Pl_ASCII85Decoder.cc
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#include <qpdf/Pl_ASCII85Decoder.hh>
#include <qpdf/QTC.hh>
#include <stdexcept>
#include <string.h>
Pl_ASCII85Decoder::Pl_ASCII85Decoder(char const* identifier, Pipeline* next) :
Pipeline(identifier, next),
pos(0),
eod(0)
{
memset(this->inbuf, 117, 5);
}
Pl_ASCII85Decoder::~Pl_ASCII85Decoder()
{
}
void
Pl_ASCII85Decoder::write(unsigned char* buf, size_t len)
{
if (eod > 1)
{
return;
}
for (size_t i = 0; i < len; ++i)
{
if (eod > 1)
{
break;
}
else if (eod == 1)
{
if (buf[i] == '>')
{
flush();
eod = 2;
}
else
{
throw std::runtime_error(
"broken end-of-data sequence in base 85 data");
}
}
else
{
switch (buf[i])
{
case ' ':
case '\f':
case '\v':
case '\t':
case '\r':
case '\n':
QTC::TC("libtests", "Pl_ASCII85Decoder ignore space");
// ignore whitespace
break;
case '~':
eod = 1;
break;
case 'z':
if (pos != 0)
{
throw std::runtime_error(
"unexpected z during base 85 decode");
}
else
{
QTC::TC("libtests", "Pl_ASCII85Decoder read z");
unsigned char zeroes[4];
memset(zeroes, '\0', 4);
getNext()->write(zeroes, 4);
}
break;
default:
if ((buf[i] < 33) || (buf[i] > 117))
{
throw std::runtime_error(
"character out of range during base 85 decode");
}
else
{
this->inbuf[this->pos++] = buf[i];
if (pos == 5)
{
flush();
}
}
break;
}
}
}
}
void
Pl_ASCII85Decoder::flush()
{
if (this->pos == 0)
{
QTC::TC("libtests", "Pl_ASCII85Decoder no-op flush");
return;
}
unsigned long lval = 0;
for (int i = 0; i < 5; ++i)
{
lval *= 85;
lval += (this->inbuf[i] - 33U);
}
unsigned char outbuf[4];
memset(outbuf, 0, 4);
for (int i = 3; i >= 0; --i)
{
outbuf[i] = lval & 0xff;
lval >>= 8;
}
QTC::TC("libtests", "Pl_ASCII85Decoder partial flush",
(this->pos == 5) ? 0 : 1);
// Reset before calling getNext()->write in case that throws an
// exception.
auto t = this->pos - 1;
this->pos = 0;
memset(this->inbuf, 117, 5);
getNext()->write(outbuf, t);
}
void
Pl_ASCII85Decoder::finish()
{
flush();
getNext()->finish();
}