" {
 SQFS_INTERNAL int istream_get_line(sqfs_istream_t *strm, char **out,
 				   size_t *line_num, int flags);
 
-/**
- * @brief Read data from an input stream
- *
- * @memberof sqfs_istream_t
- *
- * @param strm A pointer to an input stream.
- * @param data A buffer to read into.
- * @param size The number of bytes to read into the buffer.
- *
- * @return The number of bytes actually read on success, -1 on failure,
- *         0 on end-of-file.
- */
-SQFS_INTERNAL sqfs_s32 istream_read(sqfs_istream_t *strm,
-				    void *data, size_t size);
-
-/**
- * @brief Skip over a number of bytes in an input stream.
- *
- * @memberof sqfs_istream_t
- *
- * @param strm A pointer to an input stream.
- * @param size The number of bytes to seek forward.
- *
- * @return Zero on success, -1 on failure.
- */
-SQFS_INTERNAL int istream_skip(sqfs_istream_t *strm, sqfs_u64 size);
-
-/**
- * @brief Dump data from an input stream to an output stream
- *
- * @memberof sqfs_istream_t
- *
- * @param in A pointer to an input stream to read from.
- * @param out A pointer to an output stream to append to.
- * @param size The number of bytes to copy over.
- *
- * @return The number of bytes copied on success, -1 on failure,
- *         0 on end-of-file.
- */
-SQFS_INTERNAL sqfs_s32 istream_splice(sqfs_istream_t *in, sqfs_ostream_t *out,
-				      sqfs_u32 size);
-
 #ifdef __cplusplus
 }
 #endif
diff --git a/include/io/ostream.h b/include/io/ostream.h
deleted file mode 100644
index d1781d2..0000000
--- a/include/io/ostream.h
+++ /dev/null
@@ -1,60 +0,0 @@
-/* SPDX-License-Identifier: GPL-3.0-or-later */
-/*
- * ostream.h
- *
- * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
- */
-#ifndef IO_OSTREAM_H
-#define IO_OSTREAM_H
-
-#include "sqfs/predef.h"
-
-typedef struct sqfs_ostream_t sqfs_ostream_t;
-
-/**
- * @interface sqfs_ostream_t
- *
- * @extends sqfs_object_t
- *
- * @brief An append-only data stream.
- */
-struct sqfs_ostream_t {
-	sqfs_object_t base;
-
-	/**
-	 * @brief Append a block of data to an output stream.
-	 *
-	 * @param strm A pointer to an output stream.
-	 * @param data A pointer to the data block to append. If NULL,
-	 *             synthesize a chunk of zero bytes.
-	 * @param size The number of bytes to append.
-	 *
-	 * @return Zero on success, -1 on failure.
-	 */
-	int (*append)(sqfs_ostream_t *strm, const void *data, size_t size);
-
-	/**
-	 * @brief Process all pending, buffered data and flush it to disk.
-	 *
-	 * If the stream performs some kind of transformation (e.g. transparent
-	 * data compression), flushing caues the wrapped format to insert a
-	 * termination token. Only call this function when you are absolutely
-	 * DONE appending data, shortly before destroying the stream.
-	 *
-	 * @param strm A pointer to an output stream.
-	 *
-	 * @return Zero on success, -1 on failure.
-	 */
-	int (*flush)(sqfs_ostream_t *strm);
-
-	/**
-	 * @brief Get the underlying filename of a output stream.
-	 *
-	 * @param strm The output stream to get the filename from.
-	 *
-	 * @return A string holding the underlying filename.
-	 */
-	const char *(*get_filename)(sqfs_ostream_t *strm);
-};
-
-#endif /* IO_OSTREAM_H */
diff --git a/include/io/std.h b/include/io/std.h
index 3a8bbf8..f622491 100644
--- a/include/io/std.h
+++ b/include/io/std.h
@@ -8,7 +8,6 @@
 #define IO_STD_H
 
 #include "io/istream.h"
-#include "io/ostream.h"
 
 #ifdef __cplusplus
 extern "C" {
diff --git a/include/io/xfrm.h b/include/io/xfrm.h
index c54bc9f..f0ff1ce 100644
--- a/include/io/xfrm.h
+++ b/include/io/xfrm.h
@@ -8,7 +8,6 @@
 #define IO_XFRM_H
 
 #include "io/istream.h"
-#include "io/ostream.h"
 #include "xfrm/stream.h"
 
 #ifdef __cplusplus
diff --git a/include/sqfs/io.h b/include/sqfs/io.h
index a1fb169..402b6de 100644
--- a/include/sqfs/io.h
+++ b/include/sqfs/io.h
@@ -25,7 +25,12 @@
 /**
  * @file io.h
  *
- * @brief Contains the @ref sqfs_file_t interface for abstracting file I/O
+ * @brief Contains low-level interfaces for abstracting file I/O
+ *
+ * The @ref sqfs_file_t interface abstracts I/O on a random-acces sread/write
+ * file, @ref sqfs_ostream_t represents a buffered, sequential, append only
+ * data stream, @ref sqfs_istream_t represents a buffered, sequential, read only
+ * data stream.
  */
 
 /**
@@ -151,6 +156,109 @@ struct sqfs_file_t {
 	int (*truncate)(sqfs_file_t *file, sqfs_u64 size);
 };
 
+/**
+ * @interface sqfs_istream_t
+ *
+ * @extends sqfs_object_t
+ *
+ * @brief A sequential, read-only data stream.
+ */
+struct sqfs_istream_t {
+	sqfs_object_t base;
+
+	/**
+	 * @brief Peek into the data buffered in an istream
+	 *
+	 * If the internal buffer is empty, the function tries to fetch more,
+	 * which can block. It returns a positive return code if there is no
+	 * more data to be read, a negative error code if reading failed. Since
+	 * this and other functions can alter the buffer pointer and contents,
+	 * do not store the pointers returned here across function calls.
+	 *
+	 * Higher level functions like @ref sqfs_istream_read (providing a
+	 * Unix read() style API) are built on top of this primitive.
+	 *
+	 * @param strm A pointer to an sqfs_istream_t implementation.
+	 * @param out Returns a pointer into an internal buffer on success.
+	 * @param size Returns the number of bytes available in the buffer.
+	 * @param want A number of bytes that the reader would like to have.
+	 *             If there is less than this available, the implementation
+	 *             can choose to do a blocking precache.
+	 *
+	 * @return Zero on success, a negative error code on failure,
+	 *         a postive number on EOF.
+	 */
+	int (*get_buffered_data)(sqfs_istream_t *strm, const sqfs_u8 **out,
+				 size_t *size, size_t want);
+
+	/**
+	 * @brief Mark a section of the internal buffer of an istream as used
+	 *
+	 * This marks the first `count` bytes of the internal buffer as used,
+	 * forcing get_buffered_data to return data afterwards and potentially
+	 * try to load more data.
+	 *
+	 * @param strm A pointer to an sqfs_istream_t implementation.
+	 * @param count The number of bytes used up.
+	 */
+	void (*advance_buffer)(sqfs_istream_t *strm, size_t count);
+
+	/**
+	 * @brief Get the underlying filename of an input stream.
+	 *
+	 * @param strm The input stream to get the filename from.
+	 *
+	 * @return A string holding the underlying filename.
+	 */
+	const char *(*get_filename)(sqfs_istream_t *strm);
+};
+
+/**
+ * @interface sqfs_ostream_t
+ *
+ * @extends sqfs_object_t
+ *
+ * @brief An append-only data stream.
+ */
+struct sqfs_ostream_t {
+	sqfs_object_t base;
+
+	/**
+	 * @brief Append a block of data to an output stream.
+	 *
+	 * @param strm A pointer to an output stream.
+	 * @param data A pointer to the data block to append. If NULL,
+	 *             synthesize a chunk of zero bytes.
+	 * @param size The number of bytes to append.
+	 *
+	 * @return Zero on success, -1 on failure.
+	 */
+	int (*append)(sqfs_ostream_t *strm, const void *data, size_t size);
+
+	/**
+	 * @brief Process all pending, buffered data and flush it to disk.
+	 *
+	 * If the stream performs some kind of transformation (e.g. transparent
+	 * data compression), flushing caues the wrapped format to insert a
+	 * termination token. Only call this function when you are absolutely
+	 * DONE appending data, shortly before destroying the stream.
+	 *
+	 * @param strm A pointer to an output stream.
+	 *
+	 * @return Zero on success, -1 on failure.
+	 */
+	int (*flush)(sqfs_ostream_t *strm);
+
+	/**
+	 * @brief Get the underlying filename of a output stream.
+	 *
+	 * @param strm The output stream to get the filename from.
+	 *
+	 * @return A string holding the underlying filename.
+	 */
+	const char *(*get_filename)(sqfs_ostream_t *strm);
+};
+
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -174,6 +282,50 @@ extern "C" {
  */
 SQFS_API sqfs_file_t *sqfs_open_file(const char *filename, sqfs_u32 flags);
 
+/**
+ * @brief Read data from an input stream
+ *
+ * @memberof sqfs_istream_t
+ *
+ * This function implements a Unix-style read() function on top of
+ * an @ref sqfs_istream_t, taking care of buffer management internally.
+ *
+ * @param strm A pointer to an input stream.
+ * @param data A buffer to read into.
+ * @param size The number of bytes to read into the buffer.
+ *
+ * @return The number of bytes actually read on success, a
+ *         negative @ref SQFS_ERROR code on failure, 0 on end-of-file.
+ */
+SQFS_API sqfs_s32 sqfs_istream_read(sqfs_istream_t *strm,
+				    void *data, size_t size);
+
+/**
+ * @brief Skip over a number of bytes in an input stream.
+ *
+ * @memberof sqfs_istream_t
+ *
+ * @param strm A pointer to an input stream.
+ * @param size The number of bytes to seek forward.
+ *
+ * @return Zero on success, a negative @ref SQFS_ERROR code on failure.
+ */
+SQFS_API int sqfs_istream_skip(sqfs_istream_t *strm, sqfs_u64 size);
+
+/**
+ * @brief Dump data from an input stream to an output stream
+ *
+ * @memberof sqfs_istream_t
+ *
+ * @param in A pointer to an input stream to read from.
+ * @param out A pointer to an output stream to append to.
+ * @param size The number of bytes to copy over.
+ *
+ * @return Zero on success, a negative @ref SQFS_ERROR code on failure.
+ */
+SQFS_API sqfs_s32 sqfs_istream_splice(sqfs_istream_t *in, sqfs_ostream_t *out,
+				      sqfs_u32 size);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/include/sqfs/predef.h b/include/sqfs/predef.h
index b0baf92..aae95e4 100644
--- a/include/sqfs/predef.h
+++ b/include/sqfs/predef.h
@@ -96,6 +96,8 @@ typedef struct sqfs_block_processor_stats_t sqfs_block_processor_stats_t;
 typedef struct sqfs_block_processor_desc_t sqfs_block_processor_desc_t;
 typedef struct sqfs_readdir_state_t sqfs_readdir_state_t;
 typedef struct sqfs_xattr_t sqfs_xattr_t;
+typedef struct sqfs_istream_t sqfs_istream_t;
+typedef struct sqfs_ostream_t sqfs_ostream_t;
 
 typedef struct sqfs_fragment_t sqfs_fragment_t;
 typedef struct sqfs_dir_header_t sqfs_dir_header_t;
diff --git a/include/tar/tar.h b/include/tar/tar.h
index 60c2a3d..1f1b1b4 100644
--- a/include/tar/tar.h
+++ b/include/tar/tar.h
@@ -10,8 +10,8 @@
 #include "config.h"
 #include "compat.h"
 #include "io/istream.h"
-#include "io/ostream.h"
 #include "io/dir_iterator.h"
+#include "sqfs/io.h"
 
 #include <stdbool.h>
 #include <stdint.h>
diff --git a/lib/io/Makemodule.am b/lib/io/Makemodule.am
index badaa99..9e442be 100644
--- a/lib/io/Makemodule.am
+++ b/lib/io/Makemodule.am
@@ -1,7 +1,7 @@
-libio_a_SOURCES = include/io/istream.h include/io/ostream.h include/io/xfrm.h \
+libio_a_SOURCES = include/io/istream.h include/io/xfrm.h \
 	include/io/file.h include/io/std.h include/io/dir_entry.h \
 	include/io/dir_iterator.h include/io/mem.h lib/io/src/internal.h \
-	lib/io/src/istream.c lib/io/src/get_line.c lib/io/src/xfrm/ostream.c \
+	lib/io/src/get_line.c lib/io/src/xfrm/ostream.c \
 	lib/io/src/xfrm/istream.c lib/io/src/dir_tree_iterator.c \
 	lib/io/src/dir_entry.c lib/io/src/mem.c
 libio_a_CFLAGS = $(AM_CFLAGS) $(ZLIB_CFLAGS) $(XZ_CFLAGS)
@@ -18,8 +18,7 @@ endif
 
 noinst_LIBRARIES += libio.a
 
-LIBIO_TESTS = test_istream_mem test_get_line test_istream_read \
-	test_istream_skip test_stream_splice test_dir_iterator \
+LIBIO_TESTS = test_istream_mem test_get_line test_dir_iterator \
 	test_dir_tree_iterator test_dir_tree_iterator2 test_dir_tree_iterator3
 
 test_istream_mem_SOURCES = lib/io/test/istream_mem.c
@@ -30,15 +29,6 @@ test_get_line_SOURCES = lib/io/test/get_line.c
 test_get_line_LDADD = libio.a libcompat.a
 test_get_line_CPPFLAGS = $(AM_CPPFLAGS)
 
-test_istream_read_SOURCES = lib/io/test/istream_read.c
-test_istream_read_LDADD = libio.a libutil.a libcompat.a
-
-test_istream_skip_SOURCES = lib/io/test/istream_skip.c
-test_istream_skip_LDADD = libio.a libutil.a libcompat.a
-
-test_stream_splice_SOURCES = lib/io/test/stream_splice.c
-test_stream_splice_LDADD = libio.a libutil.a libcompat.a
-
 test_dir_iterator_SOURCES = lib/io/test/dir_iterator.c
 test_dir_iterator_LDADD = libio.a libutil.a libcompat.a
 test_dir_iterator_CPPFLAGS = $(AM_CPPFLAGS)
@@ -61,7 +51,7 @@ test_dir_tree_iterator3_CPPFLAGS += -DTESTPATH=$(top_srcdir)/lib/io/test/testdir
 
 if WITH_XZ
 test_io_xfrm_xz_SOURCES = lib/io/test/xfrm.c
-test_io_xfrm_xz_LDADD = libio.a libxfrm.a libcompat.a $(XZ_LIBS)
+test_io_xfrm_xz_LDADD = libsquashfs.la libio.a libxfrm.a libcompat.a $(XZ_LIBS)
 test_io_xfrm_xz_CPPFLAGS = $(AM_CPPFLAGS) -DDO_XZ=1
 
 LIBIO_TESTS += test_io_xfrm_xz
@@ -69,7 +59,8 @@ endif
 
 if WITH_BZIP2
 test_io_xfrm_bzip2_SOURCES = lib/io/test/xfrm.c
-test_io_xfrm_bzip2_LDADD = libio.a libxfrm.a libcompat.a $(BZIP2_LIBS)
+test_io_xfrm_bzip2_LDADD = libsquashfs.la libio.a libxfrm.a \
+	libcompat.a $(BZIP2_LIBS)
 test_io_xfrm_bzip2_CPPFLAGS = $(AM_CPPFLAGS) -DDO_BZIP2=1
 
 LIBIO_TESTS += test_io_xfrm_bzip2
@@ -77,7 +68,8 @@ endif
 
 if WITH_GZIP
 test_io_xfrm_gzip_SOURCES = lib/io/test/xfrm.c
-test_io_xfrm_gzip_LDADD = libio.a libxfrm.a libcompat.a $(ZLIB_LIBS)
+test_io_xfrm_gzip_LDADD = libsquashfs.la libio.a libxfrm.a \
+	libcompat.a $(ZLIB_LIBS)
 test_io_xfrm_gzip_CPPFLAGS = $(AM_CPPFLAGS) -DDO_GZIP=1
 
 LIBIO_TESTS += test_io_xfrm_gzip
@@ -86,7 +78,8 @@ endif
 if WITH_ZSTD
 if HAVE_ZSTD_STREAM
 test_io_xfrm_zstd_SOURCES = lib/io/test/xfrm.c
-test_io_xfrm_zstd_LDADD = libio.a libxfrm.a libcompat.a $(ZSTD_LIBS)
+test_io_xfrm_zstd_LDADD = libsquashfs.la libio.a libxfrm.a \
+	libcompat.a $(ZSTD_LIBS)
 test_io_xfrm_zstd_CPPFLAGS = $(AM_CPPFLAGS) -DDO_ZSTD=1
 
 LIBIO_TESTS += test_io_xfrm_zstd
diff --git a/lib/io/src/get_line.c b/lib/io/src/get_line.c
index 9ab4928..ad37be6 100644
--- a/lib/io/src/get_line.c
+++ b/lib/io/src/get_line.c
@@ -5,6 +5,7 @@
  * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
  */
 #include "internal.h"
+#include "sqfs/io.h"
 
 static void ltrim(char *buffer)
 {
diff --git a/lib/io/src/internal.h b/lib/io/src/internal.h
index 1e51012..e010727 100644
--- a/lib/io/src/internal.h
+++ b/lib/io/src/internal.h
@@ -10,7 +10,6 @@
 #include "config.h"
 #include "compat.h"
 #include "io/istream.h"
-#include "io/ostream.h"
 #include "io/file.h"
 #include "io/xfrm.h"
 #include "io/std.h"
diff --git a/lib/io/src/mem.c b/lib/io/src/mem.c
index 435a169..7150d1f 100644
--- a/lib/io/src/mem.c
+++ b/lib/io/src/mem.c
@@ -7,6 +7,7 @@
 #include "config.h"
 #include "io/mem.h"
 #include "compat.h"
+#include "sqfs/io.h"
 
 #include <stdlib.h>
 #include <string.h>
diff --git a/lib/io/src/unix/istream.c b/lib/io/src/unix/istream.c
index fc76bab..39d570f 100644
--- a/lib/io/src/unix/istream.c
+++ b/lib/io/src/unix/istream.c
@@ -5,6 +5,7 @@
  * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
  */
 #include "../internal.h"
+#include "sqfs/io.h"
 
 typedef struct {
 	sqfs_istream_t base;
diff --git a/lib/io/src/win32/istream.c b/lib/io/src/win32/istream.c
index 223b20d..e6cb266 100644
--- a/lib/io/src/win32/istream.c
+++ b/lib/io/src/win32/istream.c
@@ -5,6 +5,7 @@
  * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
  */
 #include "../internal.h"
+#include "sqfs/io.h"
 
 #define WIN32_LEAN_AND_MEAN
 #include <windows.h>
diff --git a/lib/io/src/xfrm/istream.c b/lib/io/src/xfrm/istream.c
index 5c23d28..c499f6c 100644
--- a/lib/io/src/xfrm/istream.c
+++ b/lib/io/src/xfrm/istream.c
@@ -5,6 +5,7 @@
  * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
  */
 #include "../internal.h"
+#include "sqfs/io.h"
 
 typedef struct istream_xfrm_t {
 	sqfs_istream_t base;
diff --git a/lib/io/src/xfrm/ostream.c b/lib/io/src/xfrm/ostream.c
index 81c19dd..4c77f42 100644
--- a/lib/io/src/xfrm/ostream.c
+++ b/lib/io/src/xfrm/ostream.c
@@ -5,6 +5,7 @@
  * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
  */
 #include "../internal.h"
+#include "sqfs/io.h"
 
 typedef struct ostream_xfrm_t {
 	sqfs_ostream_t base;
diff --git a/lib/io/test/istream_mem.c b/lib/io/test/istream_mem.c
index f364fd3..d5e0c2c 100644
--- a/lib/io/test/istream_mem.c
+++ b/lib/io/test/istream_mem.c
@@ -8,6 +8,7 @@
 
 #include "util/test.h"
 #include "io/mem.h"
+#include "sqfs/io.h"
 
 static const size_t end0 = 449;	/* region 1: filled with 'A' */
 static const size_t end1 = 521;	/* region 2: filled with 'B' */
diff --git a/lib/io/test/xfrm.c b/lib/io/test/xfrm.c
index 1b48e6f..b871610 100644
--- a/lib/io/test/xfrm.c
+++ b/lib/io/test/xfrm.c
@@ -7,6 +7,7 @@
 #include "xfrm/compress.h"
 #include "xfrm/stream.h"
 #include "util/test.h"
+#include "sqfs/io.h"
 #include "io/xfrm.h"
 #include "io/mem.h"
 
@@ -430,15 +431,15 @@ static void run_unpack_test(const void *blob, size_t size)
 	TEST_EQUAL_UI(((sqfs_object_t *)mem_istream)->refcount, 2);
 
 	for (i = 0; i < (sizeof(orig) - 1); ++i) {
-		ret = istream_read(istream, &c, 1);
+		ret = sqfs_istream_read(istream, &c, 1);
 		TEST_EQUAL_I(ret, 1);
 		TEST_EQUAL_I(c, orig[i]);
 	}
 
-	ret = istream_read(istream, &c, 1);
+	ret = sqfs_istream_read(istream, &c, 1);
 	TEST_EQUAL_I(ret, 0);
 
-	ret = istream_read(istream, &c, 1);
+	ret = sqfs_istream_read(istream, &c, 1);
 	TEST_EQUAL_I(ret, 0);
 
 	sqfs_drop(istream);
diff --git a/lib/sqfs/Makemodule.am b/lib/sqfs/Makemodule.am
index d54134c..2727b11 100644
--- a/lib/sqfs/Makemodule.am
+++ b/lib/sqfs/Makemodule.am
@@ -30,7 +30,7 @@ libsquashfs_la_SOURCES = $(LIBSQFS_HEARDS) lib/sqfs/src/id_table.c \
 	lib/sqfs/src/block_processor/block_processor.c \
 	lib/sqfs/src/block_processor/backend.c \
 	lib/sqfs/src/frag_table.c lib/sqfs/src/block_writer.c \
-	lib/sqfs/src/misc.c
+	lib/sqfs/src/misc.c lib/sqfs/src/istream.c
 libsquashfs_la_CPPFLAGS = $(AM_CPPFLAGS)
 libsquashfs_la_LDFLAGS = $(AM_LDFLAGS) -version-info $(LIBSQUASHFS_SO_VERSION)
 libsquashfs_la_CFLAGS = $(AM_CFLAGS) $(PTHREAD_CFLAGS) $(ZLIB_CFLAGS)
@@ -122,9 +122,18 @@ xattr_benchmark_LDADD = libcommon.a libsquashfs.la libcompat.a
 test_get_node_path_SOURCES = lib/sqfs/test/get_node_path.c
 test_get_node_path_LDADD = libcommon.a libsquashfs.la libcompat.a
 
-LIBSQFS_TESTS = \
-	test_abi test_xattr test_table test_xattr_writer test_get_node_path
+test_istream_read_SOURCES = lib/sqfs/test/istream_read.c
+test_istream_read_LDADD = libio.a libsquashfs.la libutil.a libcompat.a
+
+test_istream_skip_SOURCES = lib/sqfs/test/istream_skip.c
+test_istream_skip_LDADD = libsquashfs.la libio.a libutil.a libcompat.a
 
+test_stream_splice_SOURCES = lib/sqfs/test/stream_splice.c
+test_stream_splice_LDADD = libsquashfs.la libio.a libutil.a libcompat.a
+
+LIBSQFS_TESTS = \
+	test_abi test_xattr test_table test_xattr_writer test_get_node_path \
+	test_istream_read test_istream_skip test_stream_splice
 noinst_PROGRAMS += xattr_benchmark
 
 check_PROGRAMS += $(LIBSQFS_TESTS)
diff --git a/lib/io/src/istream.c b/lib/sqfs/src/istream.c
index 6fbc67b..3d89461 100644
--- a/lib/io/src/istream.c
+++ b/lib/sqfs/src/istream.c
@@ -1,13 +1,17 @@
-/* SPDX-License-Identifier: GPL-3.0-or-later */
+/* SPDX-License-Identifier: LGPL-3.0-or-later */
 /*
  * istream.c
  *
  * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
  */
-#include "internal.h"
+#define SQFS_BUILDING_DLL
+#include "config.h"
 
+#include "sqfs/io.h"
 
-sqfs_s32 istream_read(sqfs_istream_t *strm, void *data, size_t size)
+#include <string.h>
+
+sqfs_s32 sqfs_istream_read(sqfs_istream_t *strm, void *data, size_t size)
 {
 	sqfs_s32 total = 0;
 
@@ -38,7 +42,7 @@ sqfs_s32 istream_read(sqfs_istream_t *strm, void *data, size_t size)
 	return total;
 }
 
-int istream_skip(sqfs_istream_t *strm, sqfs_u64 size)
+int sqfs_istream_skip(sqfs_istream_t *strm, sqfs_u64 size)
 {
 	while (size > 0) {
 		const sqfs_u8 *ptr;
@@ -48,11 +52,8 @@ int istream_skip(sqfs_istream_t *strm, sqfs_u64 size)
 		ret = strm->get_buffered_data(strm, &ptr, &diff, size);
 		if (ret < 0)
 			return ret;
-		if (ret > 0) {
-			fprintf(stderr, "%s: unexpected end-of-file\n",
-				strm->get_filename(strm));
-			return -1;
-		}
+		if (ret > 0)
+			break;
 
 		if ((sqfs_u64)diff > size)
 			diff = size;
@@ -64,7 +65,8 @@ int istream_skip(sqfs_istream_t *strm, sqfs_u64 size)
 	return 0;
 }
 
-sqfs_s32 istream_splice(sqfs_istream_t *in, sqfs_ostream_t *out, sqfs_u32 size)
+sqfs_s32 sqfs_istream_splice(sqfs_istream_t *in, sqfs_ostream_t *out,
+			     sqfs_u32 size)
 {
 	sqfs_s32 total = 0;
 
@@ -85,8 +87,9 @@ sqfs_s32 istream_splice(sqfs_istream_t *in, sqfs_ostream_t *out, sqfs_u32 size)
 		if (diff > size)
 			diff = size;
 
-		if (out->append(out, ptr, diff))
-			return -1;
+		ret = out->append(out, ptr, diff);
+		if (ret)
+			return ret;
 
 		total += diff;
 		size -= diff;
diff --git a/lib/io/test/istream_read.c b/lib/sqfs/test/istream_read.c
index 66fec4b..f8facea 100644
--- a/lib/io/test/istream_read.c
+++ b/lib/sqfs/test/istream_read.c
@@ -6,8 +6,8 @@
  */
 #include "config.h"
 
-#include "io/istream.h"
 #include "util/test.h"
+#include "sqfs/io.h"
 #include "io/mem.h"
 
 static const sqfs_u64 end0 = 449;	/* region 1: filled with 'A' */
@@ -50,7 +50,7 @@ int main(int argc, char **argv)
 		if (read_diff > sizeof(read_buffer))
 			read_diff = sizeof(read_buffer);
 
-		int ret = istream_read(dummy, read_buffer, read_diff);
+		int ret = sqfs_istream_read(dummy, read_buffer, read_diff);
 		TEST_ASSERT(ret > 0);
 		TEST_ASSERT((size_t)ret <= read_diff);
 
@@ -68,7 +68,7 @@ int main(int argc, char **argv)
 		if (read_diff > sizeof(read_buffer))
 			read_diff = sizeof(read_buffer);
 
-		int ret = istream_read(dummy, read_buffer, read_diff);
+		int ret = sqfs_istream_read(dummy, read_buffer, read_diff);
 		TEST_ASSERT(ret > 0);
 		TEST_ASSERT((size_t)ret <= read_diff);
 
@@ -83,7 +83,7 @@ int main(int argc, char **argv)
 	for (;;) {
 		size_t read_diff = sizeof(read_buffer);
 
-		int ret = istream_read(dummy, read_buffer, read_diff);
+		int ret = sqfs_istream_read(dummy, read_buffer, read_diff);
 		TEST_ASSERT(ret >= 0);
 		TEST_ASSERT((size_t)ret <= read_diff);
 
diff --git a/lib/io/test/istream_skip.c b/lib/sqfs/test/istream_skip.c
index 0fc3e11..d8a81f2 100644
--- a/lib/io/test/istream_skip.c
+++ b/lib/sqfs/test/istream_skip.c
@@ -6,7 +6,7 @@
  */
 #include "config.h"
 
-#include "io/istream.h"
+#include "sqfs/io.h"
 #include "util/test.h"
 #include "io/mem.h"
 
@@ -50,7 +50,7 @@ int main(int argc, char **argv)
 		if (read_diff > sizeof(read_buffer))
 			read_diff = sizeof(read_buffer);
 
-		int ret = istream_read(dummy, read_buffer, read_diff);
+		int ret = sqfs_istream_read(dummy, read_buffer, read_diff);
 		TEST_ASSERT(ret > 0);
 		TEST_ASSERT((size_t)ret <= read_diff);
 
@@ -63,7 +63,7 @@ int main(int argc, char **argv)
 
 	/* region 2 */
 	{
-		int ret = istream_skip(dummy, end2 - end1);
+		int ret = sqfs_istream_skip(dummy, end2 - end1);
 		TEST_EQUAL_I(ret, 0);
 		read_off += (end2 - end1);
 	}
@@ -72,7 +72,7 @@ int main(int argc, char **argv)
 	for (;;) {
 		size_t read_diff = sizeof(read_buffer);
 
-		int ret = istream_read(dummy, read_buffer, read_diff);
+		int ret = sqfs_istream_read(dummy, read_buffer, read_diff);
 		TEST_ASSERT(ret >= 0);
 		TEST_ASSERT((size_t)ret <= read_diff);
 
diff --git a/lib/io/test/stream_splice.c b/lib/sqfs/test/stream_splice.c
index a9edd76..6f40d1f 100644
--- a/lib/io/test/stream_splice.c
+++ b/lib/sqfs/test/stream_splice.c
@@ -6,10 +6,9 @@
  */
 #include "config.h"
 
-#include "io/istream.h"
-#include "io/ostream.h"
 #include "io/mem.h"
 #include "util/test.h"
+#include "sqfs/io.h"
 
 static const sqfs_u64 end0 = 449;	/* region 1: filled with 'A' */
 static const sqfs_u64 end1 = 521;	/* region 2: filled with 'B' */
@@ -43,7 +42,6 @@ static sqfs_ostream_t out = {
 	out_append,
 	NULL,
 	NULL,
-	NULL,
 };
 
 static int out_append(sqfs_ostream_t *strm, const void *data, size_t size)
@@ -79,7 +77,7 @@ int main(int argc, char **argv)
 	TEST_NOT_NULL(in);
 
 	for (;;) {
-		ret = istream_splice(in, &out, 211);
+		ret = sqfs_istream_splice(in, &out, 211);
 		TEST_ASSERT(ret >= 0);
 
 		if (ret == 0)
diff --git a/lib/tar/src/iterator.c b/lib/tar/src/iterator.c
index 5920b46..93c931c 100644
--- a/lib/tar/src/iterator.c
+++ b/lib/tar/src/iterator.c
@@ -177,13 +177,13 @@ static int it_next(dir_iterator_t *it, dir_entry_t **out)
 		return tar->state;
 retry:
 	if (tar->record_size > 0) {
-		ret = istream_skip(tar->stream, tar->record_size);
+		ret = sqfs_istream_skip(tar->stream, tar->record_size);
 		if (ret)
 			goto fail;
 	}
 
 	if (tar->padding > 0) {
-		ret = istream_skip(tar->stream, tar->padding);
+		ret = sqfs_istream_skip(tar->stream, tar->padding);
 		if (ret)
 			goto fail;
 	}
diff --git a/lib/tar/src/read_header.c b/lib/tar/src/read_header.c
index 3117d8a..16fc9d7 100644
--- a/lib/tar/src/read_header.c
+++ b/lib/tar/src/read_header.c
@@ -175,7 +175,7 @@ int read_header(sqfs_istream_t *fp, tar_header_decoded_t *out)
 	memset(out, 0, sizeof(*out));
 
 	for (;;) {
-		ret = istream_read(fp, &hdr, sizeof(hdr));
+		ret = sqfs_istream_read(fp, &hdr, sizeof(hdr));
 		if (ret < 0)
 			goto fail;
 
@@ -226,7 +226,7 @@ int read_header(sqfs_istream_t *fp, tar_header_decoded_t *out)
 				goto fail;
 			if (pax_size % 512)
 				pax_size += 512 - (pax_size % 512);
-			istream_skip(fp, pax_size);
+			sqfs_istream_skip(fp, pax_size);
 			continue;
 		case TAR_TYPE_PAX:
 			clear_header(out);
diff --git a/lib/tar/src/read_sparse_map_new.c b/lib/tar/src/read_sparse_map_new.c
index a1f37fd..4e317a8 100644
--- a/lib/tar/src/read_sparse_map_new.c
+++ b/lib/tar/src/read_sparse_map_new.c
@@ -41,7 +41,7 @@ sparse_map_t *read_gnu_new_sparse(sqfs_istream_t *fp, tar_header_decoded_t *out)
 	if (out->record_size < 512)
 		goto fail_format;
 
-	ret = istream_read(fp, buffer, 512);
+	ret = sqfs_istream_read(fp, buffer, 512);
 	if (ret < 0)
 		goto fail;
 
@@ -68,7 +68,7 @@ sparse_map_t *read_gnu_new_sparse(sqfs_istream_t *fp, tar_header_decoded_t *out)
 			if (out->record_size < 512)
 				goto fail_format;
 
-			ret = istream_read(fp, buffer + 512, 512);
+			ret = sqfs_istream_read(fp, buffer + 512, 512);
 			if (ret < 0)
 				goto fail;
 
diff --git a/lib/tar/src/read_sparse_map_old.c b/lib/tar/src/read_sparse_map_old.c
index 832329b..1794073 100644
--- a/lib/tar/src/read_sparse_map_old.c
+++ b/lib/tar/src/read_sparse_map_old.c
@@ -59,7 +59,7 @@ sparse_map_t *read_gnu_old_sparse(sqfs_istream_t *fp, tar_header_t *hdr)
 		return list;
 
 	do {
-		ret = istream_read(fp, &sph, sizeof(sph));
+		ret = sqfs_istream_read(fp, &sph, sizeof(sph));
 		if (ret < 0)
 			goto fail;
 
diff --git a/lib/tar/src/record_to_memory.c b/lib/tar/src/record_to_memory.c
index 1bd31aa..597d6f8 100644
--- a/lib/tar/src/record_to_memory.c
+++ b/lib/tar/src/record_to_memory.c
@@ -18,7 +18,7 @@ char *record_to_memory(sqfs_istream_t *fp, size_t size)
 	if (buffer == NULL)
 		goto fail_errno;
 
-	ret = istream_read(fp, buffer, size);
+	ret = sqfs_istream_read(fp, buffer, size);
 	if (ret < 0)
 		goto fail;
 
@@ -28,7 +28,7 @@ char *record_to_memory(sqfs_istream_t *fp, size_t size)
 	}
 
 	if (size % 512) {
-		if (istream_skip(fp, 512 - (size % 512)))
+		if (sqfs_istream_skip(fp, 512 - (size % 512)))
 			goto fail;
 	}
 
diff --git a/lib/tar/test/tar_fuzz.c b/lib/tar/test/tar_fuzz.c
index bdea98e..92c0952 100644
--- a/lib/tar/test/tar_fuzz.c
+++ b/lib/tar/test/tar_fuzz.c
@@ -34,7 +34,7 @@ int main(int argc, char **argv)
 		if (ret < 0)
 			goto fail;
 
-		ret = istream_skip(fp, hdr.record_size);
+		ret = sqfs_istream_skip(fp, hdr.record_size);
 
 		clear_header(&hdr);
 		if (ret < 0)
diff --git a/lib/tar/test/tar_iterator.c b/lib/tar/test/tar_iterator.c
index 25e1389..f51ecd6 100644
--- a/lib/tar/test/tar_iterator.c
+++ b/lib/tar/test/tar_iterator.c
@@ -83,12 +83,12 @@ int main(int argc, char **argv)
 	TEST_EQUAL_UI(((sqfs_object_t *)ti)->refcount, 1);
 
 	/* read the data from the stream */
-	ret = istream_read(ti, buffer, sizeof(buffer));
+	ret = sqfs_istream_read(ti, buffer, sizeof(buffer));
 	TEST_EQUAL_I(ret, 5);
 	buffer[5] = '\0';
 	TEST_STR_EQUAL(buffer, "test\n");
 
-	ret = istream_read(ti, buffer, sizeof(buffer));
+	ret = sqfs_istream_read(ti, buffer, sizeof(buffer));
 	TEST_EQUAL_I(ret, 0);
 
 	sqfs_drop(ti);
diff --git a/lib/tar/test/tar_iterator2.c b/lib/tar/test/tar_iterator2.c
index 6f472ae..7483e81 100644
--- a/lib/tar/test/tar_iterator2.c
+++ b/lib/tar/test/tar_iterator2.c
@@ -76,7 +76,7 @@ int main(int argc, char **argv)
 	offset = 0;
 
 	for (;;) {
-		ret = istream_read(ti, buffer, sizeof(buffer));
+		ret = sqfs_istream_read(ti, buffer, sizeof(buffer));
 		TEST_ASSERT(ret >= 0);
 
 		if (ret == 0)
diff --git a/lib/tar/test/tar_iterator3.c b/lib/tar/test/tar_iterator3.c
index 39e7b42..11c2fd2 100644
--- a/lib/tar/test/tar_iterator3.c
+++ b/lib/tar/test/tar_iterator3.c
@@ -86,10 +86,10 @@ int main(int argc, char **argv)
 	TEST_EQUAL_I(ret, 0);
 	TEST_NOT_NULL(ti);
 
-	TEST_ASSERT(istream_read(ti, buffer, sizeof(buffer)) == 5);
+	TEST_ASSERT(sqfs_istream_read(ti, buffer, sizeof(buffer)) == 5);
 	buffer[5] = '\0';
 	TEST_STR_EQUAL(buffer, "test\n");
-	TEST_ASSERT(istream_read(ti, buffer, sizeof(buffer)) == 0);
+	TEST_ASSERT(sqfs_istream_read(ti, buffer, sizeof(buffer)) == 0);
 	ti = sqfs_drop(ti);
 
 	ret = it->next(it, &ent);
@@ -105,10 +105,10 @@ int main(int argc, char **argv)
 	TEST_EQUAL_I(ret, 0);
 	TEST_NOT_NULL(ti);
 
-	TEST_ASSERT(istream_read(ti, buffer, sizeof(buffer)) == 5);
+	TEST_ASSERT(sqfs_istream_read(ti, buffer, sizeof(buffer)) == 5);
 	buffer[5] = '\0';
 	TEST_STR_EQUAL(buffer, "test\n");
-	TEST_ASSERT(istream_read(ti, buffer, sizeof(buffer)) == 0);
+	TEST_ASSERT(sqfs_istream_read(ti, buffer, sizeof(buffer)) == 0);
 	ti = sqfs_drop(ti);
 
 	/* "deep" directory hierarchy containg a hard link */
diff --git a/lib/tar/test/tar_simple.c b/lib/tar/test/tar_simple.c
index 656e59b..a666eb5 100644
--- a/lib/tar/test/tar_simple.c
+++ b/lib/tar/test/tar_simple.c
@@ -55,7 +55,7 @@ int main(int argc, char **argv)
 	TEST_STR_EQUAL(hdr.name, fname);
 	TEST_ASSERT(!hdr.unknown_record);
 
-	TEST_ASSERT(istream_read(fp, buffer, 5) == 5);
+	TEST_ASSERT(sqfs_istream_read(fp, buffer, 5) == 5);
 	buffer[5] = '\0';
 	TEST_STR_EQUAL(buffer, "test\n");
 	clear_header(&hdr);
diff --git a/lib/tar/test/tar_target_filled.c b/lib/tar/test/tar_target_filled.c
index 815728a..4f061c0 100644
--- a/lib/tar/test/tar_target_filled.c
+++ b/lib/tar/test/tar_target_filled.c
@@ -50,10 +50,10 @@ int main(int argc, char **argv)
 		       "20_characters_here03/20_characters_here04/"
 		       "errored_file_tst");
 	TEST_EQUAL_UI(hdr.actual_size, 5);
-	TEST_ASSERT(istream_read(fp, buffer, 5) == 5);
+	TEST_ASSERT(sqfs_istream_read(fp, buffer, 5) == 5);
 	buffer[5] = '\0';
 	TEST_STR_EQUAL(buffer, "test\n");
-	TEST_ASSERT(istream_skip(fp, 512 - 5) == 0);
+	TEST_ASSERT(sqfs_istream_skip(fp, 512 - 5) == 0);
 	clear_header(&hdr);
 
 	TEST_ASSERT(read_header(fp, &hdr) == 0);
@@ -62,10 +62,10 @@ int main(int argc, char **argv)
 		       "20_characters_here03/20_characters_here04/"
 		       "some_test_file");
 	TEST_EQUAL_UI(hdr.actual_size, 5);
-	TEST_ASSERT(istream_read(fp, buffer, 5) == 5);
+	TEST_ASSERT(sqfs_istream_read(fp, buffer, 5) == 5);
 	buffer[5] = '\0';
 	TEST_STR_EQUAL(buffer, "test\n");
-	TEST_ASSERT(istream_skip(fp, 512 - 5) == 0);
+	TEST_ASSERT(sqfs_istream_skip(fp, 512 - 5) == 0);
 	clear_header(&hdr);
 
 	/* "deep" directory hierarchy containg a hard link */
diff --git a/lib/tar/test/tar_write_simple.c b/lib/tar/test/tar_write_simple.c
index 98ac25b..ca8d1e5 100644
--- a/lib/tar/test/tar_write_simple.c
+++ b/lib/tar/test/tar_write_simple.c
@@ -6,7 +6,7 @@
  */
 #include "config.h"
 #include "tar/tar.h"
-#include "io/ostream.h"
+#include "sqfs/io.h"
 #include "io/file.h"
 #include "util/test.h"
 #include "sqfs/xattr.h"
@@ -191,11 +191,11 @@ int main(int argc, char **argv)
 	fp = istream_open_file(STRVALUE(TESTPATH) "/" STRVALUE(TESTFILE));
 	TEST_NOT_NULL(fp);
 
-	ret = istream_read(fp, rd_buffer, sizeof(rd_buffer));
+	ret = sqfs_istream_read(fp, rd_buffer, sizeof(rd_buffer));
 	TEST_ASSERT(ret > 0);
 	TEST_EQUAL_UI(ret, sizeof(rd_buffer));
 
-	ret = istream_read(fp, rd_buffer, sizeof(rd_buffer));
+	ret = sqfs_istream_read(fp, rd_buffer, sizeof(rd_buffer));
 	TEST_EQUAL_I(ret, 0);
 
 	sqfs_drop(fp);
diff --git a/lib/tar/test/tar_xattr.c b/lib/tar/test/tar_xattr.c
index 657b73d..26a2cd0 100644
--- a/lib/tar/test/tar_xattr.c
+++ b/lib/tar/test/tar_xattr.c
@@ -27,7 +27,7 @@ int main(int argc, char **argv)
 	TEST_EQUAL_UI(hdr.mtime, 1543094477);
 	TEST_STR_EQUAL(hdr.name, "input.txt");
 	TEST_ASSERT(!hdr.unknown_record);
-	TEST_ASSERT(istream_read(fp, buffer, 5) == 5);
+	TEST_ASSERT(sqfs_istream_read(fp, buffer, 5) == 5);
 	buffer[5] = '\0';
 	TEST_STR_EQUAL(buffer, "test\n");
 
diff --git a/lib/tar/test/tar_xattr_bin.c b/lib/tar/test/tar_xattr_bin.c
index f897bce..94c8d76 100644
--- a/lib/tar/test/tar_xattr_bin.c
+++ b/lib/tar/test/tar_xattr_bin.c
@@ -35,7 +35,7 @@ int main(int argc, char **argv)
 	TEST_EQUAL_UI(hdr.mtime, 1543094477);
 	TEST_STR_EQUAL(hdr.name, "input.txt");
 	TEST_ASSERT(!hdr.unknown_record);
-	TEST_ASSERT(istream_read(fp, buffer, 5) == 5);
+	TEST_ASSERT(sqfs_istream_read(fp, buffer, 5) == 5);
 	buffer[5] = '\0';
 	TEST_STR_EQUAL(buffer, "test\n");