Add draft for correct symbol table implementation

draft.c

@@ -0,0 +1,117 @@
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#define SYMBOL_TABLE_CHUNK 4
+
+typedef struct symbol_t {
+	char	*ident;
+	bool	defined;
+	int		value;
+} symbol_t;
+
+
+typedef struct table_t {
+	symbol_t	**array;
+	int			size;
+	int			capacity;
+} table_t;
+
+table_t table;
+
+typedef struct bsearch_t {
+	int		pos;
+	bool	found;
+} bsearch_t;
+
+bsearch_t binary_search(symbol_t *arr[], int l, int r, char *ident)
+{
+	while (r >= l) {
+		int mid = l + (r - l) / 2;
+		int cmpres = strcmp(arr[mid]->ident, ident);
+		if (cmpres > 0) {
+			r = mid - 1;
+		} else if (cmpres < 0) {
+			l = mid + 1;
+		} else {
+			bsearch_t res = { mid, true };
+			return res;
+		}
+	} 
+	bsearch_t res = { l, false };
+	return res;
+}
+
+int insert(table_t *table, symbol_t *element, int pos)
+{
+	if (pos < 0 || pos > table->size) {
+		return -1;
+	}
+
+	if (table->size  >= table->capacity) {
+		table->array = realloc(table->array, sizeof(symbol_t *) * (table->capacity + SYMBOL_TABLE_CHUNK));
+		if (table->array == NULL) {
+			printf("Error: running out of memory\n");
+			exit(1);
+		}
+		table->capacity += SYMBOL_TABLE_CHUNK;
+	}
+
+	for (int i = table->size; i > pos; i--) {
+		table->array[i] = table->array[i-1];
+	}
+	table->array[pos] = element;
+	return ++(table->size);
+}
+
+symbol_t *intern(char *ident, bool create)
+{
+	bsearch_t res = binary_search(table.array, 0, table.size - 1, ident);
+	printf("pos:%d\n", res.pos);
+	if (create) {
+		symbol_t *new_symbol = malloc(sizeof(symbol_t));
+		new_symbol->ident = strdup(ident);
+		new_symbol->defined = false;
+		if (res.found) {
+			free(table.array[res.pos]);
+			table.array[res.pos] = new_symbol;
+		} else {
+			printf("insert:%d\n", insert(&table, new_symbol, res.pos));
+		}
+		return new_symbol;
+	} else {
+		if (res.found) {
+			return table.array[res.pos];
+		} else {
+			return NULL;
+		}
+	}
+}
+
+void init_table()
+{
+	table.array = malloc(sizeof(symbol_t *) * SYMBOL_TABLE_CHUNK);
+	if (table.array == NULL) {
+			printf("Error: running out of memory\n");
+			exit(1);
+	}
+	table.size = 0;
+	table.capacity = SYMBOL_TABLE_CHUNK;
+}
+
+int main() 
+{
+	init_table();
+	char line[256];
+	intern("chaussure\n", true);
+	while (fgets(line, sizeof(line), stdin)) {
+		printf("intern:%p\n", intern(line, true));
+		printf("after size:%d\n", table.size);
+		printf("after capacity:%d\n", table.capacity);
+		printf("\n");
+		for (int i = 0; i < table.size; i++) {
+			printf("%d.%s", i, table.array[i]->ident);
+		}
+		printf("\n");
+	}	
+}