moved to folders, updated etc

README.md

@@ -1,43 +1,15 @@
-Circular byte buffer
+Buffers
-====================
+=======
 
-**(and other buffers)**
+This is a collection of useful buffer modules for C programs.
 
-This is a circular buffer implementation, useful mainly for embedded systems (buffer for UART RX/TX queues etc).
+- **circbuf** - generic circular buffer, queue, stack
+- **matcher** - pattern matcher for character streams
+- **meanbuf** - averaging (smoothing) buffer.
 
-It should be reliable with producent / consumer threads (no race conditions, as no length variable is used).
+*Please see READMEs in the project folders for more details.*
-
-A Matching buffer, and Averaging buffer are also included—see their header files for instructions.
-
-
-Usage
------
-
-```c
-#include <stdint.h>
-#include "circbuf.h"
-
-circbuf_t cb; // buffer instance
-
-void main()
-{
-	char c;
-	cbuf_init(&cb, 32); // init the buffer
-	
-	// now it's ready for use!
-	
-	cbuf_write(&cb, 'A');
-	
-	if (cbuf_read(&cb, &c)) {
-		printf("%c", c);
-	}
-	
-	cbuf_deinit(&cb); // free the backing array (in embedded system you don't usually need to, allocate once and keep it)
-}
-```
-
-Most functions return a success flag (true - success), so make sure to check the return values.
-
-False is returned on buffer overflow / underflow. See the header file for details.
 
+The buffers were developed for embedded microcontrollers (STM32, AVR),
+but can be used anywhere, they are fully portable.
 
+Pull requests to add new buffers or improve the current ones are welcome!

circbuf.c

@@ -1,101 +0,0 @@
-#include <stdint.h>
-#include <stdbool.h>
-#include <string.h>
-#include <malloc.h>
-
-#include "circbuf.h"
-
-
-void cbuf_init(circbuf_t *inst, size_t capacity)
-{
-	inst->buf = malloc(capacity);
-	inst->cap = capacity;
-
-	cbuf_clear(inst);
-}
-
-
-void cbuf_deinit(circbuf_t *inst)
-{
-	if (inst->buf != NULL) {
-		free(inst->buf);
-	}
-}
-
-
-bool cbuf_full(circbuf_t *inst)
-{
-	return (inst->lr == inst->nw);
-}
-
-
-static bool can_read_at(circbuf_t *inst, size_t i)
-{
-	if (inst->lr < inst->nw) {
-		return i > inst->lr && i < inst->nw;
-	} else {
-		// NW < LR
-		return (i < inst->cap && i > inst->lr) || i < inst->nw;
-	}
-}
-
-
-bool cbuf_empty(circbuf_t *inst)
-{
-	return ((inst->lr + 1) % inst->cap) == inst->nw;
-}
-
-
-bool cbuf_write(circbuf_t *inst, uint8_t b)
-{
-	if (cbuf_full(inst)) return false;
-
-	inst->buf[inst->nw] = b;
-
-	// increment
-	inst->nw++;
-	if (inst->nw == inst->cap) inst->nw = 0;
-
-	return true;
-}
-
-
-bool cbuf_read(circbuf_t *inst, uint8_t *b)
-{
-	if (cbuf_empty(inst)) return false;
-
-	// increment
-	inst->lr++;
-	if (inst->lr == inst->cap) inst->lr = 0;
-
-	*b = inst->buf[inst->lr];
-
-	//zero out the read byte (for debug)
-	inst->buf[inst->lr] = 0;
-
-	return true;
-}
-
-
-bool cbuf_peek(circbuf_t *inst, size_t nth, uint8_t *b)
-{
-	// check if can read there (can't use modulo, could "wrap")
-	size_t n = inst->lr;
-	for (size_t i = 0; i <= nth; i++) {
-		// increment N
-		n++;
-		if (n == inst->cap) n = 0;
-
-		if (!can_read_at(inst, n)) return false;
-	}
-
-	*b = inst->buf[n];
-	return true;
-}
-
-
-void cbuf_clear(circbuf_t *inst)
-{
-	inst->lr = inst->cap - 1;
-	inst->nw = 0;
-}

circbuf.h

@@ -1,51 +0,0 @@
-#pragma once
-#include <stdint.h>
-#include <stdbool.h>
-#include <stdlib.h>
-
-// Circular Character Buffer implementation
-
-typedef struct CircularBuffer_struct {
-	uint8_t *buf;
-	size_t cap;
-	size_t lr; // last read pos
-	size_t nw; // next write pos
-} circbuf_t;
-
-
-/** Init a buffer */
-void cbuf_init(circbuf_t *inst, size_t capacity);
-
-
-/** Deinit a buffer (free the memory) */
-void cbuf_deinit(circbuf_t *inst);
-
-
-/** Test for full buffer */
-bool cbuf_full(circbuf_t *inst);
-
-
-/** Test for empty buffer */
-bool cbuf_empty(circbuf_t *inst);
-
-
-/** Write a byte to buffer, returns success */
-bool cbuf_write(circbuf_t *inst, uint8_t b);
-
-
-/**
- * Read a byte from the buffer, return susccess.
- * If `b` is NULL, the read byte is discarded.
- */
-bool cbuf_read(circbuf_t *inst, uint8_t *b);
-
-
-/**
- * Get n-th byte from the buffer, without removing it.
- * Returns false if offset is invalid (ie. empty buffer).
- */
-bool cbuf_peek(circbuf_t *inst, size_t nth, uint8_t *b);
-
-
-/** Remove all data from buffer */
-void cbuf_clear(circbuf_t *inst);

circbuf/README.md

@@ -0,0 +1,51 @@
+Circular buffer
+===============
+
+This is a C implementation of a circular buffer, which can also be used
+as a queue or stack.
+
+Supported operations: `push`, `pop`, `append`.
+
+To achieve thread safety (to some extent) in a producent-consumer situation,
+there is no length variable, only write pointers.
+
+The buffer has a fixed size, values are copied when inserted. The buffer is created using `malloc`.
+If your platform does not support `malloc`, you will have to customize the initialization routine.
+
+Applications
+------------
+
+- Buffer for USARTs or similar communication interfaces
+- Event queue
+- Object stack
+
+Usage
+-----
+
+```c
+#include <stdint.h>
+#include "circbuf.h"
+
+CircBuf *cb; // buffer instance
+
+void main()
+{
+	cb = cbuf_make(32, sizeof(char)); // create a char buffer of size 32.
+
+	// now it's ready for use!
+
+    // write functions return true on success:
+	cbuf_append(cb, 'A'); // append A (using as a queue)
+	cbuf_push(cb, 'B');   // push B (using as a stack)
+
+	// read all
+	char c;
+	while (cbuf_pop(cb, &c)) {
+		printf("%c", c);
+	}
+
+	cbuf_destroy(cb); // free the buffer
+}
+```
+
+For details how to use each function, please read the header file.

circbuf/circbuf.c

@@ -0,0 +1,167 @@
+#include <stdint.h>
+#include <stdbool.h>
+#include <string.h>
+#include <malloc.h>
+
+#include "circbuf.h"
+
+// --- Circbuf data structure ----
+
+/** Offset in void* buffer */
+#define PV_OFFS(pvBuf, elem_size, index) ((uint8_t*)(pvBuf) + ((elem_size)*(index)))
+
+
+// Instance structure
+struct circbuf_struct {
+	void *buf;
+	size_t elem_size;
+	size_t cap;
+	size_t lr; // last read pos
+	size_t nw; // next write pos
+};
+
+
+/**
+ * @brief Write data to a CircBuf slot
+ * @param cb     : circbuf
+ * @param index  : slot index
+ * @param source : data source
+ */
+static void write_buffer(CircBuf *cb, size_t index, const void *source)
+{
+	memcpy(PV_OFFS(cb->buf, cb->elem_size, index), source, cb->elem_size);
+}
+
+
+/**
+ * @brief Copy data from a CircBuf slot to a buffer
+ * @param cb     : circbuf
+ * @param index  : slot index
+ * @param dest   : destination buffer
+ */
+static void read_buffer(const CircBuf *cb, size_t index, void *dest)
+{
+	memcpy(dest, PV_OFFS(cb->buf, cb->elem_size, index), cb->elem_size);
+}
+
+
+/** Create a cbuf */
+CircBuf *cbuf_make(size_t capacity, size_t elem_size)
+{
+	// add one, because one is always unused.
+	capacity++;
+
+	// Allocate the structure
+	CircBuf *cb = malloc(sizeof(CircBuf));
+	if (cb == NULL) {
+		return NULL;
+	}
+
+	// allocate the buffer
+	cb->buf = malloc(capacity * elem_size);
+	if (cb->buf == NULL) {
+		free(cb); // fail - free structure.
+		return NULL;
+	}
+
+	// set capacity, clear state
+	cb->elem_size = elem_size;
+	cb->cap = capacity;
+	cbuf_clear(cb);
+
+	return cb;
+}
+
+
+/** Release cbuf memory */
+void cbuf_destroy(CircBuf *cb)
+{
+	if (cb != NULL) {
+		if (cb->buf != NULL) {
+			free(cb->buf);
+		}
+
+		free(cb);
+	}
+}
+
+
+/** Check if cbuf is full */
+bool cbuf_full(const CircBuf *cb)
+{
+	if (cb == NULL) return false;
+
+	return (cb->lr == cb->nw);
+}
+
+
+/** Check if cbuf is empty */
+bool cbuf_empty(const CircBuf *cb)
+{
+	if (cb == NULL) return true;
+
+	return ((cb->lr + 1) % cb->cap) == cb->nw;
+}
+
+
+/** Write a byte to the buffer, if space left */
+bool cbuf_append(CircBuf *cb, const void *source)
+{
+	if (cb == NULL) return false;
+	if (source == NULL) return false;
+	if (cbuf_full(cb)) return false;
+
+	write_buffer(cb, cb->nw, source);
+
+	// increment
+	cb->nw++;
+	if (cb->nw == cb->cap) cb->nw = 0;
+
+	return true;
+}
+
+
+/** Push value to the end, like a stack. */
+bool cbuf_push(CircBuf *cb, const void *source)
+{
+	if (cb == NULL) return false;
+	if (source == NULL) return false;
+	if (cbuf_full(cb)) return false;
+
+	write_buffer(cb, cb->lr, source);
+
+	// move lr back
+	if (cb->lr == 0) {
+		cb->lr = cb->cap - 1; // wrap to the end
+	} else {
+		cb->lr--;
+	}
+
+	return true;
+}
+
+
+/** Read one byte, if not empty. */
+bool cbuf_pop(CircBuf *cb, void *dest)
+{
+	if (cb == NULL || dest == NULL) return false;
+	if (cbuf_empty(cb)) return false;
+
+	// increment
+	cb->lr++;
+	if (cb->lr == cb->cap) cb->lr = 0;
+
+	read_buffer(cb, cb->lr, dest);
+
+	return true;
+}
+
+
+/** Clear a cbuf */
+void cbuf_clear(CircBuf *cb)
+{
+	if (cb == NULL) return;
+
+	cb->lr = cb->cap - 1;
+	cb->nw = 0;
+}

circbuf/circbuf.h

@@ -0,0 +1,93 @@
+/**
+ * @file circbuf.h
+ * @author Ondřej Hruška, 2016
+ *
+ * Circular buffer / queue / stack.
+ * Slots are pre-allocated, values are copied into the buffer.
+ *
+ * The buffer may be used as a stack, event queue or a simple buffer.
+ *
+ * -------------------------------------
+ *
+ *         NW        LR
+ * append -> [][][][] -> pop
+ *                    <- push
+ *
+ * NW - next write pointer (stack base)
+ * LR - last read position (stack top)
+ *
+ * -------------------------------------
+ *
+ * MIT license
+ */
+
+#pragma once
+
+#include <stdint.h>
+#include <stdbool.h>
+#include <stdlib.h>
+
+
+typedef struct circbuf_struct CircBuf;
+
+
+/**
+ * @brief Initialize a circular buffer. The buffer is malloc'd.
+ * @param capacity  : buffer capacity
+ * @param elem_size : size of one element
+ * @return pointer to the buffer instance
+ */
+CircBuf *cbuf_make(size_t capacity, size_t elem_size);
+
+
+/**
+ * @brief Destroy a buffer, freeing used memory.
+ *
+ * @attention
+ * If the buffer items have malloc'd members, you have
+ * to free them manually to avoid a memory leak.
+ *
+ * @param cb : buffer
+ */
+void cbuf_destroy(CircBuf *cb);
+
+
+/** Test for full buffer */
+bool cbuf_full(const CircBuf *cb);
+
+
+/** Test for empty buffer */
+bool cbuf_empty(const CircBuf *cb);
+
+
+/**
+ * @brief Append a value to the buffer (FIFO)
+ * @param cb     : buffer
+ * @param source : pointer to a value (will be copied)
+ * @return success
+ */
+bool cbuf_append(CircBuf *cb, const void *source);
+
+
+/**
+ * @brief Push a value into the circbuf (LIFO).
+ *
+ * @param cb     : buffer
+ * @param source : pointer to a value (will be copied)
+ * @return success
+ */
+bool cbuf_push(CircBuf *cb, const void *source);
+
+
+/**
+ * @brief Read a value from the buffer, return susccess.
+ *
+ * @param cb   : buffer
+ * @param dest : read destionation. If NULL, value is discarded.
+ * @return success
+ */
+bool cbuf_pop(CircBuf *cb, void *dest);
+
+
+/** @brief Remove all data from buffer */
+void cbuf_clear(CircBuf *cb);

matcher.h

@@ -1,21 +0,0 @@
-#pragma once
-
-#include <stdint.h>
-#include <stdbool.h>
-#include <stdlib.h>
-
-typedef struct {
-	const char *pattern;
-	size_t cursor;
-} matcher_t;
-
-
-/**
- * Consume an incoming character.
- * If this char was the last char of the pattern, returns true and rewinds.
- *
- * If the char is not in the pattern, resets match state.
- *
- * @returns true if the char concluded the expected pattern.
- */
-bool matcher_test(matcher_t * mb, uint8_t b);

matcher/README.md

@@ -0,0 +1,14 @@
+Character stream pattern matcher
+================================
+
+Matcher can be used for detecting a pattern in a stream of characters.
+With each incoming character, call `matcher_test()`. 
+
+It will return true if the character completed a match.
+
+Applications
+------------
+
+This buffer was designed for parsing responses to AT commands from ESP8266.
+
+It can be used for any similar purpose.

matcher/matcher.c

@@ -5,6 +5,11 @@
 
 #include "matcher.h"
 
+void matcher_reset(matcher_t *m)
+{
+	m->cursor = 0;
+}
+
 
 /** Handle incoming char. Returns true if this char completed the match. */
 bool matcher_test(matcher_t * m, uint8_t b)

matcher/matcher.h

@@ -0,0 +1,39 @@
+/**
+ * @file matcher.h
+ * @author Ondřej Hruška, 2016
+ *
+ * String matching utility.
+ * 
+ * Matcher can be used for detecting a pattern in a stream of characters.
+ * With each incoming character, call matcher_test(). 
+ * 
+ * It will return true if the character completed a match.
+ * 
+ * MIT license
+ */
+
+#pragma once
+
+#include <stdint.h>
+#include <stdbool.h>
+#include <stdlib.h>
+
+typedef struct {
+	const char *pattern;
+	size_t cursor;
+} matcher_t;
+
+
+/** reset match progress */
+void matcher_reset(matcher_t *m);
+
+
+/**
+ * Consume an incoming character.
+ * If this char was the last char of the pattern, returns true and resets matcher.
+ *
+ * If the char is not in the pattern, resets matcher.
+ *
+ * @returns true if the char concluded the expected pattern.
+ */
+bool matcher_test(matcher_t * mb, uint8_t b);

meanbuf.h

@@ -1,21 +0,0 @@
-#pragma once
-#include <stdlib.h>
-#include <stdint.h>
-
-
-typedef struct {
-	float * buf; // buffer (allocated at init)
-	size_t cap; // capacity
-	size_t nw; // next write index
-	float mean; // updated on write
-} meanbuf_t;
-
-
-/** Init a buffer */
-void meanbuf_init(meanbuf_t *mb, size_t size);
-
-/** Deinit a buffer (free buffer array) */
-void meanbuf_deinit(meanbuf_t *mb);
-
-/** Add a value to the buffer. Returns current mean. */
-float meanbuf_add(meanbuf_t *mb, float f);

meanbuf/README.md

@@ -0,0 +1,11 @@
+Averaging float buffer
+======================
+
+*(You can adjust it to use doubles, if you prefer.)*
+
+The `meanbuf_create()` function allocates a buffer.
+
+You can then call `meanbuf_add()` to add a new value into the buffer (and remove the oldest).
+This function returns the current average value.
+
+This buffer can be used for **signal smoothing** (such as from an analogue sensor).

meanbuf/meanbuf.c

@@ -4,9 +4,19 @@
 #include "meanbuf.h"
 
 
+struct meanbuf_struct {
+	float * buf; // buffer (allocated at init)
+	size_t cap; // capacity
+	size_t nw; // next write index
+	float mean; // updated on write
+};
+
+
 /** Init a buffer */
-void meanbuf_init(meanbuf_t *mb, size_t size)
+MeanBuf *meanbuf_create(size_t size)
 {
+	MeanBuf *mb = malloc(sizeof(MeanBuf));
+
 	if (size < 1) size = 1;
 
 	mb->buf = calloc(size, sizeof(float)); // calloc, so it starts with zeros.
@@ -18,19 +28,25 @@ void meanbuf_init(meanbuf_t *mb, size_t size)
 	for (uint16_t i = 0; i < size; i++) {
 		mb->buf[i] = 0;
 	}
+
+	return mb;
 }
 
 
-void meanbuf_deinit(meanbuf_t *mb)
+void meanbuf_destroy(MeanBuf *mb)
 {
+	if (mb == NULL) return;
+
 	if (mb->buf != NULL) {
 		free(mb->buf);
 	}
+
+	free(mb);
 }
 
 
 /** Add a value to the buffer. Returns current mean. */
-float meanbuf_add(meanbuf_t *mb, float f)
+float meanbuf_add(MeanBuf *mb, float f)
 {
 	// add sample
 	mb->buf[mb->nw++] = f;

meanbuf/meanbuf.h

@@ -0,0 +1,31 @@
+/**
+ * @file meanbuf.h
+ * @author Ondřej Hruška, 2016
+ *
+ * Averaging float buffer. (You can adjust it to use doubles, if you prefer.)
+ * 
+ * The meanbuf_create() function allocates a buffer.
+ * 
+ * You can then call meanbuf_add() to add a new value into the buffer (and remove the oldest).
+ * This function returns the current average value.
+ * 
+ * This buffer can be used for signal smoothing (such as from an analogue sensor).
+ *
+ * MIT license
+ */
+
+
+#pragma once
+#include <stdlib.h>
+#include <stdint.h>
+
+typedef struct meanbuf_struct MeanBuf;
+
+/** Init a buffer */
+MeanBuf *meanbuf_create(size_t size);
+
+/** Deinit a buffer (free buffer array) */
+void meanbuf_destroy(MeanBuf *mb);
+
+/** Add a value to the buffer. Returns current mean. */
+float meanbuf_add(MeanBuf *mb, float f);