Remove any Heap Allocation

5 files changed, 69 insertions, 79 deletions

diff --git a/libraries/fifo.c b/libraries/fifo.c
index faa9fc4..8c5ad8b 100644
--- a/libraries/fifo.c
+++ b/libraries/fifo.c
@@ -3,64 +3,59 @@
 #include "fifo.h"
 
 
-void fifo_init(FIFO *fifo, uint16_t bufferlength)
+void fifo_init(FIFO *fifo, uint8_t *buffer, uint16_t bufferlength)
 {
-    fifo->buffer_ptr = calloc(bufferlength, sizeof(uint8_t));
-    fifo->read_index = 0;
-    fifo->write_index = 0;
-    fifo->bufferlength = bufferlength;
-}
-
-void fifo_deinit(FIFO *fifo)
-{
-    free(fifo->buffer_ptr);
+	fifo->buffer_ptr = buffer;
+	fifo->bufferlength = bufferlength;
+	fifo->read_index = 0;
+	fifo->write_index = 0;
 }
 
 uint16_t fifo_get_buffersize(FIFO *fifo)
 {
-    return fifo->bufferlength;
+	return fifo->bufferlength;
 }
 
 uint16_t fifo_bytes_available(FIFO *fifo)
 {
-    if (fifo->write_index > fifo->read_index){
-        return (fifo->write_index - fifo->read_index);
-    }
-    else if (fifo->write_index < fifo->read_index){
-        return (fifo_get_buffersize(fifo) - (fifo->read_index - fifo->write_index));
-    }
-    else {  // read_index == write_index
-        return 0;
-    }
+	if (fifo->write_index > fifo->read_index){
+		return (fifo->write_index - fifo->read_index);
+	}
+	else if (fifo->write_index < fifo->read_index){
+		return (fifo_get_buffersize(fifo) - (fifo->read_index - fifo->write_index));
+	}
+	else {  // read_index == write_index
+		return 0;
+	}
 }
 
 //uint16_t fifo_lines_available(FIFO *fifo){}
 
 void fifo_move_read_index(FIFO *fifo)
 {
-    fifo->read_index++;
-    fifo->read_index %= fifo_get_buffersize(fifo);
+	fifo->read_index++;
+	fifo->read_index %= fifo_get_buffersize(fifo);
 }
 
 void fifo_move_write_index(FIFO *fifo)
 {
-    fifo->write_index++;
-    fifo->write_index %= fifo_get_buffersize(fifo);
+	fifo->write_index++;
+	fifo->write_index %= fifo_get_buffersize(fifo);
 }
 
 void fifo_get_byte(FIFO *fifo, uint8_t *data_sink)
 {
-    if(fifo_bytes_available(fifo)){
-        *data_sink = fifo->buffer_ptr[fifo->read_index];
-        fifo_move_read_index(fifo);
-    }
+	if(fifo_bytes_available(fifo)){
+		*data_sink = fifo->buffer_ptr[fifo->read_index];
+		fifo_move_read_index(fifo);
+	}
 }
 
 void fifo_put_byte(FIFO *fifo, uint8_t *data_source)
 {
-    fifo->buffer_ptr[fifo->write_index] = *data_source;
-    fifo_move_write_index(fifo);
-    if(fifo->read_index == fifo->write_index){  // buffer overflow case
-        fifo_move_read_index(fifo);
-    }
+	fifo->buffer_ptr[fifo->write_index] = *data_source;
+	fifo_move_write_index(fifo);
+	if(fifo->read_index == fifo->write_index){  // buffer overflow case
+		fifo_move_read_index(fifo);
+	}
 }
diff --git a/libraries/fifo.h b/libraries/fifo.h
index c56d410..700d2ec 100644
--- a/libraries/fifo.h
+++ b/libraries/fifo.h
@@ -1,30 +1,30 @@
 
 
-/* 
-    FIFO Ring Buffer uint8_t array ring_buffer (example length is 8) 
-       with data (x) and read and write index:
-
-     --- --- --- --- --- --- --- ---
-    |   |   | x | x | x |   |   |   |
-     --- --- --- --- --- --- --- ---
-              ^           ^
-              |           |
-          read_index      |
-                     write_index
-
-     --- --- --- --- --- --- --- ---
-    | x | x |   |   |   | x | x | x |
-     --- --- --- --- --- --- --- ---
-              ^           ^
-              |           |
-         write_index      |
-                      read_index
-
-    - input data goes to position of write_index
-    - output data comes from read_index position
-    - after input/output operation the according index has to be modified
-    - according to the idea of ring buffers the write_index could be 
-      smaller than the read_index
+/*
+	FIFO Ring Buffer uint8_t array ring_buffer (example length is 8) 
+	   with data (x) and read and write index:
+
+	 --- --- --- --- --- --- --- ---
+	|   |   | x | x | x |   |   |   |
+	 --- --- --- --- --- --- --- ---
+			  ^		   ^
+			  |		   |
+		  read_index	  |
+					 write_index
+
+	 --- --- --- --- --- --- --- ---
+	| x | x |   |   |   | x | x | x |
+	 --- --- --- --- --- --- --- ---
+			  ^		   ^
+			  |		   |
+		 write_index	  |
+					  read_index
+
+	- input data goes to position of write_index
+	- output data comes from read_index position
+	- after input/output operation the according index has to be modified
+	- according to the idea of ring buffers the write_index could be 
+	  smaller than the read_index
 */
 
 
@@ -37,15 +37,14 @@
 
 
 typedef struct FIFO{
-    uint8_t *buffer_ptr;
-    uint16_t read_index;
-    uint16_t write_index;
-    uint16_t bufferlength;
+	uint8_t *buffer_ptr;
+	uint16_t bufferlength;
+	uint16_t read_index;
+	uint16_t write_index;
 } FIFO;
 
 
-void fifo_init(FIFO *fifo, uint16_t bufferlength);
-void fifo_deinit(FIFO *fifo);
+void fifo_init(FIFO *fifo, uint8_t *buffer, uint16_t bufferlength);
 
 uint16_t fifo_get_buffersize(FIFO *fifo);
 
diff --git a/libraries/usart.c b/libraries/usart.c
index 61de99c..67dd30a 100644
--- a/libraries/usart.c
+++ b/libraries/usart.c
@@ -8,7 +8,7 @@ extern USART usart3;
 
 // init functions
 
-void usart_init(USART *usart)
+void usart_init(USART *usart, uint8_t *rx_buffer, uint16_t rx_buffersize, uint8_t *tx_buffer, uint16_t tx_buffersize)
 {
     // clock config
     rcc_periph_clock_enable(RCC_GPIOB);  // for USART3
@@ -32,14 +32,8 @@ void usart_init(USART *usart)
     usart_enable(USART3);
 
     // fifo init
-    fifo_init(&usart->rx_fifo, USART_BUFFER_SIZE);
-    fifo_init(&usart->tx_fifo, USART_BUFFER_SIZE);
-}
-
-void usart_deinit(USART *usart)
-{
-    fifo_deinit(&usart->rx_fifo);
-    fifo_deinit(&usart->tx_fifo);
+    fifo_init(&usart->rx_fifo, rx_buffer, rx_buffersize);
+    fifo_init(&usart->tx_fifo, tx_buffer, tx_buffersize);
 }
 
 
diff --git a/libraries/usart.h b/libraries/usart.h
index cac971b..8e0d98c 100644
--- a/libraries/usart.h
+++ b/libraries/usart.h
@@ -13,8 +13,6 @@
 
 #include "fifo.h"
 
-#define USART_BUFFER_SIZE 30
-
 
 typedef struct USART{
 
@@ -26,8 +24,7 @@ typedef struct USART{
 
 // init functions
 
-void usart_init(USART *usart);
-void usart_deinit(USART *usart);
+void usart_init(USART *usart, uint8_t *rx_buffer, uint16_t rx_buffersize, uint8_t *tx_buffer, uint16_t tx_buffersize);
 
 
 // write functions
diff --git a/usart_irq/main.c b/usart_irq/main.c
index c3e7966..8c79471 100644
--- a/usart_irq/main.c
+++ b/usart_irq/main.c
@@ -11,6 +11,8 @@
 
 
 #define DELAY 1000000
+#define RX_BUFFER_SIZE 50
+#define TX_BUFFER_SIZE 50
 
 
 void clock_init(void);
@@ -24,13 +26,16 @@ USART usart3;
 
 int main(void)
 {
+	uint8_t rx_buffer[RX_BUFFER_SIZE];
+	uint8_t tx_buffer[TX_BUFFER_SIZE];
+
 	clock_init();
 	gpio_init();
-	usart_init(&usart3);
+	usart_init(&usart3, rx_buffer, RX_BUFFER_SIZE, tx_buffer, TX_BUFFER_SIZE);
 
 	gpio_set(GPIOC, GPIO13);
 
-	char welcome[] = "Hallo Freunde!\r";
+	char welcome[] = "Hello world!\r";
 	usart_write(&usart3, welcome);
 
 	uint8_t buff;