From e6385cb74c35eb5a346237acecc846e52c4d6bd4 Mon Sep 17 00:00:00 2001
From: Pixel <pixel@nobis-crew.org>
Date: Sat, 12 Nov 2011 21:52:02 +0100
Subject: Adding seekable buffers. Probably would need a few more tests in the
 Handles unit test.

---
 Makefile              |  1 +
 includes/Buffer.h     | 24 ++++++++++++++++
 src/Buffer.cc         | 76 +++++++++++++++++++++++++++++++++++++++++++++++++++
 tests/test-Handles.cc | 12 ++++++++
 4 files changed, 113 insertions(+)
 create mode 100644 includes/Buffer.h
 create mode 100644 src/Buffer.cc

diff --git a/Makefile b/Makefile
index 6fd9f18..fabb147 100644
--- a/Makefile
+++ b/Makefile
@@ -121,6 +121,7 @@ Handle.cc \
 Input.cc \
 Output.cc \
 Socket.cc \
+Buffer.cc \
 \
 Task.cc \
 TaskMan.cc \
diff --git a/includes/Buffer.h b/includes/Buffer.h
new file mode 100644
index 0000000..99a57f0
--- /dev/null
+++ b/includes/Buffer.h
@@ -0,0 +1,24 @@
+#pragma once
+
+#include <Handle.h>
+
+namespace Balau {
+
+class Buffer : public SeekableHandle {
+  public:
+      Buffer() throw (GeneralException) : m_buffer(NULL), m_bufSize(0), m_numBlocks(0) { }
+    virtual void close() throw (GeneralException);
+    virtual ssize_t read(void * buf, size_t count) throw (GeneralException);
+    virtual ssize_t write(const void * buf, size_t count) throw (GeneralException);
+    virtual bool isClosed();
+    virtual bool canRead();
+    virtual bool canWrite();
+    virtual const char * getName();
+    virtual off_t getSize();
+    void reset();
+  private:
+    uint8_t * m_buffer;
+    off_t m_bufSize, m_numBlocks;
+};
+
+};
diff --git a/src/Buffer.cc b/src/Buffer.cc
new file mode 100644
index 0000000..d6ff9bb
--- /dev/null
+++ b/src/Buffer.cc
@@ -0,0 +1,76 @@
+#include <errno.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include "Buffer.h"
+#include "Task.h"
+#include "Printer.h"
+
+static const int s_blockSize = 16 * 1024;
+
+void Balau::Buffer::close() throw (GeneralException) {
+    reset();
+}
+
+ssize_t Balau::Buffer::read(void * buf, size_t count) throw (GeneralException) {
+    off_t cursor = rtell();
+    if (cursor >= m_bufSize)
+        return 0;
+    off_t avail = m_bufSize - cursor;
+
+    if (count > avail)
+        count = avail;
+
+    memcpy(buf, m_buffer + cursor, count);
+
+    rseek(cursor + count);
+
+    return count;
+}
+
+ssize_t Balau::Buffer::write(const void * buf, size_t count) throw (GeneralException) {
+    off_t cursor = wtell();
+    off_t end = cursor + count;
+    off_t endBlock = (end / s_blockSize) + ((end % s_blockSize) ? 1 : 0);
+    off_t oldEndBlock = m_numBlocks;
+
+    if (endBlock > oldEndBlock) {
+        m_buffer = (uint8_t *) realloc(m_buffer, endBlock * s_blockSize);
+        memset(m_buffer + oldEndBlock * s_blockSize, 0, (endBlock - oldEndBlock) * s_blockSize);
+    }
+
+    memcpy(m_buffer + cursor, buf, count);
+
+    wseek(cursor + count);
+
+    return count;
+}
+
+void Balau::Buffer::reset() {
+    m_buffer = (uint8_t *) realloc(m_buffer, 0);
+    m_bufSize = 0;
+    m_numBlocks = 0;
+    wseek(0);
+    rseek(0);
+}
+
+bool Balau::Buffer::isClosed() {
+    return false;
+}
+
+const char * Balau::Buffer::getName() {
+    return "Buffer";
+}
+
+off_t Balau::Buffer::getSize() {
+    return m_bufSize;
+}
+
+bool Balau::Buffer::canRead() {
+    return true;
+}
+
+bool Balau::Buffer::canWrite() {
+    return true;
+}
diff --git a/tests/test-Handles.cc b/tests/test-Handles.cc
index f9fd055..fd05c76 100644
--- a/tests/test-Handles.cc
+++ b/tests/test-Handles.cc
@@ -1,6 +1,7 @@
 #include <Main.h>
 #include <Input.h>
 #include <Output.h>
+#include <Buffer.h>
 
 #ifdef _WIN32
 void ctime_r(const time_t * t, char * str) {
@@ -70,5 +71,16 @@ void MainTask::Do() {
     Assert(s == 0);
     o->write("foo\n", 4);
 
+    IO<Handle> b(new Buffer());
+    s = b->rtell();
+    Assert(s == 0);
+    s = b->wtell();
+    Assert(s == 0);
+    b->write("foo\n", 4);
+    s = b->rtell();
+    Assert(s == 0);
+    s = b->wtell();
+    Assert(s == 4);
+
     Printer::log(M_STATUS, "Test::Handles passed.");
 }
-- 
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