// Copyright 2010-2013 RethinkDB, all rights reserved.

#ifndef CONTAINERS_PRINTF_BUFFER_HPP_

#define CONTAINERS_PRINTF_BUFFER_HPP_

#include <stdarg.h>

#include <stdio.h>

#include <string.h>

// Cannot include utils.hpp, we are included by utils.hpp.

#include "errors.hpp"

int64_t round_up_to_power_of_two(int64_t x);

// A static buffer for printing format strings, but it has a failsafe

// in case the buffer grows too large.

class printf_buffer_t {

public:

printf_buffer_t();

explicit printf_buffer_t(const char *format, ...) __attribute__((format (printf, 2, 3)));

printf_buffer_t(va_list ap, const char *format) __attribute__((format (printf, 3, 0)));

~printf_buffer_t();

// append and vappend become slow if the total size grows to N or

// greater. We still have std::vector-style amortized constant

// time growth, though.

void appendf(const char *format, ...) __attribute__((format (printf, 2, 3)));

void vappendf(const char *format, va_list ap) __attribute__((format (printf, 2, 0)));

char *data() const { return ptr_; }

const char *c_str() const { return ptr_; }

int size() const { return length_; }

static const int STATIC_DATA_SIZE = 1000;

private:

// The number of bytes that have been appended.

int64_t length_;

// Either a pointer to data_, or, if length_ >= N, a pointer to an

// array on the heap whose size is a power of two that is at least

// length_ + 1. Also, ptr_[length_] == 0, because we store a nul

// terminator.

char *ptr_;

// A data buffer for avoiding allocation in the common case.

char data_[STATIC_DATA_SIZE];

DISABLE_COPYING(printf_buffer_t);

};

#endif // CONTAINERS_PRINTF_BUFFER_HPP_