* bugs/concept_and_assignment.cc: sample code of what should not be done while assigning an image to another. --- milena/sandbox/ChangeLog | 7 ++ milena/sandbox/bugs/concept_and_assignment.cc | 84 +++++++++++++++++++++++++ 2 files changed, 91 insertions(+), 0 deletions(-) create mode 100644 milena/sandbox/bugs/concept_and_assignment.cc diff --git a/milena/sandbox/ChangeLog b/milena/sandbox/ChangeLog index 0512bfc..8c7681f 100644 --- a/milena/sandbox/ChangeLog +++ b/milena/sandbox/ChangeLog @@ -1,3 +1,10 @@ +2009-03-16 Guillaume Lazzara <z@lrde.epita.fr> + + Add a buggy sample case. + + * bugs/concept_and_assignment.cc: sample code of what should not + be done while assigning an image to another. + 2009-03-19 Fabien Freling <fabien.freling@lrde.epita.fr> Add a new file translating IGR Matlab code. diff --git a/milena/sandbox/bugs/concept_and_assignment.cc b/milena/sandbox/bugs/concept_and_assignment.cc new file mode 100644 index 0000000..379d17d --- /dev/null +++ b/milena/sandbox/bugs/concept_and_assignment.cc @@ -0,0 +1,84 @@ +/* +** We do NOT want to pass images as reference. +** +** Assigning an image to an image concept will compile but +** will not perform anything. This is ERROR PRONE. +** +** Thus, if the image passed as reference is not initialized it will remain +** uninitialized and an assertion will raised. The problem is if the image is +** already initialized. It will FAIL SILENTLY and give wrong image values. +** +** Always prefer returning images. +*/ + +#include <mln/essential/2d.hh> + +namespace mln +{ + + template <typename I> + mln_ch_value(I,value::label_8) + bar(const Image<I>& ima) + { + value::label_8 n; + + mln_ch_value(I,value::label_8) lbl; + initialize(lbl, ima); + + lbl = labeling::blobs(ima, c8(),n); + mln_assertion(lbl.is_valid()); + + return lbl; + } + + // DO NOT WORK! + template <typename I> + void foo_template_and_concept(Image<I>& lbl) + { + mln_ch_value(I,bool) ima(3,4); + + /// The difference is here! + lbl = bar(ima); + + mln_assertion(exact(lbl).is_valid()); + } + + // WORK + template <typename I> + void foo_template_concept_and_exact(Image<I>& lbl) + { + mln_ch_value(I,bool) ima(3,4); + + /// The difference is here! + exact(lbl) = bar(ima); + + mln_assertion(exact(lbl).is_valid()); + } + +} + + + +int main(int, char*argv[]) +{ + using namespace mln; + + image2d<bool> ima(3,4); + + // WORK + { + std::cout << "template with I + concept + exact" << std::endl; + image2d<value::label_8> lbl; + foo_template_concept_and_exact(lbl); + mln_assertion(lbl.is_valid()); + } + + // DO NOT WORK + { + std::cout << "template with I + concept" << std::endl; + image2d<value::label_8> lbl; + foo_template_and_concept(lbl); + mln_assertion(lbl.is_valid()); + } + +} -- 1.5.6.5