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/*
ChibiOS/RT - Copyright (C) 2006-2013 Giovanni Di Sirio
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
/**
* @file memstreams.c
* @brief Memory streams code.
*
* @addtogroup memory_streams
* @{
*/
#include <string.h>
#include "ch.h"
#include "memstreams.h"
/*===========================================================================*/
/* Driver local definitions. */
/*===========================================================================*/
/*===========================================================================*/
/* Driver exported variables. */
/*===========================================================================*/
/*===========================================================================*/
/* Driver local variables. */
/*===========================================================================*/
/*===========================================================================*/
/* Driver local functions. */
/*===========================================================================*/
static size_t writes(void *ip, const uint8_t *bp, size_t n) {
MemoryStream *msp = ip;
if (msp->size - msp->eos < n)
n = msp->size - msp->eos;
memcpy(msp->buffer + msp->eos, bp, n);
msp->eos += n;
return n;
}
static size_t reads(void *ip, uint8_t *bp, size_t n) {
MemoryStream *msp = ip;
if (msp->eos - msp->offset < n)
n = msp->eos - msp->offset;
memcpy(bp, msp->buffer + msp->offset, n);
msp->offset += n;
return n;
}
static msg_t put(void *ip, uint8_t b) {
MemoryStream *msp = ip;
if (msp->size - msp->eos <= 0)
return MSG_RESET;
*(msp->buffer + msp->eos) = b;
msp->eos += 1;
return MSG_OK;
}
static msg_t get(void *ip) {
uint8_t b;
MemoryStream *msp = ip;
if (msp->eos - msp->offset <= 0)
return MSG_RESET;
b = *(msp->buffer + msp->offset);
msp->offset += 1;
return b;
}
static const struct MemStreamVMT vmt = {writes, reads, put, get};
/*===========================================================================*/
/* Driver exported functions. */
/*===========================================================================*/
/**
* @brief Memory stream object initialization.
*
* @param[out] msp pointer to the @p MemoryStream object to be initialized
* @param[in] buffer pointer to the memory buffer for the memory stream
* @param[in] size total size of the memory stream buffer
* @param[in] eos initial End Of Stream offset. Normally you need to
* put this to zero for RAM buffers or equal to @p size
* for ROM streams.
*/
void msObjectInit(MemoryStream *msp, uint8_t *buffer,
size_t size, size_t eos) {
msp->vmt = &vmt;
msp->buffer = buffer;
msp->size = size;
msp->eos = eos;
msp->offset = 0;
}
/** @} */
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