X-Git-Url: http://git.tdb.fi/?p=libs%2Fcore.git;a=blobdiff_plain;f=source%2Fio%2Fbuffered.cpp;fp=source%2Fio%2Fbuffered.cpp;h=f53d2fc23fa49e38ede87da0188b40d3cfeadb50;hp=0000000000000000000000000000000000000000;hb=6e0fd758970bcb5bad5e3f2454b694cc4d7b4b66;hpb=b97d4e9f86e90254ab9edef7ee62a910f6333c78

diff --git a/source/io/buffered.cpp b/source/io/buffered.cpp
new file mode 100644
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