LwRB
- group LWRB
Lightweight ring buffer manager.
Typedefs
-
typedef atomic_ulong lwrb_ulong_t
-
typedef void (*lwrb_evt_fn)(struct lwrb *buff, lwrb_evt_type_t evt, size_t bp)
Event callback function type.
- Param buff
[in] Buffer handle for event
- Param evt
[in] Event type
- Param bp
[in] Number of bytes written or read (when used), depends on event type
Enums
Functions
-
uint8_t lwrb_init(lwrb_t *buff, void *buffdata, size_t size)
Initialize buffer handle to default values with size and buffer data array.
- Parameters
buff – [in] Buffer handle
buffdata – [in] Pointer to memory to use as buffer data
size – [in] Size of
buffdata
in units of bytes Maximum number of bytes buffer can hold issize - 1
- Returns
1
on success,0
otherwise
-
uint8_t lwrb_is_ready(lwrb_t *buff)
Check if buff is initialized and ready to use.
- Parameters
buff – [in] Buffer handle
- Returns
1
if ready,0
otherwise
-
void lwrb_free(lwrb_t *buff)
Free buffer memory.
Note
Since implementation does not use dynamic allocation, it just sets buffer handle to
NULL
- Parameters
buff – [in] Buffer handle
-
void lwrb_reset(lwrb_t *buff)
Resets buffer to default values. Buffer size is not modified.
Note
This function is not thread safe. When used, application must ensure there is no active read/write operation
- Parameters
buff – [in] Buffer handle
-
void lwrb_set_evt_fn(lwrb_t *buff, lwrb_evt_fn fn)
Set event function callback for different buffer operations.
- Parameters
buff – [in] Buffer handle
evt_fn – [in] Callback function
-
size_t lwrb_write(lwrb_t *buff, const void *data, size_t btw)
Write data to buffer. Copies data from
data
array to buffer and marks buffer as full for maximumbtw
number of bytes.- Parameters
buff – [in] Buffer handle
data – [in] Pointer to data to write into buffer
btw – [in] Number of bytes to write
- Returns
Number of bytes written to buffer. When returned value is less than
btw
, there was no enough memory available to copy full data array
-
size_t lwrb_read(lwrb_t *buff, void *data, size_t btr)
Read data from buffer. Copies data from buffer to
data
array and marks buffer as free for maximumbtr
number of bytes.- Parameters
buff – [in] Buffer handle
data – [out] Pointer to output memory to copy buffer data to
btr – [in] Number of bytes to read
- Returns
Number of bytes read and copied to data array
-
size_t lwrb_peek(const lwrb_t *buff, size_t skip_count, void *data, size_t btp)
Read from buffer without changing read pointer (peek only)
- Parameters
buff – [in] Buffer handle
skip_count – [in] Number of bytes to skip before reading data
data – [out] Pointer to output memory to copy buffer data to
btp – [in] Number of bytes to peek
- Returns
Number of bytes peeked and written to output array
-
size_t lwrb_get_free(const lwrb_t *buff)
Get available size in buffer for write operation.
- Parameters
buff – [in] Buffer handle
- Returns
Number of free bytes in memory
-
size_t lwrb_get_full(const lwrb_t *buff)
Get number of bytes currently available in buffer.
- Parameters
buff – [in] Buffer handle
- Returns
Number of bytes ready to be read
-
void *lwrb_get_linear_block_read_address(const lwrb_t *buff)
Get linear address for buffer for fast read.
- Parameters
buff – [in] Buffer handle
- Returns
Linear buffer start address
-
size_t lwrb_get_linear_block_read_length(const lwrb_t *buff)
Get length of linear block address before it overflows for read operation.
- Parameters
buff – [in] Buffer handle
- Returns
Linear buffer size in units of bytes for read operation
-
size_t lwrb_skip(lwrb_t *buff, size_t len)
Skip (ignore; advance read pointer) buffer data Marks data as read in the buffer and increases free memory for up to
len
bytes.Note
Useful at the end of streaming transfer such as DMA
- Parameters
buff – [in] Buffer handle
len – [in] Number of bytes to skip and mark as read
- Returns
Number of bytes skipped
-
void *lwrb_get_linear_block_write_address(const lwrb_t *buff)
Get linear address for buffer for fast read.
- Parameters
buff – [in] Buffer handle
- Returns
Linear buffer start address
-
size_t lwrb_get_linear_block_write_length(const lwrb_t *buff)
Get length of linear block address before it overflows for write operation.
- Parameters
buff – [in] Buffer handle
- Returns
Linear buffer size in units of bytes for write operation
-
size_t lwrb_advance(lwrb_t *buff, size_t len)
Advance write pointer in the buffer. Similar to skip function but modifies write pointer instead of read.
Note
Useful when hardware is writing to buffer and application needs to increase number of bytes written to buffer by hardware
- Parameters
buff – [in] Buffer handle
len – [in] Number of bytes to advance
- Returns
Number of bytes advanced for write operation
-
uint8_t lwrb_find(const lwrb_t *buff, const void *bts, size_t len, size_t start_offset, size_t *found_idx)
Searches for a needle in an array, starting from given offset.
Note
This function is not thread-safe.
- Parameters
buff – Ring buffer to search for needle in
bts – Constant byte array sequence to search for in a buffer
len – Length of the
bts array
start_offset – Start offset in the buffer
found_idx – Pointer to variable to write index in array where bts has been found Must not be set to
NULL
- Returns
1
ifbts found,
0
otherwise
-
size_t lwrb_overwrite(lwrb_t *buff, const void *data, size_t btw)
Writes data to buffer with overwrite function, if no enough space to hold complete input data object.
Note
Similar to lwrb_write but overwrites
Note
Functionality is primary two parts, always writes some linear region, then writes the wrap region if there is more data to write. The r indicator is advanced if w overtakes it. This operation is a read op as well as a write op. For thread-safety mutexes may be desired, see documentation.
- Parameters
buff – [in] Buffer handle
data – [in] Data to write to ring buffer
btw – [in] Bytes To Write, length
- Returns
Number of bytes written to buffer, will always return btw
-
size_t lwrb_move(lwrb_t *dest, lwrb_t *src)
Move one ring buffer to another, up to the amount of data in the source, or amount of data free in the destination.
Note
This operation is a read op to the source, on success it will update the r index. As well as a write op to the destination, and may update the w index. For thread-safety mutexes may be desired, see documentation.
- Parameters
dest – [in] Buffer handle that the copied data will be written to
src – [in] Buffer handle that the copied data will come from. Source buffer will be effectively read upon operation.
- Returns
Number of bytes written to destination buffer
-
struct lwrb_t
- #include <lwrb.h>
Buffer structure.
Public Members
-
uint8_t *buff
Pointer to buffer data. Buffer is considered initialized when
buff != NULL
andsize > 0
-
size_t size
Size of buffer data. Size of actual buffer is
1
byte less than value holds
-
lwrb_ulong_t r
Next read pointer. Buffer is considered empty when
r == w
and full whenw == r - 1
-
lwrb_ulong_t w
Next write pointer. Buffer is considered empty when
r == w
and full whenw == r - 1
-
lwrb_evt_fn evt_fn
Pointer to event callback function
-
uint8_t *buff
-
typedef atomic_ulong lwrb_ulong_t