Tor  0.4.5.0-alpha-dev
buffers.h
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1 /* Copyright (c) 2001 Matej Pfajfar.
2  * Copyright (c) 2001-2004, Roger Dingledine.
3  * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
4  * Copyright (c) 2007-2020, The Tor Project, Inc. */
5 /* See LICENSE for licensing information */
6 
7 /**
8  * \file buffers.h
9  *
10  * \brief Header file for buffers.c.
11  **/
12 
13 #ifndef TOR_BUFFERS_H
14 #define TOR_BUFFERS_H
15 
16 #include "lib/cc/compat_compiler.h"
17 #include "lib/cc/torint.h"
19 
20 #include <stdarg.h>
21 
22 typedef struct buf_t buf_t;
23 
24 buf_t *buf_new(void);
25 buf_t *buf_new_with_capacity(size_t size);
26 size_t buf_get_default_chunk_size(const buf_t *buf);
27 void buf_free_(buf_t *buf);
28 #define buf_free(b) FREE_AND_NULL(buf_t, buf_free_, (b))
29 void buf_clear(buf_t *buf);
30 buf_t *buf_copy(const buf_t *buf);
31 
32 /** Maximum bytes in a buffer, inclusive. */
33 #define BUF_MAX_LEN (INT_MAX - 1)
34 
35 MOCK_DECL(size_t, buf_datalen, (const buf_t *buf));
36 size_t buf_allocation(const buf_t *buf);
37 size_t buf_slack(const buf_t *buf);
38 
39 uint32_t buf_get_oldest_chunk_timestamp(const buf_t *buf, uint32_t now);
40 size_t buf_get_total_allocation(void);
41 
42 int buf_add(buf_t *buf, const char *string, size_t string_len);
43 void buf_add_string(buf_t *buf, const char *string);
44 void buf_add_printf(buf_t *buf, const char *format, ...)
45  CHECK_PRINTF(2, 3);
46 void buf_add_vprintf(buf_t *buf, const char *format, va_list args)
47  CHECK_PRINTF(2, 0);
48 int buf_move_to_buf(buf_t *buf_out, buf_t *buf_in, size_t *buf_flushlen);
49 size_t buf_move_all(buf_t *buf_out, buf_t *buf_in);
50 void buf_peek(const buf_t *buf, char *string, size_t string_len);
51 void buf_drain(buf_t *buf, size_t n);
52 int buf_get_bytes(buf_t *buf, char *string, size_t string_len);
53 int buf_get_line(buf_t *buf, char *data_out, size_t *data_len);
54 
55 #define PEEK_BUF_STARTSWITH_MAX 16
56 int buf_peek_startswith(const buf_t *buf, const char *cmd);
57 
58 int buf_set_to_copy(buf_t **output,
59  const buf_t *input);
60 
61 void buf_assert_ok(buf_t *buf);
62 
63 int buf_find_string_offset(const buf_t *buf, const char *s, size_t n);
64 void buf_pullup(buf_t *buf, size_t bytes,
65  const char **head_out, size_t *len_out);
66 char *buf_extract(buf_t *buf, size_t *sz_out);
67 
68 #ifdef BUFFERS_PRIVATE
69 #ifdef TOR_UNIT_TESTS
70 buf_t *buf_new_with_data(const char *cp, size_t sz);
71 #endif
72 size_t buf_preferred_chunk_size(size_t target);
73 
74 #define DEBUG_CHUNK_ALLOC
75 /** A single chunk on a buffer. */
76 typedef struct chunk_t {
77  struct chunk_t *next; /**< The next chunk on the buffer. */
78  size_t datalen; /**< The number of bytes stored in this chunk */
79  size_t memlen; /**< The number of usable bytes of storage in <b>mem</b>. */
80 #ifdef DEBUG_CHUNK_ALLOC
81  size_t DBG_alloc;
82 #endif
83  char *data; /**< A pointer to the first byte of data stored in <b>mem</b>. */
84  uint32_t inserted_time; /**< Timestamp when this chunk was inserted. */
85  char mem[FLEXIBLE_ARRAY_MEMBER]; /**< The actual memory used for storage in
86  * this chunk. */
87 } chunk_t;
88 
89 /** Magic value for buf_t.magic, to catch pointer errors. */
90 #define BUFFER_MAGIC 0xB0FFF312u
91 /** A resizeable buffer, optimized for reading and writing. */
92 struct buf_t {
93  uint32_t magic; /**< Magic cookie for debugging: Must be set to
94  * BUFFER_MAGIC. */
95  size_t datalen; /**< How many bytes is this buffer holding right now? */
96  size_t default_chunk_size; /**< Don't allocate any chunks smaller than
97  * this for this buffer. */
98  chunk_t *head; /**< First chunk in the list, or NULL for none. */
99  chunk_t *tail; /**< Last chunk in the list, or NULL for none. */
100 };
101 
102 chunk_t *buf_add_chunk_with_capacity(buf_t *buf, size_t capacity, int capped);
103 /** If a read onto the end of a chunk would be smaller than this number, then
104  * just start a new chunk. */
105 #define MIN_READ_LEN 8
106 
107 /** Return the number of bytes that can be written onto <b>chunk</b> without
108  * running out of space. */
109 static inline size_t
110 CHUNK_REMAINING_CAPACITY(const chunk_t *chunk)
111 {
112  return (chunk->mem + chunk->memlen) - (chunk->data + chunk->datalen);
113 }
114 
115 /** Return the next character in <b>chunk</b> onto which data can be appended.
116  * If the chunk is full, this might be off the end of chunk->mem. */
117 static inline char *
118 CHUNK_WRITE_PTR(chunk_t *chunk)
119 {
120  return chunk->data + chunk->datalen;
121 }
122 
123 #endif /* defined(BUFFERS_PRIVATE) */
124 
125 #endif /* !defined(TOR_BUFFERS_H) */
buf_assert_ok
void buf_assert_ok(buf_t *buf)
Definition: buffers.c:910
buf_datalen
size_t buf_datalen(const buf_t *buf)
Definition: buffers.c:394
buf_add_chunk_with_capacity
chunk_t * buf_add_chunk_with_capacity(buf_t *buf, size_t capacity, int capped)
Definition: buffers.c:475
buf_set_to_copy
int buf_set_to_copy(buf_t **output, const buf_t *input)
Definition: buffers.c:898
buf_preferred_chunk_size
size_t buf_preferred_chunk_size(size_t target)
Definition: buffers.c:189
buf_move_to_buf
int buf_move_to_buf(buf_t *buf_out, buf_t *buf_in, size_t *buf_flushlen)
Definition: buffers.c:657
buf_peek
void buf_peek(const buf_t *buf, char *string, size_t string_len)
Definition: buffers.c:610
torint.h
Integer definitions used throughout Tor.
buf_slack
size_t buf_slack(const buf_t *buf)
Definition: buffers.c:414
buf_new
buf_t * buf_new(void)
Definition: buffers.c:365
buf_free_
void buf_free_(buf_t *buf)
Definition: buffers.c:424
buf_pullup
void buf_pullup(buf_t *buf, size_t bytes, const char **head_out, size_t *len_out)
Definition: buffers.c:211
buf_find_string_offset
int buf_find_string_offset(const buf_t *buf, const char *s, size_t n)
Definition: buffers.c:815
MOCK_DECL
#define MOCK_DECL(rv, funcname, arglist)
Definition: testsupport.h:127
buf_get_bytes
int buf_get_bytes(buf_t *buf, char *string, size_t string_len)
Definition: buffers.c:637
buf_add_vprintf
void buf_add_vprintf(buf_t *buf, const char *format, va_list args)
Definition: buffers.c:578
buf_drain
void buf_drain(buf_t *buf, size_t n)
Definition: buffers.c:330
buf_new_with_capacity
buf_t * buf_new_with_capacity(size_t size)
Definition: buffers.c:356
buf_get_oldest_chunk_timestamp
uint32_t buf_get_oldest_chunk_timestamp(const buf_t *buf, uint32_t now)
Definition: buffers.c:506
buf_move_all
size_t buf_move_all(buf_t *buf_out, buf_t *buf_in)
Definition: buffers.c:691
buf_get_line
int buf_get_line(buf_t *buf, char *data_out, size_t *data_len)
Definition: buffers.c:874
buf_peek_startswith
int buf_peek_startswith(const buf_t *buf, const char *cmd)
Definition: buffers.c:834
testsupport.h
Macros to implement mocking and selective exposure for the test code.
buf_copy
buf_t * buf_copy(const buf_t *buf)
Definition: buffers.c:453
buf_allocation
size_t buf_allocation(const buf_t *buf)
Definition: buffers.c:401
buf_extract
char * buf_extract(buf_t *buf, size_t *sz_out)
Definition: buffers.c:592
buf_add_printf
void buf_add_printf(buf_t *buf, const char *format,...)
Definition: buffers.c:568
buf_add
int buf_add(buf_t *buf, const char *string, size_t string_len)
Definition: buffers.c:527
buf_add_string
void buf_add_string(buf_t *buf, const char *string)
Definition: buffers.c:561
buf_clear
void buf_clear(buf_t *buf)
Definition: buffers.c:381
compat_compiler.h
Utility macros to handle different features and behavior in different compilers.