318 lines
9.0 KiB
C
318 lines
9.0 KiB
C
/**
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* @file ChunkBuffer2.h
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* @author Ambroz Bizjak <ambrop7@gmail.com>
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*
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* @section LICENSE
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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 author 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" AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
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* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* @section DESCRIPTION
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*
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* Circular packet buffer
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*/
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#ifndef BADVPN_STRUCTURE_CHUNKBUFFER2_H
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#define BADVPN_STRUCTURE_CHUNKBUFFER2_H
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#include <stdint.h>
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#include <stdlib.h>
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#include <limits.h>
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#include <misc/balign.h>
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#include <misc/debug.h>
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#ifndef NDEBUG
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#define CHUNKBUFFER2_ASSERT_BUFFER(_buf) _ChunkBuffer2_assert_buffer(_buf);
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#define CHUNKBUFFER2_ASSERT_IO(_buf) _ChunkBuffer2_assert_io(_buf);
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#else
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#define CHUNKBUFFER2_ASSERT_BUFFER(_buf)
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#define CHUNKBUFFER2_ASSERT_IO(_buf)
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#endif
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struct ChunkBuffer2_block {
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int len;
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};
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typedef struct {
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struct ChunkBuffer2_block *buffer;
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int size;
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int wrap;
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int start;
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int used;
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int mtu;
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uint8_t *input_dest;
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int input_avail;
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uint8_t *output_dest;
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int output_avail;
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} ChunkBuffer2;
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// calculates a buffer size needed to hold at least 'num' packets long at least 'chunk_len'
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static int ChunkBuffer2_calc_blocks (int chunk_len, int num);
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// initialize
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static void ChunkBuffer2_Init (ChunkBuffer2 *buf, struct ChunkBuffer2_block *buffer, int blocks, int mtu);
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// submit a packet written to the buffer
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static void ChunkBuffer2_SubmitPacket (ChunkBuffer2 *buf, int len);
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// remove the first packet
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static void ChunkBuffer2_ConsumePacket (ChunkBuffer2 *buf);
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static int _ChunkBuffer2_end (ChunkBuffer2 *buf)
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{
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if (buf->used >= buf->wrap - buf->start) {
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return (buf->used - (buf->wrap - buf->start));
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} else {
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return (buf->start + buf->used);
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}
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}
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#ifndef NDEBUG
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static void _ChunkBuffer2_assert_buffer (ChunkBuffer2 *buf)
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{
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ASSERT(buf->size > 0)
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ASSERT(buf->wrap > 0)
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ASSERT(buf->wrap <= buf->size)
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ASSERT(buf->start >= 0)
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ASSERT(buf->start < buf->wrap)
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ASSERT(buf->used >= 0)
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ASSERT(buf->used <= buf->wrap)
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ASSERT(buf->wrap == buf->size || buf->used >= buf->wrap - buf->start)
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ASSERT(buf->mtu >= 0)
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}
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static void _ChunkBuffer2_assert_io (ChunkBuffer2 *buf)
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{
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// check input
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int end = _ChunkBuffer2_end(buf);
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if (buf->size - end - 1 < buf->mtu) {
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// it will never be possible to write a MTU long packet here
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ASSERT(!buf->input_dest)
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ASSERT(buf->input_avail == -1)
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} else {
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// calculate number of free blocks
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int free;
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if (buf->used >= buf->wrap - buf->start) {
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free = buf->start - end;
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} else {
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free = buf->size - end;
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}
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if (free > 0) {
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// got space at least for a header. More space will become available as packets are
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// read from the buffer, up to MTU.
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ASSERT(buf->input_dest == (uint8_t *)&buf->buffer[end + 1])
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ASSERT(buf->input_avail == (free - 1) * sizeof(struct ChunkBuffer2_block))
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} else {
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// no space
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ASSERT(!buf->input_dest)
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ASSERT(buf->input_avail == -1)
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}
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}
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// check output
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if (buf->used > 0) {
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int datalen = buf->buffer[buf->start].len;
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ASSERT(datalen >= 0)
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int blocklen = bdivide_up(datalen, sizeof(struct ChunkBuffer2_block));
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ASSERT(blocklen <= buf->used - 1)
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ASSERT(blocklen <= buf->wrap - buf->start - 1)
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ASSERT(buf->output_dest == (uint8_t *)&buf->buffer[buf->start + 1])
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ASSERT(buf->output_avail == datalen)
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} else {
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ASSERT(!buf->output_dest)
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ASSERT(buf->output_avail == -1)
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}
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}
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#endif
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static void _ChunkBuffer2_update_input (ChunkBuffer2 *buf)
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{
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int end = _ChunkBuffer2_end(buf);
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if (buf->size - end - 1 < buf->mtu) {
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// it will never be possible to write a MTU long packet here
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buf->input_dest = NULL;
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buf->input_avail = -1;
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return;
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}
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// calculate number of free blocks
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int free;
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if (buf->used >= buf->wrap - buf->start) {
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free = buf->start - end;
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} else {
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free = buf->size - end;
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}
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if (free > 0) {
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// got space at least for a header. More space will become available as packets are
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// read from the buffer, up to MTU.
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buf->input_dest = (uint8_t *)&buf->buffer[end + 1];
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buf->input_avail = (free - 1) * sizeof(struct ChunkBuffer2_block);
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} else {
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// no space
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buf->input_dest = NULL;
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buf->input_avail = -1;
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}
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}
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static void _ChunkBuffer2_update_output (ChunkBuffer2 *buf)
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{
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if (buf->used > 0) {
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int datalen = buf->buffer[buf->start].len;
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ASSERT(datalen >= 0)
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#ifndef NDEBUG
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int blocklen = bdivide_up(datalen, sizeof(struct ChunkBuffer2_block));
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ASSERT(blocklen <= buf->used - 1)
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ASSERT(blocklen <= buf->wrap - buf->start - 1)
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#endif
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buf->output_dest = (uint8_t *)&buf->buffer[buf->start + 1];
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buf->output_avail = datalen;
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} else {
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buf->output_dest = NULL;
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buf->output_avail = -1;
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}
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}
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int ChunkBuffer2_calc_blocks (int chunk_len, int num)
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{
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int chunk_data_blocks = bdivide_up(chunk_len, sizeof(struct ChunkBuffer2_block));
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if (chunk_data_blocks > INT_MAX - 1) {
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return -1;
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}
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int chunk_blocks = 1 + chunk_data_blocks;
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if (num > INT_MAX - 1) {
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return -1;
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}
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int num_chunks = num + 1;
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if (chunk_blocks > INT_MAX / num_chunks) {
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return -1;
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}
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int blocks = chunk_blocks * num_chunks;
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return blocks;
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}
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void ChunkBuffer2_Init (ChunkBuffer2 *buf, struct ChunkBuffer2_block *buffer, int blocks, int mtu)
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{
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ASSERT(blocks > 0)
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ASSERT(mtu >= 0)
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buf->buffer = buffer;
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buf->size = blocks;
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buf->wrap = blocks;
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buf->start = 0;
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buf->used = 0;
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buf->mtu = bdivide_up(mtu, sizeof(struct ChunkBuffer2_block));
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CHUNKBUFFER2_ASSERT_BUFFER(buf)
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_ChunkBuffer2_update_input(buf);
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_ChunkBuffer2_update_output(buf);
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CHUNKBUFFER2_ASSERT_IO(buf)
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}
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void ChunkBuffer2_SubmitPacket (ChunkBuffer2 *buf, int len)
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{
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ASSERT(buf->input_dest)
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ASSERT(len >= 0)
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ASSERT(len <= buf->input_avail)
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CHUNKBUFFER2_ASSERT_BUFFER(buf)
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CHUNKBUFFER2_ASSERT_IO(buf)
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int end = _ChunkBuffer2_end(buf);
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int blocklen = bdivide_up(len, sizeof(struct ChunkBuffer2_block));
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ASSERT(blocklen <= buf->size - end - 1)
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ASSERT(buf->used < buf->wrap - buf->start || blocklen <= buf->start - end - 1)
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buf->buffer[end].len = len;
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buf->used += 1 + blocklen;
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if (buf->used <= buf->wrap - buf->start && buf->mtu > buf->size - (end + 1 + blocklen) - 1) {
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buf->wrap = end + 1 + blocklen;
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}
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CHUNKBUFFER2_ASSERT_BUFFER(buf)
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// update input
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_ChunkBuffer2_update_input(buf);
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// update output
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if (buf->used == 1 + blocklen) {
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_ChunkBuffer2_update_output(buf);
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}
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CHUNKBUFFER2_ASSERT_IO(buf)
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}
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void ChunkBuffer2_ConsumePacket (ChunkBuffer2 *buf)
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{
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ASSERT(buf->output_dest)
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CHUNKBUFFER2_ASSERT_BUFFER(buf)
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CHUNKBUFFER2_ASSERT_IO(buf)
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ASSERT(1 <= buf->wrap - buf->start)
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ASSERT(1 <= buf->used)
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int blocklen = bdivide_up(buf->buffer[buf->start].len, sizeof(struct ChunkBuffer2_block));
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ASSERT(blocklen <= buf->wrap - buf->start - 1)
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ASSERT(blocklen <= buf->used - 1)
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int data_wrapped = (buf->used >= buf->wrap - buf->start);
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buf->start += 1 + blocklen;
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buf->used -= 1 + blocklen;
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if (buf->start == buf->wrap) {
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buf->start = 0;
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buf->wrap = buf->size;
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}
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CHUNKBUFFER2_ASSERT_BUFFER(buf)
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// update input
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if (data_wrapped) {
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_ChunkBuffer2_update_input(buf);
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}
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// update output
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_ChunkBuffer2_update_output(buf);
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CHUNKBUFFER2_ASSERT_IO(buf)
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}
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#endif
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