From 01c0f71f9e963b2c6fbc9417c8a414345d524609 Mon Sep 17 00:00:00 2001
From: Dan Gudmundsson <dgud@erlang.org>
Date: Wed, 20 May 2015 12:53:44 +0200
Subject: wx: Optimize event and return value construction

Preallocated an rt array of 64 items (which covers 99%) of the calls
and thus avoids allocation and copying in most cases.
---
 lib/wx/c_src/wxe_return.cpp | 125 +++++++++++++++++++++-----------------------
 1 file changed, 61 insertions(+), 64 deletions(-)

(limited to 'lib/wx/c_src/wxe_return.cpp')

diff --git a/lib/wx/c_src/wxe_return.cpp b/lib/wx/c_src/wxe_return.cpp
index accd818a14..f29c8eff4a 100644
--- a/lib/wx/c_src/wxe_return.cpp
+++ b/lib/wx/c_src/wxe_return.cpp
@@ -19,11 +19,6 @@
 
 #include "wxe_return.h"
 
-// see http://docs.wxwidgets.org/stable/wx_wxarray.html#arraymacros
-// this is a magic incantation which must be done!
-#include <wx/arrimpl.cpp> 
-WX_DEFINE_OBJARRAY(wxErlDrvTermDataArray);
-
 #define INLINE
 
 wxeReturn::wxeReturn (ErlDrvTermData   _port,
@@ -31,59 +26,51 @@ wxeReturn::wxeReturn (ErlDrvTermData   _port,
 		      bool             _isResult) {
     port    = _port;
     caller  = _caller;
-    
+
     isResult = _isResult;
-    
-     if (isResult) {
-         addAtom("_wxe_result_");
-     }
+    rtb = buff;
+    rt_max = RT_BUFF_SZ;
+    rt_n = 0;
+    if (isResult) {
+      addAtom("_wxe_result_");
+    }
+}
+
+//clear everything so we can re-use if we want
+void wxeReturn::reset() {
+  rt_n = 0;
+  temp_float.empty();
 }
 
 wxeReturn::~wxeReturn () {
-    //depending on which version of wxArray we use, we may have to clear it ourselves.
+  if(rtb != buff)
+    driver_free(rtb);
 }
 
-int wxeReturn::send() {      
-    if ((rt.GetCount() == 2 && isResult) || rt.GetCount() == 0)
-      return 1;  // not a call bail out
-    
-    if (isResult) {
-        addTupleCount(2);
-    }    
+int wxeReturn::send() {
+  if ((rt_n == 2 && isResult) || rt_n == 0)
+    return 1;  // not a call bail out
 
-    // rt to array
-    unsigned int rtLength = rt.GetCount(); //signed int
+  if (isResult) {
+    addTupleCount(2);
+  }
 
-    size_t size = sizeof(ErlDrvTermData)*(rtLength);
-    
-    ErlDrvTermData* rtData = (ErlDrvTermData *) driver_alloc(size);
-    for (unsigned int i=0; i < rtLength; i++) {
-        rtData[i] = rt[i];
-    }
- 
-    int res = erl_drv_send_term(port, caller, rtData, rtLength);
-    driver_free(rtData);
+  int res = erl_drv_send_term(port, caller, rtb, rt_n);
 
 #ifdef DEBUG
-    if(res == -1) {
-      fprintf(stderr, "Failed to send return or event msg\r\n");
-    }
+  if(res == -1) {
+    fprintf(stderr, "Failed to send return or event msg\r\n");
+  }
 #endif
 
-    reset();
-    return res;
-}
-
-//clear everything so we can re-use if we want
- void wxeReturn::reset() {
-     rt.empty();
-     temp_float.empty();
+  reset();
+  return res;
 }
 
 INLINE
 unsigned  int wxeReturn::size() {
-     return rt.GetCount();
- }
+  return rt_n;
+}
 
 
 INLINE
@@ -92,24 +79,34 @@ void wxeReturn::ensureFloatCount(size_t n) {
 }
 
 INLINE
-void wxeReturn::add(ErlDrvTermData type, ErlDrvTermData data) {
-    rt.Add(type);
-    rt.Add(data);
+void wxeReturn::do_add(ErlDrvTermData val) {
+  if(rt_n >= rt_max) {  // realloc
+    rt_max += RT_BUFF_SZ;
+    if(rtb == buff) {
+      rtb = (ErlDrvTermData *) driver_alloc(rt_max * sizeof(ErlDrvTermData));
+      for(int i = 0; i < RT_BUFF_SZ; i++)
+	rtb[i] = buff[i];
+    } else {
+      rtb = (ErlDrvTermData *) driver_realloc(rtb, rt_max * sizeof(ErlDrvTermData));
+    }
+  }
+  rtb[rt_n++] = val;
 }
 
 
-// INLINE 
-// void wxeReturn::addRef(const void *ptr, const char* className) {
-//    unsigned int ref_idx = wxe_app->getRef((void *)ptr, memEnv); 
-//    addRef(ref_idx, className);
-// }
+INLINE
+void wxeReturn::add(ErlDrvTermData type, ErlDrvTermData data) {
+  do_add(type);
+  do_add(data);
+}
+
 
 INLINE 
 void wxeReturn::addRef(const unsigned int ref, const char* className) {
    addAtom("wx_ref");
    addUint(ref);
    addAtom(className);
-   rt.Add(ERL_DRV_NIL);
+   do_add(ERL_DRV_NIL);
    addTupleCount(4);
 }
 
@@ -121,30 +118,30 @@ void wxeReturn::addAtom(const char* atomName) {
 
 INLINE 
 void wxeReturn::addBinary(const char* buf, const size_t size) {
-    rt.Add(ERL_DRV_BUF2BINARY);
-    rt.Add((ErlDrvTermData)buf);
-    rt.Add((ErlDrvTermData)size);
+    do_add(ERL_DRV_BUF2BINARY);
+    do_add((ErlDrvTermData)buf);
+    do_add((ErlDrvTermData)size);
 }
 
 INLINE 
 void wxeReturn::addExt2Term(wxeErlTerm *term) {
   if(term) {
-    rt.Add(ERL_DRV_EXT2TERM);
-    rt.Add((ErlDrvTermData)term->bin);
-    rt.Add((ErlDrvTermData)term->size);
+    do_add(ERL_DRV_EXT2TERM);
+    do_add((ErlDrvTermData)term->bin);
+    do_add((ErlDrvTermData)term->size);
   } else {
-    rt.Add(ERL_DRV_NIL);
+    do_add(ERL_DRV_NIL);
   }
 }
 
 INLINE
 void wxeReturn::addExt2Term(wxETreeItemData *val) {
   if(val) {
-    rt.Add(ERL_DRV_EXT2TERM);
-    rt.Add((ErlDrvTermData)(val->bin));
-    rt.Add((ErlDrvTermData)(val->size));
+    do_add(ERL_DRV_EXT2TERM);
+    do_add((ErlDrvTermData)(val->bin));
+    do_add((ErlDrvTermData)(val->size));
   } else
-    rt.Add(ERL_DRV_NIL);
+    do_add(ERL_DRV_NIL);
 }
 
 INLINE
@@ -174,8 +171,8 @@ void wxeReturn::addTupleCount(unsigned int n) {
 
 INLINE 
 void wxeReturn::endList(unsigned int n) {
-    rt.Add(ERL_DRV_NIL);
-    add(ERL_DRV_LIST, (ErlDrvTermData)(n+1));
+  do_add(ERL_DRV_NIL);
+  add(ERL_DRV_LIST, (ErlDrvTermData)(n+1));
 }
 
 INLINE 
-- 
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