Move files to prepare for assimilation into core

[libs/core.git] / source / io / buffered.cpp

diff --git a/source/io/buffered.cpp b/source/io/buffered.cpp
new file mode 100644 (file)
index 0000000..f53d2fc
--- /dev/null
+++ b/source/io/buffered.cpp
@@ -0,0 +1,188 @@
+#include <cstring>
+#include "buffered.h"
+#include "except.h"
+
+using namespace std;
+
+namespace Msp {
+namespace IO {
+
+Buffered::Buffered(Base &b, unsigned s):
+       below(b),
+       buf_size(s),
+       buf(new char[buf_size]),
+       begin(buf),
+       end(buf),
+       cur_op(M_NONE)
+{
+       mode = below.get_mode();
+       below.signal_flush_required.connect(sigc::mem_fun(this, &Buffered::flush));
+}
+
+Buffered::~Buffered()
+{
+       try
+       {
+               flush();
+       }
+       catch(...)
+       { }
+
+       delete[] buf;
+}
+
+void Buffered::flush()
+{
+       if(cur_op==M_WRITE)
+       {
+               unsigned used = end-begin;
+               if(used)
+               {
+                       unsigned len = below.write(begin, used);
+
+                       begin=end = buf;
+
+                       if(len<used)
+                               throw Exception("Couldn't flush all data");
+               }
+       }
+       else if(cur_op==M_READ)
+               begin=end = buf;
+}
+
+unsigned Buffered::do_write(const char *data, unsigned size)
+{
+       set_op(M_WRITE);
+
+       if(end+size<buf+buf_size)
+       {
+               // All data fits in buffer with whatever is already there
+               memcpy(end, data, size);
+               end += size;
+
+               return size;
+       }
+       else
+       {
+               // Clear the buffer to make more room
+               flush();
+
+               if(size<buf_size)
+               {
+                       // Put new data in the buffer to wait for more
+                       memcpy(end, data, size);
+                       end += size;
+
+                       return size;
+               }
+               else
+                       // New data still doesn't fit in the buffer, so write it directly
+                       return below.write(data, size);
+       }
+}
+
+unsigned Buffered::do_read(char *data, unsigned size)
+{
+       set_op(M_READ);
+
+       if(begin+size<=end)
+       {
+               // The request can be served from the buffer
+               memcpy(data, begin, size);
+               begin += size;
+
+               eof_flag = (below.eof() && begin==end);
+
+               return size;
+       }
+       else
+       {
+               // Give out whatever is in the buffer already
+               memcpy(data, begin, end-begin);
+               unsigned ret = end-begin;
+               begin=end = buf;
+
+               data += ret;
+               size -= ret;
+
+               if(size<buf_size)
+               {
+                       // Fill the buffer and serve the rest of the request from it
+                       unsigned len = below.read(end, buf+buf_size-end);
+                       end += len;
+
+                       len = min(static_cast<unsigned>(end-begin), size);
+                       memcpy(data, begin, len);
+                       begin += len;
+                       ret += len;
+               }
+               else
+                       // Read the rest directly from the underlying object
+                       ret += below.read(data, size);
+
+               eof_flag = (below.eof() && begin==end);
+
+               return ret;
+       }
+}
+
+unsigned Buffered::put(char c)
+{
+       set_op(M_WRITE);
+
+       if(end<buf+buf_size)
+       {
+               *end++ = c;
+               return 1;
+       }
+       else
+               return do_write(&c, 1);
+}
+
+bool Buffered::getline(std::string &line)
+{
+       set_op(M_READ);
+
+       for(char *i=begin; i!=end; ++i)
+               if(*i=='\n')
+               {
+                       line.assign(begin, i-begin);
+                       begin = i+1;
+                       return true;
+               }
+
+       return Base::getline(line);
+}
+
+int Buffered::get()
+{
+       set_op(M_READ);
+
+       if(begin<end)
+               return static_cast<unsigned char>(*begin++);
+
+       char c;
+       if(do_read(&c, 1)==0)
+               return -1;
+       return static_cast<unsigned char>(c);
+}
+
+void Buffered::set_op(Mode op)
+{
+       if(op!=cur_op)
+               flush();
+       cur_op = op;
+}
+
+unsigned Buffered::get_current_size() const
+{
+       return end-begin;
+}
+
+Handle Buffered::get_event_handle()
+{
+       throw Exception("Buffered doesn't support events");
+}
+
+} // namespace IO
+} // namespace Msp