Implement base64 decoder.

This commit is contained in:
Michael Jumper 2013-09-27 15:39:44 -07:00
parent 321e24c417
commit 30ec019512
2 changed files with 68 additions and 0 deletions

View File

@ -800,5 +800,14 @@ int guac_protocol_send_clipboard(guac_socket* socket, const char* data);
*/
int guac_protocol_send_name(guac_socket* socket, const char* name);
/**
* Decodes the given base64-encoded string in-place. The base64 string must
* be NULL-terminated.
*
* @param base64 The base64-encoded string to decode.
* @return The number of bytes resulting from the decode operation.
*/
int guac_protocol_decode_base64(char* base64);
#endif

View File

@ -1248,3 +1248,62 @@ int guac_protocol_send_video(guac_socket* socket, const guac_stream* stream,
}
/**
* Returns the value of a single base64 character.
*/
static int __guac_base64_value(char c) {
if (c >= 'A' && c <= 'Z')
return c - 'A';
if (c >= 'a' && c <= 'z')
return c - 'a' + 26;
if (c >= '0' && c <= '9')
return c - '0' + 52;
if (c == '+')
return 62;
if (c == '/')
return 63;
return 0;
}
int guac_protocol_decode_base64(char* base64) {
char* input = base64;
char* output = base64;
int length = 0;
int bits_read = 0;
int value = 0;
char current;
/* For all characters in string */
while ((current = *(input++)) != 0) {
/* If we've reached padding, then we're done */
if (current == '=')
break;
/* Otherwise, shift on the latest 6 bits */
value = (value << 6) | __guac_base64_value(current);
bits_read += 6;
/* If we have at least one byte, write out the latest whole byte */
if (bits_read >= 8) {
*(output++) = (value >> (bits_read % 8)) & 0xFF;
bits_read -= 8;
length++;
}
}
/* Return number of bytes written */
return length;
}