From 359d71e90050a8b83f7bc7d2ecd4ff29c477cc22 Mon Sep 17 00:00:00 2001 From: David Oberhollenzer Date: Sun, 26 Jun 2022 22:51:27 +0200 Subject: Cleanup: rename libfstream to libio, split headers Signed-off-by: David Oberhollenzer --- include/io/ostream.h | 138 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 138 insertions(+) create mode 100644 include/io/ostream.h (limited to 'include/io/ostream.h') 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 + */ +#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 */ -- cgit v1.2.3