amiro-os / os / core / src / aos_ssm.c @ e545e620
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/*
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AMiRo-OS is an operating system designed for the Autonomous Mini Robot (AMiRo) platform.
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Copyright (C) 2016..2018 Thomas Schöpping et al.
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <aos_ssm.h> |
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/**
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* @brief Sequential Stream Multiplexer write.
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*
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* @param[in] ip pointer to a @p SequentialStreamMux object
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* @param[in] bp pointer to the data buffer
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* @param[in] n the maximum amount of bytes to be transferred
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*
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* @return The minimum number of bytes written to one of the BaseSequentialStreams.
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* If the return value is lower than n, one or multiple (or even all) streams could not write all bytes as requested.
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*/
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static size_t write(void *ip, const uint8_t *bp, size_t n) |
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{ |
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// initialize the number of written bytes
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size_t outbytes = ~0;
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// iterate over all output streams associated with te mux
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ssm_output_t* out = ((SequentialStreamMux*)ip)->outputs; |
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while (out != NULL) { |
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// if the output is enabled
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if (out->flags | SSM_OUTPUT_FLAG_ENABLED) {
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// write to the stream
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register const size_t ob = streamWrite(out->stream, bp, n); |
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// retrieve the minimal number of bytes written across all streams
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outbytes = (ob < outbytes) ? ob : outbytes; |
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} |
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// iterate to the next stream
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out = out->next; |
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} |
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return (outbytes == (size_t)~0) ? 0 : outbytes; |
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} |
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/**
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* @brief Sequential Stream Multiplexer read.
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*
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* @param[in] ip pointer to a @p SequentialStreamMux object
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* @param[out] bp pointer to the data buffer
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* @param[in] n the maximum amount of data to be transferred
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*
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* @return The number of bytes transferred.
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*/
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static size_t read(void *ip, uint8_t *bp, size_t n) |
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{ |
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// check whether a input stream is set
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if ( ((SequentialStreamMux*)ip)->input != NULL ) { |
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// read from the input stream
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return streamRead(((SequentialStreamMux*)ip)->input, bp, n);
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} else {
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// return zero since
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return 0; |
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} |
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} |
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/**
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* @brief Sequential Stream Multiplexer blocking byte write
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*
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* @param[in] ip pointer to a @p SequentialStreamMux object
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* @param[in] b the byte value to be written
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*
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* @return The operation status.
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* The operation status is ORed from all enabled output streams.
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* The operation status of each output stream depends on its implementation.
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*/
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static msg_t put(void *ip, uint8_t b) |
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{ |
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// initialize the return value
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msg_t retval = MSG_OK; |
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// iterate over all output streams associated with the mux
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ssm_output_t* out = ((SequentialStreamMux*)ip)->outputs; |
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while (out != NULL) { |
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// if the output is enabled
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if (out->flags | SSM_OUTPUT_FLAG_ENABLED) {
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// put the given byte on the stream
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retval |= streamPut(out->stream, b); |
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} |
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// iterate to rhe next stream
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out = out->next; |
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} |
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return retval;
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} |
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/**
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* @brief Sequential Stream Multiplexer blocking byte read
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*
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* @param[in] ip pointer to the @p SequentialStreamMux object
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*
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* @return A byte value from the input.
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*/
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static msg_t get(void *ip) |
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{ |
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// check whether an input is set
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if ( ((SequentialStreamMux*)ip)->input != NULL) { |
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// get a byte from the input
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return streamGet(((SequentialStreamMux*)ip)->input);
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} else {
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// return an error
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return MSG_RESET;
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} |
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} |
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static const struct SequentialStreamMuxVMT vmt = { |
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write, read, put, get |
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}; |
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/**
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* @brief Initializes a @p SequentialStreamMux object
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*
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* @param[in] ssmp pointer to the @p SequentialStreamMux object
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*/
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void ssmObjectInit(SequentialStreamMux *ssmp)
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{ |
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aosDbgCheck(ssmp != NULL);
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// initialize object variables
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ssmp->vmt = &vmt; |
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ssmp->outputs = NULL;
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ssmp->input = NULL;
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return;
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} |
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/**
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* @brief Initializes a @p ssm_output_t object
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*
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* @param[in] op pointer to the @p ssm_output_t object
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*/
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void ssmOutputInit(ssm_output_t* op, BaseSequentialStream* stream)
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{ |
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aosDbgCheck(op != NULL);
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// initialize object variables
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op->stream = stream; |
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op->next = NULL;
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op->flags = 0;
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return;
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} |
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/**
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* @brief Adds an output to the SSM object.
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* @note New outputs are always prepended to the list.
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*
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* @param[in] ssmp pointer to the @p SequentialStreamMux object to be modified
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* @param[in] output pointer to the @p ssm_output_t object to be inserted
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*/
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void ssmAddOutput(SequentialStreamMux* ssmp, ssm_output_t* output)
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{ |
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aosDbgCheck(ssmp != NULL);
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aosDbgCheck(output != NULL);
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aosDbgCheck(output->next == NULL && output->flags ^ SSM_OUTPUT_FLAG_ATTACHED);
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// prepend output to the list
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output->flags = SSM_OUTPUT_FLAG_ATTACHED; |
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output->next = ssmp->outputs; |
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ssmp->outputs = output; |
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return;
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} |
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/**
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* @brief Removes an output from the SSM object.
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*
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* @param[in] ssmp pointer to the @p SequentialStreamMux object to be modified
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* @param[in] stream pointer to the @p BaseSequentialStream to remove
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* @param[out] removed pointer to the @p ssm_output_t that was removed, or NULL
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*
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* @return Error code indicating any errors or warnings.
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* @retval AOS_SUCCESS the stream was removed sucessfully
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* @retval AOS_ERROR the stream was not found in the list
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*/
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aos_status_t ssmRemoveOutput(SequentialStreamMux* ssmp, BaseSequentialStream* stream, ssm_output_t** removed) |
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{ |
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aosDbgCheck(ssmp != NULL);
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aosDbgCheck(stream != NULL);
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// local varibales
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ssm_output_t* prev = NULL;
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ssm_output_t* curr = ssmp->outputs; |
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// iterate through the list and search for the specified stream
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while (curr != NULL) { |
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// if the stream was found, remove it
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if (curr->stream == stream) {
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// special case: the first stream matches
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if (prev == NULL) { |
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ssmp->outputs->next = curr->next; |
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} else {
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prev->next = curr->next; |
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} |
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curr->next = NULL;
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curr->flags &= ~SSM_OUTPUT_FLAG_ATTACHED; |
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// set the optional output argument
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if (removed != NULL) { |
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*removed = curr; |
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} |
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return AOS_SUCCESS;
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} |
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// iterate through to the next item
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else {
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prev = curr; |
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curr = curr->next; |
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} |
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} |
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// if the stream was not found, return an error
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return AOS_ERROR;
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} |
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/**
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* @brief Enable an associated stream
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*
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* @param[in] ssmp pointer to the @p SequentialStreamMux object
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* @param[in] stream pointer to the @p BaseSequentialStream to enable
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*
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* @return The operation status.
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* @retval AOS_SUCCESS if the operation succeeded.
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* @retval AOS_ERROR if the specified stream is not associated to the @p SequentialStreamMux.
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*/
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aos_status_t ssmEnableOutput(SequentialStreamMux *ssmp, BaseSequentialStream *stream) |
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{ |
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aosDbgCheck(ssmp != NULL);
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aosDbgCheck(stream != NULL);
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// iterate over all output streams associated to the given mux
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ssm_output_t* out = ssmp->outputs; |
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while (out != NULL) { |
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// if the output was found, activate the enabled flag
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if (out->stream == stream) {
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out->flags |= SSM_OUTPUT_FLAG_ENABLED; |
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return AOS_SUCCESS;
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} else {
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out = out->next; |
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} |
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} |
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// error if the stream is not associated with the mux
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return AOS_ERROR;
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} |
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/**
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* @brief Disable an associated stream
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*
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* @param[in] ssmp pointer to the @p SequentialStreamMux or derived class
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* @param[in] stream pointer to the stream to disable
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*
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*
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* @return The operation status.
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* @retval AOS_OK if the operation succeeded.
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* @retval AOS_ERROR if the specified stream is not associated to the @p SequentialStreamMux.
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*/
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aos_status_t ssmDisableOutput(SequentialStreamMux *ssmp, BaseSequentialStream *stream) |
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{ |
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aosDbgCheck(ssmp != NULL);
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aosDbgCheck(stream != NULL);
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// iterate over all output streams associated to the given mux
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ssm_output_t* out = ssmp->outputs; |
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while (out != NULL) { |
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// if the output was found, activate the enabled flag
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if (out->stream == stream) {
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out->flags &= ~SSM_OUTPUT_FLAG_ENABLED; |
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return AOS_SUCCESS;
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} else {
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out = out->next; |
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} |
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} |
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// error if the stream is not associated with the mux
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return AOS_ERROR;
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} |