/**
* Convert ASCII encoding back to data
* out_size must match exactly the size of the data before it was encoded.
*
* @param enc the encoding
* @param enclen number of characters in @a enc (without 0-terminator, which can be missing)
* @param out location where to store the decoded data
* @param out_size size of the output buffer @a out
* @return #GNUNET_OK on success, #GNUNET_SYSERR if result has the wrong encoding
*/
int
GNUNET_STRINGS_string_to_data (const char *enc, size_t enclen,
void *out, size_t out_size)
{
unsigned int rpos;
unsigned int wpos;
unsigned int bits;
unsigned int vbit;
int ret;
int shift;
unsigned char *uout;
unsigned int encoded_len = out_size * 8;
if (0 == enclen)
{
if (0 == out_size)
return GNUNET_OK;
return GNUNET_SYSERR;
}
uout = out;
wpos = out_size;
rpos = enclen;
if ((encoded_len % 5) > 0)
{
vbit = encoded_len % 5; /* padding! */
shift = 5 - vbit;
bits = (ret = getValue__ (enc[--rpos])) >> (5 - (encoded_len % 5));
}
/**
* Convert ASCII encoding back to data
* out_size must match exactly the size of the data before it was encoded.
*
* @param enc the encoding
* @param enclen number of characters in 'enc' (without 0-terminator, which can be missing)
* @param out location where to store the decoded data
* @param out_size sizeof the output buffer
* @return GNUNET_OK on success, GNUNET_SYSERR if result has the wrong encoding
*/
int
GNUNET_STRINGS_string_to_data (const char *enc, size_t enclen,
unsigned char *out, size_t out_size)
{
unsigned int rpos;
unsigned int wpos;
unsigned int bits;
unsigned int vbit;
int ret;
int shift;
int encoded_len = out_size * 8;
if (encoded_len % 5 > 0)
{
vbit = encoded_len % 5; /* padding! */
shift = 5 - vbit;
}
else
{
vbit = 0;
shift = 0;
}
if ((encoded_len + shift) / 5 != enclen)
return GNUNET_SYSERR;
wpos = out_size;
rpos = enclen;
bits = (ret = getValue__ (enc[--rpos])) >> (5 - encoded_len % 5);
if (-1 == ret)
return GNUNET_SYSERR;
while (wpos > 0)
{
GNUNET_assert (rpos > 0);
bits = ((ret = getValue__ (enc[--rpos])) << vbit) | bits;
if (-1 == ret)
return GNUNET_SYSERR;
vbit += 5;
if (vbit >= 8)
{
out[--wpos] = (unsigned char) bits;
bits >>= 8;
vbit -= 8;
}
}