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).

1 files changed, 122 insertions, 0 deletions

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();
+}