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134 lines
3.4 KiB
C
134 lines
3.4 KiB
C
/*
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* Dropbear SSH
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*
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* Copyright (c) 2002-2004 Matt Johnston
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* All rights reserved.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE. */
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#include "includes.h"
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#include "dbutil.h"
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#include "circbuffer.h"
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#define MAX_CBUF_SIZE 100000000
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circbuffer * cbuf_new(unsigned int size) {
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circbuffer *cbuf = NULL;
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if (size > MAX_CBUF_SIZE) {
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dropbear_exit("Bad cbuf size");
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}
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cbuf = (circbuffer*)m_malloc(sizeof(circbuffer));
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/* data is malloced on first write */
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cbuf->data = NULL;
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cbuf->used = 0;
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cbuf->readpos = 0;
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cbuf->writepos = 0;
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cbuf->size = size;
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return cbuf;
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}
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void cbuf_free(circbuffer * cbuf) {
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if (cbuf->data) {
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m_burn(cbuf->data, cbuf->size);
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m_free(cbuf->data);
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}
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m_free(cbuf);
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}
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unsigned int cbuf_getused(const circbuffer * cbuf) {
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return cbuf->used;
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}
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unsigned int cbuf_getavail(const circbuffer * cbuf) {
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return cbuf->size - cbuf->used;
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}
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unsigned int cbuf_writelen(const circbuffer *cbuf) {
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dropbear_assert(cbuf->used <= cbuf->size);
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dropbear_assert(((2*cbuf->size)+cbuf->writepos-cbuf->readpos)%cbuf->size == cbuf->used%cbuf->size);
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dropbear_assert(((2*cbuf->size)+cbuf->readpos-cbuf->writepos)%cbuf->size == (cbuf->size-cbuf->used)%cbuf->size);
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if (cbuf->used == cbuf->size) {
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TRACE(("cbuf_writelen: full buffer"))
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return 0; /* full */
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}
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if (cbuf->writepos < cbuf->readpos) {
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return cbuf->readpos - cbuf->writepos;
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}
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return cbuf->size - cbuf->writepos;
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}
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void cbuf_readptrs(const circbuffer *cbuf,
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unsigned char **p1, unsigned int *len1,
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unsigned char **p2, unsigned int *len2) {
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*p1 = &cbuf->data[cbuf->readpos];
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*len1 = MIN(cbuf->used, cbuf->size - cbuf->readpos);
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if (*len1 < cbuf->used) {
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*p2 = cbuf->data;
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*len2 = cbuf->used - *len1;
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} else {
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*p2 = NULL;
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*len2 = 0;
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}
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}
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unsigned char* cbuf_writeptr(circbuffer *cbuf, unsigned int len) {
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if (len > cbuf_writelen(cbuf)) {
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dropbear_exit("Bad cbuf write");
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}
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if (!cbuf->data) {
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/* lazy allocation */
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cbuf->data = (unsigned char*)m_malloc(cbuf->size);
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}
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return &cbuf->data[cbuf->writepos];
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}
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void cbuf_incrwrite(circbuffer *cbuf, unsigned int len) {
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if (len > cbuf_writelen(cbuf)) {
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dropbear_exit("Bad cbuf write");
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}
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cbuf->used += len;
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dropbear_assert(cbuf->used <= cbuf->size);
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cbuf->writepos = (cbuf->writepos + len) % cbuf->size;
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}
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void cbuf_incrread(circbuffer *cbuf, unsigned int len) {
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dropbear_assert(cbuf->used >= len);
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cbuf->used -= len;
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cbuf->readpos = (cbuf->readpos + len) % cbuf->size;
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}
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