text: /*
   * Copyright 2019 The Hafnium Authors.
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *     https://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  #include "hf/string.h"
  
  #include "hf/static_assert.h"
  #include "hf/std.h"
  
  void string_init_empty(struct string *str)
  {
  	static_assert(sizeof(str->data) >= 1, "String buffer too small");
  	str->data[0] = '\0';
  }
  
  /**
   * Caller must guarantee that `data` points to a NULL-terminated string.
   * The constructor checks that it fits into the internal buffer and copies
   * the string there.
   */
  string_return_code string_init(struct string *str, const char *data,
  				    size_t size)
  {
  	/*
  	 * Require that the value contains exactly one NULL character and that
  	 * it is the last byte.
  	 */
  	if (size < 1 || memchr(data, '\0', size) != &data[size - 1]) {
  		return STRING_ERROR_INVALID_INPUT;
  	}
  
  	if (size > STRING_MAX_SIZE) {
  		return STRING_ERROR_TOO_LONG;
  	}
  
  	memcpy_s(str->data, STRING_MAX_SIZE, data, size);
  	return STRING_SUCCESS;
  }
  
  bool string_is_empty(const struct string *str)
  {
  	return str->data[0] == '\0';
  }
  
  const char *string_data(const struct string *str)
  {
  	return str->data;
  }
  