1 files changed, 138 insertions, 0 deletions
diff --git a/include/io/ostream.h b/include/io/ostream.h
new file mode 100644
index 0000000..15585f9
--- /dev/null
+++ b/include/io/ostream.h
@@ -0,0 +1,138 @@
+/* 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"
+#include "io/istream.h"
+
+#if defined(__GNUC__) || defined(__clang__)
+#	define PRINTF_ATTRIB(fmt, elipsis)			\
+		__attribute__ ((format (printf, fmt, elipsis)))
+#else
+#	define PRINTF_ATTRIB(fmt, elipsis)
+#endif
+
+/**
+ * @struct ostream_t
+ *
+ * @extends sqfs_object_t
+ *
+ * @brief An append-only data stream.
+ */
+typedef struct ostream_t {
+	sqfs_object_t base;
+
+	int (*append)(struct ostream_t *strm, const void *data, size_t size);
+
+	int (*append_sparse)(struct ostream_t *strm, size_t size);
+
+	int (*flush)(struct ostream_t *strm);
+
+	const char *(*get_filename)(struct ostream_t *strm);
+} ostream_t;
+
+enum {
+	OSTREAM_OPEN_OVERWRITE = 0x01,
+	OSTREAM_OPEN_SPARSE = 0x02,
+};
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @brief Append a block of data to an output stream.
+ *
+ * @memberof ostream_t
+ *
+ * @param strm A pointer to an output stream.
+ * @param data A pointer to the data block to append.
+ * @param size The number of bytes to append.
+ *
+ * @return Zero on success, -1 on failure.
+ */
+SQFS_INTERNAL int ostream_append(ostream_t *strm, const void *data,
+				 size_t size);
+
+/**
+ * @brief Append a number of zero bytes to an output stream.
+ *
+ * @memberof ostream_t
+ *
+ * If the unerlying implementation supports sparse files, this function can be
+ * used to create a "hole". If the implementation does not support it, a
+ * fallback is used that just appends a block of zeros manualy.
+ *
+ * @param strm A pointer to an output stream.
+ * @param size The number of zero bytes to append.
+ *
+ * @return Zero on success, -1 on failure.
+ */
+SQFS_INTERNAL int ostream_append_sparse(ostream_t *strm, size_t size);
+
+/**
+ * @brief Process all pending, buffered data and flush it to disk.
+ *
+ * @memberof ostream_t
+ *
+ * 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.
+ */
+SQFS_INTERNAL int ostream_flush(ostream_t *strm);
+
+/**
+ * @brief Get the underlying filename of a output stream.
+ *
+ * @memberof ostream_t
+ *
+ * @param strm The output stream to get the filename from.
+ *
+ * @return A string holding the underlying filename.
+ */
+SQFS_INTERNAL const char *ostream_get_filename(ostream_t *strm);
+
+/**
+ * @brief Printf like function that appends to an output stream
+ *
+ * @memberof ostream_t
+ *
+ * @param strm The output stream to append to.
+ * @param fmt A printf style format string.
+ *
+ * @return The number of characters written on success, -1 on failure.
+ */
+SQFS_INTERNAL int ostream_printf(ostream_t *strm, const char *fmt, ...)
+	PRINTF_ATTRIB(2, 3);
+
+/**
+ * @brief Read data from an input stream and append it to an output stream
+ *
+ * @memberof ostream_t
+ *
+ * @param out A pointer to an output stream to append to.
+ * @param in A pointer to an input stream to read from.
+ * @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 ostream_append_from_istream(ostream_t *out,
+						   istream_t *in,
+						   sqfs_u32 size);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* IO_OSTREAM_H */