buffers.h

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/* Copyright (c) 2001 Matej Pfajfar.
 * Copyright (c) 2001-2004, Roger Dingledine.
 * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
 * Copyright (c) 2007-2017, The Tor Project, Inc. */
/* See LICENSE for licensing information */

#ifndef TOR_BUFFERS_H
#define TOR_BUFFERS_H

#include "compat.h"
#include "torint.h"
#include "testsupport.h"

typedef struct buf_t buf_t;

struct tor_compress_state_t;

buf_t *buf_new(void);
buf_t *buf_new_with_capacity(size_t size);
size_t buf_get_default_chunk_size(const buf_t *buf);
void buf_free_(buf_t *buf);
#define buf_free(b) FREE_AND_NULL(buf_t, buf_free_, (b))
void buf_clear(buf_t *buf);
buf_t *buf_copy(const buf_t *buf);

MOCK_DECL(size_t, buf_datalen, (const buf_t *buf));
size_t buf_allocation(const buf_t *buf);
size_t buf_slack(const buf_t *buf);

uint32_t buf_get_oldest_chunk_timestamp(const buf_t *buf, uint32_t now);
size_t buf_get_total_allocation(void);

int buf_read_from_socket(buf_t *buf, tor_socket_t s, size_t at_most,
                         int *reached_eof,
                         int *socket_error);

int buf_flush_to_socket(buf_t *buf, tor_socket_t s, size_t sz,
                        size_t *buf_flushlen);

int buf_add(buf_t *buf, const char *string, size_t string_len);
void buf_add_string(buf_t *buf, const char *string);
void buf_add_printf(buf_t *buf, const char *format, ...)
  CHECK_PRINTF(2, 3);
void buf_add_vprintf(buf_t *buf, const char *format, va_list args)
  CHECK_PRINTF(2, 0);
int buf_add_compress(buf_t *buf, struct tor_compress_state_t *state,
                          const char *data, size_t data_len, int done);
int buf_move_to_buf(buf_t *buf_out, buf_t *buf_in, size_t *buf_flushlen);
void buf_move_all(buf_t *buf_out, buf_t *buf_in);
void buf_peek(const buf_t *buf, char *string, size_t string_len);
void buf_drain(buf_t *buf, size_t n);
int buf_get_bytes(buf_t *buf, char *string, size_t string_len);
int buf_get_line(buf_t *buf, char *data_out, size_t *data_len);

#define PEEK_BUF_STARTSWITH_MAX 16
int buf_peek_startswith(const buf_t *buf, const char *cmd);

int buf_set_to_copy(buf_t **output,
                    const buf_t *input);

void buf_assert_ok(buf_t *buf);

int buf_find_string_offset(const buf_t *buf, const char *s, size_t n);
void buf_pullup(buf_t *buf, size_t bytes,
                const char **head_out, size_t *len_out);
char *buf_extract(buf_t *buf, size_t *sz_out);

#ifdef BUFFERS_PRIVATE
#ifdef TOR_UNIT_TESTS
buf_t *buf_new_with_data(const char *cp, size_t sz);
#endif
size_t buf_preferred_chunk_size(size_t target);

#define DEBUG_CHUNK_ALLOC

typedef struct chunk_t {
  struct chunk_t *next; 
  size_t datalen; 
  size_t memlen; 
#ifdef DEBUG_CHUNK_ALLOC
  size_t DBG_alloc;
#endif
  char *data; 
  uint32_t inserted_time; 
  char mem[FLEXIBLE_ARRAY_MEMBER]; 
} chunk_t;

#define BUFFER_MAGIC 0xB0FFF312u

struct buf_t {
  uint32_t magic; 
  size_t datalen; 
  size_t default_chunk_size; 
  chunk_t *head; 
  chunk_t *tail; 
};

chunk_t *buf_add_chunk_with_capacity(buf_t *buf, size_t capacity, int capped);
#define MIN_READ_LEN 8

static inline size_t
CHUNK_REMAINING_CAPACITY(const chunk_t *chunk)
{
  return (chunk->mem + chunk->memlen) - (chunk->data + chunk->datalen);
}

static inline char *
CHUNK_WRITE_PTR(chunk_t *chunk)
{
  return chunk->data + chunk->datalen;
}

#endif /* defined(BUFFERS_PRIVATE) */

#endif /* !defined(TOR_BUFFERS_H) */