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Implement TIFF predicator (Issue #12)

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Michael R Sweet 2021-08-21 22:51:25 -04:00
parent fc028356bc
commit 3e4b01239e
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GPG Key ID: BE67C75EC81F3244
1 changed files with 60 additions and 3 deletions
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63
pdfio-stream.c
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@ -872,7 +872,64 @@ stream_read(pdfio_stream_t *st, // I - Stream
} }
else if (st->predictor == _PDFIO_PREDICTOR_TIFF2) else if (st->predictor == _PDFIO_PREDICTOR_TIFF2)
{ {
// TODO: Implement TIFF2 predictor size_t pbpixel = st->pbpixel,
// Size of pixel in bytes
remaining = st->pbsize;
// Remaining bytes
unsigned char *bufptr = (unsigned char *)buffer,
// Pointer into buffer
*bufsecond = (unsigned char *)buffer + pbpixel,
// Pointer to second pixel in buffer
*sptr = st->psbuffer;
// Current (raw) line
PDFIO_DEBUG("stream_read: TIFF predictor 2.\n");
if (bytes < st->pbsize)
{
_pdfioFileError(st->pdf, "Read buffer too small for stream.");
return (-1);
}
st->flate.next_out = (Bytef *)sptr;
st->flate.avail_out = (uInt)st->pbsize;
while (st->flate.avail_out > 0)
{
if (st->flate.avail_in == 0)
{
// Read more from the file...
if (sizeof(st->cbuffer) > st->remaining)
rbytes = _pdfioFileRead(st->pdf, st->cbuffer, st->remaining);
else
rbytes = _pdfioFileRead(st->pdf, st->cbuffer, sizeof(st->cbuffer));
if (rbytes <= 0)
return (-1); // End of file...
st->remaining -= (size_t)rbytes;
st->flate.next_in = (Bytef *)st->cbuffer;
st->flate.avail_in = (uInt)rbytes;
}
if ((status = inflate(&(st->flate), Z_NO_FLUSH)) < Z_OK)
{
_pdfioFileError(st->pdf, "Unable to decompress stream data: %d", status);
return (-1);
}
else if (status == Z_STREAM_END)
break;
}
if (st->flate.avail_out > 0)
return (-1); // Early end of stream
for (; bufptr < bufsecond; remaining --, sptr ++)
*bufptr++ = *sptr;
for (; remaining > 0; remaining --, sptr ++, bufptr ++)
*bufptr = *sptr + bufptr[-(int)pbpixel];
return ((ssize_t)st->pbsize);
} }
else else
{ {
@ -912,7 +969,7 @@ stream_read(pdfio_stream_t *st, // I - Stream
rbytes = _pdfioFileRead(st->pdf, st->cbuffer, sizeof(st->cbuffer)); rbytes = _pdfioFileRead(st->pdf, st->cbuffer, sizeof(st->cbuffer));
if (rbytes <= 0) if (rbytes <= 0)
return (-1); // End of file... return (-1); // End of file...
st->remaining -= (size_t)rbytes; st->remaining -= (size_t)rbytes;
st->flate.next_in = (Bytef *)st->cbuffer; st->flate.next_in = (Bytef *)st->cbuffer;
@ -929,7 +986,7 @@ stream_read(pdfio_stream_t *st, // I - Stream
} }
if (st->flate.avail_out > 0) if (st->flate.avail_out > 0)
return (-1); // Early end of stream return (-1); // Early end of stream
// Apply predictor for this line // Apply predictor for this line
PDFIO_DEBUG("stream_read: Line %02X %02X %02X %02X %02X.\n", sptr[-1], sptr[0], sptr[0], sptr[2], sptr[3]); PDFIO_DEBUG("stream_read: Line %02X %02X %02X %02X %02X.\n", sptr[-1], sptr[0], sptr[0], sptr[2], sptr[3]);