From 2abb9d2f1716177aa6c0ce0fd6a2519580dc12af Mon Sep 17 00:00:00 2001
From: Vadim Zeitlin <vadim@wxwidgets.org>
Date: Sat, 25 Jan 2003 23:47:33 +0000
Subject: [PATCH] added wxArray::SetCount()

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@18930 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
---
 docs/latex/wx/array.tex | 14 ++++++++++++
 include/wx/dynarray.h   | 12 +++++-----
 src/common/dynarray.cpp | 50 +++++++++++++++++++++++++++++++++--------
 3 files changed, 62 insertions(+), 14 deletions(-)

diff --git a/docs/latex/wx/array.tex b/docs/latex/wx/array.tex
index c493cd1fb7..aa07dce168 100644
--- a/docs/latex/wx/array.tex
+++ b/docs/latex/wx/array.tex
@@ -201,6 +201,7 @@ does exactly the same as \helpref{Item()}{wxarrayitem} method.
 
 \helpref{Add}{wxarrayadd}\\
 \helpref{Insert}{wxarrayinsert}\\
+\helpref{SetCount}{wxarraysetcount}\\
 \helpref{WX\_APPEND\_ARRAY}{wxappendarray}
 
 \membersection{Removing items}
@@ -590,6 +591,19 @@ array.RemoveAt(n)
 See also \helpref{WX\_CLEAR\_ARRAY}{wxcleararray} macro which deletes all
 elements of a wxArray (supposed to contain pointers).
 
+\membersection{wxArray::SetCount}\label{wxarraysetcount}
+
+\func{void}{SetCount}{\param{size\_t }{count}, \param{T }{defval = T($0$)}}
+
+This function ensures that the number of array elements is at least 
+{\it count}. If the array has already {\it count} or mroe items, nothing is
+done. Otherwise, {\tt count - GetCount()} elements are added and initialized to
+the value {\it defval}.
+
+\wxheading{See also}
+
+\helpref{GetCount}{wxarraygetcount}
+
 \membersection{wxArray::Shrink}\label{wxarrayshrink}
 
 \func{void}{Shrink}{\void}
diff --git a/include/wx/dynarray.h b/include/wx/dynarray.h
index f3dfbd09d3..6ff3d60383 100644
--- a/include/wx/dynarray.h
+++ b/include/wx/dynarray.h
@@ -90,11 +90,13 @@ public:                                                             \
   void Alloc(size_t uiSize);                                        \
   void Shrink();                                                    \
                                                                     \
-  size_t  GetCount() const { return m_nCount; }                     \
-  bool  IsEmpty() const { return m_nCount == 0; }                   \
-  size_t  Count() const { return m_nCount; }                        \
+  size_t GetCount() const { return m_nCount; }                      \
+  void SetCount(size_t n, T defval = T(0));                         \
+  bool IsEmpty() const { return m_nCount == 0; }                    \
+  size_t Count() const { return m_nCount; }                         \
                                                                     \
   typedef T base_type;                                              \
+                                                                    \
 protected:                                                          \
   T& Item(size_t uiIndex) const                                     \
     { wxASSERT( uiIndex < m_nCount ); return m_pItems[uiIndex]; }   \
@@ -112,8 +114,8 @@ protected:                                                          \
   void Sort(CMPFUNC fnCompare);                                     \
                                                                     \
 private:                                                            \
-                                                                    \
-  void    Grow(size_t nIncrement = 0);                              \
+  void Grow(size_t nIncrement = 0);                                 \
+  bool Realloc(size_t nSize);                                       \
                                                                     \
   size_t  m_nSize,                                                  \
           m_nCount;                                                 \
diff --git a/src/common/dynarray.cpp b/src/common/dynarray.cpp
index 4d0ee51d28..72284fcb73 100644
--- a/src/common/dynarray.cpp
+++ b/src/common/dynarray.cpp
@@ -106,6 +106,23 @@ name& name::operator=(const name& src)                                      \
   return *this;                                                             \
 }                                                                           \
                                                                             \
+/* allocate new buffer of the given size and move our data to it */         \
+bool name::Realloc(size_t nSize)                                            \
+{                                                                           \
+  T *pNew = new T[nSize];                                                   \
+  /* only grow if allocation succeeded */                                   \
+  if ( !pNew )                                                              \
+      return false;                                                         \
+                                                                            \
+  m_nSize = nSize;                                                          \
+  /* copy data to new location */                                           \
+  memcpy(pNew, m_pItems, m_nCount*sizeof(T));                               \
+  delete [] m_pItems;                                                       \
+  m_pItems = pNew;                                                          \
+                                                                            \
+  return true;                                                              \
+}                                                                           \
+                                                                            \
 /* grow the array */                                                        \
 void name::Grow(size_t nIncrement)                                          \
 {                                                                           \
@@ -131,19 +148,34 @@ void name::Grow(size_t nIncrement)                                          \
         ndefIncrement = ARRAY_MAXSIZE_INCREMENT;                            \
       if ( nIncrement < ndefIncrement )                                     \
         nIncrement = ndefIncrement;                                         \
-      T *pNew = new T[m_nSize + nIncrement];                                \
-      /* only grow if allocation succeeded */                               \
-      if ( pNew ) {                                                         \
-          m_nSize += nIncrement;                                            \
-          /* copy data to new location */                                   \
-          memcpy(pNew, m_pItems, m_nCount*sizeof(T));                       \
-          delete [] m_pItems;                                               \
-          m_pItems = pNew;                                                  \
-      }                                                                     \
+      Realloc(m_nSize + nIncrement);                                        \
     }                                                                       \
   }                                                                         \
 }                                                                           \
                                                                             \
+/* make sure that the array has at least count elements */                  \
+void name::SetCount(size_t count, T defval)                                 \
+{                                                                           \
+    if ( m_nSize < count )                                                  \
+    {                                                                       \
+        /* need to realloc memory: don't overallocate it here as if */      \
+        /* SetCount() is called, it probably means that the caller  */      \
+        /* knows in advance how many elements there will be in the  */      \
+        /* array and so it won't be necessary to realloc it later   */      \
+        if ( !Realloc(count) )                                              \
+        {                                                                   \
+            /* out of memory -- what can we do? */                          \
+            return;                                                         \
+        }                                                                   \
+    }                                                                       \
+                                                                            \
+    /* add new elements if we extend the array */                           \
+    while ( m_nCount < count )                                              \
+    {                                                                       \
+        m_pItems[m_nCount++] = defval;                                      \
+    }                                                                       \
+}                                                                           \
+                                                                            \
 /* dtor */                                                                  \
 name::~name()                                                               \
 {                                                                           \
-- 
2.50.0

