//===-- String Writer class for printf -----------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_LIBC_SRC_STDIO_PRINTF_CORE_STRING_WRITER_H
#define LLVM_LIBC_SRC_STDIO_PRINTF_CORE_STRING_WRITER_H

#include "src/string/memory_utils/memcpy_implementations.h"
#include <stddef.h>

namespace __llvm_libc {
namespace printf_core {

class StringWriter {
  char *__restrict cur_buffer;
  size_t available_capacity;

public:
  // StringWriter is intended to take a copy of the cur_buffer pointer, as well
  // as the maximum length of the string. This maximum length should not include
  // the null terminator, since that's written separately.
  StringWriter(char *__restrict buffer, size_t max_len = ~size_t(0))
      : cur_buffer(buffer), available_capacity(max_len) {}

  void write(const char *__restrict to_write, size_t len) {
    if (len > available_capacity)
      len = available_capacity;

    if (len > 0) {
      inline_memcpy(cur_buffer, to_write, len);
      cur_buffer += len;
      available_capacity -= len;
    }
  }
  // Terminate should only be called if the original max length passed to
  // snprintf was greater than 0. It writes a null byte to the end of the
  // cur_buffer, regardless of available_capacity.
  void terminate() { *cur_buffer = '\0'; }
};

// write_to_string treats raw_pointer as a StringWriter and calls its write
// function.
void write_to_string(void *raw_pointer, const char *__restrict to_write,
                     size_t len) {
  StringWriter *string_writer = reinterpret_cast<StringWriter *>(raw_pointer);
  string_writer->write(to_write, len);
}

} // namespace printf_core
} // namespace __llvm_libc

#endif // LLVM_LIBC_SRC_STDIO_PRINTF_CORE_STRING_WRITER_H