Ast alloc dealloc (#62)

* AST Prototypes

* AST create, init and free

include/ast.h

@@ -47,4 +47,34 @@ typedef struct ASTNode {
     } extra;
 } ASTNode;
 
+
+/**
+ * Allocate a new AST Node, and initialize it with the given type
+ * 
+ * @param  type The type of the AST Node
+ *
+ * @return A pointer to a heap allocated AST Node on success,
+ *         NULL on failure
+ */
+ASTNode* ast_node_create(ASTNodeType type);
+
+
+/**
+ * Initialize an AST Node
+ *
+ * @param  node A Pointer to the AST Node to initialize
+ * @param  type The type of the AST Node
+ *
+ * @return  0 on success, -1 on failure
+ */
+int ast_node_init(ASTNode* node, ASTNodeType type);
+
+
+/**
+ * Release memory allocated for the given AST Node
+ *
+ * @param node The AST Node to free
+ */
+void ast_node_free(ASTNode* node);
+
 #endif // REGEX_AST

src/ast.c

@@ -0,0 +1,53 @@
+#include <stdlib.h>
+
+#include "ast.h"
+
+// Allocate a new AST Node, and initialize it with the given type
+ASTNode* ast_node_create(ASTNodeType type) {
+    ASTNode* node = malloc(sizeof(ASTNode));
+
+    // Initialize the created node, this implicitly checks for NULL
+    if (ast_node_init(node, type) != 0) {
+        free(node);  // free of NULL is a no-op
+        return NULL;
+    }
+
+    return node;
+}
+
+
+// Initialize an AST Node
+int ast_node_init(ASTNode* node, ASTNodeType type) {
+    if (node == NULL) {
+        return -1;
+    }
+
+    *node = (ASTNode){
+        .type = type,
+        .child1 = NULL,
+        .extra = {0},
+    };
+
+    return 0;
+}
+
+
+// Release memory allocated for the given AST Node
+void ast_node_free(ASTNode* node) {
+    if (node == NULL) {
+        return;
+    }
+
+    if (node->type == CHAR_NODE) {
+        free(node);
+        return;
+    }
+
+    ast_node_free(node->child1);
+
+    if (node->type == OR_NODE || node->type == CONCAT_NODE) {
+        ast_node_free(node->extra.child2);
+    }
+
+    free(node);
+}

tests/test_ast.c

@@ -0,0 +1,72 @@
+#include "testlib/asserts.h"
+#include "testlib/tests.h"
+#include "ast.h"
+
+// Test creating AST dynamically
+int test_ast_create() {
+    TEST_BEGIN;
+    ASTNodeType types[] = {
+        CHAR_NODE, STAR_NODE, PLUS_NODE,
+        OR_NODE, QUESTION_NODE, CONCAT_NODE,
+    };
+
+    size_t n_types = sizeof(types) / sizeof(ASTNodeType);
+
+    for (size_t i = 0; i < n_types; i++) {
+        ASTNode* node = ast_node_create(types[i]);
+
+        assert_is_not_null(node);
+        assert_equals_int(node->type, types[i]);
+        ast_node_free(node);
+    }
+    TEST_END;
+}
+
+int test_ast_init() {
+    TEST_BEGIN;
+    ASTNodeType types[] = {
+        CHAR_NODE, STAR_NODE, PLUS_NODE,
+        OR_NODE, QUESTION_NODE, CONCAT_NODE,
+    };
+
+    size_t n_types = sizeof(types) / sizeof(ASTNodeType);
+
+    ASTNode node;
+    for (size_t i = 0; i < n_types; i++) {
+        int ret = ast_node_init(&node, types[i]);
+
+        assert_equals_int(ret, 0);
+        assert_equals_int(node.type, types[i]);
+    }
+
+    int ret = ast_node_init(NULL, *types);
+    assert_equals_int(ret, -1);
+
+    TEST_END;
+}
+
+
+Test tests[] = {
+    {.name="test_ast_create", .func=test_ast_create},
+    {.name="test_ast_init", .func=test_ast_init},
+    {.name=NULL},
+};
+
+
+int main(int argc, char* argv[]) {
+    TestOpts opts;
+    int ret = parse_test_opts(&opts, &argv[1], argc - 1);
+    if (ret != 0) {
+        printf("%s\n", str_parse_error(ret));
+        exit(1);
+    }
+
+    const TestSuite* suite = create_test_suite(&opts);
+
+    int n_failures = run_test_suite(suite);
+
+    free_opts(&opts);
+    free_test_suite(suite);
+
+    return n_failures;
+}