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#include <qpdf/Pl_Flate.hh>
#include <zlib.h>
#include <qpdf/QUtil.hh>
Pl_Flate::Pl_Flate(char const* identifier, Pipeline* next,
action_e action, int out_bufsize) :
Pipeline(identifier, next),
out_bufsize(out_bufsize),
action(action),
initialized(false)
{
this->outbuf = new unsigned char[out_bufsize];
// Indirect through zdata to reach the z_stream so we don't have
// to include zlib.h in Pl_Flate.hh. This means people using
// shared library versions of qpdf don't have to have zlib
// development files available, which particularly helps in a
// Windows environment.
this->zdata = new z_stream;
z_stream& zstream = *((z_stream*) this->zdata);
zstream.zalloc = (alloc_func)0;
zstream.zfree = (free_func)0;
zstream.opaque = (voidpf)0;
zstream.next_in = 0;
zstream.avail_in = 0;
zstream.next_out = this->outbuf;
zstream.avail_out = out_bufsize;
}
Pl_Flate::~Pl_Flate()
{
if (this->outbuf)
{
delete [] this->outbuf;
this->outbuf = 0;
}
delete (z_stream*)this->zdata;
this->zdata = 0;
}
void
Pl_Flate::write(unsigned char* data, size_t len)
{
if (this->outbuf == 0)
{
throw std::logic_error(
this->identifier +
": Pl_Flate: write() called after finish() called");
}
// Write in chunks in case len is too big to fit in an int.
// Assume int is at least 32 bits.
static size_t const max_bytes = 1 << 30;
size_t bytes_left = len;
unsigned char* buf = data;
while (bytes_left > 0)
{
size_t bytes = (bytes_left >= max_bytes ? max_bytes : bytes_left);
handleData(buf, (int)bytes, Z_NO_FLUSH);
bytes_left -= bytes;
buf += bytes;
}
}
void
Pl_Flate::handleData(unsigned char* data, int len, int flush)
{
z_stream& zstream = *((z_stream*) this->zdata);
zstream.next_in = data;
zstream.avail_in = len;
if (! this->initialized)
{
int err = Z_OK;
if (this->action == a_deflate)
{
err = deflateInit(&zstream, Z_DEFAULT_COMPRESSION);
}
else
{
err = inflateInit(&zstream);
}
checkError("Init", err);
this->initialized = true;
}
int err = Z_OK;
bool done = false;
while (! done)
{
if (action == a_deflate)
{
err = deflate(&zstream, flush);
}
else
{
err = inflate(&zstream, flush);
}
switch (err)
{
case Z_BUF_ERROR:
// Probably shouldn't be able to happen, but possible as a
// boundary condition: if the last call to inflate exactly
// filled the output buffer, it's possible that the next
// call to inflate could have nothing to do.
done = true;
break;
case Z_STREAM_END:
done = true;
// fall through
case Z_OK:
{
if ((zstream.avail_in == 0) &&
(zstream.avail_out > 0))
{
// There is nothing left to read, and there was
// sufficient buffer space to write everything we
// needed, so we're done for now.
done = true;
}
uLong ready = (this->out_bufsize - zstream.avail_out);
if (ready > 0)
{
this->getNext()->write(this->outbuf, ready);
zstream.next_out = this->outbuf;
zstream.avail_out = this->out_bufsize;
}
}
break;
default:
this->checkError("data", err);
break;
}
}
}
void
Pl_Flate::finish()
{
if (this->outbuf)
{
if (this->initialized)
{
z_stream& zstream = *((z_stream*) this->zdata);
unsigned char buf[1];
buf[0] = '\0';
handleData(buf, 0, Z_FINISH);
int err = Z_OK;
if (action == a_deflate)
{
err = deflateEnd(&zstream);
}
else
{
err = inflateEnd(&zstream);
}
checkError("End", err);
}
delete [] this->outbuf;
this->outbuf = 0;
}
this->getNext()->finish();
}
void
Pl_Flate::checkError(char const* prefix, int error_code)
{
z_stream& zstream = *((z_stream*) this->zdata);
if (error_code != Z_OK)
{
char const* action_str = (action == a_deflate ? "deflate" : "inflate");
std::string msg =
this->identifier + ": " + action_str + ": " + prefix + ": ";
if (zstream.msg)
{
msg += zstream.msg;
}
else
{
switch (error_code)
{
case Z_ERRNO:
msg += "zlib system error";
break;
case Z_STREAM_ERROR:
msg += "zlib stream error";
break;
case Z_DATA_ERROR:
msg += "zlib data error";
break;
case Z_MEM_ERROR:
msg += "zlib memory error";
break;
case Z_BUF_ERROR:
msg += "zlib buffer error";
break;
case Z_VERSION_ERROR:
msg += "zlib version error";
break;
default:
msg += std::string("zlib unknown error (") +
QUtil::int_to_string(error_code) + ")";
break;
}
}
throw std::runtime_error(msg);
}
}
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