base64.cpp@ 34079

Last change on this file since 34079 was 33540, checked in by vboxsync, 14 years ago
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1	/* $Id: base64.cpp 33540 2010-10-28 09:27:05Z vboxsync $ */
2	/** @file
3	* IPRT - Base64, MIME content transfer encoding.
4	*/
5
6	/*
7	* Copyright (C) 2009 Oracle Corporation
8	*
9	* This file is part of VirtualBox Open Source Edition (OSE), as
10	* available from http://www.virtualbox.org. This file is free software;
11	* you can redistribute it and/or modify it under the terms of the GNU
12	* General Public License (GPL) as published by the Free Software
13	* Foundation, in version 2 as it comes in the "COPYING" file of the
14	* VirtualBox OSE distribution. VirtualBox OSE is distributed in the
15	* hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
16	*
17	* The contents of this file may alternatively be used under the terms
18	* of the Common Development and Distribution License Version 1.0
19	* (CDDL) only, as it comes in the "COPYING.CDDL" file of the
20	* VirtualBox OSE distribution, in which case the provisions of the
21	* CDDL are applicable instead of those of the GPL.
22	*
23	* You may elect to license modified versions of this file under the
24	* terms and conditions of either the GPL or the CDDL or both.
25	*/
26
27
28	/*******************************************************************************
29	* Header Files *
30	*******************************************************************************/
31	#include <iprt/base64.h>
32	#include "internal/iprt.h"
33
34	#include <iprt/assert.h>
35	#include <iprt/err.h>
36	#include <iprt/ctype.h>
37	#ifdef RT_STRICT
38	# include <iprt/asm.h>
39	#endif
40
41
42	/*******************************************************************************
43	* Defined Constants And Macros *
44	*******************************************************************************/
45	/** The line length used for encoding. */
46	#define RTBASE64_LINE_LEN 64
47
48	/** @name Special g_au8CharToVal values
49	* @{ */
50	#define BASE64_SPACE 0xc0
51	#define BASE64_PAD 0xe0
52	#define BASE64_INVALID 0xff
53	/** @} */
54
55
56	/*******************************************************************************
57	* Global Variables *
58	*******************************************************************************/
59	/** Base64 character to value. (RFC 2045)
60	* ASSUMES ASCII / UTF-8. */
61	static const uint8_t g_au8CharToVal[256] =
62	{
63	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xc0, 0xc0, 0xc0, 0xc0, 0xc0, 0xff, 0xff, /* 0x00..0x0f */
64	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 0x10..0x1f */
65	0xc0, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 62, 0xff, 0xff, 0xff, 63, /* 0x20..0x2f */
66	52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 0xff, 0xff, 0xff, 0xe0, 0xff, 0xff, /* 0x30..0x3f */
67	0xff, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, /* 0x40..0x4f */
68	15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 0xff, 0xff, 0xff, 0xff, 0xff, /* 0x50..0x5f */
69	0xff, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, /* 0x60..0x6f */
70	41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 0xff, 0xff, 0xff, 0xff, 0xff, /* 0x70..0x7f */
71	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 0x80..0x8f */
72	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 0x90..0x9f */
73	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 0xa0..0xaf */
74	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 0xb0..0xbf */
75	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 0xc0..0xcf */
76	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 0xd0..0xdf */
77	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 0xe0..0xef */
78	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff /* 0xf0..0xff */
79	};
80
81	/** Value to Base64 character. (RFC 2045) */
82	static const char g_szValToChar[64+1] =
83	"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
84
85
86	#ifdef RT_STRICT
87	/**
88	* Perform table sanity checks on the first call.
89	*/
90	static void rtBase64Sanity(void)
91	{
92	static bool s_fSane = false;
93	if (RT_UNLIKELY(!s_fSane))
94	{
95	for (unsigned i = 0; i < 64; i++)
96	{
97	unsigned ch = g_szValToChar[i];
98	Assert(ch);
99	Assert(g_au8CharToVal[ch] == i);
100	}
101
102	for (unsigned i = 0; i < 256; i++)
103	{
104	uint8_t u8 = g_au8CharToVal[i];
105	Assert( ( u8 == BASE64_INVALID
106	&& !RT_C_IS_ALNUM(i)
107	&& !RT_C_IS_SPACE(i))
108	\|\| ( u8 == BASE64_PAD
109	&& i == '=')
110	\|\| ( u8 == BASE64_SPACE
111	&& ( RT_C_IS_SPACE(i)
112	\|\| (i == '\r'))) /* Carriage return is handled as a space character as well. */
113	\|\| ( u8 < 64
114	&& (unsigned)g_szValToChar[u8] == i));
115	}
116	ASMAtomicWriteBool(&s_fSane, true);
117	}
118	}
119	#endif /* RT_STRICT */
120
121
122	/**
123	* Calculates the decoded data size for a Base64 encoded string.
124	*
125	* @returns The length in bytes. -1 if the encoding is bad.
126	*
127	* @param pszString The Base64 encoded string.
128	* @param ppszEnd If not NULL, this will point to the first char
129	* following the Base64 encoded text block. If
130	* NULL the entire string is assumed to be Base64.
131	*/
132	RTDECL(ssize_t) RTBase64DecodedSize(const char pszString, char *ppszEnd)
133	{
134	#ifdef RT_STRICT
135	rtBase64Sanity();
136	#endif
137
138	/*
139	* Walk the string until a non-encoded or non-space character is encountered.
140	*/
141	uint32_t c6Bits = 0;
142	uint8_t u8 = BASE64_INVALID;
143	unsigned ch;
144	AssertCompile(sizeof(char) == sizeof(uint8_t));
145
146	while ((ch = *pszString))
147	{
148	u8 = g_au8CharToVal[ch];
149	if (u8 < 64)
150	c6Bits++;
151	else if (RT_UNLIKELY(u8 != BASE64_SPACE))
152	break;
153
154	/* advance */
155	pszString++;
156	}
157
158	/*
159	* Padding can only be found at the end and there is
160	* only 1 or 2 padding chars. Deal with it first.
161	*/
162	unsigned cbPad = 0;
163	if (u8 == BASE64_PAD)
164	{
165	cbPad = 1;
166	c6Bits++;
167	pszString++;
168	while ((ch = *pszString))
169	{
170	u8 = g_au8CharToVal[ch];
171	if (u8 != BASE64_SPACE)
172	{
173	if (u8 != BASE64_PAD)
174	break;
175	c6Bits++;
176	cbPad++;
177	}
178	pszString++;
179	}
180	if (cbPad >= 3)
181	return -1;
182	}
183
184	/*
185	* Invalid char and no where to indicate where the
186	* Base64 text ends? Return failure.
187	*/
188	if ( u8 == BASE64_INVALID
189	&& !ppszEnd
190	&& ch)
191	return -1;
192
193	/*
194	* Recalc 6-bit to 8-bit and adjust for padding.
195	*/
196	size_t cb;
197	if (c6Bits * 3 / 3 == c6Bits)
198	{
199	if ((c6Bits * 3 % 4) != 0)
200	return -1;
201	cb = c6Bits * 3 / 4;
202	}
203	else
204	{
205	if ((c6Bits * (uint64_t)3 % 4) != 0)
206	return -1;
207	cb = c6Bits * (uint64_t)3 / 4;
208	}
209
210	if (cb < cbPad)
211	return -1;
212	cb -= cbPad;
213
214	if (ppszEnd)
215	ppszEnd = (char )pszString;
216	return cb;
217	}
218	RT_EXPORT_SYMBOL(RTBase64DecodedSize);
219
220
221	/**
222	* Decodes a Base64 encoded string into the buffer supplied by the caller.
223	*
224	* @returns IPRT status code.
225	* @retval VERR_BUFFER_OVERFLOW if the buffer is too small. pcbActual will not
226	* be set, nor will ppszEnd.
227	* @retval VERR_INVALID_BASE64_ENCODING if the encoding is wrong.
228	*
229	* @param pszString The Base64 string. Whether the entire string or
230	* just the start of the string is in Base64 depends
231	* on whether ppszEnd is specified or not.
232	* @param pvData Where to store the decoded data.
233	* @param cbData The size of the output buffer that pvData points to.
234	* @param pcbActual Where to store the actual number of bytes returned.
235	* Optional.
236	* @param ppszEnd Indicates that the string may contain other stuff
237	* after the Base64 encoded data when not NULL. Will
238	* be set to point to the first char that's not part of
239	* the encoding. If NULL the entire string must be part
240	* of the Base64 encoded data.
241	*/
242	RTDECL(int) RTBase64Decode(const char pszString, void pvData, size_t cbData, size_t pcbActual, char *ppszEnd)
243	{
244	#ifdef RT_STRICT
245	rtBase64Sanity();
246	#endif
247
248	/*
249	* Process input in groups of 4 input / 3 output chars.
250	*/
251	uint8_t u8Trio[3] = { 0, 0, 0 }; /* shuts up gcc */
252	uint8_t pbData = (uint8_t )pvData;
253	uint8_t u8 = BASE64_INVALID;
254	unsigned c6Bits = 0;
255	unsigned ch;
256	AssertCompile(sizeof(char) == sizeof(uint8_t));
257
258	for (;;)
259	{
260	/* The first 6-bit group. */
261	while ((u8 = g_au8CharToVal[ch = *pszString]) == BASE64_SPACE)
262	pszString++;
263	if (u8 >= 64)
264	{
265	c6Bits = 0;
266	break;
267	}
268	u8Trio[0] = u8 << 2;
269	pszString++;
270
271	/* The second 6-bit group. */
272	while ((u8 = g_au8CharToVal[ch = *pszString]) == BASE64_SPACE)
273	pszString++;
274	if (u8 >= 64)
275	{
276	c6Bits = 1;
277	break;
278	}
279	u8Trio[0] \|= u8 >> 4;
280	u8Trio[1] = u8 << 4;
281	pszString++;
282
283	/* The third 6-bit group. */
284	while ((u8 = g_au8CharToVal[ch = *pszString]) == BASE64_SPACE)
285	pszString++;
286	if (u8 >= 64)
287	{
288	c6Bits = 2;
289	break;
290	}
291	u8Trio[1] \|= u8 >> 2;
292	u8Trio[2] = u8 << 6;
293	pszString++;
294
295	/* The fourth 6-bit group. */
296	while ((u8 = g_au8CharToVal[ch = *pszString]) == BASE64_SPACE)
297	pszString++;
298	if (u8 >= 64)
299	{
300	c6Bits = 3;
301	break;
302	}
303	u8Trio[2] \|= u8;
304	pszString++;
305
306	/* flush the trio */
307	if (cbData < 3)
308	return VERR_BUFFER_OVERFLOW;
309	cbData -= 3;
310	pbData[0] = u8Trio[0];
311	pbData[1] = u8Trio[1];
312	pbData[2] = u8Trio[2];
313	pbData += 3;
314	}
315
316	/*
317	* Padding can only be found at the end and there is
318	* only 1 or 2 padding chars. Deal with it first.
319	*/
320	unsigned cbPad = 0;
321	if (u8 == BASE64_PAD)
322	{
323	cbPad = 1;
324	pszString++;
325	while ((ch = *pszString))
326	{
327	u8 = g_au8CharToVal[ch];
328	if (u8 != BASE64_SPACE)
329	{
330	if (u8 != BASE64_PAD)
331	break;
332	cbPad++;
333	}
334	pszString++;
335	}
336	if (cbPad >= 3)
337	return VERR_INVALID_BASE64_ENCODING;
338	}
339
340	/*
341	* Invalid char and no where to indicate where the
342	* Base64 text ends? Return failure.
343	*/
344	if ( u8 == BASE64_INVALID
345	&& !ppszEnd
346	&& ch)
347	return VERR_INVALID_BASE64_ENCODING;
348
349	/*
350	* Check padding vs. pending sextets, if anything left to do finish it off.
351	*/
352	if (c6Bits \|\| cbPad)
353	{
354	if (c6Bits + cbPad != 4)
355	return VERR_INVALID_BASE64_ENCODING;
356
357	switch (c6Bits)
358	{
359	case 1:
360	u8Trio[1] = u8Trio[2] = 0;
361	break;
362	case 2:
363	u8Trio[2] = 0;
364	break;
365	case 3:
366	default:
367	break;
368	}
369	switch (3 - cbPad)
370	{
371	case 1:
372	if (cbData < 1)
373	return VERR_BUFFER_OVERFLOW;
374	cbData--;
375	pbData[0] = u8Trio[0];
376	pbData++;
377	break;
378
379	case 2:
380	if (cbData < 2)
381	return VERR_BUFFER_OVERFLOW;
382	cbData -= 2;
383	pbData[0] = u8Trio[0];
384	pbData[1] = u8Trio[1];
385	pbData += 2;
386	break;
387
388	default:
389	break;
390	}
391	}
392
393	/*
394	* Set optional return values and return successfully.
395	*/
396	if (ppszEnd)
397	ppszEnd = (char )pszString;
398	if (pcbActual)
399	pcbActual = pbData - (uint8_t )pvData;
400	return VINF_SUCCESS;
401	}
402	RT_EXPORT_SYMBOL(RTBase64Decode);
403
404
405	/**
406	* Calculates the length of the Base64 encoding of a given number of bytes of
407	* data.
408	*
409	* This will assume line breaks every 64 chars. A RTBase64EncodedLengthEx
410	* function can be added if closer control over the output is found to be
411	* required.
412	*
413	* @returns The Base64 string length.
414	* @param cbData The number of bytes to encode.
415	*/
416	RTDECL(size_t) RTBase64EncodedLength(size_t cbData)
417	{
418	if (cbData * 8 / 8 != cbData)
419	{
420	AssertReturn(sizeof(size_t) == sizeof(uint64_t), ~(size_t)0);
421	uint64_t cch = cbData * (uint64_t)8;
422	while (cch % 24)
423	cch += 8;
424	cch /= 6;
425
426	cch += (cch / RTBASE64_LINE_LEN) * RTBASE64_EOL_SIZE;
427	cch -= (cch % RTBASE64_LINE_LEN) == 0;
428	return cch;
429	}
430
431	size_t cch = cbData * 8;
432	while (cch % 24)
433	cch += 8;
434	cch /= 6;
435
436	cch += (cch / RTBASE64_LINE_LEN) * RTBASE64_EOL_SIZE;
437	cch -= (cch % RTBASE64_LINE_LEN) == 0;
438	return cch;
439	}
440	RT_EXPORT_SYMBOL(RTBase64EncodedLength);
441
442
443	/**
444	* Encodes the specifed data into a Base64 string, the caller supplies the
445	* output buffer.
446	*
447	* This will make the same assumptions about line breaks and EOL size as
448	* RTBase64EncodedLength() does. A RTBase64EncodeEx function can be added if
449	* more strict control over the output formatting is found necessary.
450	*
451	* @returns IRPT status code.
452	* @retval VERR_BUFFER_OVERFLOW if the output buffer is too small. The buffer
453	* may contain an invalid Base64 string.
454	*
455	* @param pvData The data to encode.
456	* @param cbData The number of bytes to encode.
457	* @param pszBuf Where to put the Base64 string.
458	* @param cbBuf The size of the output buffer, including the terminator.
459	* @param pcchActual The actual number of characters returned.
460	*/
461	RTDECL(int) RTBase64Encode(const void pvData, size_t cbData, char pszBuf, size_t cbBuf, size_t *pcchActual)
462	{
463	/*
464	* Process whole "trios" of input data.
465	*/
466	uint8_t u8A;
467	uint8_t u8B;
468	uint8_t u8C;
469	size_t cbLineFeed = cbBuf - RTBASE64_LINE_LEN;
470	const uint8_t pbSrc = (const uint8_t )pvData;
471	char *pchDst = pszBuf;
472	while (cbData >= 3)
473	{
474	if (cbBuf < 4 + 1)
475	return VERR_BUFFER_OVERFLOW;
476
477	/* encode */
478	u8A = pbSrc[0];
479	pchDst[0] = g_szValToChar[u8A >> 2];
480	u8B = pbSrc[1];
481	pchDst[1] = g_szValToChar[((u8A << 4) & 0x3f) \| (u8B >> 4)];
482	u8C = pbSrc[2];
483	pchDst[2] = g_szValToChar[((u8B << 2) & 0x3f) \| (u8C >> 6)];
484	pchDst[3] = g_szValToChar[u8C & 0x3f];
485
486	/* advance */
487	cbBuf -= 4;
488	pchDst += 4;
489	cbData -= 3;
490	pbSrc += 3;
491
492	/* deal out linefeeds */
493	if (cbBuf == cbLineFeed && cbData)
494	{
495	if (cbBuf < RTBASE64_EOL_SIZE + 1)
496	return VERR_BUFFER_OVERFLOW;
497	cbBuf -= RTBASE64_EOL_SIZE;
498	if (RTBASE64_EOL_SIZE == 2)
499	*pchDst++ = '\r';
500	*pchDst++ = '\n';
501	cbLineFeed = cbBuf - RTBASE64_LINE_LEN;
502	}
503	}
504
505	/*
506	* Deal with the odd bytes and string termination.
507	*/
508	if (cbData)
509	{
510	if (cbBuf < 4 + 1)
511	return VERR_BUFFER_OVERFLOW;
512	switch (cbData)
513	{
514	case 1:
515	u8A = pbSrc[0];
516	pchDst[0] = g_szValToChar[u8A >> 2];
517	pchDst[1] = g_szValToChar[(u8A << 4) & 0x3f];
518	pchDst[2] = '=';
519	pchDst[3] = '=';
520	break;
521	case 2:
522	u8A = pbSrc[0];
523	pchDst[0] = g_szValToChar[u8A >> 2];
524	u8B = pbSrc[1];
525	pchDst[1] = g_szValToChar[((u8A << 4) & 0x3f) \| (u8B >> 4)];
526	pchDst[2] = g_szValToChar[(u8B << 2) & 0x3f];
527	pchDst[3] = '=';
528	break;
529	}
530	pchDst += 4;
531	}
532
533	*pchDst = '\0';
534
535	if (pcchActual)
536	*pcchActual = pchDst - pszBuf;
537	return VINF_SUCCESS;
538	}
539	RT_EXPORT_SYMBOL(RTBase64Encode);
540

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