base64.cpp@ 72426

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1	/* $Id: base64.cpp 69111 2017-10-17 14:26:02Z vboxsync $ */
2	/** @file
3	* IPRT - Base64, MIME content transfer encoding.
4	*/
5
6	/*
7	* Copyright (C) 2009-2017 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	#include <iprt/string.h>
38	#ifdef RT_STRICT
39	# include <iprt/asm.h>
40	#endif
41
42
43	/*********************************************************************************************************************************
44	* Defined Constants And Macros *
45	*********************************************************************************************************************************/
46	/** The line length used for encoding. */
47	#define RTBASE64_LINE_LEN 64
48
49	/** @name Special g_au8CharToVal values
50	* @{ */
51	#define BASE64_SPACE 0xc0
52	#define BASE64_PAD 0xe0
53	#define BASE64_INVALID 0xff
54	/** @} */
55
56
57	/*********************************************************************************************************************************
58	* Global Variables *
59	*********************************************************************************************************************************/
60	/** Base64 character to value. (RFC 2045)
61	* ASSUMES ASCII / UTF-8. */
62	static const uint8_t g_au8CharToVal[256] =
63	{
64	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xc0, 0xc0, 0xc0, 0xc0, 0xc0, 0xff, 0xff, /* 0x00..0x0f */
65	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 0x10..0x1f */
66	0xc0, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 62, 0xff, 0xff, 0xff, 63, /* 0x20..0x2f */
67	52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 0xff, 0xff, 0xff, 0xe0, 0xff, 0xff, /* 0x30..0x3f */
68	0xff, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, /* 0x40..0x4f */
69	15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 0xff, 0xff, 0xff, 0xff, 0xff, /* 0x50..0x5f */
70	0xff, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, /* 0x60..0x6f */
71	41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 0xff, 0xff, 0xff, 0xff, 0xff, /* 0x70..0x7f */
72	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 0x80..0x8f */
73	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 0x90..0x9f */
74	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 0xa0..0xaf */
75	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 0xb0..0xbf */
76	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 0xc0..0xcf */
77	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 0xd0..0xdf */
78	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 0xe0..0xef */
79	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff /* 0xf0..0xff */
80	};
81
82	/** Value to Base64 character. (RFC 2045) */
83	static const char g_szValToChar[64+1] =
84	"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
85
86
87	#ifdef RT_STRICT
88	/**
89	* Perform table sanity checks on the first call.
90	*/
91	static void rtBase64Sanity(void)
92	{
93	static bool s_fSane = false;
94	if (RT_UNLIKELY(!s_fSane))
95	{
96	for (unsigned i = 0; i < 64; i++)
97	{
98	unsigned ch = g_szValToChar[i];
99	Assert(ch);
100	Assert(g_au8CharToVal[ch] == i);
101	}
102
103	for (unsigned i = 0; i < 256; i++)
104	{
105	uint8_t u8 = g_au8CharToVal[i];
106	Assert( ( u8 == BASE64_INVALID
107	&& !RT_C_IS_ALNUM(i)
108	&& !RT_C_IS_SPACE(i))
109	\|\| ( u8 == BASE64_PAD
110	&& i == '=')
111	\|\| ( u8 == BASE64_SPACE
112	&& RT_C_IS_SPACE(i))
113	\|\| ( u8 < 64
114	&& (unsigned)g_szValToChar[u8] == i));
115	}
116	ASMAtomicWriteBool(&s_fSane, true);
117	}
118	}
119	#endif /* RT_STRICT */
120
121
122	RTDECL(ssize_t) RTBase64DecodedSizeEx(const char pszString, size_t cchStringMax, char *ppszEnd)
123	{
124	#ifdef RT_STRICT
125	rtBase64Sanity();
126	#endif
127
128	/*
129	* Walk the string until a non-encoded or non-space character is encountered.
130	*/
131	uint32_t c6Bits = 0;
132	uint8_t u8 = BASE64_INVALID;
133	unsigned ch = 0;
134	AssertCompile(sizeof(char) == sizeof(uint8_t));
135
136	while (cchStringMax > 0 && (ch = *pszString))
137	{
138	u8 = g_au8CharToVal[ch];
139	if (u8 < 64)
140	c6Bits++;
141	else if (RT_UNLIKELY(u8 != BASE64_SPACE))
142	break;
143
144	/* advance */
145	pszString++;
146	cchStringMax--;
147	}
148
149	/*
150	* Padding can only be found at the end and there is
151	* only 1 or 2 padding chars. Deal with it first.
152	*/
153	unsigned cbPad = 0;
154	if (u8 == BASE64_PAD)
155	{
156	cbPad = 1;
157	c6Bits++;
158	pszString++;
159	cchStringMax--;
160	while (cchStringMax > 0 && (ch = *pszString))
161	{
162	u8 = g_au8CharToVal[ch];
163	if (u8 != BASE64_SPACE)
164	{
165	if (u8 != BASE64_PAD)
166	break;
167	c6Bits++;
168	cbPad++;
169	}
170	pszString++;
171	cchStringMax--;
172	}
173	if (cbPad >= 3)
174	return -1;
175	}
176
177	/*
178	* Invalid char and no where to indicate where the
179	* Base64 text ends? Return failure.
180	*/
181	if ( u8 == BASE64_INVALID
182	&& !ppszEnd
183	&& ch)
184	return -1;
185
186	/*
187	* Recalc 6-bit to 8-bit and adjust for padding.
188	*/
189	size_t cb;
190	if (c6Bits * 3 / 3 == c6Bits)
191	{
192	if ((c6Bits * 3 % 4) != 0)
193	return -1;
194	cb = c6Bits * 3 / 4;
195	}
196	else
197	{
198	if ((c6Bits * (uint64_t)3 % 4) != 0)
199	return -1;
200	cb = c6Bits * (uint64_t)3 / 4;
201	}
202
203	if (cb < cbPad)
204	return -1;
205	cb -= cbPad;
206
207	if (ppszEnd)
208	ppszEnd = (char )pszString;
209	return cb;
210	}
211	RT_EXPORT_SYMBOL(RTBase64DecodedSizeEx);
212
213
214	RTDECL(ssize_t) RTBase64DecodedSize(const char pszString, char *ppszEnd)
215	{
216	return RTBase64DecodedSizeEx(pszString, RTSTR_MAX, ppszEnd);
217	}
218	RT_EXPORT_SYMBOL(RTBase64DecodedSize);
219
220
221	RTDECL(int) RTBase64DecodeEx(const char pszString, size_t cchStringMax, void pvData, size_t cbData,
222	size_t pcbActual, char *ppszEnd)
223	{
224	#ifdef RT_STRICT
225	rtBase64Sanity();
226	#endif
227
228	/*
229	* Process input in groups of 4 input / 3 output chars.
230	*/
231	uint8_t u8Trio[3] = { 0, 0, 0 }; /* shuts up gcc */
232	uint8_t pbData = (uint8_t )pvData;
233	unsigned ch;
234	uint8_t u8;
235	unsigned c6Bits = 0;
236	AssertCompile(sizeof(char) == sizeof(uint8_t));
237
238	for (;;)
239	{
240	/* The first 6-bit group. */
241	while ((u8 = g_au8CharToVal[ch = cchStringMax > 0 ? (uint8_t)*pszString : 0]) == BASE64_SPACE)
242	pszString++, cchStringMax--;
243	if (u8 >= 64)
244	{
245	c6Bits = 0;
246	break;
247	}
248	u8Trio[0] = u8 << 2;
249	pszString++;
250	cchStringMax--;
251
252	/* The second 6-bit group. */
253	while ((u8 = g_au8CharToVal[ch = cchStringMax > 0 ? (uint8_t)*pszString : 0]) == BASE64_SPACE)
254	pszString++, cchStringMax--;
255	if (u8 >= 64)
256	{
257	c6Bits = 1;
258	break;
259	}
260	u8Trio[0] \|= u8 >> 4;
261	u8Trio[1] = u8 << 4;
262	pszString++;
263	cchStringMax--;
264
265	/* The third 6-bit group. */
266	u8 = BASE64_INVALID;
267	while ((u8 = g_au8CharToVal[ch = cchStringMax > 0 ? (uint8_t)*pszString : 0]) == BASE64_SPACE)
268	pszString++, cchStringMax--;
269	if (u8 >= 64)
270	{
271	c6Bits = 2;
272	break;
273	}
274	u8Trio[1] \|= u8 >> 2;
275	u8Trio[2] = u8 << 6;
276	pszString++;
277	cchStringMax--;
278
279	/* The fourth 6-bit group. */
280	u8 = BASE64_INVALID;
281	while ((u8 = g_au8CharToVal[ch = cchStringMax > 0 ? (uint8_t)*pszString : 0]) == BASE64_SPACE)
282	pszString++, cchStringMax--;
283	if (u8 >= 64)
284	{
285	c6Bits = 3;
286	break;
287	}
288	u8Trio[2] \|= u8;
289	pszString++;
290	cchStringMax--;
291
292	/* flush the trio */
293	if (cbData < 3)
294	return VERR_BUFFER_OVERFLOW;
295	cbData -= 3;
296	pbData[0] = u8Trio[0];
297	pbData[1] = u8Trio[1];
298	pbData[2] = u8Trio[2];
299	pbData += 3;
300	}
301
302	/*
303	* Padding can only be found at the end and there is
304	* only 1 or 2 padding chars. Deal with it first.
305	*/
306	unsigned cbPad = 0;
307	if (u8 == BASE64_PAD)
308	{
309	cbPad = 1;
310	pszString++;
311	cchStringMax--;
312	while (cchStringMax > 0 && (ch = (uint8_t)*pszString))
313	{
314	u8 = g_au8CharToVal[ch];
315	if (u8 != BASE64_SPACE)
316	{
317	if (u8 != BASE64_PAD)
318	break;
319	cbPad++;
320	}
321	pszString++;
322	cchStringMax--;
323	}
324	if (cbPad >= 3)
325	return VERR_INVALID_BASE64_ENCODING;
326	}
327
328	/*
329	* Invalid char and no where to indicate where the
330	* Base64 text ends? Return failure.
331	*/
332	if ( u8 == BASE64_INVALID
333	&& !ppszEnd
334	&& ch != '\0')
335	return VERR_INVALID_BASE64_ENCODING;
336
337	/*
338	* Check padding vs. pending sextets, if anything left to do finish it off.
339	*/
340	if (c6Bits \|\| cbPad)
341	{
342	if (c6Bits + cbPad != 4)
343	return VERR_INVALID_BASE64_ENCODING;
344
345	switch (c6Bits)
346	{
347	case 1:
348	u8Trio[1] = u8Trio[2] = 0;
349	break;
350	case 2:
351	u8Trio[2] = 0;
352	break;
353	case 3:
354	default:
355	break;
356	}
357	switch (3 - cbPad)
358	{
359	case 1:
360	if (cbData < 1)
361	return VERR_BUFFER_OVERFLOW;
362	cbData--;
363	pbData[0] = u8Trio[0];
364	pbData++;
365	break;
366
367	case 2:
368	if (cbData < 2)
369	return VERR_BUFFER_OVERFLOW;
370	cbData -= 2;
371	pbData[0] = u8Trio[0];
372	pbData[1] = u8Trio[1];
373	pbData += 2;
374	break;
375
376	default:
377	break;
378	}
379	}
380
381	/*
382	* Set optional return values and return successfully.
383	*/
384	if (ppszEnd)
385	ppszEnd = (char )pszString;
386	if (pcbActual)
387	pcbActual = pbData - (uint8_t )pvData;
388	return VINF_SUCCESS;
389	}
390	RT_EXPORT_SYMBOL(RTBase64DecodeEx);
391
392
393	RTDECL(int) RTBase64Decode(const char pszString, void pvData, size_t cbData, size_t pcbActual, char *ppszEnd)
394	{
395	return RTBase64DecodeEx(pszString, RTSTR_MAX, pvData, cbData, pcbActual, ppszEnd);
396	}
397	RT_EXPORT_SYMBOL(RTBase64Decode);
398
399
400	/**
401	* Calculates the length of the Base64 encoding of a given number of bytes of
402	* data.
403	*
404	* This will assume line breaks every 64 chars. A RTBase64EncodedLengthEx
405	* function can be added if closer control over the output is found to be
406	* required.
407	*
408	* @returns The Base64 string length.
409	* @param cbData The number of bytes to encode.
410	*/
411	RTDECL(size_t) RTBase64EncodedLength(size_t cbData)
412	{
413	if (cbData * 8 / 8 != cbData)
414	{
415	AssertReturn(sizeof(size_t) == sizeof(uint64_t), ~(size_t)0);
416	uint64_t cch = cbData * (uint64_t)8;
417	while (cch % 24)
418	cch += 8;
419	cch /= 6;
420
421	cch += ((cch - 1) / RTBASE64_LINE_LEN) * RTBASE64_EOL_SIZE;
422	return cch;
423	}
424
425	size_t cch = cbData * 8;
426	while (cch % 24)
427	cch += 8;
428	cch /= 6;
429
430	cch += ((cch - 1) / RTBASE64_LINE_LEN) * RTBASE64_EOL_SIZE;
431	return cch;
432	}
433	RT_EXPORT_SYMBOL(RTBase64EncodedLength);
434
435
436	/**
437	* Encodes the specifed data into a Base64 string, the caller supplies the
438	* output buffer.
439	*
440	* This will make the same assumptions about line breaks and EOL size as
441	* RTBase64EncodedLength() does. A RTBase64EncodeEx function can be added if
442	* more strict control over the output formatting is found necessary.
443	*
444	* @returns IRPT status code.
445	* @retval VERR_BUFFER_OVERFLOW if the output buffer is too small. The buffer
446	* may contain an invalid Base64 string.
447	*
448	* @param pvData The data to encode.
449	* @param cbData The number of bytes to encode.
450	* @param pszBuf Where to put the Base64 string.
451	* @param cbBuf The size of the output buffer, including the terminator.
452	* @param pcchActual The actual number of characters returned.
453	*/
454	RTDECL(int) RTBase64Encode(const void pvData, size_t cbData, char pszBuf, size_t cbBuf, size_t *pcchActual)
455	{
456	/*
457	* Process whole "trios" of input data.
458	*/
459	uint8_t u8A;
460	uint8_t u8B;
461	uint8_t u8C;
462	size_t cbLineFeed = cbBuf - RTBASE64_LINE_LEN;
463	const uint8_t pbSrc = (const uint8_t )pvData;
464	char *pchDst = pszBuf;
465	while (cbData >= 3)
466	{
467	if (cbBuf < 4 + 1)
468	return VERR_BUFFER_OVERFLOW;
469
470	/* encode */
471	u8A = pbSrc[0];
472	pchDst[0] = g_szValToChar[u8A >> 2];
473	u8B = pbSrc[1];
474	pchDst[1] = g_szValToChar[((u8A << 4) & 0x3f) \| (u8B >> 4)];
475	u8C = pbSrc[2];
476	pchDst[2] = g_szValToChar[((u8B << 2) & 0x3f) \| (u8C >> 6)];
477	pchDst[3] = g_szValToChar[u8C & 0x3f];
478
479	/* advance */
480	cbBuf -= 4;
481	pchDst += 4;
482	cbData -= 3;
483	pbSrc += 3;
484
485	/* deal out linefeeds */
486	if (cbBuf == cbLineFeed && cbData)
487	{
488	if (cbBuf < RTBASE64_EOL_SIZE + 1)
489	return VERR_BUFFER_OVERFLOW;
490	cbBuf -= RTBASE64_EOL_SIZE;
491	if (RTBASE64_EOL_SIZE == 2)
492	*pchDst++ = '\r';
493	*pchDst++ = '\n';
494	cbLineFeed = cbBuf - RTBASE64_LINE_LEN;
495	}
496	}
497
498	/*
499	* Deal with the odd bytes and string termination.
500	*/
501	if (cbData)
502	{
503	if (cbBuf < 4 + 1)
504	return VERR_BUFFER_OVERFLOW;
505	switch (cbData)
506	{
507	case 1:
508	u8A = pbSrc[0];
509	pchDst[0] = g_szValToChar[u8A >> 2];
510	pchDst[1] = g_szValToChar[(u8A << 4) & 0x3f];
511	pchDst[2] = '=';
512	pchDst[3] = '=';
513	break;
514	case 2:
515	u8A = pbSrc[0];
516	pchDst[0] = g_szValToChar[u8A >> 2];
517	u8B = pbSrc[1];
518	pchDst[1] = g_szValToChar[((u8A << 4) & 0x3f) \| (u8B >> 4)];
519	pchDst[2] = g_szValToChar[(u8B << 2) & 0x3f];
520	pchDst[3] = '=';
521	break;
522	}
523	pchDst += 4;
524	}
525
526	*pchDst = '\0';
527
528	if (pcchActual)
529	*pcchActual = pchDst - pszBuf;
530	return VINF_SUCCESS;
531	}
532	RT_EXPORT_SYMBOL(RTBase64Encode);
533

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