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115 lines
3.7 KiB
C
115 lines
3.7 KiB
C
4 years ago
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/*
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ChibiOS - Copyright (C) 2006..2018 Giovanni Di Sirio
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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/**
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* @file memstreams.c
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* @brief Memory streams code.
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*
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* @addtogroup HAL_MEMORY_STREAMS
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* @details Memory buffers handled as streams.
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* @{
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*/
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#include <string.h>
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#include "hal.h"
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#include "memstreams.h"
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/*===========================================================================*/
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/* Driver local definitions. */
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/*===========================================================================*/
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/*===========================================================================*/
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/* Driver exported variables. */
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/*===========================================================================*/
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/*===========================================================================*/
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/* Driver local variables. */
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/*===========================================================================*/
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/*===========================================================================*/
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/* Driver local functions. */
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/*===========================================================================*/
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static size_t _writes(void *ip, const uint8_t *bp, size_t n) {
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MemoryStream *msp = ip;
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if (msp->size - msp->eos < n)
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n = msp->size - msp->eos;
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memcpy(msp->buffer + msp->eos, bp, n);
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msp->eos += n;
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return n;
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}
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static size_t _reads(void *ip, uint8_t *bp, size_t n) {
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MemoryStream *msp = ip;
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if (msp->eos - msp->offset < n)
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n = msp->eos - msp->offset;
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memcpy(bp, msp->buffer + msp->offset, n);
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msp->offset += n;
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return n;
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}
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static msg_t _put(void *ip, uint8_t b) {
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MemoryStream *msp = ip;
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if (msp->size - msp->eos <= 0)
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return MSG_RESET;
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*(msp->buffer + msp->eos) = b;
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msp->eos += 1;
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return MSG_OK;
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}
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static msg_t _get(void *ip) {
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uint8_t b;
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MemoryStream *msp = ip;
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if (msp->eos - msp->offset <= 0)
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return MSG_RESET;
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b = *(msp->buffer + msp->offset);
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msp->offset += 1;
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return b;
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}
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static const struct MemStreamVMT vmt = {(size_t)0, _writes, _reads, _put, _get};
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/*===========================================================================*/
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/* Driver exported functions. */
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/*===========================================================================*/
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/**
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* @brief Memory stream object initialization.
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*
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* @param[out] msp pointer to the @p MemoryStream object to be initialized
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* @param[in] buffer pointer to the memory buffer for the memory stream
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* @param[in] size total size of the memory stream buffer
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* @param[in] eos initial End Of Stream offset. Normally you need to
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* put this to zero for RAM buffers or equal to @p size
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* for ROM streams.
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*/
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void msObjectInit(MemoryStream *msp, uint8_t *buffer,
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size_t size, size_t eos) {
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msp->vmt = &vmt;
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msp->buffer = buffer;
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msp->size = size;
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msp->eos = eos;
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msp->offset = 0;
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}
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/** @} */
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