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Annotation of embedaddon/dhcp/includes/omapip/buffer.h, revision 1.1

1.1     ! misho       1: /* buffer.h
        !             2: 
        !             3:    Definitions for the object management API protocol buffering... */
        !             4: 
        !             5: /*
        !             6:  * Copyright (c) 2004,2009 by Internet Systems Consortium, Inc. ("ISC")
        !             7:  * Copyright (c) 1996-2003 by Internet Software Consortium
        !             8:  *
        !             9:  * Permission to use, copy, modify, and distribute this software for any
        !            10:  * purpose with or without fee is hereby granted, provided that the above
        !            11:  * copyright notice and this permission notice appear in all copies.
        !            12:  *
        !            13:  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
        !            14:  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
        !            15:  * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
        !            16:  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
        !            17:  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
        !            18:  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
        !            19:  * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
        !            20:  *
        !            21:  *   Internet Systems Consortium, Inc.
        !            22:  *   950 Charter Street
        !            23:  *   Redwood City, CA 94063
        !            24:  *   <info@isc.org>
        !            25:  *   https://www.isc.org/
        !            26:  *
        !            27:  * This software has been written for Internet Systems Consortium
        !            28:  * by Ted Lemon in cooperation with Vixie Enterprises and Nominum, Inc.
        !            29:  * To learn more about Internet Systems Consortium, see
        !            30:  * ``https://www.isc.org/''.  To learn more about Vixie Enterprises,
        !            31:  * see ``http://www.vix.com''.   To learn more about Nominum, Inc., see
        !            32:  * ``http://www.nominum.com''.
        !            33:  */
        !            34: 
        !            35: /* OMAPI buffers are ring buffers, which means that the beginning of the
        !            36:    buffer and the end of the buffer chase each other around.   As long as
        !            37:    the tail never catches up to the head, there's room in the buffer for
        !            38:    data.
        !            39: 
        !            40:        - If the tail and the head are equal, the buffer is empty.
        !            41: 
        !            42:        - If the tail is less than the head, the contents of the buffer
        !            43:          are the bytes from the head to the end of buffer, and in addition,
        !            44:          the bytes between the beginning of the buffer and the tail, not
        !            45:          including the byte addressed by the tail.
        !            46: 
        !            47:        - If the tail is greater than the head, then the buffer contains
        !            48:          valid bytes starting with the byte addressed by the head, and
        !            49:          ending with the byte before the byte addressed by the tail.
        !            50: 
        !            51:    There will always be at least one byte of waste, because the tail can't
        !            52:    increase so that it's equal to the head (that would represent an empty
        !            53:    buffer. */
        !            54: #define OMAPI_BUF_SIZE 4048
        !            55: typedef struct _omapi_buffer {
        !            56:        struct _omapi_buffer *next;     /* Buffers can be chained. */
        !            57:        u_int32_t refcnt;               /* Buffers are reference counted. */
        !            58:        u_int16_t head, tail;           /* Buffers are organized in a ring. */
        !            59:        char buf [OMAPI_BUF_SIZE];      /* The actual buffer is included in
        !            60:                                           the buffer data structure. */
        !            61: } omapi_buffer_t;      
        !            62: 
        !            63: #define BUFFER_BYTES_FREE(x)   \
        !            64:        ((x) -> tail > (x) -> head \
        !            65:          ? sizeof ((x) -> buf) - ((x) -> tail - (x) -> head) \
        !            66:          : (x) -> head - (x) -> tail)
        !            67: 
        !            68: #define BYTES_IN_BUFFER(x)     \
        !            69:        ((x) -> tail > (x) -> head \
        !            70:         ? (x) -> tail - (x) -> head - 1 \
        !            71:         : sizeof ((x) -> buf) - ((x) -> head - (x) -> tail) - 1)
        !            72: 
        !            73: isc_result_t omapi_connection_require (omapi_object_t *, unsigned);
        !            74: isc_result_t omapi_connection_copyout (unsigned char *,
        !            75:                                       omapi_object_t *, unsigned);
        !            76: isc_result_t omapi_connection_copyin (omapi_object_t *,
        !            77:                                      const unsigned char *, unsigned);
        !            78: isc_result_t omapi_connection_flush (omapi_object_t *);
        !            79: isc_result_t omapi_connection_get_uint32 (omapi_object_t *, u_int32_t *);
        !            80: isc_result_t omapi_connection_put_uint32 (omapi_object_t *, u_int32_t);
        !            81: isc_result_t omapi_connection_get_uint16 (omapi_object_t *, u_int16_t *);
        !            82: isc_result_t omapi_connection_put_uint16 (omapi_object_t *, u_int32_t);
        !            83: