C++ symbolOop::byte_at方法代码示例

// Check if it is a valid array signature
bool FieldType::is_valid_array_signature(symbolOop sig) {
  assert(sig->utf8_length() > 1, "this should already have been checked");
  assert(sig->byte_at(0) == '[', "this should already have been checked");
  // The first character is already checked
  int i = 1;
  int len = sig->utf8_length();
  // First skip all '['s
  while(i < len - 1 && sig->byte_at(i) == '[') i++;

  // Check type
  switch(sig->byte_at(i)) {
    case 'B': // T_BYTE
    case 'C': // T_CHAR
    case 'D': // T_DOUBLE
    case 'F': // T_FLOAT
    case 'I': // T_INT
    case 'J': // T_LONG
    case 'S': // T_SHORT
    case 'Z': // T_BOOLEAN
      // If it is an array, the type is the last character
      return (i + 1 == len);
    case 'L':
      // If it is an object, the last character must be a ';'
      return sig->byte_at(len - 1) == ';';
  }

  return false;
}

void FieldType::skip_optional_size(symbolOop signature, int* index) {
  jchar c = signature->byte_at(*index);
  while (c >= '0' && c <= '9') {
    *index = *index + 1;
    c = signature->byte_at(*index);
  }
}

 static bool is_obj(symbolOop signature) {
    int sig_length = signature->utf8_length();
    // Must start with 'L' and end with ';'
    return (sig_length >= 2 &&
            (signature->byte_at(0) == 'L') &&
            (signature->byte_at(sig_length - 1) == ';'));
 }

static bool print_selector_with_arguments(prettyPrintStream*       output, 
                                          symbolOop                selector,
                                          GrowableArray<astNode*>* arguments,
                                          bool                     split) {
  if (selector->is_binary()) {
    // binary send
    output->print(selector->as_string());
    output->space();
    astNode* arg = arguments->at(0);
    bool wrap = should_wrap(1, arg);
    if (wrap) output->print("(");
    bool result = arg->print(output);
    if (wrap) output->print(")");
    return result;
  }

  int arg = arguments->length();

  if (arg == 0) {
    output->print(selector->as_string());
    return false;
  }

  for (int index = 1; index <= selector->length(); index++) {
    int c = selector->byte_at(index);
    output->print_char(c);
    if (c == ':') {
      output->space();
      astNode* a = arguments->at(--arg);
      bool wrap = should_wrap(2, a);
      if (wrap) output->print("(");
      a->print(output); 
      if (wrap) output->print(")");
         
      if (index < selector->length()) {
      	if (split) output->newline();
        else       output->space();
      }
    }
  }
  return split;
}

BasicType FieldType::get_array_info(symbolOop signature, jint* dimension, symbolOop* object_key, TRAPS) {
  assert(basic_type(signature) == T_ARRAY, "must be array");
  int index = 1;
  int dim   = 1;
  skip_optional_size(signature, &index);
  while (signature->byte_at(index) == '[') {
    index++;
    dim++;
    skip_optional_size(signature, &index);
  }
  ResourceMark rm;
  symbolOop element = oopFactory::new_symbol(signature->as_C_string() + index, CHECK_(T_BYTE));
  BasicType element_type = FieldType::basic_type(element);
  if (element_type == T_OBJECT) {
    char* object_type = element->as_C_string();
    object_type[element->utf8_length() - 1] = '\0';
    *object_key = oopFactory::new_symbol(object_type + 1, CHECK_(T_BYTE));
  }
  // Pass dimension back to caller
  *dimension = dim;
  return element_type;
}

BasicType FieldType::basic_type(symbolOop signature) {
  return char2type(signature->byte_at(0));
}

 // Testing
 static bool is_array(symbolOop signature) { return signature->utf8_length() > 1 && signature->byte_at(0) == '[' && is_valid_array_signature(signature); }