allow loading a Buffer from in-memory data

src/core/Buffer.cc

@@ -4,17 +4,24 @@
 #include "File.h"
 #include "TextLoader.h"
 #include <cassert>
+#include <string.h>
+
+Buffer::Buffer()
+{
+    load_empty_buffer();
+}
 
 Buffer::Buffer(const char * filename)
 {
-    if (filename != nullptr)
+    if (!load_from_file(filename))
     {
-        if (!load_from_file(filename))
-        {
-            load_empty_buffer();
-        }
+        load_empty_buffer();
     }
-    else
+}
+
+Buffer::Buffer(const uint8_t * data, size_t data_length)
+{
+    if (!load_from_memory(data, data_length))
     {
         load_empty_buffer();
     }
@@ -54,15 +61,36 @@ bool Buffer::load_from_file(const char * filename)
         return false;
     }
 
+    load_text_in_buffer(buffer, buffer_size, file_size);
+
+    return true;
+}
+
+bool Buffer::load_from_memory(const uint8_t * data, size_t data_length)
+{
+    size_t buffer_size = ((unsigned long)data_length + 2u * System::page_size) & System::page_base_mask;
+    uint8_t * buffer = (uint8_t *)System::alloc_pages(buffer_size >> System::page_size_log);
+    if (buffer == NULL)
+    {
+        return false;
+    }
+
+    memcpy(buffer, data, data_length);
+
+    load_text_in_buffer(buffer, buffer_size, data_length);
+
+    return true;
+}
+
+void Buffer::load_text_in_buffer(uint8_t * buffer, size_t buffer_size, size_t data_length)
+{
     TextLoader text_loader;
     size_t loaded_size;
-    text_loader.load_buffer(buffer, file_size, &loaded_size);
+    text_loader.load_buffer(buffer, data_length, &loaded_size);
 
     m_gap_buffer = std::make_shared<GapBuffer>(buffer, buffer_size, loaded_size, text_loader.get_encoding());
     m_eol_at_eof = text_loader.get_eol_at_eof();
     m_line_endings = text_loader.get_line_endings();
-
-    return true;
 }
 
 bool Buffer::write_to_file(const char * filename)

src/core/Buffer.h

@@ -10,7 +10,9 @@
 class Buffer
 {
 public:
-    Buffer(const char * filename = nullptr);
+    Buffer();
+    Buffer(const char * filename);
+    Buffer(const uint8_t * data, size_t data_length);
     bool write_to_file(const char * filename);
 
     typedef GapBuffer::Cursor Cursor;
@@ -28,6 +30,8 @@ protected:
 
     bool load_from_file(const char * filename);
     void load_empty_buffer();
+    bool load_from_memory(const uint8_t * data, size_t data_length);
+    void load_text_in_buffer(uint8_t * buffer, size_t buffer_size, size_t data_length);
 };
 
 #endif