89 lines
3.9 KiB
C
89 lines
3.9 KiB
C
/*
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* Copyright (c) 2018, Sam Kumar <samkumar@cs.berkeley.edu>
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* Copyright (c) 2018, University of California, Berkeley
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the copyright holder nor the
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* names of its contributors may be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#ifndef LBUF_H_
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#define LBUF_H_
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#include <stddef.h>
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#include <stdint.h>
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struct otLinkedBuffer;
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/* LINKED BUFFER */
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struct lbufhead {
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struct otLinkedBuffer* head;
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struct otLinkedBuffer* tail;
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size_t offset;
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size_t length;
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};
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/* Initializes a linked buffer. */
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void lbuf_init(struct lbufhead* buffer);
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/* Returns the contents of the buffer as a linked buffer chain, or NULL if the buffer has
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no head. */
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static inline struct otLinkedBuffer* lbuf_head(struct lbufhead* buffer) {
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return buffer->head;
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}
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/* Adds the contents of NEWENTRY to the buffer by appending it to the end of
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the current chain. */
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void lbuf_append(struct lbufhead* buffer, struct otLinkedBuffer* newentry);
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/* Extends the last entry of the buffer by the specified number of bytes. */
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void lbuf_extend(struct lbufhead* buffer, size_t numbytes);
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/* Removes the first NUMBYTES bytes from the buffer, and returns the number of
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bytes removed (which is fewer than NUMBYTES if there were fewer than
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NUMBYTES bytes in the buffer to begin with). *NTRAVERSED is incremented once
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for each entry in the buffer that is no longer referenced and can be
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reclaimed. */
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size_t lbuf_pop(struct lbufhead* buffer, size_t numbytes, uint32_t* ntraversed);
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/* Given a range of indices, specified by an OFFSET from the start and a
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length NUMBYTES, this function locates the chain of linked buffer entries
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that reference the corresponding bytes.
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A pointer to the first entry in the range is stored into FIRST, and the
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number of bytes in the entry before the start of the range is stored into
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FIRSTOFFSET. A pointer to the last entry in the range is stored into LAST,
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and the number of bytes in that entry after the end of the range is stored
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into LASTEXTRA.
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Returns 0 on success and 1 on failure. On failure, FIRST, LAST, FIRSTOFFSET,
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and LASTEXTRA are not set. The only failure condition is when there are not
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enough bytes in the buffer to do the full traversal. */
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int lbuf_getrange(struct lbufhead* buffer, size_t offset, size_t numbytes,
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struct otLinkedBuffer** first, size_t* firstoffset,
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struct otLinkedBuffer** last, size_t* lastextra);
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/* Returns the total number of bytes stored in the buffer. */
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size_t lbuf_used_space(const struct lbufhead* buffer);
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#endif
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