From 2f8d6420f346b6ee8c98860030b03d79ff88a9c4 Mon Sep 17 00:00:00 2001
From: Rye <rye@alchemyviewer.org>
Date: Sun, 11 Jan 2026 13:22:32 -0500
Subject: Reduce temporary istringstream allocations during LLDate and GLTF
 override parsing

---
 indra/llcommon/lldate.cpp            | 7 +++++--
 indra/llprimitive/llgltfmaterial.cpp | 2 +-
 indra/newview/llgltfmateriallist.cpp | 2 +-
 3 files changed, 7 insertions(+), 4 deletions(-)

diff --git a/indra/llcommon/lldate.cpp b/indra/llcommon/lldate.cpp
index 5205699b92..5545bb71af 100644
--- a/indra/llcommon/lldate.cpp
+++ b/indra/llcommon/lldate.cpp
@@ -41,6 +41,9 @@
 #include "llstring.h"
 #include "llfasttimer.h"
 
+#include <boost/iostreams/device/array.hpp>
+#include <boost/iostreams/stream.hpp>
+
 static const F64 LL_APR_USEC_PER_SEC = 1000000.0;
     // should be APR_USEC_PER_SEC, but that relies on INT64_C which
     // isn't defined in glib under our build set up for some reason
@@ -64,7 +67,7 @@ std::string LLDate::asString() const
 {
     std::ostringstream stream;
     toStream(stream);
-    return stream.str();
+    return std::move(stream).str();
 }
 
 //@ brief Converts time in seconds since EPOCH
@@ -184,7 +187,7 @@ bool LLDate::split(S32 *year, S32 *month, S32 *day, S32 *hour, S32 *min, S32 *se
 
 bool LLDate::fromString(const std::string& iso8601_date)
 {
-    std::istringstream stream(iso8601_date);
+    boost::iostreams::stream<boost::iostreams::array_source> stream(iso8601_date.data(), iso8601_date.size());
     return fromStream(stream);
 }
 
diff --git a/indra/llprimitive/llgltfmaterial.cpp b/indra/llprimitive/llgltfmaterial.cpp
index 930222e3db..b2cd1dc597 100644
--- a/indra/llprimitive/llgltfmaterial.cpp
+++ b/indra/llprimitive/llgltfmaterial.cpp
@@ -214,7 +214,7 @@ std::string LLGLTFMaterial::asJSON(bool prettyprint) const
     // to WriteGltfSceneToStream in the viewer.
     gltf.WriteGltfSceneToStream(&model_out, str, prettyprint, false);
 
-    return str.str();
+    return std::move(str).str();
 }
 
 void LLGLTFMaterial::setFromModel(const tinygltf::Model& model, S32 mat_index)
diff --git a/indra/newview/llgltfmateriallist.cpp b/indra/newview/llgltfmateriallist.cpp
index ac8477a615..b784419780 100644
--- a/indra/newview/llgltfmateriallist.cpp
+++ b/indra/newview/llgltfmateriallist.cpp
@@ -170,7 +170,7 @@ namespace
 
 void LLGLTFMaterialList::applyOverrideMessage(LLMessageSystem* msg, const std::string& data_in)
 {
-    std::istringstream str(data_in);
+    boost::iostreams::stream<boost::iostreams::array_source> str(data_in.data(), data_in.size());
 
     LLSD data;
 
-- 
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