/* the Music Player Daemon (MPD) * Copyright (C) 2003-2007 by Warren Dukes (warren.dukes@gmail.com) * This project's homepage is: http://www.musicpd.org * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #ifndef MPD_INPUT_STREAM_H #define MPD_INPUT_STREAM_H #include <stddef.h> #include <stdbool.h> #include <sys/types.h> struct input_stream; struct input_plugin { bool (*open)(struct input_stream *is, const char *url); void (*close)(struct input_stream *is); struct tag *(*tag)(struct input_stream *is); int (*buffer)(struct input_stream *is); size_t (*read)(struct input_stream *is, void *ptr, size_t size); bool (*eof)(struct input_stream *is); bool (*seek)(struct input_stream *is, off_t offset, int whence); }; struct input_stream { /** * the plugin which implements this input stream */ const struct input_plugin *plugin; /** * an opaque pointer managed by the plugin */ void *data; /** * indicates whether the stream is ready for reading and * whether the other attributes in this struct are valid */ bool ready; /** * if true, then the stream is fully seekable */ bool seekable; /** * an optional errno error code, set to non-zero after an error occured */ int error; /** * the size of the resource, or -1 if unknown */ off_t size; /** * the current offset within the stream */ off_t offset; /** * the MIME content type of the resource, or NULL if unknown */ char *mime; }; /** * Initializes this library and all input_stream implementations. */ void input_stream_global_init(void); /** * Deinitializes this library and all input_stream implementations. */ void input_stream_global_finish(void); /** * Opens a new input stream. You may not access it until the "ready" * flag is set. * * @param is the input_stream object allocated by the caller * @return true on success */ bool input_stream_open(struct input_stream *is, const char *url); /** * Closes the input stream and free resources. This does not free the * input_stream pointer itself, because it is assumed to be allocated * by the caller. */ void input_stream_close(struct input_stream *is); /** * Seeks to the specified position in the stream. This will most * likely fail if the "seekable" flag is false. * * @param is the input_stream object * @param offset the relative offset * @param whence the base of the seek, one of SEEK_SET, SEEK_CUR, SEEK_END */ bool input_stream_seek(struct input_stream *is, off_t offset, int whence); /** * Returns true if the stream has reached end-of-file. */ bool input_stream_eof(struct input_stream *is); /** * Reads the tag from the stream. * * @return a tag object which must be freed with tag_free(), or NULL * if the tag has not changed since the last call */ struct tag * input_stream_tag(struct input_stream *is); /** * Reads some of the stream into its buffer. The following return * codes are defined: -1 = error, 1 = something was buffered, 0 = * nothing was buffered. * * The semantics of this function are not well-defined, and it will * eventually be removed. */ int input_stream_buffer(struct input_stream *is); /** * Reads data from the stream into the caller-supplied buffer. * Returns 0 on error or eof (check with input_stream_eof()). * * @param is the input_stream object * @param ptr the buffer to read into * @param size the maximum number of bytes to read * @return the number of bytes read */ size_t input_stream_read(struct input_stream *is, void *ptr, size_t size); #endif