3 * Testy, Virtual(-izable) Buffer of guint8*'s
5 * "Testy" -- the buffer gets mad when an attempt is made to access data
6 * beyond the bounds of the buffer. An exception is thrown.
8 * "Virtual" -- the buffer can have its own data, can use a subset of
9 * the data of a backing tvbuff, or can be a composite of
12 * $Id: tvbuff.h,v 1.29 2002/08/28 20:40:45 jmayer Exp $
14 * Copyright (c) 2000 by Gilbert Ramirez <gram@alumni.rice.edu>
16 * Ethereal - Network traffic analyzer
17 * By Gerald Combs <gerald@ethereal.com>
18 * Copyright 1998 Gerald Combs
20 * This program is free software; you can redistribute it and/or
21 * modify it under the terms of the GNU General Public License
22 * as published by the Free Software Foundation; either version 2
23 * of the License, or (at your option) any later version.
25 * This program is distributed in the hope that it will be useful,
26 * but WITHOUT ANY WARRANTY; without even the implied warranty of
27 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
28 * GNU General Public License for more details.
30 * You should have received a copy of the GNU General Public License
31 * along with this program; if not, write to the Free Software
32 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
39 #include "exceptions.h"
41 typedef struct tvbuff tvbuff_t;
43 typedef void (*tvbuff_free_cb_t)(void*);
45 /* The different types of tvbuff's */
52 /* TVBUFF_REAL_DATA contains a guint8* that points to real data.
53 * The data is allocated and contiguous.
55 * TVBUFF_SUBSET has a backing tvbuff. The TVBUFF_SUBSET is a "window"
56 * through which the program sees only a portion of the backing tvbuff.
58 * TVBUFF_COMPOSITE combines multiple tvbuffs sequentually to produce
59 * a larger byte array.
61 * tvbuff's of any type can be used as the backing-tvbuff of a
62 * TVBUFF_SUBSET or as the member of a TVBUFF_COMPOSITE.
63 * TVBUFF_COMPOSITEs can have member-tvbuffs of different types.
65 * Once a tvbuff is create/initialized/finalized, the tvbuff is read-only.
66 * That is, it cannot point to any other data. A new tvbuff must be created if
67 * you want a tvbuff that points to other data.
71 /* "class" initialization. Called once during execution of program
72 * so that tvbuff.c can initialize its data. */
73 extern void tvbuff_init(void);
75 /* "class" cleanup. Called once during execution of program
76 * so that tvbuff.c can clean up its data. */
77 extern void tvbuff_cleanup(void);
80 /* Returns a pointer to a newly initialized tvbuff. Note that
81 * tvbuff's of types TVBUFF_SUBSET and TVBUFF_COMPOSITE
82 * require further initialization via the appropriate functions */
83 extern tvbuff_t* tvb_new(tvbuff_type);
85 /* Marks a tvbuff for freeing. The guint8* data of a TVBUFF_REAL_DATA
86 * is *never* freed by the tvbuff routines. The tvbuff itself is actually freed
87 * once its usage count drops to 0.
89 * Usage counts increment for any time the tvbuff is
90 * used as a member of another tvbuff, i.e., as the backing buffer for
91 * a TVBUFF_SUBSET or as a member of a TVBUFF_COMPOSITE.
93 * Although you may call tvb_free(), the tvbuff may still be in use
94 * by other tvbuff's (TVBUFF_SUBSET or TVBUFF_COMPOSITE), so it is not
95 * safe, unless you know otherwise, to free your guint8* data. If you
96 * cannot be sure that your TVBUFF_REAL_DATA is not in use by another
97 * tvbuff, register a callback with tvb_set_free_cb(); when your tvbuff
98 * is _really_ freed, then your callback will be called, and at that time
99 * you can free your original data.
101 * The caller can artificially increment/decrement the usage count
102 * with tvbuff_increment_usage_count()/tvbuff_decrement_usage_count().
104 extern void tvb_free(tvbuff_t*);
106 /* Free the tvbuff_t and all tvbuff's created from it. */
107 extern void tvb_free_chain(tvbuff_t*);
109 /* Both return the new usage count, after the increment or decrement */
110 extern guint tvb_increment_usage_count(tvbuff_t*, guint count);
112 /* If a decrement causes the usage count to drop to 0, a the tvbuff
113 * is immediately freed. Be sure you know exactly what you're doing
114 * if you decide to use this function, as another tvbuff could
115 * still have a pointer to the just-freed tvbuff, causing corrupted data
116 * or a segfault in the future */
117 extern guint tvb_decrement_usage_count(tvbuff_t*, guint count);
119 /* Set a callback function to call when a tvbuff is actually freed
120 * (once the usage count drops to 0). One argument is passed to
121 * that callback --- a void* that points to the real data.
122 * Obviously, this only applies to a TVBUFF_REAL_DATA tvbuff. */
123 extern void tvb_set_free_cb(tvbuff_t*, tvbuff_free_cb_t);
126 /* Attach a TVBUFF_REAL_DATA tvbuff to a parent tvbuff. This connection
127 * is used during a tvb_free_chain()... the "child" TVBUFF_REAL_DATA acts
128 * as if is part of the chain-of-creation of the parent tvbuff, although it
129 * isn't. This is useful if you need to take the data from some tvbuff,
130 * run some operation on it, like decryption or decompression, and make a new
131 * tvbuff from it, yet want the new tvbuff to be part of the chain. The reality
132 * is that the new tvbuff *is* part of the "chain of creation", but in a way
133 * that these tvbuff routines is ignorant of. Use this function to make
134 * the tvbuff routines knowledgable of this fact. */
135 extern void tvb_set_child_real_data_tvbuff(tvbuff_t* parent, tvbuff_t* child);
137 /* Sets parameters for TVBUFF_REAL_DATA. Can throw ReportedBoundsError. */
138 extern void tvb_set_real_data(tvbuff_t*, const guint8* data, guint length,
139 gint reported_length);
141 /* Combination of tvb_new() and tvb_set_real_data(). Can throw ReportedBoundsError. */
142 extern tvbuff_t* tvb_new_real_data(const guint8* data, guint length,
143 gint reported_length);
146 /* Define the subset of the backing buffer to use.
148 * 'backing_offset' can be negative, to indicate bytes from
149 * the end of the backing buffer.
151 * 'backing_length' can be 0, although the usefulness of the buffer would
154 * 'backing_length' of -1 means "to the end of the backing buffer"
156 * Will throw BoundsError if 'backing_offset'/'length'
157 * is beyond the bounds of the backing tvbuff.
158 * Can throw ReportedBoundsError. */
159 extern void tvb_set_subset(tvbuff_t* tvb, tvbuff_t* backing,
160 gint backing_offset, gint backing_length, gint reported_length);
162 /* Combination of tvb_new() and tvb_set_subset()
163 * Can throw ReportedBoundsError. */
164 extern tvbuff_t* tvb_new_subset(tvbuff_t* backing,
165 gint backing_offset, gint backing_length, gint reported_length);
168 /* Both tvb_composite_append and tvb_composite_prepend can throw
169 * BoundsError if member_offset/member_length goes beyond bounds of
170 * the 'member' tvbuff. */
172 /* Append to the list of tvbuffs that make up this composite tvbuff */
173 extern void tvb_composite_append(tvbuff_t* tvb, tvbuff_t* member);
175 /* Prepend to the list of tvbuffs that make up this composite tvbuff */
176 extern void tvb_composite_prepend(tvbuff_t* tvb, tvbuff_t* member);
178 /* Helper function that calls tvb_new(TVBUFF_COMPOSITE).
179 * Provided only to maintain symmetry with other constructors */
180 extern tvbuff_t* tvb_new_composite(void);
182 /* Mark a composite tvbuff as initialized. No further appends or prepends
183 * occur, data access can finally happen after this finalization. */
184 extern void tvb_composite_finalize(tvbuff_t* tvb);
187 /* Get total length of buffer */
188 extern guint tvb_length(tvbuff_t*);
190 /* Computes bytes to end of buffer, from offset (which can be negative,
191 * to indicate bytes from end of buffer). Function returns -1 to
192 * indicate that offset is out of bounds. No exception is thrown. */
193 extern gint tvb_length_remaining(tvbuff_t*, gint offset);
195 /* Same as above, but throws an exception if the offset is out of bounds. */
196 extern guint tvb_ensure_length_remaining(tvbuff_t*, gint offset);
198 /* Checks (w/o throwing exception) that the bytes referred to by
199 * 'offset'/'length' actually exist in the buffer */
200 extern gboolean tvb_bytes_exist(tvbuff_t*, gint offset, gint length);
202 /* Checks that the bytes referred to by 'offset'/'length' actually exist
203 * in the buffer, and throws an exception if they aren't. */
204 extern void tvb_ensure_bytes_exist(tvbuff_t *tvb, gint offset, gint length);
206 /* Checks (w/o throwing exception) that offset exists in buffer */
207 extern gboolean tvb_offset_exists(tvbuff_t*, gint offset);
209 /* Get reported length of buffer */
210 extern guint tvb_reported_length(tvbuff_t*);
212 /* Computes bytes of reported packet data to end of buffer, from offset
213 * (which can be negative, to indicate bytes from end of buffer). Function
214 * returns -1 to indicate that offset is out of bounds. No exception is
216 extern gint tvb_reported_length_remaining(tvbuff_t *tvb, gint offset);
218 /* Set the reported length of a tvbuff to a given value; used for protocols
219 whose headers contain an explicit length and where the calling
220 dissector's payload may include padding as well as the packet for
223 Also adjusts the data length. */
224 extern void tvb_set_reported_length(tvbuff_t*, guint);
226 /* Returns the offset from the first byte of real data. */
227 extern gint tvb_raw_offset(tvbuff_t*);
229 /************** START OF ACCESSORS ****************/
230 /* All accessors will throw an exception if appropriate */
232 extern guint8 tvb_get_guint8(tvbuff_t*, gint offset);
234 extern guint16 tvb_get_ntohs(tvbuff_t*, gint offset);
235 extern guint32 tvb_get_ntoh24(tvbuff_t*, gint offset);
236 extern guint32 tvb_get_ntohl(tvbuff_t*, gint offset);
237 extern gfloat tvb_get_ntohieee_float(tvbuff_t*, gint offset);
238 extern gdouble tvb_get_ntohieee_double(tvbuff_t*, gint offset);
240 extern guint16 tvb_get_letohs(tvbuff_t*, gint offset);
241 extern guint32 tvb_get_letoh24(tvbuff_t*, gint offset);
242 extern guint32 tvb_get_letohl(tvbuff_t*, gint offset);
243 extern gfloat tvb_get_letohieee_float(tvbuff_t*, gint offset);
244 extern gdouble tvb_get_letohieee_double(tvbuff_t*, gint offset);
246 /* Returns target for convenience. Does not suffer from possible
247 * expense of tvb_get_ptr(), since this routine is smart enough
248 * to copy data in chunks if the request range actually exists in
249 * different TVBUFF_REAL_DATA tvbuffs. This function assumes that the
250 * target memory is already allocated; it does not allocate or free the
252 extern guint8* tvb_memcpy(tvbuff_t*, guint8* target, gint offset, gint length);
254 /* It is the user's responsibility to g_free() the memory allocated by
255 * tvb_memdup(). Calls tvb_memcpy() */
256 extern guint8* tvb_memdup(tvbuff_t*, gint offset, gint length);
258 /* WARNING! This function is possibly expensive, temporarily allocating
259 * another copy of the packet data. Furthermore, it's dangerous because once
260 * this pointer is given to the user, there's no guarantee that the user will
261 * honor the 'length' and not overstep the boundaries of the buffer.
263 * The returned pointer is data that is internal to the tvbuff, so do not
264 * attempt to free it. Don't modify the data, either, because another tvbuff
265 * that might be using this tvbuff may have already copied that portion of
266 * the data (sometimes tvbuff's need to make copies of data, but that's the
267 * internal implementation that you need not worry about). Assume that the
268 * guint8* points to read-only data that the tvbuff manages.
270 * Return a pointer into our buffer if the data asked for via 'offset'/'length'
271 * is contiguous (which might not be the case for TVBUFF_COMPOSITE). If the
272 * data is not contiguous, a tvb_memdup() is called for the entire buffer
273 * and the pointer to the newly-contiguous data is returned. This dynamically-
274 * allocated memory will be freed when the tvbuff is freed, after the
275 * tvbuff_free_cb_t() is called, if any. */
276 extern const guint8* tvb_get_ptr(tvbuff_t*, gint offset, gint length);
278 /* Find first occurence of any of the needles in tvbuff, starting at offset.
279 * Searches at most maxlength number of bytes; if maxlength is -1, searches
281 * Returns the offset of the found needle, or -1 if not found.
282 * Will not throw an exception, even if maxlength exceeds boundary of tvbuff;
283 * in that case, -1 will be returned if the boundary is reached before
285 extern gint tvb_find_guint8(tvbuff_t*, gint offset, gint maxlength,
288 /* Find first occurence of any of the needles in tvbuff, starting at offset.
289 * Searches at most maxlength number of bytes. Returns the offset of the
290 * found needle, or -1 if not found. Will not throw an exception, even if
291 * maxlength exceeds boundary of tvbuff; in that case, -1 will be returned if
292 * the boundary is reached before finding needle. */
293 extern gint tvb_pbrk_guint8(tvbuff_t *, gint offset, gint maxlength,
296 /* Find size of stringz (NUL-terminated string) by looking for terminating
297 * NUL. The size of the string includes the terminating NUL.
299 * If the NUL isn't found, it throws the appropriate exception.
301 extern guint tvb_strsize(tvbuff_t *tvb, gint offset);
303 /* Find length of string by looking for end of string ('\0'), up to
304 * 'maxlength' characters'; if 'maxlength' is -1, searches to end
306 * Returns -1 if 'maxlength' reached before finding EOS. */
307 extern gint tvb_strnlen(tvbuff_t*, gint offset, guint maxlength);
310 * Format the data in the tvb from offset for size ...
312 extern guint8 * tvb_format_text(tvbuff_t *tvb, gint offset, gint size);
314 /* Looks for a stringz (NUL-terminated string) in tvbuff and copies
315 * no more than maxlength number of bytes, including terminating NUL, to buffer.
316 * Returns length of string (not including terminating NUL), or -1 if the string was
317 * truncated in the buffer due to not having reached the terminating NUL.
318 * In this way, it acts like snprintf().
320 * When processing a packet where the remaining number of bytes is less
321 * than maxlength, an exception is not thrown if the end of the packet
322 * is reached before the NUL is found. If no NUL is found before reaching
323 * the end of the short packet, -1 is still returned, and the string
324 * is truncated with a NUL, albeit not at buffer[maxlength], but
325 * at the correct spot, terminating the string.
327 extern gint tvb_get_nstringz(tvbuff_t *tvb, gint offset, guint maxlength,
330 /* Like tvb_get_nstringz(), but never returns -1. The string is guaranteed to
331 * have a terminating NUL. If the string was truncated when copied into buffer,
332 * a NUL is placed at the end of buffer to terminate it.
334 extern gint tvb_get_nstringz0(tvbuff_t *tvb, gint offset, guint maxlength,
338 * Given a tvbuff, an offset into the tvbuff, and a length that starts
339 * at that offset (which may be -1 for "all the way to the end of the
340 * tvbuff"), find the end of the (putative) line that starts at the
341 * specified offset in the tvbuff, going no further than the specified
344 * Return the length of the line (not counting the line terminator at
345 * the end), or, if we don't find a line terminator:
347 * if "deseg" is true, return -1;
349 * if "deseg" is false, return the amount of data remaining in
352 * Set "*next_offset" to the offset of the character past the line
353 * terminator, or past the end of the buffer if we don't find a line
354 * terminator. (It's not set if we return -1.)
356 extern gint tvb_find_line_end(tvbuff_t *tvb, gint offset, int len,
357 gint *next_offset, gboolean desegment);
360 * Given a tvbuff, an offset into the tvbuff, and a length that starts
361 * at that offset (which may be -1 for "all the way to the end of the
362 * tvbuff"), find the end of the (putative) line that starts at the
363 * specified offset in the tvbuff, going no further than the specified
366 * However, treat quoted strings inside the buffer specially - don't
367 * treat newlines in quoted strings as line terminators.
369 * Return the length of the line (not counting the line terminator at
370 * the end), or the amount of data remaining in the buffer if we don't
371 * find a line terminator.
373 * Set "*next_offset" to the offset of the character past the line
374 * terminator, or past the end of the buffer if we don't find a line
377 extern gint tvb_find_line_end_unquoted(tvbuff_t *tvb, gint offset, int len,
381 * Call strncmp after checking if enough chars left, returning 0 if
382 * it returns 0 (meaning "equal") and -1 otherwise, otherwise return -1.
384 extern gint tvb_strneql(tvbuff_t *tvb, gint offset, const guint8 *str,
388 * Call strncasecmp after checking if enough chars left, returning 0 if
389 * it returns 0 (meaning "equal") and -1 otherwise, otherwise return -1.
391 extern gint tvb_strncaseeql(tvbuff_t *tvb, gint offset, const guint8 *str,
395 * Call memcmp after checking if enough chars left, returning 0 if
396 * it returns 0 (meaning "equal") and -1 otherwise, otherwise return -1.
398 extern gint tvb_memeql(tvbuff_t *tvb, gint offset, const guint8 *str,
402 * Format a bunch of data from a tvbuff as bytes, returning a pointer
403 * to the string with the formatted data.
405 extern gchar *tvb_bytes_to_str(tvbuff_t *tvb, gint offset, gint len);
407 extern tvbuff_t *tvb_get_ds_tvb(tvbuff_t *tvb);
409 /************** END OF ACCESSORS ****************/
411 #endif /* __TVBUFF_H__ */