aboutsummaryrefslogtreecommitdiffstats
path: root/include/apr_encode.h
blob: 20fc932f6f5464b011b9a084d8f4bd54ea1a697a (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
/* Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/**
 * @file apr_encode.h
 * @brief APR-UTIL Encoding
 */
#ifndef APR_ENCODE_H
#define APR_ENCODE_H

#include "apr.h"
#include "apr_general.h"

#ifdef __cplusplus
extern "C" {
#endif

/**
 * @defgroup APR_Util_Encode Base64/Base64Url/Base32/Base32Hex/Base16 Encoding
 * @ingroup APR_Util
 * @{
 */

/**
 * RFC4648 and RFC7515 compliant BASE64, BASE64URL, BASE32, BASE32HEX
 * and BASE16 encode/decode functions.
 *
 * The following encodings are supported:
 *
 * - Base 64 Encoding
 *
 *   o Use flag APR_ENCODE_NONE
 *   o https://tools.ietf.org/html/rfc4648#section-4
 *
 * - Base 64 Encoding with URL and Filename Safe Alphabet
 *
 *   o Use flag APR_ENCODE_URL
 *   o https://tools.ietf.org/html/rfc4648#section-5
 *
 * - Base 64 URL Encoding without Padding
 *
 *   o Use flag APR_ENCODE_BASE64URL
 *   o https://tools.ietf.org/html/rfc7515#appendix-C
 *
 * - Base 32 Encoding
 *
 *   o Use flag APR_ENCODE_NONE
 *   o https://tools.ietf.org/html/rfc4648#section-6
 *
 * - Base 32 Encoding with Extended Hex Alphabet
 *
 *   o Use flag APR_ENCODE_BASE32HEX
 *   o https://tools.ietf.org/html/rfc4648#section-7
 *
 * - Base 16 Encoding
 *
 *   o Use flags APR_ENCODE_NONE/APR_ENCODE_COLON
 *   o https://tools.ietf.org/html/rfc4648#section-8
 *
 * If a non valid character of any kind including whitespace is passed to any
 * of the decoder functions, APR_BADCH will be returned. In this case decoding
 * will still take place, but the results can not be trusted.
 *
 * If APR_ENCODE_RELAXED is passed to the decoder functions, decoding will be
 * attempted up until the first non valid character. If this results in an
 * invalid state in the decoder, such as but not limited to an odd number of
 * base16 characters, APR_BADCH will still be returned.
 *
 * If APR_ENCODE_RELAXED is not passed to a decoder function, the decoding will
 * be done in constant time regardless of whether the result returns APR_SUCCESS
 * or APR_BADCH.
 *
 * If the dest parameter is NULL, the maximum theoretical buffer size is
 * returned in the len field, including space for a terminating zero character
 * if the destination is a string. This value can be used to allocate buffers
 * of a suitable safe size.
 *
 * If the dest parameter is provided, the encoding or decoding will take place,
 * and the actual number of characters written is returned in the len field,
 * ignoring any terminating zero.
 *
 * Plain strings are not assumed '\0' terminated unless APR_ENCODE_STRING is
 * provided.
 *
 */

/**
 * When passing a string to one of the encode functions, this value can be
 * passed to indicate a string-valued key, and have the length computed
 * automatically.
 */
#define APR_ENCODE_STRING      (-1)

/**
 * Generate RFC4648 base16/base32/base64.
 */
#define APR_ENCODE_NONE 0

/**
 * If relaxed, decode up until the first non base16/base32/base64 character.
 */
#define APR_ENCODE_RELAXED 1

/**
 * Omit the padding character (=) while encoding.
 */
#define APR_ENCODE_NOPADDING 2

/**
 * Generate RFC4648 Base 64 Encoding with URL and Filename Safe Alphabet
 */
#define APR_ENCODE_URL 4

/**
 * Generate RFC7515 BASE64URL
 */
#define APR_ENCODE_BASE64URL (APR_ENCODE_NOPADDING | APR_ENCODE_URL)

/**
 * Generate base32hex encoding instead of base32 encoding
 */
#define APR_ENCODE_BASE32HEX 8

/**
 * Generate base16 with colons between each token.
 */
#define APR_ENCODE_COLON 16

/**
 * Generate base16 with lower case characters.
 */
#define APR_ENCODE_LOWER 32

/**
 * Convert text data to base64.
 * @param dest The destination string, can be NULL.
 * @param src The original string.
 * @param slen The length of the original string, or APR_ENCODE_STRING if
 * NUL terminated.
 * @param flags If APR_ENCODE_NONE, emit RFC4648 Base 64 Encoding. If
 *  APR_ENCODE_NOPADDING, omit the = padding character.	If APR_ENCODE_URL,
 *  use RFC4648 Base 64 Encoding with URL and Filename Safe Alphabet.
 * 	If APR_ENCODE_BASE64URL, use RFC7515 base64url Encoding.
 * @param len If present and src is NULL, returns the maximum possible length
 *  of the destination string, including a zero pad. If present and src is
 *  not NULL, returns the number of characters actually written.
 * @return APR_SUCCESS, or APR_NOTFOUND if the string was NULL.
 */
APR_DECLARE(apr_status_t) apr_encode_base64(char *dest, const char *src,
        apr_ssize_t slen, int flags, apr_size_t * len);

/**
 * Convert binary data to base64.
 * @param dest The destination string, can be NULL.
 * @param src The original buffer.
 * @param slen The length of the original buffer.
 * @param flags If APR_ENCODE_NONE, emit RFC4648 Base 64 Encoding. If
 *  APR_ENCODE_NOPADDING, omit the = padding character.	If APR_ENCODE_URL,
 *  use RFC4648 Base 64 Encoding with URL and Filename Safe Alphabet.
 * 	If APR_ENCODE_BASE64URL, use RFC7515 base64url Encoding.
 * @param len If present and src is NULL, returns the maximum possible length
 *  of the destination string, including a zero pad. If present and src is
 *  not NULL, returns the number of characters actually written.
 * @return APR_SUCCESS, or APR_NOTFOUND if the string was NULL.
 */
APR_DECLARE(apr_status_t) apr_encode_base64_binary(char *dest, const unsigned char *src,
        apr_ssize_t slen, int flags, apr_size_t * len);

/**
 * Convert text data to base64, and return the results from a pool.
 * @param p Pool to allocate from.
 * @param src The original string.
 * @param slen The length of the original string, or APR_ENCODE_STRING if
 * NUL terminated.
 * @param flags If APR_ENCODE_NONE, emit RFC4648 Base 64 Encoding. If
 *  APR_ENCODE_NOPADDING, omit the = padding character.	If APR_ENCODE_URL,
 *  use RFC4648 Base 64 Encoding with URL and Filename Safe Alphabet.
 * 	If APR_ENCODE_BASE64URL, use RFC7515 base64url Encoding.
 * @param len If present, returns the number of characters written excluding
 *  the zero pad.
 * @return A zero padded string allocated from the pool on success, or
 * NULL if src was NULL.
 */
APR_DECLARE(const char *)apr_pencode_base64(apr_pool_t * p, const char *src,
        apr_ssize_t slen, int flags, apr_size_t * len)__attribute__((nonnull(1)));

/**
 * Convert binary data to base64, and return the results from a pool.
 * @param p Pool to allocate from.
 * @param src The original buffer.
 * @param slen The length of the original buffer.
 * @param flags If APR_ENCODE_NONE, emit RFC4648 Base 64 Encoding. If
 *  APR_ENCODE_NOPADDING, omit the = padding character.	If APR_ENCODE_URL,
 *  use RFC4648 Base 64 Encoding with URL and Filename Safe Alphabet.
 * 	If APR_ENCODE_BASE64URL, use RFC7515 base64url Encoding.
 * @param len If present, returns the number of characters written excluding
 *  the zero pad.
 * @return A zero padded string allocated from the pool on success, or
 * NULL if src was NULL.
 */
APR_DECLARE(const char *)apr_pencode_base64_binary(apr_pool_t * p, const unsigned char *src,
        apr_ssize_t slen, int flags, apr_size_t * len)__attribute__((nonnull(1)));

/**
 * Convert base64 or base64url with or without padding to text data.
 * @param dest The destination string, can be NULL.
 * @param src The original string.
 * @param slen The length of the original string, or APR_ENCODE_STRING if
 * NUL terminated.
 * @param flags If APR_ENCODE_NONE, attempt to decode the full original buffer,
 *  and return NULL if any bad character is detected. If APR_ENCODE_RELAXED,
 *  decode until the first non base64/base64url character.
 * @param len If present and src is NULL, returns the maximum possible length
 *  of the destination string, including a zero pad. If present and src is
 *  not NULL, returns the number of characters actually written.
 * @return APR_SUCCESS, or APR_NOTFOUND if the string was NULL, or APR_BADCH
 * if a non hex character is present.
 */
APR_DECLARE(apr_status_t) apr_decode_base64(char *dest, const char *src,
        apr_ssize_t slen, int flags, apr_size_t * len);

/**
 * Convert base64 or base64url with or without padding to binary data.
 * @param dest The destination buffer, can be NULL.
 * @param src The original string.
 * @param slen The length of the original string, or APR_ENCODE_STRING if
 * NUL terminated.
 * @param flags If APR_ENCODE_NONE, attempt to decode the full original buffer,
 *  and return NULL if any bad character is detected. If APR_ENCODE_RELAXED,
 *  decode until the first non base64/base64url character.
 * @param len If present and src is NULL, returns the maximum possible length
 *  of the destination buffer, including a zero pad. If present and src is
 *  not NULL, returns the number of characters actually written.
 * @return APR_SUCCESS, or APR_NOTFOUND if the src was NULL, or APR_BADCH
 * if a non base64 character is present.
 */
APR_DECLARE(apr_status_t) apr_decode_base64_binary(unsigned char *dest,
        const char *src, apr_ssize_t slen, int flags, apr_size_t * len);

/**
 * Convert base64 or base64url with or without padding to text data, and
 * return the results from a pool.
 * @param p Pool to allocate from.
 * @param src The base64 string to decode.
 * @param slen The length of the base64 string, or APR_ENCODE_STRING if
 * NUL terminated.
 * @param flags If APR_ENCODE_NONE, attempt to decode the full original buffer,
 *  and return NULL if any bad character is detected. If APR_ENCODE_RELAXED,
 *  decode until the first non base64/base64url character.
 * @param len If present, returns the number of characters written, excluding
 *  the zero padding.
 * @return A string allocated from the pool containing the result with a zero
 *  pad. If src was NULL, or an error occurred, NULL is returned.
 */
APR_DECLARE(const char *)apr_pdecode_base64(apr_pool_t * p, const char *src,
        apr_ssize_t slen, int flags, apr_size_t * len)
        __attribute__((nonnull(1)));

/**
 * Convert base64 or base64url with or without padding to binary data, and
 * return the results from a pool.
 * @param p Pool to allocate from.
 * @param src The original string.
 * @param slen The length of the original string, or APR_ENCODE_STRING if
 *  NUL terminated.
 * @param flags If APR_ENCODE_NONE, attempt to decode the full original buffer,
 *  and return NULL if any bad character is detected. If APR_ENCODE_RELAXED,
 *  decode until the first non base64/base64url character.
 * @param len If present, returns the number of characters written, excluding
 *  the zero padding.
 * @return A buffer allocated from the pool containing the result with a zero
 *  pad. If src was NULL, or an error occurred, NULL is returned.
 */
APR_DECLARE(const unsigned char *)apr_pdecode_base64_binary(apr_pool_t * p,
        const char *src, apr_ssize_t slen, int flags, apr_size_t * len)
        __attribute__((nonnull(1)));

/**
 * Convert text data to base32.
 * @param dest The destination string, can be NULL.
 * @param src The original string.
 * @param slen The length of the original string, or APR_ENCODE_STRING if
 * NUL terminated.
 * @param flags If APR_ENCODE_NONE, emit RFC4648 Base 32 Encoding. If
 *  APR_ENCODE_NOPADDING, omit the = padding character.	If APR_ENCODE_BASE32HEX,
 *  use RFC4648 base32hex Encoding.
 * @param len If present and src is NULL, returns the maximum possible length
 *  of the destination string, including a zero pad. If present and src is
 *  not NULL, returns the number of characters actually written.
 * @return APR_SUCCESS, or APR_NOTFOUND if the string was NULL.
 */
APR_DECLARE(apr_status_t) apr_encode_base32(char *dest, const char *src,
        apr_ssize_t slen, int flags, apr_size_t * len);

/**
 * Convert binary data to base32.
 * @param dest The destination string, can be NULL.
 * @param src The original buffer.
 * @param slen The length of the original buffer.
 * @param flags If APR_ENCODE_NONE, emit RFC4648 Base 32 Encoding. If
 *  APR_ENCODE_NOPADDING, omit the = padding character.	If APR_ENCODE_BASE32HEX,
 *  use RFC4648 base32hex Encoding.
 * @param len If present and src is NULL, returns the maximum possible length
 *  of the destination string, including a zero pad. If present and src is
 *  not NULL, returns the number of characters actually written.
 * @return APR_SUCCESS, or APR_NOTFOUND if the string was NULL.
 */
APR_DECLARE(apr_status_t) apr_encode_base32_binary(char *dest, const unsigned char *src,
        apr_ssize_t slen, int flags, apr_size_t * len);

/**
 * Convert text data to base32, and return the results from a pool.
 * @param p Pool to allocate from.
 * @param src The original string.
 * @param slen The length of the original string, or APR_ENCODE_STRING if
 * NUL terminated.
 * @param flags If APR_ENCODE_NONE, emit RFC4648 Base 32 Encoding. If
 *  APR_ENCODE_NOPADDING, omit the = padding character.	If APR_ENCODE_BASE32HEX,
 *  use RFC4648 base32hex Encoding.
 * @param len If present, returns the number of characters written excluding
 *  the zero pad.
 * @return A zero padded string allocated from the pool on success, or
 * NULL if src was NULL.
 */
APR_DECLARE(const char *)apr_pencode_base32(apr_pool_t * p, const char *src,
        apr_ssize_t slen, int flags, apr_size_t * len)
        __attribute__((nonnull(1)));

/**
 * Convert binary data to base32, and return the results from a pool.
 * @param p Pool to allocate from.
 * @param src The original buffer.
 * @param slen The length of the original buffer.
 * @param flags If APR_ENCODE_NONE, emit RFC4648 Base 32 Encoding. If
 *  APR_ENCODE_NOPADDING, omit the = padding character.	If APR_ENCODE_BASE32HEX,
 *  use RFC7515 base32hex Encoding.
 * @param len If present, returns the number of characters written excluding
 *  the zero pad.
 * @return A zero padded string allocated from the pool on success, or
 * NULL if src was NULL.
 */
APR_DECLARE(const char *)apr_pencode_base32_binary(apr_pool_t * p, const unsigned char *src,
        apr_ssize_t slen, int flags, apr_size_t * len)
        __attribute__((nonnull(1)));

/**
 * Convert base32 or base32hex with or without padding to text data.
 * @param dest The destination string, can be NULL.
 * @param src The original string.
 * @param slen The length of the original string, or APR_ENCODE_STRING if
 * NUL terminated.
 * @param flags If APR_ENCODE_NONE, parse RFC4648 Base 32 Encoding. If
 *  APR_ENCODE_BASE32HEX, use RFC4648 base32hex Encoding.
 * @param len If present and src is NULL, returns the maximum possible length
 *  of the destination buffer, including a zero pad. If present and src is
 *  not NULL, returns the number of characters actually written.
 * @return APR_SUCCESS, or APR_NOTFOUND if the string was NULL, or APR_BADCH
 * if a non base32 character is present.
 */
APR_DECLARE(apr_status_t) apr_decode_base32(char *dest, const char *src,
        apr_ssize_t slen, int flags, apr_size_t * len);

/**
 * Convert base32 or base32hex with or without padding to binary data.
 * @param dest The destination buffer, can be NULL.
 * @param src The original string.
 * @param slen The length of the original string, or APR_ENCODE_STRING if
 * NUL terminated.
 * @param flags If APR_ENCODE_NONE, parse RFC4648 Base 32 Encoding. If
 *  APR_ENCODE_BASE32HEX, use RFC4648 base32hex Encoding.
 * @param len If present and src is NULL, returns the maximum possible length
 *  of the destination buffer, including a zero pad. If present and src is
 *  not NULL, returns the number of characters actually written.
 * @return APR_SUCCESS, or APR_NOTFOUND if the src was NULL, or APR_BADCH
 * if a non base32 character is present.
 */
APR_DECLARE(apr_status_t) apr_decode_base32_binary(unsigned char *dest,
        const char *src, apr_ssize_t slen, int flags, apr_size_t * len);

/**
 * Convert base32 or base32hex with or without padding to text data, and
 * return the results from a pool.
 * @param p Pool to allocate from.
 * @param src The base32 string to decode.
 * @param slen The length of the base32 string, or APR_ENCODE_STRING if
 * NUL terminated.
 * @param flags If APR_ENCODE_NONE, parse RFC4648 Base 32 Encoding. If
 *  APR_ENCODE_BASE32HEX, use RFC4648 base32hex Encoding.
 * @param len If present, returns the number of characters written, excluding
 *  the zero padding.
 * @return A string allocated from the pool containing the result with a zero
 *  pad. If src was NULL, or an error occurred, NULL is returned.
 */
APR_DECLARE(const char *)apr_pdecode_base32(apr_pool_t * p, const char *src,
        apr_ssize_t slen, int flags, apr_size_t * len)
        __attribute__((nonnull(1)));

/**
 * Convert base32 or base32hex with or without padding to binary data, and
 * return the results from a pool.
 * @param p Pool to allocate from.
 * @param src The original string.
 * @param slen The length of the original string, or APR_ENCODE_STRING if
 *  NUL terminated.
 * @param flags If APR_ENCODE_NONE, parse RFC4648 Base 32 Encoding. If
 *  APR_ENCODE_BASE32HEX, use RFC4648 base32hex Encoding.
 * @param len If present, returns the number of characters written, excluding
 *  the zero padding.
 * @return A buffer allocated from the pool containing the result with a zero
 *  pad. If src was NULL, or an error occurred, NULL is returned.
 */
APR_DECLARE(const unsigned char *)apr_pdecode_base32_binary(apr_pool_t * p,
        const char *src, apr_ssize_t slen, int flags, apr_size_t * len)
        __attribute__((nonnull(1)));

/**
 * Convert text data to base16 (hex).
 * @param dest The destination string, can be NULL.
 * @param src The original string.
 * @param slen The length of the original string, or APR_ENCODE_STRING if
 * NUL terminated.
 * @param flags If APR_ENCODE_NONE, emit RFC4648 Base 16 Encoding. If
 *  APR_ENCODE_COLON, separate each token with a colon.
 * @param len If present and src is NULL, returns the maximum possible length
 *  of the destination buffer, including a zero pad. If present and src is
 *  not NULL, returns the number of characters actually written.
 * @return APR_SUCCESS, or APR_NOTFOUND if the string was NULL.
 */
APR_DECLARE(apr_status_t) apr_encode_base16(char *dest, const char *src,
        apr_ssize_t slen, int flags, apr_size_t * len);

/**
 * Convert binary data to base16 (hex).
 * @param dest The destination string, can be NULL.
 * @param src The original buffer.
 * @param slen The length of the original buffer.
 * @param flags If APR_ENCODE_NONE, emit RFC4648 Base 16 Encoding. If
 *  APR_ENCODE_COLON, separate each token with a colon.
 * @param len If present and src is NULL, returns the maximum possible length
 *  of the destination buffer, including a zero pad. If present and src is
 *  not NULL, returns the number of characters actually written.
 * @return APR_SUCCESS, or APR_NOTFOUND if the string was NULL.
 */
APR_DECLARE(apr_status_t) apr_encode_base16_binary(char *dest,
        const unsigned char *src, apr_ssize_t slen, int flags,
        apr_size_t * len);

/**
 * Convert text data to base16 (hex), and return the results from a
 * pool.
 * @param p Pool to allocate from.
 * @param src The original string.
 * @param slen The length of the original string, or APR_ENCODE_STRING if
 * NUL terminated.
 * @param flags If APR_ENCODE_NONE, emit RFC4648 Base 16 Encoding. If
 *  APR_ENCODE_COLON, separate each token with a colon.
 * @param len If present, returns the number of characters written, excluding
 *  the zero padding.
 * @return A string allocated from the pool containing the result with a zero
 *  pad. If src was NULL, or an error occurred, NULL is returned.
 */
APR_DECLARE(const char *)apr_pencode_base16(apr_pool_t * p, const char *src,
        apr_ssize_t slen, int flags, apr_size_t * len)
        __attribute__((nonnull(1)));

/**
 * Convert binary data to base16 (hex), and return the results from a
 * pool.
 * @param p Pool to allocate from.
 * @param src The original buffer.
 * @param slen The length of the original buffer.
 * @param flags If APR_ENCODE_NONE, emit RFC4648 Base 16 Encoding. If
 *  APR_ENCODE_COLON, separate each token with a colon.
 * @param len If present, returns the number of characters written, excluding
 *  the zero padding.
 * @return A string allocated from the pool containing the result with a zero
 *  pad. If src was NULL, or an error occurred, NULL is returned.
 */
APR_DECLARE(const char *)apr_pencode_base16_binary(apr_pool_t * p,
        const unsigned char *src, apr_ssize_t slen,
        int flags, apr_size_t * len)__attribute__((nonnull(1)));

/**
 * Convert base16 (hex) to text data.
 * @param dest The destination string, can be NULL.
 * @param src The original string.
 * @param slen The length of the original string, or APR_ENCODE_STRING if
 * NUL terminated.
 * @param flags If APR_ENCODE_NONE, parse RFC4648 Base 16 Encoding. If
 *  APR_ENCODE_COLON, allow tokens to be separated with a colon.
 * @param len If present and src is NULL, returns the maximum possible length
 *  of the destination buffer, including a zero pad. If present and src is
 *  not NULL, returns the number of characters actually written.
 * @return APR_SUCCESS, or APR_NOTFOUND if the string was NULL, or APR_BADCH
 * if a non hex character is present. A zero pad is appended to the buffer.
 */
APR_DECLARE(apr_status_t) apr_decode_base16(char *dest, const char *src,
        apr_ssize_t slen, int flags, apr_size_t * len);

/**
 * Convert base16 (hex) to binary data.
 * @param dest The destination buffer, can be NULL.
 * @param src The original string.
 * @param slen The length of the original string, or APR_ENCODE_STRING if
 * NUL terminated.
 * @param flags If APR_ENCODE_NONE, parse RFC4648 Base 16 Encoding. If
 *  APR_ENCODE_COLON, allow tokens to be separated with a colon.
 * @param len If present and src is NULL, returns the maximum possible length
 *  of the destination buffer, including a zero pad. If present and src is
 *  not NULL, returns the number of characters actually written.
 * @return APR_SUCCESS, or APR_NOTFOUND if the string was NULL, or APR_BADCH
 * if a non hex character is present. No zero pad is written to the buffer.
 */
APR_DECLARE(apr_status_t) apr_decode_base16_binary(unsigned char *dest,
        const char *src, apr_ssize_t slen, int flags, apr_size_t * len);

/**
 * Convert base16 (hex) and return the results from a pool.
 * @param p Pool to allocate from.
 * @param src The original string.
 * @param slen The length of the original string, or APR_ENCODE_STRING if
 * NUL terminated.
 * @param flags If APR_ENCODE_NONE, parse RFC4648 Base 16 Encoding. If
 *  APR_ENCODE_COLON, allow tokens to be separated with a colon.
 * @param len If present, returns the number of characters written, excluding
 *  the zero padding.
 * @return A buffer allocated from the pool containing the result with a zero
 *  pad. If src was NULL, or an error occurred, NULL is returned.
 */
APR_DECLARE(const char *)apr_pdecode_base16(apr_pool_t * p, const char *src,
        apr_ssize_t slen, int flags, apr_size_t * len)
        __attribute__((nonnull(1)));

/**
 * Convert base16 (hex) to binary data, and return the results from a pool.
 * @param p Pool to allocate from.
 * @param src The original string.
 * @param slen The length of the original string, or APR_ENCODE_STRING if
 * NUL terminated.
 * @param flags If APR_ENCODE_NONE, parse RFC4648 Base 16 Encoding. If
 *  APR_ENCODE_COLON, allow tokens to be separated with a colon.
 * @param len If present, returns the number of characters written, excluding
 *  the zero padding.
 * @return A buffer allocated from the pool containing the result with a zero
 *  pad. If src was NULL, or an error occurred, NULL is returned.
 */
APR_DECLARE(const unsigned char *)apr_pdecode_base16_binary(apr_pool_t * p,
        const char *src, apr_ssize_t slen, int flags, apr_size_t * len)
        __attribute__((nonnull(1)));

/** @} */
#ifdef __cplusplus
}
#endif

#endif                          /* !APR_ENCODE_H */