#include "asn.h"
#include "misc.h"
#include <assert.h>unsigned int DERLengthEncode(unsigned int length, byte *output)
{
unsigned int i=0;
if (length <= 0x7f)
{
output[i++] = byte(length);
}
else
{
output[i++] = byte(BytePrecision(length) | 0x80);
for (int j=BytePrecision(length); j; --j)
{
output[i++] = byte (length >> (j-1)*8);
}
}
return i;
}unsigned int DERLengthEncode(unsigned int length, BufferedTransformation &bt)
{
byte buf[10]; // should be more than enough
unsigned int i = DERLengthEncode(length, buf);
bt.Put(buf, i);
return i;
}boolean BERLengthDecode(BufferedTransformation &bt, unsigned int &length)
{
byte b; if (!bt.Get(b))
BERDecodeError(); if (!(b & 0x80))
length = b;
else
{
unsigned int lengthBytes = b & 0x7f;
if (bt.MaxRetrieveable() < lengthBytes)
BERDecodeError(); bt.Get(b);
while (!b && lengthBytes>1)
{
bt.Get(b);
lengthBytes--;
} switch (lengthBytes)
{
case 0:
return FALSE; // indefinite length
case 1:
length = b;
break;
case 2:
length = b << 8;
length |= (bt.Get(b), b);
break;
default:
BERDecodeError();
}
}
return TRUE;
}BERSequenceDecoder::BERSequenceDecoder(BufferedTransformation &inQueue)
: inQueue(inQueue)
{
byte b;
if (!inQueue.Get(b) || b != (SEQUENCE | CONSTRUCTED))
BERDecodeError(); definiteLength = BERLengthDecode(inQueue, length);
}BERSequenceDecoder::~BERSequenceDecoder()
{
if (!definiteLength)
{ // remove end-of-content octects
word16 i;
if (!inQueue.GetShort(i) || (i!=0))
BERDecodeError();
}
}DERSequenceEncoder::DERSequenceEncoder(BufferedTransformation &outQueue)
: outQueue(outQueue)
{
}DERSequenceEncoder::~DERSequenceEncoder()
{
unsigned int length = (unsigned int)CurrentSize();
outQueue.Put(SEQUENCE | CONSTRUCTED);
DERLengthEncode(length, outQueue);
TransferTo(outQueue);
}
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