Added support for 'labels' in the Scanner.

src/scanner.c

@@ -92,14 +92,18 @@ Token* ParseNumber(void) {
         while(!ScannerAtEnd() && isdigit(PeekScanner())) AdvanceScanner();
     }
 
-    char* lexeme = calloc(Position - start + 1, sizeof(char));
+    int length = Position - start;
+
+    if (length == 0) return NULL;
+
+    char* lexeme = calloc(sizeof(char), length);
 
     if (!lexeme) {
         fprintf(stderr, "Failed to calloc space for number.\n");
         return NULL;
     }
 
-    memcpy(lexeme, &SourceCode[start], Position - start);
+    memcpy(lexeme, &SourceCode[start], length);
 
     if (base == 10) return CreateToken(NUMBER, lexeme);
 
@@ -110,17 +114,19 @@ Token* ParseDirective(void) {
     int start = Position;
 
     while(!ScannerAtEnd() && PeekScanner() != ' ' && PeekScanner() != '\n') AdvanceScanner();
-        
-    if (start == Position) return NULL;
 
-    char* directive = calloc(Position - start + 1, sizeof(char));
+    int length = Position - start;
+
+    if (length == 0) return NULL;
+
+    char* directive = calloc(sizeof(char), length);
 
     if (!directive) {
         fprintf(stderr, "Failed to calloc for the assmebler directive.\n");
         return NULL;
     }
 
-    memcpy(directive, &SourceCode[start], Position - start);
+    memcpy(directive, &SourceCode[start], length);
 
     if (strcmp(directive, ".db") == 0) {
         return CreateToken(DB, directive);
@@ -154,8 +160,12 @@ Token* ParseString(void) {
         AdvanceScanner();
     }
 
-    char* lexeme = calloc(Position - start, sizeof(char));
-    memcpy(lexeme, &SourceCode[start], Position - start);
+    int length = Position - start;
+
+    if (length == 0) return NULL;
+
+    char* lexeme = calloc(sizeof(char), length);
+    memcpy(lexeme, &SourceCode[start], length);
 
     AdvanceScanner(); //Consume the trailing double quote.
 
@@ -171,14 +181,17 @@ Token* ParseIdentifier(void) {
         AdvanceScanner();
     }
 
-    if (Position - start == 0) return NULL;
+    int length = Position - start;
+
+    if (length == 0) return NULL;
     
-    char* lexeme = calloc(Position - start, sizeof(char));
-    TokenType type;
-    memcpy(lexeme, &SourceCode[start], Position - start);
+    TokenType type;    
+    char* lexeme = calloc(sizeof(char), length);
+    memcpy(lexeme, &SourceCode[start], length);
 
     if (IsOpcode(lexeme, &type)) return CreateToken(type, lexeme);
     if (IsRegister(lexeme, &type)) return CreateToken(type, lexeme);
+    if (lexeme[length - 1] == ':') return CreateToken(LABEL, lexeme);
 
     return CreateToken(IDENTIFIER, lexeme);
 }