unleashed-firmware/furi/core/stream_buffer.h

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/**
* @file stream_buffer.h
* Furi stream buffer primitive.
*
* Stream buffers are used to send a continuous stream of data from one task or
* interrupt to another. Their implementation is light weight, making them
* particularly suited for interrupt to task and core to core communication
* scenarios.
*
* ***NOTE***: Stream buffer implementation assumes there is only one task or
* interrupt that will write to the buffer (the writer), and only one task or
* interrupt that will read from the buffer (the reader).
*/
#pragma once
#include <stdint.h>
#include <stddef.h>
#ifdef __cplusplus
extern "C" {
#endif
typedef void FuriStreamBuffer;
/**
* @brief Allocate stream buffer instance.
* Stream buffer implementation assumes there is only one task or
* interrupt that will write to the buffer (the writer), and only one task or
* interrupt that will read from the buffer (the reader).
*
* @param size The total number of bytes the stream buffer will be able to hold at any one time.
* @param trigger_level The number of bytes that must be in the stream buffer
* before a task that is blocked on the stream buffer to wait for data is moved out of the blocked state.
* @return The stream buffer instance.
*/
FuriStreamBuffer* furi_stream_buffer_alloc(size_t size, size_t trigger_level);
/**
* @brief Free stream buffer instance
*
* @param stream_buffer The stream buffer instance.
*/
void furi_stream_buffer_free(FuriStreamBuffer* stream_buffer);
/**
* @brief Set trigger level for stream buffer.
* A stream buffer's trigger level is the number of bytes that must be in the
* stream buffer before a task that is blocked on the stream buffer to
* wait for data is moved out of the blocked state.
*
* @param stream_buffer The stream buffer instance
* @param trigger_level The new trigger level for the stream buffer.
* @return true if trigger level can be be updated (new trigger level was less than or equal to the stream buffer's length).
* @return false if trigger level can't be be updated (new trigger level was greater than the stream buffer's length).
*/
bool furi_stream_set_trigger_level(FuriStreamBuffer* stream_buffer, size_t trigger_level);
/**
* @brief Sends bytes to a stream buffer. The bytes are copied into the stream buffer.
* Wakes up task waiting for data to become available if called from ISR.
*
* @param stream_buffer The stream buffer instance.
* @param data A pointer to the data that is to be copied into the stream buffer.
* @param length The maximum number of bytes to copy from data into the stream buffer.
* @param timeout The maximum amount of time the task should remain in the
* Blocked state to wait for space to become available if the stream buffer is full.
* Will return immediately if timeout is zero.
* Setting timeout to FuriWaitForever will cause the task to wait indefinitely.
* Ignored if called from ISR.
* @return The number of bytes actually written to the stream buffer.
*/
size_t furi_stream_buffer_send(
FuriStreamBuffer* stream_buffer,
const void* data,
size_t length,
uint32_t timeout);
/**
* @brief Receives bytes from a stream buffer.
* Wakes up task waiting for space to become available if called from ISR.
*
* @param stream_buffer The stream buffer instance.
* @param data A pointer to the buffer into which the received bytes will be
* copied.
* @param length The length of the buffer pointed to by the data parameter.
* @param timeout The maximum amount of time the task should remain in the
* Blocked state to wait for data to become available if the stream buffer is empty.
* Will return immediately if timeout is zero.
* Setting timeout to FuriWaitForever will cause the task to wait indefinitely.
* Ignored if called from ISR.
* @return The number of bytes read from the stream buffer, if any.
*/
size_t furi_stream_buffer_receive(
FuriStreamBuffer* stream_buffer,
void* data,
size_t length,
uint32_t timeout);
/**
* @brief Queries a stream buffer to see how much data it contains, which is equal to
* the number of bytes that can be read from the stream buffer before the stream
* buffer would be empty.
*
* @param stream_buffer The stream buffer instance.
* @return The number of bytes that can be read from the stream buffer before
* the stream buffer would be empty.
*/
size_t furi_stream_buffer_bytes_available(FuriStreamBuffer* stream_buffer);
/**
* @brief Queries a stream buffer to see how much free space it contains, which is
* equal to the amount of data that can be sent to the stream buffer before it
* is full.
*
* @param stream_buffer The stream buffer instance.
* @return The number of bytes that can be written to the stream buffer before
* the stream buffer would be full.
*/
size_t furi_stream_buffer_spaces_available(FuriStreamBuffer* stream_buffer);
/**
* @brief Queries a stream buffer to see if it is full.
*
* @param stream_buffer stream buffer instance.
* @return true if the stream buffer is full.
* @return false if the stream buffer is not full.
*/
bool furi_stream_buffer_is_full(FuriStreamBuffer* stream_buffer);
/**
* @brief Queries a stream buffer to see if it is empty.
*
* @param stream_buffer The stream buffer instance.
* @return true if the stream buffer is empty.
* @return false if the stream buffer is not empty.
*/
bool furi_stream_buffer_is_empty(FuriStreamBuffer* stream_buffer);
/**
* @brief Resets a stream buffer to its initial, empty, state. Any data that was
* in the stream buffer is discarded. A stream buffer can only be reset if there
* are no tasks blocked waiting to either send to or receive from the stream buffer.
*
* @param stream_buffer The stream buffer instance.
* @return FuriStatusOk if the stream buffer is reset.
* @return FuriStatusError if there was a task blocked waiting to send to or read
* from the stream buffer then the stream buffer is not reset.
*/
FuriStatus furi_stream_buffer_reset(FuriStreamBuffer* stream_buffer);
#ifdef __cplusplus
}
#endif