/src/nspr/lib/libc/src/base64.c

Source (jump to first uncovered line)
/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "plbase64.h"
#include "prlog.h" /* For PR_NOT_REACHED */
#include "prmem.h" /* for malloc / PR_MALLOC */

#include <string.h> /* for strlen */

static unsigned char *base = (unsigned char *)"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

static void encode3to4(const unsigned char* src, unsigned char* dest) {
  PRUint32 b32 = (PRUint32)0;
  PRIntn i, j = 18;

  for (i = 0; i < 3; i++) {
    b32 <<= 8;
    b32 |= (PRUint32)src[i];
  }

  for (i = 0; i < 4; i++) {
    dest[i] = base[(PRUint32)((b32 >> j) & 0x3F)];
    j -= 6;
  }

  return;
}

static void encode2to4(const unsigned char* src, unsigned char* dest) {
  dest[0] = base[(PRUint32)((src[0] >> 2) & 0x3F)];
  dest[1] = base[(PRUint32)(((src[0] & 0x03) << 4) | ((src[1] >> 4) & 0x0F))];
  dest[2] = base[(PRUint32)((src[1] & 0x0F) << 2)];
  dest[3] = (unsigned char)'=';
  return;
}

static void encode1to4(const unsigned char* src, unsigned char* dest) {
  dest[0] = base[(PRUint32)((src[0] >> 2) & 0x3F)];
  dest[1] = base[(PRUint32)((src[0] & 0x03) << 4)];
  dest[2] = (unsigned char)'=';
  dest[3] = (unsigned char)'=';
  return;
}

static void encode(const unsigned char* src, PRUint32 srclen,
                   unsigned char* dest) {
  while (srclen >= 3) {
    encode3to4(src, dest);
    src += 3;
    dest += 4;
    srclen -= 3;
  }

  switch (srclen) {
    case 2:
      encode2to4(src, dest);
      break;
    case 1:
      encode1to4(src, dest);
      break;
    case 0:
      break;
    default:
      PR_NOT_REACHED("coding error");
  }

  return;
}

/*
 * PL_Base64Encode
 *
 * If the destination argument is NULL, a return buffer is
 * allocated, and the data therein will be null-terminated.
 * If the destination argument is not NULL, it is assumed to
 * be of sufficient size, and the contents will not be null-
 * terminated by this routine.
 *
 * Returns null if the allocation fails.
 */

PR_IMPLEMENT(char*)
PL_Base64Encode(const char* src, PRUint32 srclen, char* dest) {
  if (0 == srclen) {
    size_t len = strlen(src);
    srclen = len;
    /* Detect truncation. */
    if (srclen != len) {
      return (char*)0;
    }
  }

  if ((char*)0 == dest) {
    PRUint32 destlen;
    /* Ensure all PRUint32 values stay within range. */
    if (srclen > (PR_UINT32_MAX / 4) * 3) {
      return (char*)0;
    }
    destlen = ((srclen + 2) / 3) * 4;
    dest = (char*)PR_MALLOC(destlen + 1);
    if ((char*)0 == dest) {
      return (char*)0;
    }
    dest[destlen] = (char)0; /* null terminate */
  }

  encode((const unsigned char*)src, srclen, (unsigned char*)dest);
  return dest;
}

static PRInt32 codetovalue(unsigned char c) {
  if ((c >= (unsigned char)'A') && (c <= (unsigned char)'Z')) {
    return (PRInt32)(c - (unsigned char)'A');
  } else if ((c >= (unsigned char)'a') && (c <= (unsigned char)'z')) {
    return ((PRInt32)(c - (unsigned char)'a') + 26);
  } else if ((c >= (unsigned char)'0') && (c <= (unsigned char)'9')) {
    return ((PRInt32)(c - (unsigned char)'0') + 52);
  } else if ((unsigned char)'+' == c) {
    return (PRInt32)62;
  } else if ((unsigned char)'/' == c) {
    return (PRInt32)63;
  } else {
    return -1;
  }
}

static PRStatus decode4to3(const unsigned char* src, unsigned char* dest) {
  PRUint32 b32 = (PRUint32)0;
  PRInt32 bits;
  PRIntn i;

  for (i = 0; i < 4; i++) {
    bits = codetovalue(src[i]);
    if (bits < 0) {
      return PR_FAILURE;
    }

    b32 <<= 6;
    b32 |= bits;
  }

  dest[0] = (unsigned char)((b32 >> 16) & 0xFF);
  dest[1] = (unsigned char)((b32 >> 8) & 0xFF);
  dest[2] = (unsigned char)((b32) & 0xFF);

  return PR_SUCCESS;
}

static PRStatus decode3to2(const unsigned char* src, unsigned char* dest) {
  PRUint32 b32 = (PRUint32)0;
  PRInt32 bits;
  PRUint32 ubits;

  bits = codetovalue(src[0]);
  if (bits < 0) {
    return PR_FAILURE;
  }

  b32 = (PRUint32)bits;
  b32 <<= 6;

  bits = codetovalue(src[1]);
  if (bits < 0) {
    return PR_FAILURE;
  }

  b32 |= (PRUint32)bits;
  b32 <<= 4;

  bits = codetovalue(src[2]);
  if (bits < 0) {
    return PR_FAILURE;
  }

  ubits = (PRUint32)bits;
  b32 |= (ubits >> 2);

  dest[0] = (unsigned char)((b32 >> 8) & 0xFF);
  dest[1] = (unsigned char)((b32) & 0xFF);

  return PR_SUCCESS;
}

static PRStatus decode2to1(const unsigned char* src, unsigned char* dest) {
  PRUint32 b32;
  PRUint32 ubits;
  PRInt32 bits;

  bits = codetovalue(src[0]);
  if (bits < 0) {
    return PR_FAILURE;
  }

  ubits = (PRUint32)bits;
  b32 = (ubits << 2);

  bits = codetovalue(src[1]);
  if (bits < 0) {
    return PR_FAILURE;
  }

  ubits = (PRUint32)bits;
  b32 |= (ubits >> 4);

  dest[0] = (unsigned char)b32;

  return PR_SUCCESS;
}

static PRStatus decode(const unsigned char* src, PRUint32 srclen,
                       unsigned char* dest) {
  PRStatus rv;

  while (srclen >= 4) {
    rv = decode4to3(src, dest);
    if (PR_SUCCESS != rv) {
      return PR_FAILURE;
    }

    src += 4;
    dest += 3;
    srclen -= 4;
  }

  switch (srclen) {
    case 3:
      rv = decode3to2(src, dest);
      break;
    case 2:
      rv = decode2to1(src, dest);
      break;
    case 1:
      rv = PR_FAILURE;
      break;
    case 0:
      rv = PR_SUCCESS;
      break;
    default:
      PR_NOT_REACHED("coding error");
  }

  return rv;
}

/*
 * PL_Base64Decode
 *
 * If the destination argument is NULL, a return buffer is
 * allocated and the data therein will be null-terminated.
 * If the destination argument is not null, it is assumed
 * to be of sufficient size, and the data will not be null-
 * terminated by this routine.
 *
 * Returns null if the allocation fails, or if the source string is
 * not well-formed.
 */

PR_IMPLEMENT(char*)
PL_Base64Decode(const char* src, PRUint32 srclen, char* dest) {
  PRStatus status;
  PRBool allocated = PR_FALSE;

  if ((char*)0 == src) {
    return (char*)0;
  }

  if (0 == srclen) {
    size_t len = strlen(src);
    srclen = len;
    /* Detect truncation. */
    if (srclen != len) {
      return (char*)0;
    }
  }

  if (srclen && (0 == (srclen & 3))) {
    if ((char)'=' == src[srclen - 1]) {
      if ((char)'=' == src[srclen - 2]) {
        srclen -= 2;
      } else {
        srclen -= 1;
      }
    }
  }

  if ((char*)0 == dest) {
    /* The following computes ((srclen * 3) / 4) without overflow. */
    PRUint32 destlen = (srclen / 4) * 3 + ((srclen % 4) * 3) / 4;
    dest = (char*)PR_MALLOC(destlen + 1);
    if ((char*)0 == dest) {
      return (char*)0;
    }
    dest[destlen] = (char)0; /* null terminate */
    allocated = PR_TRUE;
  }

  status = decode((const unsigned char*)src, srclen, (unsigned char*)dest);
  if (PR_SUCCESS != status) {
    if (PR_TRUE == allocated) {
      PR_DELETE(dest);
    }

    return (char*)0;
  }

  return dest;
}

Coverage Report

Created: 2025-07-04 06:19

Line	Count	Source (jump to first uncovered line)
1		/* -- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -- */
2		/* This Source Code Form is subject to the terms of the Mozilla Public
3		* License, v. 2.0. If a copy of the MPL was not distributed with this
4		* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
5
6		#include "plbase64.h"
7		#include "prlog.h" /* For PR_NOT_REACHED */
8		#include "prmem.h" /* for malloc / PR_MALLOC */
9
10		#include <string.h> /* for strlen */
11
12		static unsigned char base = (unsigned char )"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
13
14	0	static void encode3to4(const unsigned char* src, unsigned char* dest) {
15	0	PRUint32 b32 = (PRUint32)0;
16	0	PRIntn i, j = 18;
17
18	0	for (i = 0; i < 3; i++) {
19	0	b32 <<= 8;
20	0	b32 \|= (PRUint32)src[i];
21	0	}
22
23	0	for (i = 0; i < 4; i++) {
24	0	dest[i] = base[(PRUint32)((b32 >> j) & 0x3F)];
25	0	j -= 6;
26	0	}
27
28	0	return;
29	0	}
30
31	0	static void encode2to4(const unsigned char* src, unsigned char* dest) {
32	0	dest[0] = base[(PRUint32)((src[0] >> 2) & 0x3F)];
33	0	dest[1] = base[(PRUint32)(((src[0] & 0x03) << 4) \| ((src[1] >> 4) & 0x0F))];
34	0	dest[2] = base[(PRUint32)((src[1] & 0x0F) << 2)];
35	0	dest[3] = (unsigned char)'=';
36	0	return;
37	0	}
38
39	0	static void encode1to4(const unsigned char* src, unsigned char* dest) {
40	0	dest[0] = base[(PRUint32)((src[0] >> 2) & 0x3F)];
41	0	dest[1] = base[(PRUint32)((src[0] & 0x03) << 4)];
42	0	dest[2] = (unsigned char)'=';
43	0	dest[3] = (unsigned char)'=';
44	0	return;
45	0	}
46
47		static void encode(const unsigned char* src, PRUint32 srclen,
48	0	unsigned char* dest) {
49	0	while (srclen >= 3) {
50	0	encode3to4(src, dest);
51	0	src += 3;
52	0	dest += 4;
53	0	srclen -= 3;
54	0	}
55
56	0	switch (srclen) {
57	0	case 2:
58	0	encode2to4(src, dest);
59	0	break;
60	0	case 1:
61	0	encode1to4(src, dest);
62	0	break;
63	0	case 0:
64	0	break;
65	0	default:
66	0	PR_NOT_REACHED("coding error");
67	0	}
68
69	0	return;
70	0	}
71
72		/*
73		* PL_Base64Encode
74		*
75		* If the destination argument is NULL, a return buffer is
76		* allocated, and the data therein will be null-terminated.
77		* If the destination argument is not NULL, it is assumed to
78		* be of sufficient size, and the contents will not be null-
79		* terminated by this routine.
80		*
81		* Returns null if the allocation fails.
82		*/
83
84		PR_IMPLEMENT(char*)
85	0	PL_Base64Encode(const char* src, PRUint32 srclen, char* dest) {
86	0	if (0 == srclen) {
87	0	size_t len = strlen(src);
88	0	srclen = len;
89		/* Detect truncation. */
90	0	if (srclen != len) {
91	0	return (char*)0;
92	0	}
93	0	}
94
95	0	if ((char*)0 == dest) {
96	0	PRUint32 destlen;
97		/* Ensure all PRUint32 values stay within range. */
98	0	if (srclen > (PR_UINT32_MAX / 4) * 3) {
99	0	return (char*)0;
100	0	}
101	0	destlen = ((srclen + 2) / 3) * 4;
102	0	dest = (char*)PR_MALLOC(destlen + 1);
103	0	if ((char*)0 == dest) {
104	0	return (char*)0;
105	0	}
106	0	dest[destlen] = (char)0; /* null terminate */
107	0	}
108
109	0	encode((const unsigned char)src, srclen, (unsigned char)dest);
110	0	return dest;
111	0	}
112
113	0	static PRInt32 codetovalue(unsigned char c) {
114	0	if ((c >= (unsigned char)'A') && (c <= (unsigned char)'Z')) {
115	0	return (PRInt32)(c - (unsigned char)'A');
116	0	} else if ((c >= (unsigned char)'a') && (c <= (unsigned char)'z')) {
117	0	return ((PRInt32)(c - (unsigned char)'a') + 26);
118	0	} else if ((c >= (unsigned char)'0') && (c <= (unsigned char)'9')) {
119	0	return ((PRInt32)(c - (unsigned char)'0') + 52);
120	0	} else if ((unsigned char)'+' == c) {
121	0	return (PRInt32)62;
122	0	} else if ((unsigned char)'/' == c) {
123	0	return (PRInt32)63;
124	0	} else {
125	0	return -1;
126	0	}
127	0	}
128
129	0	static PRStatus decode4to3(const unsigned char* src, unsigned char* dest) {
130	0	PRUint32 b32 = (PRUint32)0;
131	0	PRInt32 bits;
132	0	PRIntn i;
133
134	0	for (i = 0; i < 4; i++) {
135	0	bits = codetovalue(src[i]);
136	0	if (bits < 0) {
137	0	return PR_FAILURE;
138	0	}
139
140	0	b32 <<= 6;
141	0	b32 \|= bits;
142	0	}
143
144	0	dest[0] = (unsigned char)((b32 >> 16) & 0xFF);
145	0	dest[1] = (unsigned char)((b32 >> 8) & 0xFF);
146	0	dest[2] = (unsigned char)((b32) & 0xFF);
147
148	0	return PR_SUCCESS;
149	0	}
150
151	0	static PRStatus decode3to2(const unsigned char* src, unsigned char* dest) {
152	0	PRUint32 b32 = (PRUint32)0;
153	0	PRInt32 bits;
154	0	PRUint32 ubits;
155
156	0	bits = codetovalue(src[0]);
157	0	if (bits < 0) {
158	0	return PR_FAILURE;
159	0	}
160
161	0	b32 = (PRUint32)bits;
162	0	b32 <<= 6;
163
164	0	bits = codetovalue(src[1]);
165	0	if (bits < 0) {
166	0	return PR_FAILURE;
167	0	}
168
169	0	b32 \|= (PRUint32)bits;
170	0	b32 <<= 4;
171
172	0	bits = codetovalue(src[2]);
173	0	if (bits < 0) {
174	0	return PR_FAILURE;
175	0	}
176
177	0	ubits = (PRUint32)bits;
178	0	b32 \|= (ubits >> 2);
179
180	0	dest[0] = (unsigned char)((b32 >> 8) & 0xFF);
181	0	dest[1] = (unsigned char)((b32) & 0xFF);
182
183	0	return PR_SUCCESS;
184	0	}
185
186	0	static PRStatus decode2to1(const unsigned char* src, unsigned char* dest) {
187	0	PRUint32 b32;
188	0	PRUint32 ubits;
189	0	PRInt32 bits;
190
191	0	bits = codetovalue(src[0]);
192	0	if (bits < 0) {
193	0	return PR_FAILURE;
194	0	}
195
196	0	ubits = (PRUint32)bits;
197	0	b32 = (ubits << 2);
198
199	0	bits = codetovalue(src[1]);
200	0	if (bits < 0) {
201	0	return PR_FAILURE;
202	0	}
203
204	0	ubits = (PRUint32)bits;
205	0	b32 \|= (ubits >> 4);
206
207	0	dest[0] = (unsigned char)b32;
208
209	0	return PR_SUCCESS;
210	0	}
211
212		static PRStatus decode(const unsigned char* src, PRUint32 srclen,
213	0	unsigned char* dest) {
214	0	PRStatus rv;
215
216	0	while (srclen >= 4) {
217	0	rv = decode4to3(src, dest);
218	0	if (PR_SUCCESS != rv) {
219	0	return PR_FAILURE;
220	0	}
221
222	0	src += 4;
223	0	dest += 3;
224	0	srclen -= 4;
225	0	}
226
227	0	switch (srclen) {
228	0	case 3:
229	0	rv = decode3to2(src, dest);
230	0	break;
231	0	case 2:
232	0	rv = decode2to1(src, dest);
233	0	break;
234	0	case 1:
235	0	rv = PR_FAILURE;
236	0	break;
237	0	case 0:
238	0	rv = PR_SUCCESS;
239	0	break;
240	0	default:
241	0	PR_NOT_REACHED("coding error");
242	0	}
243
244	0	return rv;
245	0	}
246
247		/*
248		* PL_Base64Decode
249		*
250		* If the destination argument is NULL, a return buffer is
251		* allocated and the data therein will be null-terminated.
252		* If the destination argument is not null, it is assumed
253		* to be of sufficient size, and the data will not be null-
254		* terminated by this routine.
255		*
256		* Returns null if the allocation fails, or if the source string is
257		* not well-formed.
258		*/
259
260		PR_IMPLEMENT(char*)
261	0	PL_Base64Decode(const char* src, PRUint32 srclen, char* dest) {
262	0	PRStatus status;
263	0	PRBool allocated = PR_FALSE;
264
265	0	if ((char*)0 == src) {
266	0	return (char*)0;
267	0	}
268
269	0	if (0 == srclen) {
270	0	size_t len = strlen(src);
271	0	srclen = len;
272		/* Detect truncation. */
273	0	if (srclen != len) {
274	0	return (char*)0;
275	0	}
276	0	}
277
278	0	if (srclen && (0 == (srclen & 3))) {
279	0	if ((char)'=' == src[srclen - 1]) {
280	0	if ((char)'=' == src[srclen - 2]) {
281	0	srclen -= 2;
282	0	} else {
283	0	srclen -= 1;
284	0	}
285	0	}
286	0	}
287
288	0	if ((char*)0 == dest) {
289		/* The following computes ((srclen * 3) / 4) without overflow. */
290	0	PRUint32 destlen = (srclen / 4) * 3 + ((srclen % 4) * 3) / 4;
291	0	dest = (char*)PR_MALLOC(destlen + 1);
292	0	if ((char*)0 == dest) {
293	0	return (char*)0;
294	0	}
295	0	dest[destlen] = (char)0; /* null terminate */
296	0	allocated = PR_TRUE;
297	0	}
298
299	0	status = decode((const unsigned char)src, srclen, (unsigned char)dest);
300	0	if (PR_SUCCESS != status) {
301	0	if (PR_TRUE == allocated) {
302	0	PR_DELETE(dest);
303	0	}
304
305	0	return (char*)0;
306	0	}
307
308	0	return dest;
309	0	}