Second Life viewer sources 1.13.2.15

1 files changed, 59 insertions, 0 deletions

diff --git a/linden/indra/lscript/lscript_library/lscript_alloc.cpp b/linden/indra/lscript/lscript_library/lscript_alloc.cpp
index 978d7f2..4636c0b 100644
--- a/linden/indra/lscript/lscript_library/lscript_alloc.cpp
+++ b/linden/indra/lscript/lscript_library/lscript_alloc.cpp
@@ -1119,3 +1119,62 @@ S32 lsa_postadd_lists(U8 *buffer, S32 offset1, LLScriptLibData *data, S32 heapsi
         return lsa_heap_add_data(buffer, list1, heapsize, TRUE);
 }
 
+
+LLScriptLibData* lsa_randomize(LLScriptLibData* src, S32 stride)
+{
+        S32 number = src->getListLength();
+        if (number <= 0)
+        {
+                return NULL;
+        }
+        if (stride <= 0)
+        {
+                stride = 1;
+        }
+        if(number % stride)
+        {
+                LLScriptLibData* retval = src->mListp;
+                src->mListp = NULL;
+                return retval;
+        }
+        S32 buckets = number / stride;
+
+        // Copy everything into a special vector for sorting;
+        std::vector<LLScriptLibData*> sort_array;
+        sort_array.reserve(number);
+        LLScriptLibData* temp = src->mListp;
+        while(temp)
+        {
+                sort_array.push_back(temp);
+                temp = temp->mListp;
+        }
+
+        // We cannot simply call random_shuffle or similar algorithm since
+        // we need to obey the stride. So, we iterate over what we have
+        // and swap each with a random other segment.
+        S32 index = 0;
+        S32 ii = 0;
+        for(; ii < number; ii += stride)
+        {
+                index = ll_rand(buckets) * stride;
+                for(S32 jj = 0; jj < stride; ++jj)
+                {
+                        std::swap(sort_array[ii + jj], sort_array[index + jj]);
+                }
+        }
+
+        // copy the pointers back out
+        ii = 1;
+        temp = sort_array[0];
+        while (ii < number)
+        {
+                temp->mListp = sort_array[ii++];
+                temp = temp->mListp;
+        }
+        temp->mListp = NULL;
+
+        src->mListp = NULL;
+
+        LLScriptLibData* ret_value = sort_array[0];
+        return ret_value;
+}