1 files changed, 128 insertions, 0 deletions
diff --git a/include/io/istream.h b/include/io/istream.h
new file mode 100644
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--- /dev/null
+++ b/include/io/istream.h
@@ -0,0 +1,128 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+/*
+ * istream.h
+ *
+ * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
+ */
+#ifndef IO_ISTREAM_H
+#define IO_ISTREAM_H
+
+#include "sqfs/predef.h"
+
+/**
+ * @struct istream_t
+ *
+ * @extends sqfs_object_t
+ *
+ * @brief A sequential, read-only data stream.
+ */
+typedef struct istream_t {
+	sqfs_object_t base;
+
+	size_t buffer_used;
+	size_t buffer_offset;
+	bool eof;
+
+	sqfs_u8 *buffer;
+
+	int (*precache)(struct istream_t *strm);
+
+	const char *(*get_filename)(struct istream_t *strm);
+} istream_t;
+
+enum {
+	ISTREAM_LINE_LTRIM = 0x01,
+	ISTREAM_LINE_RTRIM = 0x02,
+	ISTREAM_LINE_SKIP_EMPTY = 0x04,
+};
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @brief Read a line of text from an input stream
+ *
+ * @memberof istream_t
+ *
+ * The line returned is allocated using malloc and must subsequently be
+ * freed when it is no longer needed. The line itself is always null-terminated
+ * and never includes the line break characters (LF or CR-LF).
+ *
+ * If the flag @ref ISTREAM_LINE_LTRIM is set, leading white space characters
+ * are removed. If the flag @ref ISTREAM_LINE_RTRIM is set, trailing white space
+ * characters are remvoed.
+ *
+ * If the flag @ref ISTREAM_LINE_SKIP_EMPTY is set and a line is discovered to
+ * be empty (after the optional trimming), the function discards the empty line
+ * and retries. The given line_num pointer is used to increment the line
+ * number.
+ *
+ * @param strm A pointer to an input stream.
+ * @param out Returns a pointer to a line on success.
+ * @param line_num This is incremented if lines are skipped.
+ * @param flags A combination of flags controling the functions behaviour.
+ *
+ * @return Zero on success, a negative value on error, a positive value if
+ *         end-of-file was reached without reading any data.
+ */
+SQFS_INTERNAL int istream_get_line(istream_t *strm, char **out,
+				   size_t *line_num, int flags);
+
+/**
+ * @brief Read data from an input stream
+ *
+ * @memberof 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(istream_t *strm, void *data, size_t size);
+
+/**
+ * @brief Adjust and refill the internal buffer of an input stream
+ *
+ * @memberof istream_t
+ *
+ * This function resets the buffer offset of an input stream (moving any unread
+ * data up front if it has to) and calls an internal callback of the input
+ * stream to fill the rest of the buffer to the extent possible.
+ *
+ * @param strm A pointer to an input stream.
+ *
+ * @return 0 on success, -1 on failure.
+ */
+SQFS_INTERNAL int istream_precache(istream_t *strm);
+
+/**
+ * @brief Get the underlying filename of an input stream.
+ *
+ * @memberof istream_t
+ *
+ * @param strm The input stream to get the filename from.
+ *
+ * @return A string holding the underlying filename.
+ */
+SQFS_INTERNAL const char *istream_get_filename(istream_t *strm);
+
+/**
+ * @brief Skip over a number of bytes in an input stream.
+ *
+ * @memberof 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(istream_t *strm, sqfs_u64 size);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* IO_ISTREAM_H */