esp-idf/components/freertos/ringbuf.c

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// Copyright 2015-2016 Espressif Systems (Shanghai) PTE LTD
//
// 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.
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "freertos/semphr.h"
#include "freertos/queue.h"
#include "freertos/xtensa_api.h"
#include "freertos/ringbuf.h"
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#include "esp_attr.h"
#include <stdint.h>
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
typedef enum {
flag_allowsplit = 1,
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flag_bytebuf = 2,
} rbflag_t;
typedef enum {
iflag_free = 1, //Buffer is not read and given back by application, free to overwrite
iflag_dummydata = 2, //Data from here to end of ringbuffer is dummy. Restart reading at start of ringbuffer.
iflag_wrap = 4, //Valid for RINGBUF_TYPE_ALLOWSPLIT, indicating that rest of the data is wrapped around
} itemflag_t;
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typedef struct ringbuf_t ringbuf_t;
//The ringbuffer structure
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struct ringbuf_t {
SemaphoreHandle_t free_space_sem; //Binary semaphore, wakes up writing threads when there's more free space
SemaphoreHandle_t items_buffered_sem; //Binary semaphore, indicates there are new packets in the circular buffer. See remark.
size_t size; //Size of the data storage
uint8_t *write_ptr; //Pointer where the next item is written
uint8_t *read_ptr; //Pointer from where the next item is read
uint8_t *free_ptr; //Pointer to the last block that hasn't been given back to the ringbuffer yet
uint8_t *data; //Data storage
portMUX_TYPE mux; //Spinlock for actual data/ptr/struct modification
rbflag_t flags;
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size_t maxItemSize;
//The following keep function pointers to hold different implementations for ringbuffer management.
BaseType_t (*copyItemToRingbufImpl)(ringbuf_t *rb, uint8_t *buffer, size_t buffer_size);
uint8_t *(*getItemFromRingbufImpl)(ringbuf_t *rb, size_t *length, int wanted_length);
void (*returnItemToRingbufImpl)(ringbuf_t *rb, void *item);
size_t (*getFreeSizeImpl)(ringbuf_t *rb);
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};
/*
Remark: A counting semaphore for items_buffered_sem would be more logical, but counting semaphores in
FreeRTOS need a maximum count, and allocate more memory the larger the maximum count is. Here, we
would need to set the maximum to the maximum amount of times a null-byte unit firs in the buffer,
which is quite high and so would waste a fair amount of memory.
*/
//The header prepended to each ringbuffer entry. Size is assumed to be a multiple of 32bits.
typedef struct {
size_t len;
itemflag_t flags;
} buf_entry_hdr_t;
//Calculate space free in the buffer
static int ringbufferFreeMem(ringbuf_t *rb)
{
int free_size = rb->free_ptr-rb->write_ptr;
if (free_size <= 0) free_size += rb->size;
//Reserve one byte. If we do not do this and the entire buffer is filled, we get a situation
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//where read_ptr == free_ptr, messing up the next calculation.
return free_size-1;
}
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//Copies a single item to the ring buffer; refuses to split items. Assumes there is space in the ringbuffer and
//the ringbuffer is locked. Increases write_ptr to the next item. Returns pdTRUE on
//success, pdFALSE if it can't make the item fit and the calling routine needs to retry
//later or fail.
//This function by itself is not threadsafe, always call from within a muxed section.
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static BaseType_t copyItemToRingbufNoSplit(ringbuf_t *rb, uint8_t *buffer, size_t buffer_size)
{
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size_t rbuffer_size;
rbuffer_size=(buffer_size+3)&~3; //Payload length, rounded to next 32-bit value
configASSERT(((int)rb->write_ptr&3)==0); //write_ptr needs to be 32-bit aligned
configASSERT(rb->write_ptr-(rb->data+rb->size) >= sizeof(buf_entry_hdr_t)); //need to have at least the size
//of a header to the end of the ringbuff
size_t rem_len=(rb->data + rb->size) - rb->write_ptr; //length remaining until end of ringbuffer
//See if we have enough contiguous space to write the buffer.
if (rem_len < rbuffer_size + sizeof(buf_entry_hdr_t)) {
//Buffer plus header is not going to fit in the room from wr_pos to the end of the
//ringbuffer... but we're not allowed to split the buffer. We need to fill the
//rest of the ringbuffer with a dummy item so we can place the data at the _start_ of
//the ringbuffer..
//First, find out if we actually have enough space at the start of the ringbuffer to
//make this work (Again, we need 4 bytes extra because otherwise read_ptr==free_ptr)
if (rb->free_ptr-rb->data < rbuffer_size+sizeof(buf_entry_hdr_t)+4) {
//Will not fit.
return pdFALSE;
}
//If the read buffer hasn't wrapped around yet, there's no way this will work either.
if (rb->free_ptr > rb->write_ptr) {
//No luck.
return pdFALSE;
}
//Okay, it will fit. Mark the rest of the ringbuffer space with a dummy packet.
buf_entry_hdr_t *hdr=(buf_entry_hdr_t *)rb->write_ptr;
hdr->flags=iflag_dummydata;
//Reset the write pointer to the start of the ringbuffer so the code later on can
//happily write the data.
rb->write_ptr=rb->data;
} else {
//No special handling needed. Checking if it's gonna fit probably still is a good idea.
if (ringbufferFreeMem(rb) < sizeof(buf_entry_hdr_t)+rbuffer_size) {
//Buffer is not going to fit, period.
return pdFALSE;
}
}
//If we are here, the buffer is guaranteed to fit in the space starting at the write pointer.
buf_entry_hdr_t *hdr=(buf_entry_hdr_t *)rb->write_ptr;
hdr->len=buffer_size;
hdr->flags=0;
rb->write_ptr+=sizeof(buf_entry_hdr_t);
memcpy(rb->write_ptr, buffer, buffer_size);
rb->write_ptr+=rbuffer_size;
//The buffer will wrap around if we don't have room for a header anymore.
if ((rb->data+rb->size)-rb->write_ptr < sizeof(buf_entry_hdr_t)) {
//'Forward' the write buffer until we are at the start of the ringbuffer.
//The read pointer will always be at the start of a full header, which cannot
//exist at the point of the current write pointer, so there's no chance of overtaking
//that.
rb->write_ptr=rb->data;
}
return pdTRUE;
}
//Copies a single item to the ring buffer; allows split items. Assumes there is space in the ringbuffer and
//the ringbuffer is locked. Increases write_ptr to the next item. Returns pdTRUE on
//success, pdFALSE if it can't make the item fit and the calling routine needs to retry
//later or fail.
//This function by itself is not threadsafe, always call from within a muxed section.
static BaseType_t copyItemToRingbufAllowSplit(ringbuf_t *rb, uint8_t *buffer, size_t buffer_size)
{
size_t rbuffer_size;
rbuffer_size=(buffer_size+3)&~3; //Payload length, rounded to next 32-bit value
configASSERT(((int)rb->write_ptr&3)==0); //write_ptr needs to be 32-bit aligned
configASSERT(rb->write_ptr-(rb->data+rb->size) >= sizeof(buf_entry_hdr_t)); //need to have at least the size
//of a header to the end of the ringbuff
size_t rem_len=(rb->data + rb->size) - rb->write_ptr; //length remaining until end of ringbuffer
//See if we have enough contiguous space to write the buffer.
if (rem_len < rbuffer_size + sizeof(buf_entry_hdr_t)) {
//The buffer can't be contiguously written to the ringbuffer, but needs special handling. Do
//that depending on how the ringbuffer is configured.
//The code here is also expected to check if the buffer, mangled in whatever way is implemented,
//will still fit, and return pdFALSE if that is not the case.
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//Buffer plus header is not going to fit in the room from wr_pos to the end of the
//ringbuffer... we need to split the write in two.
//First, see if this will fit at all.
if (ringbufferFreeMem(rb) < (sizeof(buf_entry_hdr_t)*2)+rbuffer_size) {
//Will not fit.
return pdFALSE;
}
//Because the code at the end of the function makes sure we always have
//room for a header, this should never assert.
configASSERT(rem_len>=sizeof(buf_entry_hdr_t));
//Okay, it should fit. Write everything.
//First, place bit of buffer that does fit. Write header first...
buf_entry_hdr_t *hdr=(buf_entry_hdr_t *)rb->write_ptr;
hdr->flags=0;
hdr->len=rem_len-sizeof(buf_entry_hdr_t);
rb->write_ptr+=sizeof(buf_entry_hdr_t);
rem_len-=sizeof(buf_entry_hdr_t);
if (rem_len!=0) {
//..then write the data bit that fits.
memcpy(rb->write_ptr, buffer, rem_len);
//Update vars so the code later on will write the rest of the data.
buffer+=rem_len;
buffer_size-=rem_len;
//Re-adjust the rbuffer value to be 4 byte aligned
rbuffer_size=(buffer_size+3)&~3;
//It is possible that we are here because we checked for 4byte aligned
//size, but actual data was smaller.
//Eg. For buffer_size = 34, rbuffer_size will be 36. Suppose we had only
//42 bytes of memory available, the top level check will fail, as it will
//check for availability of 36 + 8 = 44 bytes.
//However, the 42 bytes available memory is sufficient for 34 + 8 bytes data
//and so, we can return after writing the data. Hence, this check
if (buffer_size == 0) {
rb->write_ptr=rb->data;
return pdTRUE;
} else {
/* Indicate the wrapping */
hdr->flags|=iflag_wrap;
}
} else {
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//Huh, only the header fit. Mark as dummy so the receive function doesn't receive
//an useless zero-byte packet.
hdr->flags|=iflag_dummydata;
}
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rb->write_ptr=rb->data;
} else {
//No special handling needed. Checking if it's gonna fit probably still is a good idea.
if (ringbufferFreeMem(rb) < sizeof(buf_entry_hdr_t)+rbuffer_size) {
//Buffer is not going to fit, period.
return pdFALSE;
}
}
//If we are here, the buffer is guaranteed to fit in the space starting at the write pointer.
buf_entry_hdr_t *hdr=(buf_entry_hdr_t *)rb->write_ptr;
hdr->len=buffer_size;
hdr->flags=0;
rb->write_ptr+=sizeof(buf_entry_hdr_t);
memcpy(rb->write_ptr, buffer, buffer_size);
rb->write_ptr+=rbuffer_size;
//The buffer will wrap around if we don't have room for a header anymore.
if ((rb->data+rb->size)-rb->write_ptr < sizeof(buf_entry_hdr_t)) {
//'Forward' the write buffer until we are at the start of the ringbuffer.
//The read pointer will always be at the start of a full header, which cannot
//exist at the point of the current write pointer, so there's no chance of overtaking
//that.
rb->write_ptr=rb->data;
}
return pdTRUE;
}
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//Copies a bunch of daya to the ring bytebuffer. Assumes there is space in the ringbuffer and
//the ringbuffer is locked. Increases write_ptr to the next item. Returns pdTRUE on
//success, pdFALSE if it can't make the item fit and the calling routine needs to retry
//later or fail.
//This function by itself is not threadsafe, always call from within a muxed section.
static BaseType_t copyItemToRingbufByteBuf(ringbuf_t *rb, uint8_t *buffer, size_t buffer_size)
{
size_t rem_len=(rb->data + rb->size) - rb->write_ptr; //length remaining until end of ringbuffer
//See if we have enough contiguous space to write the buffer.
if (rem_len < buffer_size) {
//...Nope. Write the data bit that fits.
memcpy(rb->write_ptr, buffer, rem_len);
//Update vars so the code later on will write the rest of the data.
buffer+=rem_len;
buffer_size-=rem_len;
rb->write_ptr=rb->data;
}
//If we are here, the buffer is guaranteed to fit in the space starting at the write pointer.
memcpy(rb->write_ptr, buffer, buffer_size);
rb->write_ptr+=buffer_size;
//The buffer will wrap around if we're at the end.
if ((rb->data+rb->size)==rb->write_ptr) {
rb->write_ptr=rb->data;
}
return pdTRUE;
}
//Retrieves a pointer to the data of the next item, or NULL if this is not possible.
//This function by itself is not threadsafe, always call from within a muxed section.
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//Because we always return one item, this function ignores the wanted_length variable.
static uint8_t *getItemFromRingbufDefault(ringbuf_t *rb, size_t *length, int wanted_length)
{
uint8_t *ret;
configASSERT(((int)rb->read_ptr&3)==0);
if (rb->read_ptr == rb->write_ptr) {
//No data available.
return NULL;
}
//The item written at the point of the read pointer may be a dummy item.
//We need to skip past it first, if that's the case.
buf_entry_hdr_t *hdr=(buf_entry_hdr_t *)rb->read_ptr;
configASSERT((hdr->len < rb->size) || (hdr->flags & iflag_dummydata));
if (hdr->flags & iflag_dummydata) {
//Hdr is dummy data. Reset to start of ringbuffer.
rb->read_ptr=rb->data;
//Get real header
hdr=(buf_entry_hdr_t *)rb->read_ptr;
configASSERT(hdr->len < rb->size);
//No need to re-check if the ringbuffer is empty: the write routine will
//always write a dummy item plus the real data item in one go, so now we must
//be at the real data item by definition.
}
//Okay, pass the data back.
ret=rb->read_ptr+sizeof(buf_entry_hdr_t);
*length=hdr->len;
//...and move the read pointer past the data.
rb->read_ptr+=sizeof(buf_entry_hdr_t)+((hdr->len+3)&~3);
//The buffer will wrap around if we don't have room for a header anymore.
//Integer typecasting is used because the first operand can result into a -ve
//value for cases wherein the ringbuffer size is not a multiple of 4, but the
//implementation logic aligns read_ptr to 4-byte boundary
if ((int)((rb->data + rb->size) - rb->read_ptr) < (int)sizeof(buf_entry_hdr_t)) {
rb->read_ptr=rb->data;
}
return ret;
}
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//Retrieves a pointer to the data in the buffer, or NULL if this is not possible.
//This function by itself is not threadsafe, always call from within a muxed section.
//This function honours the wanted_length and will never return more data than this.
static uint8_t *getItemFromRingbufByteBuf(ringbuf_t *rb, size_t *length, int wanted_length)
{
uint8_t *ret;
if (rb->read_ptr != rb->free_ptr) {
//This type of ringbuff does not support multiple outstanding buffers.
return NULL;
}
if (rb->read_ptr == rb->write_ptr) {
//No data available.
return NULL;
}
ret=rb->read_ptr;
if (rb->read_ptr > rb->write_ptr) {
//Available data wraps around. Give data until the end of the buffer.
*length=rb->size-(rb->read_ptr - rb->data);
if (wanted_length != 0 && *length > wanted_length) {
*length=wanted_length;
rb->read_ptr+=wanted_length;
} else {
rb->read_ptr=rb->data;
}
} else {
//Return data up to write pointer.
*length=rb->write_ptr -rb->read_ptr;
if (wanted_length != 0 && *length > wanted_length) {
*length=wanted_length;
rb->read_ptr+=wanted_length;
} else {
rb->read_ptr=rb->write_ptr;
}
}
return ret;
}
//Returns an item to the ringbuffer. Will mark the item as free, and will see if the free pointer
//can be increase.
//This function by itself is not threadsafe, always call from within a muxed section.
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static void returnItemToRingbufDefault(ringbuf_t *rb, void *item) {
uint8_t *data=(uint8_t*)item;
configASSERT(((int)rb->free_ptr&3)==0);
configASSERT(data >= rb->data);
configASSERT(data <= rb->data+rb->size);
//Grab the buffer entry that preceeds the buffer
buf_entry_hdr_t *hdr=(buf_entry_hdr_t*)(data-sizeof(buf_entry_hdr_t));
configASSERT(hdr->len < rb->size);
configASSERT((hdr->flags & iflag_dummydata)==0);
configASSERT((hdr->flags & iflag_free)==0);
//Mark the buffer as free.
hdr->flags&=~iflag_wrap;
hdr->flags|=iflag_free;
//Do a cleanup pass.
hdr=(buf_entry_hdr_t *)rb->free_ptr;
//basically forward free_ptr until we run into either a block that is still in use or the write pointer.
while (((hdr->flags & iflag_free) || (hdr->flags & iflag_dummydata)) && rb->free_ptr != rb->write_ptr) {
if (hdr->flags & iflag_dummydata) {
//Rest is dummy data. Reset to start of ringbuffer.
rb->free_ptr=rb->data;
} else {
//Skip past item
rb->free_ptr+=sizeof(buf_entry_hdr_t);
//Check if the free_ptr overshoots the buffer.
//Checking this before aligning free_ptr since it is possible that alignment
//will cause pointer to overshoot, if the ringbuf size is not a multiple of 4
configASSERT(rb->free_ptr+hdr->len<=rb->data+rb->size);
//Align free_ptr to 4 byte boundary. Overshoot condition will result in wrap around below
size_t len=(hdr->len+3)&~3;
rb->free_ptr+=len;
}
//The buffer will wrap around if we don't have room for a header anymore.
//Integer typecasting is used because the first operand can result into a -ve
//value for cases wherein the ringbuffer size is not a multiple of 4, but the
//implementation logic aligns free_ptr to 4-byte boundary
if ((int)((rb->data+rb->size)-rb->free_ptr) < (int)sizeof(buf_entry_hdr_t)) {
rb->free_ptr=rb->data;
}
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//The free_ptr can not exceed read_ptr, otherwise write_ptr might overwrite read_ptr.
//Read_ptr can not set to rb->data with free_ptr, otherwise write_ptr might wrap around to rb->data.
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if(rb->free_ptr == rb->read_ptr) break;
//Next header
hdr=(buf_entry_hdr_t *)rb->free_ptr;
}
}
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//Returns an item to the ringbuffer. Will mark the item as free, and will see if the free pointer
//can be increase.
//This function by itself is not threadsafe, always call from within a muxed section.
static void returnItemToRingbufBytebuf(ringbuf_t *rb, void *item) {
configASSERT((uint8_t *)item >= rb->data);
configASSERT((uint8_t *)item < rb->data+rb->size);
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//Free the read memory.
rb->free_ptr=rb->read_ptr;
}
void xRingbufferPrintInfo(RingbufHandle_t ringbuf)
{
ringbuf_t *rb=(ringbuf_t *)ringbuf;
configASSERT(rb);
ets_printf("Rb size %d free %d rptr %d freeptr %d wptr %d\n",
rb->size, ringbufferFreeMem(rb), rb->read_ptr-rb->data, rb->free_ptr-rb->data, rb->write_ptr-rb->data);
}
size_t xRingbufferGetCurFreeSize(RingbufHandle_t ringbuf)
{
ringbuf_t *rb=(ringbuf_t *)ringbuf;
configASSERT(rb);
configASSERT(rb->getFreeSizeImpl);
int free_size = rb->getFreeSizeImpl(rb);
//Reserve one byte. If we do not do this and the entire buffer is filled, we get a situation
//where read_ptr == free_ptr, messing up the next calculation.
return free_size - 1;
}
static size_t getCurFreeSizeByteBuf(ringbuf_t *rb)
{
//Return whatever space is available depending on relative positions of
//the free pointer and write pointer. There is no overhead of headers in
//this mode
int free_size = rb->free_ptr-rb->write_ptr;
if (free_size <= 0)
free_size += rb->size;
return free_size;
}
static size_t getCurFreeSizeAllowSplit(ringbuf_t *rb)
{
int free_size;
//If Both, the write and free pointer are at the start. Hence, the entire buffer
//is available (minus the space for the header)
if (rb->write_ptr == rb->free_ptr && rb->write_ptr == rb->data) {
free_size = rb->size - sizeof(buf_entry_hdr_t);
} else if (rb->write_ptr < rb->free_ptr) {
//Else if the free pointer is beyond the write pointer, only the space between
//them would be available (minus the space for the header)
free_size = rb->free_ptr - rb->write_ptr - sizeof(buf_entry_hdr_t);
} else {
//Else the data can wrap around and 2 headers will be required
free_size = rb->free_ptr - rb->write_ptr + rb->size - (2 * sizeof(buf_entry_hdr_t));
}
return free_size;
}
static size_t getCurFreeSizeNoSplit(ringbuf_t *rb)
{
int free_size;
//If the free pointer is beyond the write pointer, only the space between
//them would be available
if (rb->write_ptr < rb->free_ptr) {
free_size = rb->free_ptr - rb->write_ptr;
} else {
//Else check which one is bigger amongst the below 2
//1) Space from the write pointer to the end of buffer
int size1 = rb->data + rb->size - rb->write_ptr;
//2) Space from the start of buffer to the free pointer
int size2 = rb->free_ptr - rb->data;
//And then select the larger of the two
free_size = size1 > size2 ? size1 : size2;
}
//In any case, a single header will be used, so subtracting the space that
//would be required for it
return free_size - sizeof(buf_entry_hdr_t);
}
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RingbufHandle_t xRingbufferCreate(size_t buf_length, ringbuf_type_t type)
{
ringbuf_t *rb = malloc(sizeof(ringbuf_t));
if (rb==NULL) goto err;
memset(rb, 0, sizeof(ringbuf_t));
rb->data = malloc(buf_length);
if (rb->data == NULL) goto err;
rb->size = buf_length;
rb->free_ptr = rb->data;
rb->read_ptr = rb->data;
rb->write_ptr = rb->data;
rb->free_space_sem = xSemaphoreCreateBinary();
rb->items_buffered_sem = xSemaphoreCreateBinary();
rb->flags=0;
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if (type==RINGBUF_TYPE_ALLOWSPLIT) {
rb->flags|=flag_allowsplit;
rb->copyItemToRingbufImpl=copyItemToRingbufAllowSplit;
rb->getItemFromRingbufImpl=getItemFromRingbufDefault;
rb->returnItemToRingbufImpl=returnItemToRingbufDefault;
//Calculate max item size. Worst case, we need to split an item into two, which means two headers of overhead.
rb->maxItemSize=rb->size-(sizeof(buf_entry_hdr_t)*2)-4;
rb->getFreeSizeImpl=getCurFreeSizeAllowSplit;
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} else if (type==RINGBUF_TYPE_BYTEBUF) {
rb->flags|=flag_bytebuf;
rb->copyItemToRingbufImpl=copyItemToRingbufByteBuf;
rb->getItemFromRingbufImpl=getItemFromRingbufByteBuf;
rb->returnItemToRingbufImpl=returnItemToRingbufBytebuf;
//Calculate max item size. We have no headers and can split anywhere -> size is total size minus one.
rb->maxItemSize=rb->size-1;
rb->getFreeSizeImpl=getCurFreeSizeByteBuf;
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} else if (type==RINGBUF_TYPE_NOSPLIT) {
rb->copyItemToRingbufImpl=copyItemToRingbufNoSplit;
rb->getItemFromRingbufImpl=getItemFromRingbufDefault;
rb->returnItemToRingbufImpl=returnItemToRingbufDefault;
//Calculate max item size. Worst case, we have the write ptr in such a position that we are lacking four bytes of free
//memory to put an item into the rest of the memory. If this happens, we have to dummy-fill
//(item_data-4) bytes of buffer, then we only have (size-(item_data-4) bytes left to fill
//with the real item. (item size being header+data)
rb->maxItemSize=(rb->size/2)-sizeof(buf_entry_hdr_t)-4;
rb->getFreeSizeImpl=getCurFreeSizeNoSplit;
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} else {
configASSERT(0);
}
if (rb->free_space_sem == NULL || rb->items_buffered_sem == NULL) goto err;
vPortCPUInitializeMutex(&rb->mux);
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return (RingbufHandle_t)rb;
err:
//Some error has happened. Free/destroy all allocated things and return NULL.
if (rb) {
free(rb->data);
if (rb->free_space_sem) vSemaphoreDelete(rb->free_space_sem);
if (rb->items_buffered_sem) vSemaphoreDelete(rb->items_buffered_sem);
}
free(rb);
return NULL;
}
RingbufHandle_t xRingbufferCreateNoSplit(size_t item_size, size_t num_item)
{
size_t aligned_size = (item_size+3)&~3;
return xRingbufferCreate((aligned_size + sizeof(buf_entry_hdr_t)) * num_item, RINGBUF_TYPE_NOSPLIT);
}
void vRingbufferDelete(RingbufHandle_t ringbuf) {
ringbuf_t *rb=(ringbuf_t *)ringbuf;
if (rb) {
free(rb->data);
if (rb->free_space_sem) vSemaphoreDelete(rb->free_space_sem);
if (rb->items_buffered_sem) vSemaphoreDelete(rb->items_buffered_sem);
}
free(rb);
}
size_t xRingbufferGetMaxItemSize(RingbufHandle_t ringbuf)
{
ringbuf_t *rb=(ringbuf_t *)ringbuf;
configASSERT(rb);
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return rb->maxItemSize;
}
bool xRingbufferIsNextItemWrapped(RingbufHandle_t ringbuf)
{
ringbuf_t *rb=(ringbuf_t *)ringbuf;
configASSERT(rb);
buf_entry_hdr_t *hdr=(buf_entry_hdr_t *)rb->read_ptr;
return hdr->flags & iflag_wrap;
}
BaseType_t xRingbufferSend(RingbufHandle_t ringbuf, void *data, size_t dataSize, TickType_t ticks_to_wait)
{
ringbuf_t *rb=(ringbuf_t *)ringbuf;
size_t needed_size=dataSize+sizeof(buf_entry_hdr_t);
BaseType_t done=pdFALSE;
TickType_t ticks_end = xTaskGetTickCount() + ticks_to_wait;
TickType_t ticks_remaining = ticks_to_wait;
configASSERT(rb);
if (dataSize > xRingbufferGetMaxItemSize(ringbuf)) {
//Data will never ever fit in the queue.
return pdFALSE;
}
while (!done) {
//Check if there is enough room in the buffer. If not, wait until there is.
do {
if (ringbufferFreeMem(rb) < needed_size) {
//Data does not fit yet. Wait until the free_space_sem is given, then re-evaluate.
BaseType_t r = xSemaphoreTake(rb->free_space_sem, ticks_remaining);
if (r == pdFALSE) {
//Timeout.
return pdFALSE;
}
//Adjust ticks_remaining; we may have waited less than that and in the case the free memory still is not enough,
//we will need to wait some more.
if (ticks_to_wait != portMAX_DELAY) {
ticks_remaining = ticks_end - xTaskGetTickCount();
// ticks_remaining will always be less than or equal to the original ticks_to_wait,
// unless the timeout is reached - in which case it unsigned underflows to a much
// higher value.
//
// (Check is written this non-intuitive way to allow for the case where xTaskGetTickCount()
// has overflowed but the ticks_end value has not overflowed.)
if(ticks_remaining > ticks_to_wait) {
//Timeout, but there is not enough free space for the item that need to be sent.
xSemaphoreGive(rb->free_space_sem);
return pdFALSE;
}
}
}
} while (ringbufferFreeMem(rb) < needed_size);
//Lock the mux in order to make sure no one else is messing with the ringbuffer and do the copy.
portENTER_CRITICAL(&rb->mux);
//Another thread may have been able to sneak its write first. Check again now we locked the ringbuff, and retry
//everything if this is the case. Otherwise, we can write and are done.
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done=rb->copyItemToRingbufImpl(rb, data, dataSize);
portEXIT_CRITICAL(&rb->mux);
}
xSemaphoreGive(rb->items_buffered_sem);
return pdTRUE;
}
BaseType_t xRingbufferSendFromISR(RingbufHandle_t ringbuf, void *data, size_t dataSize, BaseType_t *higher_prio_task_awoken)
{
ringbuf_t *rb=(ringbuf_t *)ringbuf;
BaseType_t write_succeeded;
configASSERT(rb);
size_t needed_size=dataSize+sizeof(buf_entry_hdr_t);
portENTER_CRITICAL_ISR(&rb->mux);
if (needed_size>ringbufferFreeMem(rb)) {
//Does not fit in the remaining space in the ringbuffer.
write_succeeded=pdFALSE;
} else {
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write_succeeded = rb->copyItemToRingbufImpl(rb, data, dataSize);
}
portEXIT_CRITICAL_ISR(&rb->mux);
if (write_succeeded) {
xSemaphoreGiveFromISR(rb->items_buffered_sem, higher_prio_task_awoken);
}
return write_succeeded;
}
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static void *xRingbufferReceiveGeneric(RingbufHandle_t ringbuf, size_t *item_size, TickType_t ticks_to_wait, size_t wanted_size)
{
ringbuf_t *rb=(ringbuf_t *)ringbuf;
uint8_t *itemData;
BaseType_t done=pdFALSE;
configASSERT(rb);
while(!done) {
//See if there's any data available. If not, wait until there is.
while (rb->read_ptr == rb->write_ptr) {
BaseType_t r=xSemaphoreTake(rb->items_buffered_sem, ticks_to_wait);
if (r == pdFALSE) {
//Timeout.
return NULL;
}
}
//Okay, we seem to have data in the buffer. Grab the mux and copy it out if it's still there.
portENTER_CRITICAL(&rb->mux);
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itemData=rb->getItemFromRingbufImpl(rb, item_size, wanted_size);
portEXIT_CRITICAL(&rb->mux);
if (itemData) {
//We managed to get an item.
done=pdTRUE;
}
}
return (void*)itemData;
}
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void *xRingbufferReceive(RingbufHandle_t ringbuf, size_t *item_size, TickType_t ticks_to_wait)
{
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return xRingbufferReceiveGeneric(ringbuf, item_size, ticks_to_wait, 0);
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}
void *xRingbufferReceiveFromISR(RingbufHandle_t ringbuf, size_t *item_size)
{
ringbuf_t *rb=(ringbuf_t *)ringbuf;
uint8_t *itemData;
configASSERT(rb);
portENTER_CRITICAL_ISR(&rb->mux);
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itemData=rb->getItemFromRingbufImpl(rb, item_size, 0);
portEXIT_CRITICAL_ISR(&rb->mux);
return (void*)itemData;
}
void *xRingbufferReceiveUpTo(RingbufHandle_t ringbuf, size_t *item_size, TickType_t ticks_to_wait, size_t wanted_size) {
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if (wanted_size == 0) return NULL;
configASSERT(ringbuf);
configASSERT(((ringbuf_t *)ringbuf)->flags & flag_bytebuf);
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return xRingbufferReceiveGeneric(ringbuf, item_size, ticks_to_wait, wanted_size);
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}
void *xRingbufferReceiveUpToFromISR(RingbufHandle_t ringbuf, size_t *item_size, size_t wanted_size)
{
ringbuf_t *rb=(ringbuf_t *)ringbuf;
uint8_t *itemData;
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if (wanted_size == 0) return NULL;
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configASSERT(rb);
configASSERT(rb->flags & flag_bytebuf);
portENTER_CRITICAL_ISR(&rb->mux);
itemData=rb->getItemFromRingbufImpl(rb, item_size, wanted_size);
portEXIT_CRITICAL_ISR(&rb->mux);
return (void*)itemData;
}
void vRingbufferReturnItem(RingbufHandle_t ringbuf, void *item)
{
ringbuf_t *rb=(ringbuf_t *)ringbuf;
portENTER_CRITICAL(&rb->mux);
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rb->returnItemToRingbufImpl(rb, item);
portEXIT_CRITICAL(&rb->mux);
xSemaphoreGive(rb->free_space_sem);
}
void vRingbufferReturnItemFromISR(RingbufHandle_t ringbuf, void *item, BaseType_t *higher_prio_task_awoken)
{
ringbuf_t *rb=(ringbuf_t *)ringbuf;
portENTER_CRITICAL_ISR(&rb->mux);
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rb->returnItemToRingbufImpl(rb, item);
portEXIT_CRITICAL_ISR(&rb->mux);
xSemaphoreGiveFromISR(rb->free_space_sem, higher_prio_task_awoken);
}
BaseType_t xRingbufferAddToQueueSetRead(RingbufHandle_t ringbuf, QueueSetHandle_t xQueueSet)
{
ringbuf_t *rb=(ringbuf_t *)ringbuf;
configASSERT(rb);
return xQueueAddToSet(rb->items_buffered_sem, xQueueSet);
}
BaseType_t xRingbufferAddToQueueSetWrite(RingbufHandle_t ringbuf, QueueSetHandle_t xQueueSet)
{
ringbuf_t *rb=(ringbuf_t *)ringbuf;
configASSERT(rb);
return xQueueAddToSet(rb->free_space_sem, xQueueSet);
}
BaseType_t xRingbufferRemoveFromQueueSetRead(RingbufHandle_t ringbuf, QueueSetHandle_t xQueueSet)
{
ringbuf_t *rb=(ringbuf_t *)ringbuf;
configASSERT(rb);
return xQueueRemoveFromSet(rb->items_buffered_sem, xQueueSet);
}
BaseType_t xRingbufferRemoveFromQueueSetWrite(RingbufHandle_t ringbuf, QueueSetHandle_t xQueueSet)
{
ringbuf_t *rb=(ringbuf_t *)ringbuf;
configASSERT(rb);
return xQueueRemoveFromSet(rb->free_space_sem, xQueueSet);
}