/**
* Decodes a BASE64 encoded data block. Returns True if string has been
* successfully decoded, or False if it cannot be decoded (or memory
* allocation fails). Does not destroy the original contents of the
* buffer
*/
STATIC Bool BASE64_InternalDecode(Base64Decode * decode)
{
/* remember the original length so that we can undo the damage */
Buffer* out = decode->out;
size_t origLen = (out ? BUFFER_Size(out) : 0);
/* read the bulk of the data */
int n;
Bool ok = True;
I8u chunk[4];
while ((n = BASE64_ReadChunk(decode, chunk)) == 4) {
if (out) {
if (!BUFFER_PutByte(out,BASE64_DECODE_1(chunk[0],chunk[1])) ||
!BUFFER_PutByte(out,BASE64_DECODE_2(chunk[1],chunk[2])) ||
!BUFFER_PutByte(out,BASE64_DECODE_3(chunk[2],chunk[3]))) {
/* out of memory */
ok = False;
break;
}
}
}
/* deal with the trailer */
if (out && ok) {
switch (n) {
case 0:
break;
case 1:
/* premature end of BASE64 stream */
decode->flags |= FLAG_ERROR;
break;
case 2:
if (!BUFFER_PutByte(out,BASE64_DECODE_1(chunk[0],chunk[1]))) {
/* out of memory */
ok = False;
}
break;
case 3:
if (!BUFFER_PutByte(out,BASE64_DECODE_1(chunk[0],chunk[1])) ||
!BUFFER_PutByte(out,BASE64_DECODE_2(chunk[1],chunk[2]))) {
/* out of memory */
ok = False;
}
break;
case 4:
if (!BUFFER_PutByte(out,BASE64_DECODE_1(chunk[0],chunk[1])) ||
!BUFFER_PutByte(out,BASE64_DECODE_2(chunk[1],chunk[2])) ||
!BUFFER_PutByte(out,BASE64_DECODE_3(chunk[2],chunk[3]))) {
/* out of memory */
ok = False;
}
break;
}
}
/* return True if the input was a valid BASE64 sequence */
if ((decode->flags & FLAG_ERROR) || !ok) {
if (out) {
BUFFER_Unput(out,BUFFER_Size(out)-origLen);
ASSERT(BUFFER_Size(out) == (int)origLen);
}
return False;
} else {
return True;
}
}
/**
* Decodes a BASE32 encoded data block. Returns True if string has been
* successfully decoded, or False if it cannot be decoded (or memory
* allocation fails). Does not destroy the original contents of the
* buffer
*/
STATIC Bool BASE32_InternalDecode(Base32Decode * decode)
{
/* remember the original length so that we can undo the damage */
Buffer * out = decode->out;
int origLen = (out ? BUFFER_Size(out) : 0);
/* read the bulk of the data */
int n;
Bool ok = True;
I8u b[DECODE_CHUNK_SIZE];
while ((n = BASE32_ReadChunk(decode, b)) == DECODE_CHUNK_SIZE) {
if (out) {
if (!BUFFER_PutByte(out,BASE32_DECODE_1(b[0],b[1])) ||
!BUFFER_PutByte(out,BASE32_DECODE_2(b[1],b[2],b[3])) ||
!BUFFER_PutByte(out,BASE32_DECODE_3(b[3],b[4])) ||
!BUFFER_PutByte(out,BASE32_DECODE_4(b[4],b[5],b[6])) ||
!BUFFER_PutByte(out,BASE32_DECODE_5(b[6],b[7]))) {
/* out of memory */
ok = False;
break;
}
}
}
/*
* +--- octet 0 ---+--- octet 1 ---+--- octet 2 ---+
* |7 6 5 4 3 2 1 0|7 6 5 4 3 2 1 0|7 6 5 4 3 2 1 0|
* +---------+-----+---+---------+-+-------+-------+
* |4 3 2 1 0|4 3 2 1 0|4 3 2 1 0|4 3 2 1 0|4 3 2 1
* +-0.index-+-1.index-+-2.index-+-3.index-+-4.index
*
* +--- octet 3 ---+--- octet 4 ---+
* |7 6 5 4 3 2 1 0|7 6 5 4 3 2 1 0|
* +-+---------+---+-----+---------+
* 0|4 3 2 1 0|4 3 2 1 0|4 3 2 1 0|
* --+-5.index-+-6.index-+-7.index-+
*/
/* deal with the trailer */
if (out && ok) {
switch (n) {
case 0:
break;
case 1:
case 3:
case 6:
/* incorrect trailer */
decode->flags |= FLAG_ERROR;
break;
case 2:
if (!BUFFER_PutByte(out,BASE32_DECODE_1(b[0],b[1]))) {
/* out of memory */
ok = False;
}
break;
case 4:
if (!BUFFER_PutByte(out,BASE32_DECODE_1(b[0],b[1])) ||
!BUFFER_PutByte(out,BASE32_DECODE_2(b[1],b[2],b[3]))) {
/* out of memory */
ok = False;
return False;
}
break;
case 5:
if (!BUFFER_PutByte(out,BASE32_DECODE_1(b[0],b[1])) ||
!BUFFER_PutByte(out,BASE32_DECODE_2(b[1],b[2],b[3])) ||
!BUFFER_PutByte(out,BASE32_DECODE_3(b[3],b[4]))) {
/* out of memory */
ok = False;
return False;
}
break;
case 7:
if (!BUFFER_PutByte(out,BASE32_DECODE_1(b[0],b[1])) ||
!BUFFER_PutByte(out,BASE32_DECODE_2(b[1],b[2],b[3])) ||
!BUFFER_PutByte(out,BASE32_DECODE_3(b[3],b[4])) ||
!BUFFER_PutByte(out,BASE32_DECODE_4(b[4],b[5],b[6]))) {
/* out of memory */
ok = False;
return False;
}
break;
}
}
/* return True if the input was a valid BASE32 sequence */
if ((decode->flags & FLAG_ERROR) || !ok) {
if (out) {
BUFFER_Unput(out,BUFFER_Size(out)-origLen);
ASSERT(BUFFER_Size(out) == origLen);
}
return False;
} else {
return True;
}
}
