static int
TIFFFillStripPartial( TIFF *tif, int strip, tmsize_t read_ahead, int restart )
{
static const char module[] = "TIFFFillStripPartial";
register TIFFDirectory *td = &tif->tif_dir;
tmsize_t unused_data;
uint64 read_offset;
tmsize_t to_read;
tmsize_t read_ahead_mod;
/* tmsize_t bytecountm; */
if (!_TIFFFillStriles( tif ) || !tif->tif_dir.td_stripbytecount)
return 0;
/*
* Expand raw data buffer, if needed, to hold data
* strip coming from file (perhaps should set upper
* bound on the size of a buffer we'll use?).
*/
/* bytecountm=(tmsize_t) td->td_stripbytecount[strip]; */
/* Not completely sure where the * 2 comes from, but probably for */
/* an exponentional growth strategy of tif_rawdatasize */
if( read_ahead < TIFF_TMSIZE_T_MAX / 2 )
read_ahead_mod = read_ahead * 2;
else
read_ahead_mod = read_ahead;
if (read_ahead_mod > tif->tif_rawdatasize) {
assert( restart );
tif->tif_curstrip = NOSTRIP;
if ((tif->tif_flags & TIFF_MYBUFFER) == 0) {
TIFFErrorExt(tif->tif_clientdata, module,
"Data buffer too small to hold part of strip %lu",
(unsigned long) strip);
return (0);
}
}
if( restart )
{
tif->tif_rawdataloaded = 0;
tif->tif_rawdataoff = 0;
}
/*
** If we are reading more data, move any unused data to the
** start of the buffer.
*/
if( tif->tif_rawdataloaded > 0 )
unused_data = tif->tif_rawdataloaded - (tif->tif_rawcp - tif->tif_rawdata);
else
unused_data = 0;
if( unused_data > 0 )
{
assert((tif->tif_flags&TIFF_BUFFERMMAP)==0);
memmove( tif->tif_rawdata, tif->tif_rawcp, unused_data );
}
/*
** Seek to the point in the file where more data should be read.
*/
read_offset = td->td_stripoffset[strip]
+ tif->tif_rawdataoff + tif->tif_rawdataloaded;
if (!SeekOK(tif, read_offset)) {
TIFFErrorExt(tif->tif_clientdata, module,
"Seek error at scanline %lu, strip %lu",
(unsigned long) tif->tif_row, (unsigned long) strip);
return 0;
}
/*
** How much do we want to read?
*/
if( read_ahead_mod > tif->tif_rawdatasize )
to_read = read_ahead_mod - unused_data;
else
to_read = tif->tif_rawdatasize - unused_data;
if( (uint64) to_read > td->td_stripbytecount[strip]
- tif->tif_rawdataoff - tif->tif_rawdataloaded )
{
to_read = (tmsize_t) td->td_stripbytecount[strip]
- tif->tif_rawdataoff - tif->tif_rawdataloaded;
}
assert((tif->tif_flags&TIFF_BUFFERMMAP)==0);
if( !TIFFReadAndRealloc( tif, to_read, unused_data,
1, /* is_strip */
0, /* strip_or_tile */
module) )
{
return 0;
}
tif->tif_rawdataoff = tif->tif_rawdataoff + tif->tif_rawdataloaded - unused_data ;
tif->tif_rawdataloaded = unused_data + to_read;
tif->tif_rawcc = tif->tif_rawdataloaded;
tif->tif_rawcp = tif->tif_rawdata;
if (!isFillOrder(tif, td->td_fillorder) &&
(tif->tif_flags & TIFF_NOBITREV) == 0) {
assert((tif->tif_flags&TIFF_BUFFERMMAP)==0);
TIFFReverseBits(tif->tif_rawdata + unused_data, to_read );
}
/*
** When starting a strip from the beginning we need to
** restart the decoder.
*/
if( restart )
{
#ifdef JPEG_SUPPORT
/* A bit messy since breaks the codec abstraction. Ultimately */
/* there should be a function pointer for that, but it seems */
/* only JPEG is affected. */
/* For JPEG, if there are multiple scans (can generally be known */
/* with the read_ahead used), we need to read the whole strip */
if( tif->tif_dir.td_compression==COMPRESSION_JPEG &&
(uint64)tif->tif_rawcc < td->td_stripbytecount[strip] )
{
if( TIFFJPEGIsFullStripRequired(tif) )
{
return TIFFFillStrip(tif, strip);
}
}
#endif
return TIFFStartStrip(tif, strip);
}
else
{
return 1;
}
}
/*
* Seek to a random row+sample in a file.
*
* Only used by TIFFReadScanline, and is only used on
* strip organized files. We do some tricky stuff to try
* and avoid reading the whole compressed raw data for big
* strips.
*/
static int
TIFFSeek(TIFF* tif, uint32 row, uint16 sample )
{
register TIFFDirectory *td = &tif->tif_dir;
uint32 strip;
int whole_strip;
tmsize_t read_ahead = 0;
/*
** Establish what strip we are working from.
*/
if (row >= td->td_imagelength) { /* out of range */
TIFFErrorExt(tif->tif_clientdata, tif->tif_name,
"%lu: Row out of range, max %lu",
(unsigned long) row,
(unsigned long) td->td_imagelength);
return (0);
}
if (td->td_planarconfig == PLANARCONFIG_SEPARATE) {
if (sample >= td->td_samplesperpixel) {
TIFFErrorExt(tif->tif_clientdata, tif->tif_name,
"%lu: Sample out of range, max %lu",
(unsigned long) sample, (unsigned long) td->td_samplesperpixel);
return (0);
}
strip = (uint32)sample*td->td_stripsperimage + row/td->td_rowsperstrip;
} else
strip = row / td->td_rowsperstrip;
/*
* Do we want to treat this strip as one whole chunk or
* read it a few lines at a time?
*/
#if defined(CHUNKY_STRIP_READ_SUPPORT)
if (!_TIFFFillStriles( tif ) || !tif->tif_dir.td_stripbytecount)
return 0;
whole_strip = tif->tif_dir.td_stripbytecount[strip] < 10
|| isMapped(tif);
if( td->td_compression == COMPRESSION_LERC )
{
/* Ideally plugins should have a way to declare they don't support
* chunk strip */
whole_strip = 1;
}
#else
whole_strip = 1;
#endif
if( !whole_strip )
{
/* 16 is for YCbCr mode where we may need to read 16 */
/* lines at a time to get a decompressed line, and 5000 */
/* is some constant value, for example for JPEG tables */
if( tif->tif_scanlinesize < TIFF_TMSIZE_T_MAX / 16 &&
tif->tif_scanlinesize * 16 < TIFF_TMSIZE_T_MAX - 5000 )
{
read_ahead = tif->tif_scanlinesize * 16 + 5000;
}
else
{
read_ahead = tif->tif_scanlinesize;
}
}
/*
* If we haven't loaded this strip, do so now, possibly
* only reading the first part.
*/
if (strip != tif->tif_curstrip) { /* different strip, refill */
if( whole_strip )
{
if (!TIFFFillStrip(tif, strip))
return (0);
}
else
{
if( !TIFFFillStripPartial(tif,strip,read_ahead,1) )
return 0;
}
}
/*
** If we already have some data loaded, do we need to read some more?
*/
else if( !whole_strip )
{
if( ((tif->tif_rawdata + tif->tif_rawdataloaded) - tif->tif_rawcp) < read_ahead
&& (uint64) tif->tif_rawdataoff+tif->tif_rawdataloaded < td->td_stripbytecount[strip] )
{
if( !TIFFFillStripPartial(tif,strip,read_ahead,0) )
return 0;
}
}
if (row < tif->tif_row) {
/*
* Moving backwards within the same strip: backup
* to the start and then decode forward (below).
*
* NB: If you're planning on lots of random access within a
* strip, it's better to just read and decode the entire
* strip, and then access the decoded data in a random fashion.
*/
if( tif->tif_rawdataoff != 0 )
{
if( !TIFFFillStripPartial(tif,strip,read_ahead,1) )
return 0;
}
else
{
if (!TIFFStartStrip(tif, strip))
return (0);
}
}
if (row != tif->tif_row) {
/*
* Seek forward to the desired row.
*/
/* TODO: Will this really work with partial buffers? */
if (!(*tif->tif_seek)(tif, row - tif->tif_row))
return (0);
tif->tif_row = row;
}
return (1);
}
/*
* Read a strip of data and decompress the specified
* amount into the user-supplied buffer.
*/
tmsize_t
TIFFReadEncodedStrip(TIFF* tif, uint32 strip, void* buf, tmsize_t size)
{
static const char module[] = "TIFFReadEncodedStrip";
TIFFDirectory *td = &tif->tif_dir;
uint32 rowsperstrip;
uint32 stripsperplane;
uint32 stripinplane;
uint16 plane;
uint32 rows;
tmsize_t stripsize;
if (!TIFFCheckRead(tif,0))
return((tmsize_t)(-1));
if (strip>=td->td_nstrips)
{
TIFFErrorExt(tif->tif_clientdata,module,
"%lu: Strip out of range, max %lu",(unsigned long)strip,
(unsigned long)td->td_nstrips);
return((tmsize_t)(-1));
}
/*
* Calculate the strip size according to the number of
* rows in the strip (check for truncated last strip on any
* of the separations).
*/
rowsperstrip=td->td_rowsperstrip;
if (rowsperstrip>td->td_imagelength)
rowsperstrip=td->td_imagelength;
stripsperplane= TIFFhowmany_32_maxuint_compat(td->td_imagelength, rowsperstrip);
stripinplane=(strip%stripsperplane);
plane=(uint16)(strip/stripsperplane);
rows=td->td_imagelength-stripinplane*rowsperstrip;
if (rows>rowsperstrip)
rows=rowsperstrip;
stripsize=TIFFVStripSize(tif,rows);
if (stripsize==0)
return((tmsize_t)(-1));
/* shortcut to avoid an extra memcpy() */
if( td->td_compression == COMPRESSION_NONE &&
size!=(tmsize_t)(-1) && size >= stripsize &&
!isMapped(tif) &&
((tif->tif_flags&TIFF_NOREADRAW)==0) )
{
if (TIFFReadRawStrip1(tif, strip, buf, stripsize, module) != stripsize)
return ((tmsize_t)(-1));
if (!isFillOrder(tif, td->td_fillorder) &&
(tif->tif_flags & TIFF_NOBITREV) == 0)
TIFFReverseBits(buf,stripsize);
(*tif->tif_postdecode)(tif,buf,stripsize);
return (stripsize);
}
if ((size!=(tmsize_t)(-1))&&(size<stripsize))
stripsize=size;
if (!TIFFFillStrip(tif,strip))
return((tmsize_t)(-1));
if ((*tif->tif_decodestrip)(tif,buf,stripsize,plane)<=0)
return((tmsize_t)(-1));
(*tif->tif_postdecode)(tif,buf,stripsize);
return(stripsize);
}
