From 2d8015c2aeacee5e3a3d3bcef1e26007245b30c3 Mon Sep 17 00:00:00 2001
From: jyelon <jyelon@gmail.com>
Date: Wed, 4 Sep 2024 23:14:39 -0400
Subject: [PATCH] Add StreamBuffer::open

---
 luprex/cpp/core/enginewrapper.hpp |  4 ++--
 luprex/ext/base-buffer.hpp        | 30 ++++++++++++++++++++----------
 2 files changed, 22 insertions(+), 12 deletions(-)

diff --git a/luprex/cpp/core/enginewrapper.hpp b/luprex/cpp/core/enginewrapper.hpp
index 41ffaba3..477b9233 100644
--- a/luprex/cpp/core/enginewrapper.hpp
+++ b/luprex/cpp/core/enginewrapper.hpp
@@ -22,10 +22,10 @@
 
 enum class InvocationKind {
     INVALID,
-    LUA_CALL,
+    LUA_INVOKE,
+    LUA_PROBE,
     LUA_EXPR,
     LUA_SOURCE,
-    LUA_PROBE,
     FLUSH_PRINTS,
     TICK,
 };
diff --git a/luprex/ext/base-buffer.hpp b/luprex/ext/base-buffer.hpp
index b5ded800..07971072 100644
--- a/luprex/ext/base-buffer.hpp
+++ b/luprex/ext/base-buffer.hpp
@@ -349,6 +349,14 @@ public:
         init(true, false, const_cast<char *>(data.data()), data.size());
         write_cursor_ = buf_hi_;
     }
+
+    // Modify an existing streambuffer to read from an external block of bytes.
+    //
+    void open(std::string_view data) {
+        if (owned_ && (buf_lo_ != 0)) CoreHandler::basebuffer_free(buf_lo_);
+        init(true, false, const_cast<char *>(data.data()), data.size());
+        write_cursor_ = buf_hi_;
+    }
     
     // Destructor.  Frees the buffer, if any.
     //
@@ -420,19 +428,21 @@ public:
     }
 
     // Discard all data.  Reset total read and write counts.
-    // Releases the allocated buffer, if any.
+    // May release the allocated buffer, if it is large.
     //
     void clear() {
-        assert(owned_);
-        if ((!fixed_size_) && (buf_lo_ != nullptr) && ((buf_hi_ - buf_lo_) > 100000)) {
-            CoreHandler::basebuffer_free(buf_lo_);
-            buf_lo_ = nullptr;
-            buf_hi_ = nullptr;
+        if (!owned_) {
+            open("");
+        } else {
+            if ((!fixed_size_) && (buf_lo_ != nullptr) && ((buf_hi_ - buf_lo_) > 100000)) {
+                CoreHandler::basebuffer_free(buf_lo_);
+                buf_lo_ = nullptr;
+                buf_hi_ = nullptr;
+            }
+            read_cursor_ = buf_lo_;
+            write_cursor_ = buf_lo_;
+            pre_read_count_ = 0;
         }
-        owned_ = true;
-        read_cursor_ = buf_lo_;
-        write_cursor_ = buf_lo_;
-        pre_read_count_ = 0;
     }
 
     // Write block of bytes into the buffer.