From 2a43a12b7b870c6fd775f417c1c2e85222e47238 Mon Sep 17 00:00:00 2001
From: Greg Ercolano <erco@seriss.com>
Date: Sun, 6 Nov 2022 21:59:36 -0800
Subject: Added empty(), ensure size() enlarges new vals = 0

---
 FL/Fl_Int_Vector.H    | 23 ++++++++++++++++-------
 src/Fl_Int_Vector.cxx | 22 ++++++++++++++--------
 2 files changed, 30 insertions(+), 15 deletions(-)

diff --git a/FL/Fl_Int_Vector.H b/FL/Fl_Int_Vector.H
index 89e2d29af..9a2cd45f9 100644
--- a/FL/Fl_Int_Vector.H
+++ b/FL/Fl_Int_Vector.H
@@ -32,14 +32,15 @@
 
   Common use:
   \code
+  #include <stdio.h>
   #include <FL/Fl_Int_Vector.H>
   int main() {
       Fl_Int_Vector v;
 
-      // Create an array of values 1,2,3:
-      v.push_back(1);   // add first element
-      v.push_back(2);   // add second element
-      v.push_back(3);   // add third element
+      // Create an array of values 11,22,33:
+      v.push_back(11);   // add first element
+      v.push_back(22);   // add second element
+      v.push_back(33);   // add third element
 
       // Loop through printing the values
       for ( unsigned int i=0; i<v.size(); i++ )
@@ -52,7 +53,7 @@
   \endcode
 
   \todo
-      - Add other std::vector methods like empty(), erase(), etc.
+      - Add other std::vector methods like erase(), etc.
       - Make memory blocking size flexible, and add related methods like capacity(), reserve(), shrink_to_fit(), etc.
       - Add non-std methods that are nevertheless needed, e.g. insert(index,val), delete(index), delete(start, end), swap(a_idx,b_idx)
       - Add a way to change the elements by index, e.g. v[2] = 222; (which is currently NOT supported)
@@ -123,7 +124,7 @@ public:
     Removes the last element the last element and returns its value.
 
     \warning You must not call pop_back() if the array is empty, i.e. if (size() == 0).
-    \todo Internals should probably assert(size_ != 0)
+    \todo Internals should maybe assert(size_ != 0)
   */
   int pop_back() {
     int tmp = arr_[size_ - 1];
@@ -141,11 +142,19 @@ public:
   /**
     Return the last element in the array.
     \warning You must not call back() if the array is empty, i.e. if (size() == 0).
-    \todo Internals should probably assert(size_ != 0)
+    \todo Internals should maybe assert(size_ != 0)
   */
   int back() {
     return arr_[size_ - 1];
   }
+
+  /**
+    Checks if array has no elements.
+    Same as a test for (size() == 0).
+  */
+  bool empty() const {
+    return (size_ == 0) ? true : false;
+  }
 };
 
 #endif // Fl_Int_Vector_H
diff --git a/src/Fl_Int_Vector.cxx b/src/Fl_Int_Vector.cxx
index 08e45c4cc..0815661dc 100644
--- a/src/Fl_Int_Vector.cxx
+++ b/src/Fl_Int_Vector.cxx
@@ -36,24 +36,30 @@ Fl_Int_Vector::~Fl_Int_Vector() {
 /**
   Set the size of the array to \p count.
 
-  A size of zero empties the array completely and frees all memory.
+  Setting size to zero clears the array and frees any memory it used.
+
+  Shrinking truncates the array and frees memory of truncated elements.
+  Enlarging creates new elements that are zero in value.
 
   \warning
-    - Only advised use currently is to shrink the array size, i.e. (count < size()).
-    - Currently enlarging the array leaves the new values uninitialized.
-    - When assignment via indexes is supported, i.e. v[x] = 123, array enlargement should zero new values
-  \todo Check if count > size, and if so init new values to 0.
+    Only currently advised use is to shrink the array size, i.e. (count < size()),
+    since assignment via index (e.g. v[x] = 123) is not yet supported.
 */
 void Fl_Int_Vector::size(unsigned int count) {
-  if (count <= 0) {
+  if (count == 0) {             // zero? special case frees memory
     if (arr_)
       free(arr_);
     arr_ = 0;
     size_ = 0;
     return;
   }
-  if (count > size_) {
+  if (count > size_) {          // array enlarged? realloc + init new vals to 0
     arr_ = (int *)realloc(arr_, count * sizeof(int));
-    size_ = count;
+    while ( size_ < count ) {
+      arr_[size_++] = 0;
+    }
+    return;                     // leaves with size_ == count
   }
+  // count <= size_? just truncate
+  size_ = count;
 }
-- 
cgit v1.2.3