base: Rewrite the CircleBuf to fix bugs and add serialization

The CircleBuf class has at least one bug causing it to overwrite the
wrong elements when wrapping. The current code has a lot of unused
functionality and duplicated code. This changeset replaces the old
implementation with a new version that supports serialization and
arbitrary types in the buffer (not just char).

3 files changed, 123 insertions, 77 deletions

diff --git a/src/unittest/SConscript b/src/unittest/SConscript
index ae22225b3..0275cdb42 100644
--- a/src/unittest/SConscript
+++ b/src/unittest/SConscript
@@ -34,7 +34,7 @@ Source('unittest.cc')
 
 UnitTest('bituniontest', 'bituniontest.cc')
 UnitTest('bitvectest', 'bitvectest.cc')
-UnitTest('circletest', 'circletest.cc')
+UnitTest('circlebuf', 'circlebuf.cc')
 UnitTest('cprintftest', 'cprintftest.cc')
 UnitTest('cprintftime', 'cprintftest.cc')
 UnitTest('fbtest', 'fbtest.cc')
diff --git a/src/unittest/circlebuf.cc b/src/unittest/circlebuf.cc
new file mode 100644
index 000000000..887d2c01b
--- /dev/null
+++ b/src/unittest/circlebuf.cc
@@ -0,0 +1,122 @@
+/*
+ * Copyright (c) 2015 ARM Limited
+ * All rights reserved
+ *
+ * The license below extends only to copyright in the software and shall
+ * not be construed as granting a license to any other intellectual
+ * property including but not limited to intellectual property relating
+ * to a hardware implementation of the functionality of the software
+ * licensed hereunder.  You may use the software subject to the license
+ * terms below provided that you ensure that this notice is replicated
+ * unmodified and in its entirety in all distributions of the software,
+ * modified or unmodified, in source code or in binary form.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met: redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer;
+ * redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution;
+ * neither the name of the copyright holders nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Authors: Andreas Sandberg
+ */
+
+#include "base/circlebuf.hh"
+
+#include "unittest/unittest.hh"
+
+const char data[] = {
+    0x0, 0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7,
+    0x8, 0x9, 0xa, 0xb, 0xc, 0xd, 0xe, 0xf,
+};
+
+int
+main(int argc, char *argv[])
+{
+    UnitTest::setCase("Basic non-overflow functionality");
+    {
+        CircleBuf<char> buf(8);
+        char foo[16];
+
+        // Write empty buffer, no overflow
+        buf.write(data, 8);
+        EXPECT_EQ(buf.size(), 8);
+        buf.peek(foo, 8);
+        EXPECT_EQ(memcmp(foo, data, 8), 0);
+
+        // Read 2
+        buf.read(foo, 2);
+        EXPECT_EQ(memcmp(foo, data, 2), 0);
+        EXPECT_EQ(buf.size(), 6);
+        buf.read(foo, 6);
+        EXPECT_EQ(memcmp(foo, data + 2, 6), 0);
+        EXPECT_EQ(buf.size(), 0);
+    }
+
+    UnitTest::setCase("Basic single write overflow functionality");
+    {
+        CircleBuf<char> buf(8);
+        char foo[16];
+
+        buf.write(data, 16);
+        EXPECT_EQ(buf.size(), 8);
+        buf.peek(foo, 8);
+        EXPECT_EQ(memcmp(data + 8, foo, 8), 0);
+    }
+
+
+    UnitTest::setCase("Multi-write overflow functionality");
+    {
+        CircleBuf<char> buf(8);
+        char foo[16];
+
+        // Write, no overflow, write overflow
+        buf.write(data, 6);
+        buf.write(data + 8, 6);
+        EXPECT_EQ(buf.size(), 8);
+        buf.peek(foo, 8);
+        EXPECT_EQ(memcmp(data + 4, foo, 2), 0);
+        EXPECT_EQ(memcmp(data + 8, foo + 2, 6), 0);
+    }
+
+    UnitTest::setCase("Pointer wrap around");
+    {
+        CircleBuf<char> buf(8);
+        char foo[16];
+
+        // _start == 0, _stop = 8
+        buf.write(data, 8);
+        // _start == 4, _stop = 8
+        buf.read(foo, 4);
+        // _start == 4, _stop = 12
+        buf.write(data + 8, 4);
+        EXPECT_EQ(buf.size(), 8);
+        // _start == 10, _stop = 12
+        // Normalized: _start == 2, _stop = 4
+        buf.read(foo + 4, 6);
+        EXPECT_EQ(buf.size(), 2);
+        EXPECT_EQ(memcmp(data, foo, 10), 0);
+        // Normalized: _start == 4, _stop = 4
+        buf.read(foo + 10, 2);
+        EXPECT_EQ(buf.size(), 0);
+        EXPECT_EQ(memcmp(data, foo, 12), 0);
+    }
+
+    return UnitTest::printResults();
+}
diff --git a/src/unittest/circletest.cc b/src/unittest/circletest.cc
deleted file mode 100644
index 2ee75b6df..000000000
--- a/src/unittest/circletest.cc
+++ /dev/null
@@ -1,76 +0,0 @@
-/*
- * Copyright (c) 2002-2005 The Regents of The University of Michigan
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met: redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer;
- * redistributions in binary form must reproduce the above copyright
- * notice, this list of conditions and the following disclaimer in the
- * documentation and/or other materials provided with the distribution;
- * neither the name of the copyright holders nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- *
- * Authors: Nathan Binkert
- */
-
-#include <fcntl.h>
-#include <unistd.h>
-
-#include <iostream>
-
-#include "base/circlebuf.hh"
-
-const char *strings[] = {
-    "This is the first test\n",
-    "he went with his woman to the store\n",
-    "the man with the bat hit the woman with the hat\n",
-    "that that is is that that was\n",
-    "sue sells sea shells by the sea shore\n",
-    "go to the store and buy me some milk and bread\n",
-    "the friendly flight attendants spoke soothingly to "
-    "the frightened passengers in their native languages\n"
-};
-
-const int num_strings = sizeof(strings) / sizeof(char *);
-
-int
-main()
-{
-    CircleBuf buf(1024);
-
-    for (int count = 0; count < 100; count++)
-        buf.write(strings[count % num_strings]);
-    buf.read(STDOUT_FILENO);
-    write(STDOUT_FILENO, "<\n", 2);
-
-    for (int count = 0; count < 100; count++)
-        buf.write(strings[count % num_strings]);
-    buf.read(STDOUT_FILENO, 100);
-    write(STDOUT_FILENO, "<\n", 2);
-
-    buf.flush();
-    buf.write("asdfa asdf asd fasdf asdf\n");
-    buf.write("");
-    buf.write("");
-    buf.write("");
-    buf.write("");
-    buf.write("");
-    buf.write("");
-    buf.read(STDOUT_FILENO);
-    write(STDOUT_FILENO, "<\n", 2);
-}