#include "base64.h"
#include "string.h"
-static const char Base64[] =
- "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
+static const unsigned char base64_tab[256] = {
+ 255, 255, 255, 255, 255, 255, 255, 255, /* 00-07 */
+ 255, 255, 255, 255, 255, 255, 255, 255, /* 08-0f */
+ 255, 255, 255, 255, 255, 255, 255, 255, /* 10-17 */
+ 255, 255, 255, 255, 255, 255, 255, 255, /* 18-1f */
+ 255, 255, 255, 255, 255, 255, 255, 255, /* 20-2f */
+ 255, 255, 255, 62, 255, 255, 255, 63, /* 28-2f */
+ 52 , 53, 54, 55, 56, 57, 58, 59, /* 30-37 */
+ 60 , 61, 255, 255, 255, 255, 255, 255, /* 38-3f */
+ 255, 0, 1, 2, 3, 4, 5, 6, /* 40-47 */
+ 7 , 8, 9, 10, 11, 12, 13, 14, /* 48-4f */
+ 15 , 16, 17, 18, 19, 20, 21, 22, /* 50-57 */
+ 23 , 24, 25, 255, 255, 255, 255, 255, /* 58-5f */
+ 255, 26, 27, 28, 29, 30, 31, 32, /* 60-6f */
+ 33 , 34, 35, 36, 37, 38, 39, 40, /* 68-6f */
+ 41 , 42, 43, 44, 45, 46, 47, 48, /* 70-77 */
+ 49 , 50, 51, 255, 255, 255, 255, 255, /* 78-7f */
+ 255, 255, 255, 255, 255, 255, 255, 255, /* 80-87 */
+ 255, 255, 255, 255, 255, 255, 255, 255, /* 88-8f */
+ 255, 255, 255, 255, 255, 255, 255, 255, /* 90-97 */
+ 255, 255, 255, 255, 255, 255, 255, 255, /* 98-9f */
+ 255, 255, 255, 255, 255, 255, 255, 255, /* a0-a7 */
+ 255, 255, 255, 255, 255, 255, 255, 255, /* a8-af */
+ 255, 255, 255, 255, 255, 255, 255, 255, /* b0-b7 */
+ 255, 255, 255, 255, 255, 255, 255, 255, /* b8-bf */
+ 255, 255, 255, 255, 255, 255, 255, 255, /* c0-c7 */
+ 255, 255, 255, 255, 255, 255, 255, 255, /* c8-cf */
+ 255, 255, 255, 255, 255, 255, 255, 255, /* d0-d7 */
+ 255, 255, 255, 255, 255, 255, 255, 255, /* d8-df */
+ 255, 255, 255, 255, 255, 255, 255, 255, /* e0-e7 */
+ 255, 255, 255, 255, 255, 255, 255, 255, /* e8-ef */
+ 255, 255, 255, 255, 255, 255, 255, 255, /* f0-f7 */
+ 255, 255, 255, 255, 255, 255, 255, 255, /* f8-ff */
+};
/** Maximal possible size of the decoded data. */
#define BASE64_MAX_DECODED_SIZE(_encoded_size) ((_encoded_size) / 4 * 3)
int base64_decode(char const *src, size_t encoded_size, char **result,
size_t *decoded_size)
{
- unsigned int tarindex, state;
- int ch;
- char *pos;
- const char *end = src + encoded_size;
- unsigned char *target;
+ size_t i, j, state; /* source/target indices */
+ const char *end = src + encoded_size, *p;
+ unsigned char *target, uch;
if (encoded_size == (size_t)-1)
encoded_size = strlen(src);
target = para_malloc(BASE64_MAX_DECODED_SIZE(encoded_size) + 1);
- state = 0;
- tarindex = 0;
-
- while (src < end) {
- ch = *src++;
- if (para_isspace(ch)) /* Skip whitespace anywhere. */
+ for (
+ i = 0, j = 0, state = 0;
+ i < encoded_size && (uch = src[i]) != '\0';
+ i++
+ ) {
+ if (para_isspace(uch)) /* Skip whitespace anywhere. */
continue;
-
- if (ch == PAD64)
+ if (uch == PAD64)
break;
-
- pos = strchr(Base64, ch);
- if (pos == NULL) /* A non-base64 character. */
+ if (base64_tab[uch] == 255) /* A non-base64 character. */
goto fail;
-
+ uch = base64_tab[uch];
switch (state) {
case 0:
- target[tarindex] = (pos - Base64) << 2;
- state = 1;
+ target[j] = uch << 2;
break;
case 1:
- target[tarindex] |= (pos - Base64) >> 4;
- target[tarindex + 1] = ((pos - Base64) & 0x0f) << 4;
- tarindex++;
- state = 2;
+ target[j] |= uch >> 4;
+ j++;
+ target[j] = (uch & 0x0f) << 4;
break;
case 2:
- target[tarindex] |= (pos - Base64) >> 2;
- target[tarindex + 1] = ((pos - Base64) & 0x03) << 6;
- tarindex++;
- state = 3;
+ target[j] |= uch >> 2;
+ j++;
+ target[j] = (uch & 0x03) << 6;
break;
case 3:
- target[tarindex] |= pos - Base64;
- tarindex++;
- state = 0;
+ target[j] |= uch;
+ j++;
break;
}
+ state = (state + 1) % 4;
}
-
+ p = (i < encoded_size)? src + i : NULL;
/*
* We are done decoding Base-64 chars. Let's see if we ended
* on a byte boundary, and/or with erroneous trailing characters.
*/
-
- if (*src == PAD64) { /* We got a pad char. */
- ch = *src++; /* Skip it, get next. */
+ if (p && *p == PAD64) { /* We got a pad char. Skip it, get next. */
+ p++;
switch (state) {
- case 0: /* Invalid = in first position */
- case 1: /* Invalid = in second position */
+ case 0: /* Invalid = in first position */
+ case 1: /* Invalid = in second position */
goto fail;
- case 2: /* Valid, means one byte of info */
+ case 2: /* Valid, means one byte of info */
/* Skip any number of spaces. */
- for (; ch != '\0'; ch = *src++)
- if (!isspace(ch))
+ for (; p < end && *p != '\0'; p++)
+ if (!para_isspace(*p))
break;
/* Make sure there is another trailing = sign. */
- if (ch != PAD64)
+ if (*p != PAD64)
goto fail;
- ch = *src++; /* Skip the = */
/* Fall through to "single trailing =" case. */
- /* FALLTHROUGH */
+ p++;
- case 3: /* Valid, means two bytes of info */
+ case 3: /* Valid, means two bytes of info */
/*
* We know this char is an =. Is there anything but
* whitespace after it?
*/
- for (; ch != '\0'; ch = *src++)
- if (!isspace(ch))
+ for (; p < end && *p != '\0'; p++)
+ if (!para_isspace(*p))
goto fail;
-
/*
* Now make sure for cases 2 and 3 that the "extra"
* bits that slopped past the last full byte were
* zeros. If we don't check them, they become a
* subliminal channel.
*/
- if (target[tarindex] != 0)
+ if (target[j] != 0)
goto fail;
}
} else {
goto fail;
}
/* success */
- target[tarindex] = '\0'; /* just to be sure */
- *result = (char *)target;
+ target[j] = '\0'; /* just to be sure */
if (decoded_size)
- *decoded_size = tarindex;
+ *decoded_size = j;
+ *result = (char *)target;
return 1;
fail:
free(target);
projects / paraslash.git / blobdiff