implemented the lexer

utils.c

@@ -0,0 +1,87 @@
+#include "utils.h"
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+
+void trie_insert(trie_node *root, arena *a, char *key, uint16_t value)
+{
+	trie_node *node = root;
+	while (*key) {
+		if (!node->children[(usize)*key]) {
+			node->children[(usize)*key] = arena_alloc(a, sizeof(trie_node));
+			memset(node->children[(usize)*key], 0x0, sizeof(trie_node));
+		}
+		node = node->children[(usize)*key];
+
+		key++;
+	}
+
+	node->value = value;
+}
+
+uint16_t trie_get(trie_node *root, char *key, usize len)
+{
+	trie_node *node = root;
+	for (usize i=0; i < len; i++) {
+		if (!node->children[(usize)(key[i])]) {
+			return 0;
+		}
+		node = node->children[(usize)(key[i])];
+	}
+
+	return node->value;
+}
+
+#ifndef DEFAULT_ALIGNMENT
+#define DEFAULT_ALIGNMENT (2 * sizeof(void *))
+#endif
+
+static usize align_forward(usize ptr, usize align) {
+	uintptr_t p = ptr;
+	uintptr_t a = (uintptr_t)align;
+	uintptr_t modulo = p & (a - 1);
+
+	if (modulo != 0) {
+		p += a - modulo;
+	}
+	return (usize)p;
+}
+
+arena arena_init(usize size)
+{
+	return (arena){
+		.capacity = size,
+		.position = 0,
+		.memory = malloc(size),
+	};
+}
+
+void *arena_alloc(arena *a, usize size) {
+	uintptr_t current_addr = (uintptr_t)a->memory + a->position;
+	uintptr_t padding = align_forward(current_addr, DEFAULT_ALIGNMENT) - current_addr;
+	if (a->position + padding + size > a->capacity) return NULL;
+	void *ret = (unsigned char *)a->memory + a->position + padding;
+	a->position += (size + padding); 
+
+	return ret;
+}
+
+snapshot arena_snapshot(arena a)
+{
+	return a.position;
+}
+
+void arena_reset_to_snapshot(arena *a, snapshot s)
+{
+	a->position = s;
+}
+
+void arena_reset(arena *a)
+{
+	arena_reset_to_snapshot(a, 0);
+}
+
+void arena_deinit(arena a)
+{
+	free(a.memory);
+}