Store extension strings individually

And dynamically build the full AL_EXTENSIONS string

1 files changed, 79 insertions, 87 deletions

diff --git a/alc/context.cpp b/alc/context.cpp
index 2fbf67af..d920d4b6 100644
--- a/alc/context.cpp
+++ b/alc/context.cpp
@@ -11,6 +11,7 @@
 #include <numeric>
 #include <stddef.h>
 #include <stdexcept>
+#include <string_view>
 #include <utility>
 
 #include "AL/efx.h"
@@ -48,48 +49,52 @@ using namespace std::placeholders;
 using voidp = void*;
 
 /* Default context extensions */
-constexpr ALchar alExtList[] =
-    "AL_EXT_ALAW "
-    "AL_EXT_BFORMAT "
-    "AL_EXTX_debug "
-    "AL_EXT_DOUBLE "
-    "AL_EXT_EXPONENT_DISTANCE "
-    "AL_EXT_FLOAT32 "
-    "AL_EXT_IMA4 "
-    "AL_EXT_LINEAR_DISTANCE "
-    "AL_EXT_MCFORMATS "
-    "AL_EXT_MULAW "
-    "AL_EXT_MULAW_BFORMAT "
-    "AL_EXT_MULAW_MCFORMATS "
-    "AL_EXT_OFFSET "
-    "AL_EXT_source_distance_model "
-    "AL_EXT_SOURCE_RADIUS "
-    "AL_EXT_STATIC_BUFFER "
-    "AL_EXT_STEREO_ANGLES "
-    "AL_LOKI_quadriphonic "
-    "AL_SOFT_bformat_ex "
-    "AL_SOFTX_bformat_hoa "
-    "AL_SOFT_block_alignment "
-    "AL_SOFT_buffer_length_query "
-    "AL_SOFT_callback_buffer "
-    "AL_SOFTX_convolution_reverb "
-    "AL_SOFT_deferred_updates "
-    "AL_SOFT_direct_channels "
-    "AL_SOFT_direct_channels_remix "
-    "AL_SOFT_effect_target "
-    "AL_SOFT_events "
-    "AL_SOFT_gain_clamp_ex "
-    "AL_SOFTX_hold_on_disconnect "
-    "AL_SOFT_loop_points "
-    "AL_SOFTX_map_buffer "
-    "AL_SOFT_MSADPCM "
-    "AL_SOFT_source_latency "
-    "AL_SOFT_source_length "
-    "AL_SOFT_source_resampler "
-    "AL_SOFT_source_spatialize "
-    "AL_SOFT_source_start_delay "
-    "AL_SOFT_UHJ "
-    "AL_SOFT_UHJ_ex";
+std::vector<std::string_view> getContextExtensions() noexcept
+{
+    return std::vector<std::string_view>{
+        "AL_EXT_ALAW",
+        "AL_EXT_BFORMAT",
+        "AL_EXTX_debug",
+        "AL_EXT_DOUBLE",
+        "AL_EXT_EXPONENT_DISTANCE",
+        "AL_EXT_FLOAT32",
+        "AL_EXT_IMA4",
+        "AL_EXT_LINEAR_DISTANCE",
+        "AL_EXT_MCFORMATS",
+        "AL_EXT_MULAW",
+        "AL_EXT_MULAW_BFORMAT",
+        "AL_EXT_MULAW_MCFORMATS",
+        "AL_EXT_OFFSET",
+        "AL_EXT_source_distance_model",
+        "AL_EXT_SOURCE_RADIUS",
+        "AL_EXT_STATIC_BUFFER",
+        "AL_EXT_STEREO_ANGLES",
+        "AL_LOKI_quadriphonic",
+        "AL_SOFT_bformat_ex",
+        "AL_SOFTX_bformat_hoa",
+        "AL_SOFT_block_alignment",
+        "AL_SOFT_buffer_length_query",
+        "AL_SOFT_callback_buffer",
+        "AL_SOFTX_convolution_reverb",
+        "AL_SOFT_deferred_updates",
+        "AL_SOFT_direct_channels",
+        "AL_SOFT_direct_channels_remix",
+        "AL_SOFT_effect_target",
+        "AL_SOFT_events",
+        "AL_SOFT_gain_clamp_ex",
+        "AL_SOFTX_hold_on_disconnect",
+        "AL_SOFT_loop_points",
+        "AL_SOFTX_map_buffer",
+        "AL_SOFT_MSADPCM",
+        "AL_SOFT_source_latency",
+        "AL_SOFT_source_length",
+        "AL_SOFT_source_resampler",
+        "AL_SOFT_source_spatialize",
+        "AL_SOFT_source_start_delay",
+        "AL_SOFT_UHJ",
+        "AL_SOFT_UHJ_ex",
+    };
+}
 
 } // namespace
 
@@ -179,26 +184,41 @@ void ALCcontext::init()
         mCurrentVoiceChange.store(cur, std::memory_order_relaxed);
     }
 
-    mExtensionList = alExtList;
+    mExtensions = getContextExtensions();
 
     if(sBufferSubDataCompat)
     {
-        std::string extlist{mExtensionList};
-
-        const auto pos = extlist.find("AL_EXT_SOURCE_RADIUS ");
-        if(pos != std::string::npos)
-            extlist.replace(pos, 20, "AL_SOFT_buffer_sub_data");
-        else
-            extlist += " AL_SOFT_buffer_sub_data";
-
-        mExtensionListOverride = std::move(extlist);
-        mExtensionList = mExtensionListOverride.c_str();
+        auto iter = std::find(mExtensions.begin(), mExtensions.end(), "AL_EXT_SOURCE_RADIUS");
+        if(iter != mExtensions.end()) mExtensions.erase(iter);
+        /* TODO: Would be nice to sort this alphabetically. Needs case-
+         * insensitive searching.
+         */
+        mExtensions.emplace_back("AL_SOFT_buffer_sub_data");
     }
 
 #ifdef ALSOFT_EAX
     eax_initialize_extensions();
 #endif // ALSOFT_EAX
 
+    if(!mExtensions.empty())
+    {
+        const size_t len{std::accumulate(mExtensions.cbegin()+1, mExtensions.cend(),
+            mExtensions.front().length(),
+            [](size_t current, std::string_view ext) noexcept
+            { return current + ext.length() + 1; })};
+
+        std::string extensions;
+        extensions.reserve(len);
+        extensions += mExtensions.front();
+        for(std::string_view ext : al::span{mExtensions}.subspan<1>())
+        {
+            extensions += ' ';
+            extensions += ext;
+        }
+
+        mExtensionsString = std::move(extensions);
+    }
+
     mParams.Position = alu::Vector{0.0f, 0.0f, 0.0f, 1.0f};
     mParams.Matrix = alu::Matrix::Identity();
     mParams.Velocity = alu::Vector{};
@@ -457,43 +477,15 @@ void ALCcontext::eax_initialize_extensions()
     if(!eax_g_is_enabled)
         return;
 
-    const auto string_max_capacity =
-        std::strlen(mExtensionList) + 1 +
-        std::strlen(eax1_ext_name) + 1 +
-        std::strlen(eax2_ext_name) + 1 +
-        std::strlen(eax3_ext_name) + 1 +
-        std::strlen(eax4_ext_name) + 1 +
-        std::strlen(eax5_ext_name) + 1 +
-        std::strlen(eax_x_ram_ext_name) + 1;
-
-    std::string extlist;
-    extlist.reserve(string_max_capacity);
-
+    mExtensions.emplace(mExtensions.begin(), eax_x_ram_ext_name);
     if(eaxIsCapable())
     {
-        extlist += eax1_ext_name;
-        extlist += ' ';
-
-        extlist += eax2_ext_name;
-        extlist += ' ';
-
-        extlist += eax3_ext_name;
-        extlist += ' ';
-
-        extlist += eax4_ext_name;
-        extlist += ' ';
-
-        extlist += eax5_ext_name;
-        extlist += ' ';
+        mExtensions.emplace(mExtensions.begin(), eax5_ext_name);
+        mExtensions.emplace(mExtensions.begin(), eax4_ext_name);
+        mExtensions.emplace(mExtensions.begin(), eax3_ext_name);
+        mExtensions.emplace(mExtensions.begin(), eax2_ext_name);
+        mExtensions.emplace(mExtensions.begin(), eax1_ext_name);
     }
-
-    extlist += eax_x_ram_ext_name;
-    extlist += ' ';
-
-    extlist += mExtensionList;
-
-    mExtensionListOverride = std::move(extlist);
-    mExtensionList = mExtensionListOverride.c_str();
 }
 
 void ALCcontext::eax_initialize()