#771: use longer ints for counting raster cells
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Reporter: hamish | Owner: grass-dev@lists.osgeo.org
Type: task | Status: new
Priority: normal | Milestone: 6.4.0
Component: Raster | Version: svn-develbranch6
Keywords: overflow | Platform: All
Cpu: Unspecified |
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Hi,
when region sizes exceed a bit more than 45000x45000 plain int no longer
has the bitspace to keep track of the number of cells and overflows.
'unsigned int' only buys us a little time until region size exceeds
65536x65536.
in these cases 'unsigned long long' could be used to make the size bigger.
not all compilers know about long long though so ./configure does a check
for it and sets a macro.
* r.stats and r.univar are a priority here.
r.info and g.region seem to have working implimentations,
example code from 6.5's g.region:
{{{
#ifdef HAVE_LONG_LONG_INT
fprintf(stdout, "%-*s %lld\n", width, "cells:",
(long long)window->rows * window->cols);
if (print_flag & PRINT_3D)
fprintf(stdout, "%-*s %lld\n", width, "3dcells:",
(long long)window->rows3 * window->cols3 *
window->depths);
#else
fprintf(stdout, "%-*s %ld\n", width, "cells:",
(long)window->rows * window->cols);
if (print_flag & PRINT_3D)
fprintf(stdout, "%-*s %ld\n", width, "3dcells:",
(long)window->rows3 * window->cols3 *
window->depths);
#endif
}}}
r.info:
{{{
#ifdef HAVE_LONG_LONG_INT
compose_line(out, " Total Cells: %llu",
(unsigned long long)cellhd.rows * cellhd.cols);
#else
compose_line(out,
" Total Cells: %lu (accuracy - see r.info
manual)",
(unsigned long)cellhd.rows * cellhd.cols);
#endif
}}}
r.info man page:
{{{
Some standards (ISO-C90) and compilers do not support the 'long long' type
as a 64-bit type. In the case that GRASS was built with such a compiler,
an accuracy message may be displayed in the output of <em>r.info</em>
after Total Cells:
}}}
we should standardize on something. any reason not to make it unsigned?
comments?
Hamish
--
Ticket URL: <https://trac.osgeo.org/grass/ticket/771>
GRASS GIS <http://grass.osgeo.org>