random access iterators in ArithmeticalDSL

[troussil]

we provide random access services to iterators of ArithmeticalDSL/DSS

[dcoeurjo]

In classical STL concepts, the return type of "distance_to" is an unsigned scalar.
Position could also have been typdefed as an unsigned version of TCoordinate, what do you think ?

[troussil]

I am not agree. In STL, distances between random access iterators are
signed (they supports arithmetic operators + and -). For instance, for
pointers, difference_type is basically ptrdiff_t, which is a signed integer
type. See http://www.cplusplus.com/reference/iterator/iterator_traits/

2014-04-19 10:16 GMT+02:00 David Coeurjolly [email protected]:

In src/DGtal/geometry/curves/ArithmeticalDSL.h:

•  /**
  

•   \* Moves @a myCurrentPoint lying at position i to the
  

•   \* point of the DSL lying at position i + @a aShift
  

•   \* @param aShift position difference
  

•   \* NB: in O(1)
  

•   */
  

•  void advance(const Position& aShift);
  

•  /**
  

•   \* Computes the distance between *this and @a aOther, ie.
  

•   \* the difference between their positions
  

•   \* @param aOther any other iterator
  

•   \* @return distance between the two iterators
  

•   */
  

•  Position distance_to(const ConstIterator& aOther) const;
  

In classical STL concepts, the return type of "distance_to" is an unsigned
scalar.
Position could also have been typdefed as an unsigned version of
TCoordinate, what do you think ?

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[dcoeurjo]

Agree. My mistake I thought it was a size_t sort of thing..

Le 19 avr. 2014 à 18:44, troussil [email protected] a écrit :

In src/DGtal/geometry/curves/ArithmeticalDSL.h:

•  /**
  

•   \* Moves @a myCurrentPoint lying at position i to the 
  

•   \* point of the DSL lying at position i + @a aShift
  

•   \* @param aShift position difference
  

•   \* NB: in O(1)
  

•   */
  

•  void advance(const Position& aShift);
  

•  /**
  

•   \* Computes the distance between *this and @a aOther, ie.
  

•   \* the difference between their positions
  

•   \* @param aOther any other iterator 
  

•   \* @return distance between the two iterators
  

•   */
  

•  Position distance_to(const ConstIterator& aOther) const; 
  

  I am not agree. In STL, distances between random access iterators are signed (they supports arithmetic operators + and -). For instance, for pointers, difference_type is basically ptrdiff_t, which is a signed integer type. See http://www.cplusplus.com/reference/iterator/iterator_traits/ 2014-04-19 10:16 GMT+02:00 David Coeurjolly [email protected]:
  …
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  Reply to this email directly or view it on GitHub.

[dcoeurjo]

otherwise this PR is fine... thanks.
(waiting for your comment on the typedef before merging)

[dcoeurjo]

Okay, merging.. Could you please add a line to the changelog ?

[dcoeurjo]

(Just push to the same branch)