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- /*
- * ustream - library for stream buffer management
- *
- * Copyright (C) 2012 Felix Fietkau <nbd@openwrt.org>
- *
- * Permission to use, copy, modify, and/or distribute this software for any
- * purpose with or without fee is hereby granted, provided that the above
- * copyright notice and this permission notice appear in all copies.
- *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
- */
- #ifndef __USTREAM_H
- #define __USTREAM_H
- #include <stdarg.h>
- #include "uloop.h"
- struct ustream;
- struct ustream_buf;
- enum read_blocked_reason {
- READ_BLOCKED_USER = (1 << 0),
- READ_BLOCKED_FULL = (1 << 1),
- };
- struct ustream_buf_list {
- struct ustream_buf *head;
- struct ustream_buf *data_tail;
- struct ustream_buf *tail;
- int (*alloc)(struct ustream *s, struct ustream_buf_list *l);
- int data_bytes;
- int min_buffers;
- int max_buffers;
- int buffer_len;
- int buffers;
- };
- struct ustream {
- struct ustream_buf_list r, w;
- struct uloop_timeout state_change;
- struct ustream *next;
- /*
- * notify_read: (optional)
- * called by the ustream core to notify that new data is available
- * for reading.
- * must not free the ustream from this callback
- */
- void (*notify_read)(struct ustream *s, int bytes_new);
- /*
- * notify_write: (optional)
- * called by the ustream core to notify that some buffered data has
- * been written to the stream.
- * must not free the ustream from this callback
- */
- void (*notify_write)(struct ustream *s, int bytes);
- /*
- * notify_state: (optional)
- * called by the ustream implementation to notify that the read
- * side of the stream is closed (eof is set) or there was a write
- * error (write_error is set).
- * will be called again after the write buffer has been emptied when
- * the read side has hit EOF.
- */
- void (*notify_state)(struct ustream *s);
- /*
- * write:
- * must be defined by ustream implementation, accepts new write data.
- * 'more' is used to indicate that a subsequent call will provide more
- * data (useful for aggregating writes)
- * returns the number of bytes accepted, or -1 if no more writes can
- * be accepted (link error)
- */
- int (*write)(struct ustream *s, const char *buf, int len, bool more);
- /*
- * free: (optional)
- * defined by ustream implementation, tears down the ustream and frees data
- */
- void (*free)(struct ustream *s);
- /*
- * set_read_blocked: (optional)
- * defined by ustream implementation, called when the read_blocked flag
- * changes
- */
- void (*set_read_blocked)(struct ustream *s);
- /*
- * poll: (optional)
- * defined by the upstream implementation, called to request polling for
- * available data.
- * returns true if data was fetched.
- */
- bool (*poll)(struct ustream *s);
- /*
- * ustream user should set this if the input stream is expected
- * to contain string data. the core will keep all data 0-terminated.
- */
- bool string_data;
- bool write_error;
- bool eof, eof_write_done;
- enum read_blocked_reason read_blocked;
- };
- struct ustream_fd {
- struct ustream stream;
- struct uloop_fd fd;
- };
- struct ustream_buf {
- struct ustream_buf *next;
- char *data;
- char *tail;
- char *end;
- char head[];
- };
- /* ustream_fd_init: create a file descriptor ustream (uses uloop) */
- void ustream_fd_init(struct ustream_fd *s, int fd);
- /* ustream_free: free all buffers and data associated with a ustream */
- void ustream_free(struct ustream *s);
- /* ustream_consume: remove data from the head of the read buffer */
- void ustream_consume(struct ustream *s, int len);
- /*
- * ustream_read: read and consume data in read buffer into caller-specified
- * area. Return length of data read.
- */
- int ustream_read(struct ustream *s, char *buf, int buflen);
- /* ustream_write: add data to the write buffer */
- int ustream_write(struct ustream *s, const char *buf, int len, bool more);
- int ustream_printf(struct ustream *s, const char *format, ...)
- __attribute__ ((format (printf, 2, 3)));
- int ustream_vprintf(struct ustream *s, const char *format, va_list arg)
- __attribute__ ((format (printf, 2, 0)));
- /* ustream_get_read_buf: get a pointer to the next read buffer data */
- char *ustream_get_read_buf(struct ustream *s, int *buflen);
- /*
- * ustream_set_read_blocked: set read blocked state
- *
- * if set, the ustream will no longer fetch pending data.
- */
- void ustream_set_read_blocked(struct ustream *s, bool set);
- static inline bool ustream_read_blocked(struct ustream *s)
- {
- return !!(s->read_blocked & READ_BLOCKED_USER);
- }
- static inline int ustream_pending_data(struct ustream *s, bool write)
- {
- struct ustream_buf_list *b = write ? &s->w : &s->r;
- return b->data_bytes;
- }
- static inline bool ustream_read_buf_full(struct ustream *s)
- {
- struct ustream_buf *buf = s->r.data_tail;
- return buf && buf->data == buf->head && buf->tail == buf->end &&
- s->r.buffers == s->r.max_buffers;
- }
- /*** --- functions only used by ustream implementations --- ***/
- /* ustream_init_defaults: fill default callbacks and options */
- void ustream_init_defaults(struct ustream *s);
- /*
- * ustream_reserve: allocate rx buffer space
- *
- * len: hint for how much space is needed (not guaranteed to be met)
- * maxlen: pointer to where the actual buffer size is going to be stored
- */
- char *ustream_reserve(struct ustream *s, int len, int *maxlen);
- /* ustream_fill_read: mark rx buffer space as filled */
- void ustream_fill_read(struct ustream *s, int len);
- /*
- * ustream_write_pending: attempt to write more data from write buffers
- * returns true if all write buffers have been emptied.
- */
- bool ustream_write_pending(struct ustream *s);
- static inline void ustream_state_change(struct ustream *s)
- {
- uloop_timeout_set(&s->state_change, 0);
- }
- static inline bool ustream_poll(struct ustream *s)
- {
- if (!s->poll)
- return false;
- return s->poll(s);
- }
- #endif
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