Add support for negative steps in Python slices on the STL containers

git-svn-id: https://swig.svn.sourceforge.net/svnroot/swig/trunk@12903 626c5289-ae23-0410-ae9c-e8d60b6d4f22

CHANGES.current

@@ -5,14 +5,10 @@ See the RELEASENOTES file for a summary of changes in each release.
 Version 2.0.5 (in progress)
 ===========================
 
-2012-01-23: klickverbot
+2012-01-24: wsfulton
-            [D] Correctly annotate function pointers with C linkage.
-            [D] Exception and Error have become blessed names; removed d_exception_name test case.
-
-2012-01-20: wsfulton
             [Python] Add Python stepped slicing support to the STL wrappers (std::vector, std::list).
             Assigning to a slice, reading a slice and deleting a slice with steps now work.
-            Positive steps only at the moment. For example:
+            For example:
 
             %template(vector_i) std::vector<int>
 
@@ -22,13 +18,18 @@ Version 2.0.5 (in progress)
               print list(vi)
               del vi[3:10:3]
               print list(vi)
+              print list(vi[::-1])
 
             gives (same behaviour as native Python sequences such as list):
 
               [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
               [0, 111, 2, 333, 4, 5, 6, 7, 8, 9]
               [0, 111, 2, 4, 5, 7, 8]
+              [8, 7, 5, 4, 2, 111, 0]
 
+2012-01-23: klickverbot
+            [D] Correctly annotate function pointers with C linkage.
+            [D] Exception and Error have become blessed names; removed d_exception_name test case.
 
 2012-01-20: wsfulton
             [Python] Fix some indexing bugs in Python STL wrappers when the index is negative, eg:

Examples/test-suite/python/li_std_containers_int_runme.py

@@ -191,10 +191,29 @@ compare_containers(ps[-1:7:1], iv[-1:7:1], il[-1:7:1])
 compare_containers(ps[-1:7:2], iv[-1:7:2], il[-1:7:2])
 compare_containers(ps[-6:7:2], iv[-6:7:2], il[-6:7:2])
 compare_containers(ps[-100:7:2], iv[-100:7:2], il[-100:7:2])
-
 compare_containers(ps[::1], iv[::1], il[::1])
 compare_containers(ps[::2], iv[::2], il[::2])
-#compare_containers(ps[::-1], iv[::-1], il[])
+
+compare_containers(ps[::-1], iv[::-1], il[::-1])
+compare_containers(ps[6::-1], iv[6::-1], il[6::-1])
+compare_containers(ps[:-3:-1], iv[:-3:-1], il[:-3:-1])
+compare_containers(ps[:-6:-1], iv[:-6:-1], il[:-6:-1])
+compare_containers(ps[:-7:-1], iv[:-7:-1], il[:-7:-1])
+compare_containers(ps[:-8:-1], iv[:-8:-1], il[:-8:-1])
+compare_containers(ps[:-100:-1], iv[:-100:-1], il[:-100:-1])
+compare_containers(ps[4:6:-1], iv[4:6:-1], il[4:6:-1])
+compare_containers(ps[4:5:-1], iv[4:5:-1], il[4:5:-1])
+compare_containers(ps[4:4:-1], iv[4:4:-1], il[4:4:-1])
+compare_containers(ps[4:3:-1], iv[4:3:-1], il[4:3:-1])
+compare_containers(ps[4:2:-1], iv[4:2:-1], il[4:2:-1])
+compare_containers(ps[100:104:-1], iv[100:104:-1], il[100:104:-1])
+compare_containers(ps[104:100:-1], iv[104:100:-1], il[104:100:-1])
+compare_containers(ps[-100:-104:-1], iv[-100:-104:-1], il[-100:-104:-1])
+compare_containers(ps[-104:-100:-1], iv[-104:-100:-1], il[-104:-100:-1])
+compare_containers(ps[::-2], iv[::-2], il[::-2])
+compare_containers(ps[::-3], iv[::-3], il[::-3])
+compare_containers(ps[::-4], iv[::-4], il[::-4])
+compare_containers(ps[::-5], iv[::-5], il[::-5])
 
 
 # insert sequences (growing, shrinking and staying same size)
@@ -217,7 +236,7 @@ for start in [-102, -100, -7, -6, -5, -4, -3, -2, -1, 0, 1, 2, 3, 4, 5, 6, 7, 10
   container_delete_step(start, None, None)
   for end in [-102, -100, -7, -6, -5, -4, -3, -2, -1, 0, 1, 2, 3, 4, 5, 6, 7, 100, 102]:
     container_delete_step(start, end, None)
-    for step in range(1,7):
+    for step in range(-7,7):
       container_delete_step(start, end, step)
 
 ps = range(6)
@@ -227,7 +246,7 @@ del ps[:]; del iv[:]; del il[:]
 compare_containers(ps, iv, il)
 
 for end in range(7):
-  for step in range(1,7):
+  for step in range(-7,7):
     for start in range(7):
       container_insert_step(start, end, step, [111, 222, 333, 444, 555, 666, 777])
       container_insert_step(start, end, step, [111, 222, 333, 444, 555, 666])

Lib/python/pycontainer.swg

@@ -202,24 +202,40 @@ namespace swig {
   }
 
   void
-  slice_adjust(ptrdiff_t i, ptrdiff_t j, ptrdiff_t step, size_t size, size_t &ii, size_t &jj, bool insert = false) {
+  slice_adjust(ptrdiff_t i, ptrdiff_t j, ptrdiff_t step, size_t size, ptrdiff_t &ii, ptrdiff_t &jj, bool insert = false) {
-    if ( i < 0 ) {
+    if (step == 0) {
-      ii = 0;
+      throw std::invalid_argument("slice step cannot be zero");
-    } else if ( (size_t) i < size ) {
+    } else if (step > 0) {
-      ii = (size_t) i;
+      // Required range: 0 <= i < size, 0 <= j < size
-    } else if (insert && ((size_t) i >= size)) {
+      if (i < 0) {
-      ii = size;
+        ii = 0;
+      } else if (i < (ptrdiff_t)size) {
+        ii = i;
+      } else if (insert && (i >= (ptrdiff_t)size)) {
+        ii = (ptrdiff_t)size;
+      }
+      if ( j < 0 ) {
+        jj = 0;
+      } else {
+        jj = (j < (ptrdiff_t)size) ? j : (ptrdiff_t)size;
+      }
     } else {
-      throw std::out_of_range("index out of range");
+      // Required range: -1 <= i < size-1, -1 <= j < size-1
-    }
+      if (i < -1) {
-    if ( j < 0 ) {
+        ii = -1;
-      jj = 0;
+      } else if (i < (ptrdiff_t) size) {
-    } else {
+        ii = i;
-      jj = ( (size_t) j < size ) ? ((size_t) j) : size;
+      } else if (i >= (ptrdiff_t)(size-1)) {
+        ii = (ptrdiff_t)(size-1);
+      }
+      if (j < -1) {
+        jj = -1;
+      } else {
+        jj = (j < (ptrdiff_t)size ) ? j : (ptrdiff_t)(size-1);
+      }
     }
   }
 
-
   template <class Sequence, class Difference>
   inline typename Sequence::iterator
   getpos(Sequence* self, Difference i)  {
@@ -239,18 +255,12 @@ namespace swig {
   template <class Sequence, class Difference>
   inline Sequence*
   getslice(const Sequence* self, Difference i, Difference j, Py_ssize_t step) {
-    if (step == 0)
-      throw std::invalid_argument("slice step cannot be zero");
-
-    if (step < 0)
-      throw std::invalid_argument("negative steps not implemented");
-
     typename Sequence::size_type size = self->size();
-    typename Sequence::size_type ii = 0;
+    Difference ii = 0;
-    typename Sequence::size_type jj = 0;
+    Difference jj = 0;
     swig::slice_adjust(i, j, step, size, ii, jj);
 
-    if (jj > ii) {
+    if (step > 0) {
       typename Sequence::const_iterator sb = self->begin();
       typename Sequence::const_iterator se = self->begin();
       std::advance(sb,ii);
@@ -258,68 +268,94 @@ namespace swig {
       if (step == 1) {
         return new Sequence(sb, se);
       } else {
-        typename Sequence::const_iterator it = sb;
         Sequence *sequence = new Sequence();
+        typename Sequence::const_iterator it = sb;
         while (it!=se) {
           sequence->push_back(*it);
           for (typename Sequence::size_type c=0; c<step && it!=se; ++c)
             it++;
         }
         return sequence;
-      }
+      } 
     } else {
-      return new Sequence();
+      Sequence *sequence = new Sequence();
+      if (ii > jj) {
+        typename Sequence::const_reverse_iterator sb = self->rbegin();
+        typename Sequence::const_reverse_iterator se = self->rbegin();
+        std::advance(sb,size-ii-1);
+        std::advance(se,size-jj-1);
+        typename Sequence::const_reverse_iterator it = sb;
+        while (it!=se) {
+          sequence->push_back(*it);
+          for (typename Sequence::size_type c=0; c<-step && it!=se; ++c)
+            it++;
+        }
+      }
+      return sequence;
     }
   }
 
   template <class Sequence, class Difference, class InputSeq>
   inline void
   setslice(Sequence* self, Difference i, Difference j, Py_ssize_t step, const InputSeq& is = InputSeq()) {
-    if (step == 0)
-      throw std::invalid_argument("slice step cannot be zero");
-
-    if (step < 0)
-      throw std::invalid_argument("negative steps not implemented");
-
     typename Sequence::size_type size = self->size();
-    typename Sequence::size_type ii = 0;
+    Difference ii = 0;
-    typename Sequence::size_type jj = 0;
+    Difference jj = 0;
     swig::slice_adjust(i, j, step, size, ii, jj, true);
-    if (jj < ii)
+    if (step > 0) {
-      jj = ii;
+      if (jj < ii)
-    if (step == 1) {
+        jj = ii;
-      size_t ssize = jj - ii;
+      if (step == 1) {
-      if (ssize <= is.size()) {
+        size_t ssize = jj - ii;
-        // expanding/staying the same size
+        if (ssize <= is.size()) {
-        typename Sequence::iterator sb = self->begin();
+          // expanding/staying the same size
-        typename InputSeq::const_iterator isit = is.begin();
+          typename Sequence::iterator sb = self->begin();
-        std::advance(sb,ii);
+          typename InputSeq::const_iterator isit = is.begin();
-        std::advance(isit, jj - ii);
+          std::advance(sb,ii);
-        self->insert(std::copy(is.begin(), isit, sb), isit, is.end());
+          std::advance(isit, jj - ii);
+          self->insert(std::copy(is.begin(), isit, sb), isit, is.end());
+        } else {
+          // shrinking
+          typename Sequence::iterator sb = self->begin();
+          typename Sequence::iterator se = self->begin();
+          std::advance(sb,ii);
+          std::advance(se,jj);
+          self->erase(sb,se);
+          sb = self->begin();
+          std::advance(sb,ii);
+          self->insert(sb, is.begin(), is.end());
+        }
       } else {
-        // shrinking
+        size_t replacecount = (jj - ii + step - 1) / step;
-        typename Sequence::iterator sb = self->begin();
+        if (is.size() != replacecount) {
-        typename Sequence::iterator se = self->begin();
+          char msg[1024];
-        std::advance(sb,ii);
+          sprintf(msg, "attempt to assign sequence of size %d to extended slice of size %d", is.size(), replacecount);
-        std::advance(se,jj);
+          throw std::invalid_argument(msg);
-        self->erase(sb,se);
+        }
-        sb = self->begin();
+        typename Sequence::const_iterator isit = is.begin();
-        std::advance(sb,ii);
+        typename Sequence::iterator it = self->begin();
-        self->insert(sb, is.begin(), is.end());
+        std::advance(it,ii);
+        for (size_t rc=0; rc<replacecount; ++rc) {
+          *it++ = *isit++;
+          for (typename Sequence::size_type c=0; c<(step-1); ++c)
+            it++;
+        }
       }
     } else {
-      size_t replacecount = (jj - ii + step - 1) / step;
+      if (jj > ii)
+        jj = ii;
+      size_t replacecount = (ii - jj - step - 1) / -step;
       if (is.size() != replacecount) {
         char msg[1024];
         sprintf(msg, "attempt to assign sequence of size %d to extended slice of size %d", is.size(), replacecount);
         throw std::invalid_argument(msg);
       }
       typename Sequence::const_iterator isit = is.begin();
-      typename Sequence::iterator it = self->begin();
+      typename Sequence::reverse_iterator it = self->rbegin();
-      std::advance(it,ii);
+      std::advance(it,size-ii-1);
       for (size_t rc=0; rc<replacecount; ++rc) {
         *it++ = *isit++;
-        for (typename Sequence::size_type c=0; c<(step-1); ++c)
+        for (typename Sequence::size_type c=0; c<(-step-1); ++c)
           it++;
       }
     }
@@ -328,32 +364,42 @@ namespace swig {
   template <class Sequence, class Difference>
   inline void
   delslice(Sequence* self, Difference i, Difference j, Py_ssize_t step) {
-    if (step == 0)
-      throw std::invalid_argument("slice step cannot be zero");
-
-    if (step < 0)
-      throw std::invalid_argument("negative steps not implemented");
-
     typename Sequence::size_type size = self->size();
-    typename Sequence::size_type ii = 0;
+    Difference ii = 0;
-    typename Sequence::size_type jj = 0;
+    Difference jj = 0;
     swig::slice_adjust(i, j, step, size, ii, jj, true);
-    if (jj > ii) {
+    if (step > 0) {
-      typename Sequence::iterator sb = self->begin();
+      if (jj > ii) {
-      typename Sequence::iterator se = self->begin();
+        typename Sequence::iterator sb = self->begin();
-      std::advance(sb,ii);
+        std::advance(sb,ii);
-      if (step == 1) {
+        if (step == 1) {
-        std::advance(se,jj);
+          typename Sequence::iterator se = self->begin();
-        self->erase(sb,se);
+          std::advance(se,jj);
-      } else {
+          self->erase(sb,se);
-        typename Sequence::iterator it = sb;
+        } else {
-        std::advance(se,jj-1);
+          typename Sequence::iterator it = sb;
-        size_t delcount = (jj - ii + step - 1) / step;
+          size_t delcount = (jj - ii + step - 1) / step;
+          while (delcount) {
+            it = self->erase(it);
+            if (it==self->end())
+              break;
+            for (typename Sequence::size_type c=0; c<(step-1); ++c)
+              it++;
+            delcount--;
+          }
+        }
+      }
+    } else {
+      if (ii > jj) {
+        typename Sequence::reverse_iterator sb = self->rbegin();
+        std::advance(sb,size-ii-1);
+        typename Sequence::reverse_iterator it = sb;
+        size_t delcount = (ii - jj - step - 1) / -step;
         while (delcount) {
-          it = self->erase(it);
+          self->erase((++it).base());
-          if (it==self->end())
+          if (it==self->rend())
             break;
-          for (typename Sequence::size_type c=0; c<(step-1); ++c)
+          for (typename Sequence::size_type c=0; c<(-step-1); ++c)
             it++;
           delcount--;
         }
@@ -747,7 +793,7 @@ namespace swig
 
 /* deprecated in Python 2 */
 #if 1
-    Sequence* __getslice__(difference_type i, difference_type j) throw (std::out_of_range) {
+    Sequence* __getslice__(difference_type i, difference_type j) throw (std::out_of_range, std::invalid_argument) {
       return swig::getslice(self, i, j, 1);
     }
 
@@ -756,7 +802,7 @@ namespace swig
       swig::setslice(self, i, j, 1, v);
     }
 
-    void __delslice__(difference_type i, difference_type j) throw (std::out_of_range) {
+    void __delslice__(difference_type i, difference_type j) throw (std::out_of_range, std::invalid_argument) {
       swig::delslice(self, i, j, 1);
     }
 #endif
@@ -791,7 +837,7 @@ namespace swig
     }
 
     void __setitem__(PySliceObject *slice)
-      throw (std::out_of_range) {
+      throw (std::out_of_range, std::invalid_argument) {
       Py_ssize_t i, j, step;
       if( !PySlice_Check(slice) ) {
         SWIG_Error(SWIG_TypeError, "Slice object expected.");
@@ -802,7 +848,7 @@ namespace swig
     }
 
     void __delitem__(PySliceObject *slice)
-      throw (std::out_of_range) {
+      throw (std::out_of_range, std::invalid_argument) {
       Py_ssize_t i, j, step;
       if( !PySlice_Check(slice) ) {
         SWIG_Error(SWIG_TypeError, "Slice object expected.");