(c) queue implementation testing

clang/Makefile

@@ -37,6 +37,7 @@ C_FLAGS := $(C_DEF) \
            -Wfloat-equal \
            -Wlogical-op \
            -Wno-maybe-uninitialized \
+           -Wno-unused \
            -Werror
 
 BINARY := $(BIN_DIR)/$(NAME)

clang/src/main.c

@@ -3,22 +3,73 @@
 #include <stdio.h>
 #include <string.h>
 
-#define ARRAY_SIZE  ( ( int ) 16 )
+#define QUEUE_SIZE          ( ( uint32_t ) 4u )
+#define QUEUE_EMPTY_VALUE   ( ( uint32_t ) 0u )
+
+typedef struct {
+    uint32_t head;
+    uint32_t tail;
+    uint32_t queue_data[ QUEUE_SIZE ];
+} queue_t;
+
+static void queue_initialise( queue_t *queue );
+static int queue_enqueue( queue_t *queue, uint32_t message );
+static int queue_dequeue( queue_t *queue, uint32_t* message );
 
 int main(void)
 {
-    char string[256];
+    queue_t queue;
-    char blargh[] = "hello.world";
+    queue_initialise( &queue );
-    char* temp;
-    size_t len;
 
-    temp = strrchr( blargh, '.' );
+    for ( int n = 0; n < ( int )QUEUE_SIZE + 1; n++ )
-    len = strlen( temp );
+    {
+        if ( queue_enqueue( &queue, ( uint32_t )n ) )
+        {
+            printf( "failed to queue message: 0x%4x\n", n );
+        }
+        else
+        {
+            printf( "successfully queued message: 0x%4x\n", n );
+        }
+    }
+    return 0;
+}
 
-    printf( "temp[ %ld ] = %s\n", len, &temp[ 1 ] );
+void queue_initialise( queue_t *queue )
+{
+    queue->head = 0;
+    queue->tail = 0;
+}
 
-    strncpy( &string[ 0 ], &temp[ 1 ], len - 1 );
+int queue_enqueue( queue_t *queue, uint32_t message )
-    strncpy( &string[ len - 1 ], blargh, ( size_t )( temp - blargh ) );
+{
+    if ( !queue ) return -1;
 
-    printf( "string = %s\n", string );
+    if ( ( queue->head + 1 ) % QUEUE_SIZE == queue->tail )
+    {
+        // queue full
+        return -1;
+    }
+
+    queue->queue_data[ queue->head ] = message;
+    queue->head = ( queue->head + 1 ) % QUEUE_SIZE;
+
+    return 0;
+}
+
+int queue_dequeue( queue_t *queue, uint32_t* message )
+{
+    if ( !queue ) return -1;
+    if ( !message ) return -1;
+
+    if ( queue->head == queue->tail )
+    {
+        // queue empty
+        return -1;
+    }
+
+    *message = queue->queue_data[ queue->tail ];
+    queue->tail = ( queue->tail + 1 ) % QUEUE_SIZE;
+
+    return 0;
 }