summaryrefslogtreecommitdiff
path: root/lib/base64.c
blob: 9edc83212a93a27f77c8f6718903a80deca2e2e9 (plain)
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
/***************************************************************************
 *                                  _   _ ____  _
 *  Project                     ___| | | |  _ \| |
 *                             / __| | | | |_) | |
 *                            | (__| |_| |  _ <| |___
 *                             \___|\___/|_| \_\_____|
 *
 * Copyright (C) 1998 - 2007, Daniel Stenberg, <daniel@haxx.se>, et al.
 *
 * This software is licensed as described in the file COPYING, which
 * you should have received as part of this distribution. The terms
 * are also available at http://curl.haxx.se/docs/copyright.html.
 *
 * You may opt to use, copy, modify, merge, publish, distribute and/or sell
 * copies of the Software, and permit persons to whom the Software is
 * furnished to do so, under the terms of the COPYING file.
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
 * KIND, either express or implied.
 *
 * $Id$
 ***************************************************************************/

/* Base64 encoding/decoding
 *
 * Test harnesses down the bottom - compile with -DTEST_ENCODE for
 * a program that will read in raw data from stdin and write out
 * a base64-encoded version to stdout, and the length returned by the
 * encoding function to stderr. Compile with -DTEST_DECODE for a program that
 * will go the other way.
 *
 * This code will break if int is smaller than 32 bits
 */

#include "setup.h"

#include <stdlib.h>
#include <string.h>

#define _MPRINTF_REPLACE /* use our functions only */
#include <curl/mprintf.h>

#include "urldata.h" /* for the SessionHandle definition */
#include "easyif.h"  /* for Curl_convert_... prototypes */
#include "base64.h"
#include "memory.h"

/* include memdebug.h last */
#include "memdebug.h"

/* ---- Base64 Encoding/Decoding Table --- */
static const char table64[]=
  "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

static void decodeQuantum(unsigned char *dest, const char *src)
{
  unsigned int x = 0;
  int i;
  char *found;

  for(i = 0; i < 4; i++) {
    if((found = strchr(table64, src[i])) != NULL)
      x = (x << 6) + (unsigned int)(found - table64);
    else if(src[i] == '=')
      x = (x << 6);
  }

  dest[2] = (unsigned char)(x & 255);
  x >>= 8;
  dest[1] = (unsigned char)(x & 255);
  x >>= 8;
  dest[0] = (unsigned char)(x & 255);
}

/*
 * Curl_base64_decode()
 *
 * Given a base64 string at src, decode it and return an allocated memory in
 * the *outptr. Returns the length of the decoded data.
 */
size_t Curl_base64_decode(const char *src, unsigned char **outptr)
{
  int length = 0;
  int equalsTerm = 0;
  int i;
  int numQuantums;
  unsigned char lastQuantum[3];
  size_t rawlen=0;
  unsigned char *newstr;

  *outptr = NULL;

  while((src[length] != '=') && src[length])
    length++;
  /* A maximum of two = padding characters is allowed */
  if(src[length] == '=') {
    equalsTerm++;
    if(src[length+equalsTerm] == '=')
      equalsTerm++;
  }
  numQuantums = (length + equalsTerm) / 4;

  /* Don't allocate a buffer if the decoded length is 0 */
  if(numQuantums <= 0)
    return 0;

  rawlen = (numQuantums * 3) - equalsTerm;

  /* The buffer must be large enough to make room for the last quantum
  (which may be partially thrown out) and the zero terminator. */
  newstr = malloc(rawlen+4);
  if(!newstr)
    return 0;

  *outptr = newstr;

  /* Decode all but the last quantum (which may not decode to a
  multiple of 3 bytes) */
  for(i = 0; i < numQuantums - 1; i++) {
    decodeQuantum((unsigned char *)newstr, src);
    newstr += 3; src += 4;
  }

  /* This final decode may actually read slightly past the end of the buffer
  if the input string is missing pad bytes.  This will almost always be
  harmless. */
  decodeQuantum(lastQuantum, src);
  for(i = 0; i < 3 - equalsTerm; i++)
    newstr[i] = lastQuantum[i];

  newstr[i] = 0; /* zero terminate */
  return rawlen;
}

/*
 * Curl_base64_encode()
 *
 * Returns the length of the newly created base64 string. The third argument
 * is a pointer to an allocated area holding the base64 data. If something
 * went wrong, 0 is returned.
 *
 */
size_t Curl_base64_encode(struct SessionHandle *data,
                          const char *inp, size_t insize, char **outptr)
{
  unsigned char ibuf[3];
  unsigned char obuf[4];
  int i;
  int inputparts;
  char *output;
  char *base64data;
#ifdef CURL_DOES_CONVERSIONS
  char *convbuf = NULL;
#endif

  char *indata = (char *)inp;

  *outptr = NULL; /* set to NULL in case of failure before we reach the end */

  if(0 == insize)
    insize = strlen(indata);

  base64data = output = (char*)malloc(insize*4/3+4);
  if(NULL == output)
    return 0;

#ifdef CURL_DOES_CONVERSIONS
  /*
   * The base64 data needs to be created using the network encoding
   * not the host encoding.  And we can't change the actual input
   * so we copy it to a buffer, translate it, and use that instead.
   */
  if(data) {
    convbuf = (char*)malloc(insize);
    if(!convbuf) {
      free(output);
      return 0;
    }
    memcpy(convbuf, indata, insize);
    if(CURLE_OK != Curl_convert_to_network(data, convbuf, insize)) {
      free(convbuf);
      free(output);
      return 0;
    }
    indata = convbuf; /* switch to the converted buffer */
  }
#else
  (void)data;
#endif

  while(insize > 0) {
    for (i = inputparts = 0; i < 3; i++) {
      if(insize > 0) {
        inputparts++;
        ibuf[i] = *indata;
        indata++;
        insize--;
      }
      else
        ibuf[i] = 0;
    }

    obuf[0] = (unsigned char)  ((ibuf[0] & 0xFC) >> 2);
    obuf[1] = (unsigned char) (((ibuf[0] & 0x03) << 4) | \
                               ((ibuf[1] & 0xF0) >> 4));
    obuf[2] = (unsigned char) (((ibuf[1] & 0x0F) << 2) | \
                               ((ibuf[2] & 0xC0) >> 6));
    obuf[3] = (unsigned char)   (ibuf[2] & 0x3F);

    switch(inputparts) {
    case 1: /* only one byte read */
      snprintf(output, 5, "%c%c==",
               table64[obuf[0]],
               table64[obuf[1]]);
      break;
    case 2: /* two bytes read */
      snprintf(output, 5, "%c%c%c=",
               table64[obuf[0]],
               table64[obuf[1]],
               table64[obuf[2]]);
      break;
    default:
      snprintf(output, 5, "%c%c%c%c",
               table64[obuf[0]],
               table64[obuf[1]],
               table64[obuf[2]],
               table64[obuf[3]] );
      break;
    }
    output += 4;
  }
  *output=0;
  *outptr = base64data; /* make it return the actual data memory */

#ifdef CURL_DOES_CONVERSIONS
  if(data)
    free(convbuf);
#endif
  return strlen(base64data); /* return the length of the new data */
}
/* ---- End of Base64 Encoding ---- */

/************* TEST HARNESS STUFF ****************/


#ifdef TEST_ENCODE
/* encoding test harness. Read in standard input and write out the length
 * returned by Curl_base64_encode, followed by the base64'd data itself
 */
#include <stdio.h>

#define TEST_NEED_SUCK
void *suck(int *);

int main(int argc, argv_item_t argv[], char **envp)
{
  char *base64;
  size_t base64Len;
  unsigned char *data;
  int dataLen;
  struct SessionHandle *handle = NULL;

#ifdef CURL_DOES_CONVERSIONS
  /* get a Curl handle so Curl_base64_encode can translate properly */
  handle = curl_easy_init();
  if(handle == NULL) {
    fprintf(stderr, "Error: curl_easy_init failed\n");
    return 1;
  }
#endif
  data = (unsigned char *)suck(&dataLen);
  base64Len = Curl_base64_encode(handle, data, dataLen, &base64);

  fprintf(stderr, "%d\n", base64Len);
  fprintf(stdout, "%s\n", base64);

  free(base64); free(data);
#ifdef CURL_DOES_CONVERSIONS
  curl_easy_cleanup(handle);
#endif
  return 0;
}
#endif

#ifdef TEST_DECODE
/* decoding test harness. Read in a base64 string from stdin and write out the
 * length returned by Curl_base64_decode, followed by the decoded data itself
 *
 * gcc -DTEST_DECODE base64.c -o base64 mprintf.o memdebug.o
 */
#include <stdio.h>

#define TEST_NEED_SUCK
void *suck(int *);

int main(int argc, argv_item_t argv[], char **envp)
{
  char *base64;
  int base64Len;
  unsigned char *data;
  int dataLen;
  int i, j;
#ifdef CURL_DOES_CONVERSIONS
  /* get a Curl handle so main can translate properly */
  struct SessionHandle *handle = curl_easy_init();
  if(handle == NULL) {
    fprintf(stderr, "Error: curl_easy_init failed\n");
    return 1;
  }
#endif

  base64 = (char *)suck(&base64Len);
  dataLen = Curl_base64_decode(base64, &data);

  fprintf(stderr, "%d\n", dataLen);

  for(i=0; i < dataLen; i+=0x10) {
    printf("0x%02x: ", i);
    for(j=0; j < 0x10; j++)
      if((j+i) < dataLen)
        printf("%02x ", data[i+j]);
      else
        printf("   ");

    printf(" | ");

    for(j=0; j < 0x10; j++)
      if((j+i) < dataLen) {
#ifdef CURL_DOES_CONVERSIONS
        if(CURLE_OK !=
             Curl_convert_from_network(handle, &data[i+j], (size_t)1))
          data[i+j] = '.';
#endif /* CURL_DOES_CONVERSIONS */
        printf("%c", ISGRAPH(data[i+j])?data[i+j]:'.');
      } else
        break;
    puts("");
  }

#ifdef CURL_DOES_CONVERSIONS
  curl_easy_cleanup(handle);
#endif
  free(base64); free(data);
  return 0;
}
#endif

#ifdef TEST_NEED_SUCK
/* this function 'sucks' in as much as possible from stdin */
void *suck(int *lenptr)
{
  int cursize = 8192;
  unsigned char *buf = NULL;
  int lastread;
  int len = 0;

  do {
    cursize *= 2;
    buf = (unsigned char *)realloc(buf, cursize);
    memset(buf + len, 0, cursize - len);
    lastread = fread(buf + len, 1, cursize - len, stdin);
    len += lastread;
  } while(!feof(stdin));

  lenptr[0] = len;
  return (void *)buf;
}
#endif