Add conversion/comparison operators to Buffer

examples/kafka_consumer.cpp

@@ -81,10 +81,10 @@ int main(int argc, char* argv[]) {
             else {
                 // Print the key (if any)
                 if (msg.get_key()) {
-                    cout << msg.get_key().as_string() << " -> ";
+                    cout << msg.get_key() << " -> ";
                 }
                 // Print the payload
-                cout << msg.get_payload().as_string() << endl;
+                cout << msg.get_payload() << endl;
                 // Now commit the message
                 consumer.commit(msg);
             }

include/cppkafka/buffer.h

@@ -31,6 +31,8 @@
 #define CPPKAFKA_BUFFER_H
 
 #include <cstddef>
+#include <vector>
+#include <iosfwd>
 #include <algorithm>
 
 namespace cppkafka {
@@ -63,7 +65,7 @@ public:
     template <typename T>
     Buffer(const T* data, size_t size) 
     : data_(reinterpret_cast<const DataType*>(data)), size_(size) {
-        static_assert(sizeof(T) == 1, "Buffer must point to elements of 1 byte");
+        static_assert(sizeof(T) == sizeof(DataType), "sizeof(T) != sizeof(DataType)");
     }
 
     /**
@@ -100,7 +102,33 @@ public:
     /**
      * Converts the contents of the buffer into a string
      */
-    std::string as_string() const;
+    operator std::string() const;
+
+    /**
+     * \brief Converts the contents of the buffer into a vector.
+     *
+     * The vector must contain some type of size 1 (e.g. uint8_t, char, etc).
+     */
+    template <typename T>
+    operator std::vector<T>() const {
+        static_assert(sizeof(T) == sizeof(DataType), "sizeof(T) != sizeof(DataType)");
+        return std::vector<T>(data_, data_ + size_);
+    }
+
+    /**
+     * Compares this Buffer for equality 
+     */
+    bool operator==(const Buffer& rhs) const;
+
+    /**
+     * Compares this Buffer for inequality 
+     */
+    bool operator!=(const Buffer& rhs) const;
+
+    /**
+     * Output operator
+     */
+    friend std::ostream& operator<<(std::ostream& output, const Buffer& rhs);
 private:
     const DataType* data_;
     size_t size_;

src/buffer.cpp

@@ -27,9 +27,16 @@
  *
  */
 
+#include <algorithm>
+#include <iostream>
+#include <iomanip>
 #include "buffer.h"
 
 using std::string;
+using std::equal;
+using std::ostream;
+using std::hex;
+using std::dec;
 
 namespace cppkafka {
 
@@ -55,8 +62,36 @@ Buffer::operator bool() const {
     return data_ != nullptr;
 }
 
-string Buffer::as_string() const {
+Buffer::operator string() const {
     return string(data_, data_ + size_);
 }
 
+bool Buffer::operator==(const Buffer& rhs) const {
+    if (get_size() != rhs.get_size()) {
+        return false;
+    }
+    return equal(get_data(), get_data() + get_size(), rhs.get_data());
+}
+
+bool Buffer::operator!=(const Buffer& rhs) const { 
+    return !(*this == rhs);
+}
+
+ostream& operator<<(ostream& output, const Buffer& rhs) {
+    for (size_t i = 0; i < rhs.get_size(); ++i) {
+        char c = static_cast<char>(rhs.get_data()[i]);
+        if (c >= ' ' && c < 127) {
+            output << c;
+        }
+        else {
+            output << "\\x";
+            if (c < 16) {
+                output << '0';
+            }
+            output << hex << (int)c << dec;
+        }
+    }
+    return output;
+}
+
 } // cppkafka

tests/CMakeLists.txt

@@ -30,6 +30,8 @@ create_test(producer)
 create_test(kafka_handle_base)
 create_test(topic_partition_list)
 create_test(configuration)
+create_test(buffer)
+
 if (ENABLE_ZOOKEEPER)
     create_test(zookeeper_watcher)
 endif()

tests/buffer_test.cpp

@@ -0,0 +1,62 @@
+#include <string>
+#include <vector>
+#include <sstream>
+#include <gtest/gtest.h>
+#include "cppkafka/buffer.h"
+
+using std::string;
+using std::vector;
+using std::ostringstream;
+
+using namespace cppkafka;
+
+class BufferTest : public testing::Test {
+public:
+    
+};
+
+TEST_F(BufferTest, StringConversion) {
+    string data = "Hello world!";
+    Buffer buffer(data);
+    string buffer_as_string = buffer;
+    EXPECT_EQ(data, buffer_as_string);
+}
+
+TEST_F(BufferTest, StringConversionOnEmptyBuffer) {
+    Buffer buffer;
+    EXPECT_EQ("", static_cast<string>(buffer));
+}
+
+TEST_F(BufferTest, VectorConversion) {
+    string data = "Hello world!";
+    Buffer buffer(data);
+    vector<char> buffer_as_vector = buffer;
+    EXPECT_EQ(data, string(buffer_as_vector.begin(), buffer_as_vector.end()));
+}
+
+TEST_F(BufferTest, Equality) {
+    string data = "Hello world!";
+    Buffer buffer1(data);
+    Buffer buffer2(data);
+
+    EXPECT_EQ(buffer1, buffer2);
+}
+
+TEST_F(BufferTest, InEquality) {
+    string data1 = "Hello world!";
+    string data2 = "Hello worldz";
+    Buffer buffer1(data1);
+    Buffer buffer2(data2);
+
+    EXPECT_NE(buffer1, buffer2);
+}
+
+TEST_F(BufferTest, OutputOperator) {
+    string data = "Hello \x7fwor\x03ld!";
+    string pretty_string = "Hello \\x7fwor\\x03ld!";
+    Buffer buffer(data);
+
+    ostringstream output;
+    output << buffer;
+    EXPECT_EQ(pretty_string, output.str());
+}

tests/producer_test.cpp

@@ -120,8 +120,8 @@ TEST_F(ProducerTest, OneMessageOnFixedPartition) {
     const auto& messages = runner.get_messages();
     ASSERT_EQ(1, messages.size());
     const auto& message = messages[0];
-    EXPECT_EQ(payload, message.get_payload().as_string());
+    EXPECT_EQ(Buffer(payload), message.get_payload());
-    EXPECT_EQ("", message.get_key().as_string());
+    EXPECT_FALSE(message.get_key());
     EXPECT_EQ(KAFKA_TOPIC, message.get_topic());
     EXPECT_EQ(partition, message.get_partition());
     EXPECT_EQ(0, message.get_error());
@@ -151,8 +151,8 @@ TEST_F(ProducerTest, OneMessageUsingKey) {
     const auto& messages = runner.get_messages();
     ASSERT_EQ(1, messages.size());
     const auto& message = messages[0];
-    EXPECT_EQ(payload, message.get_payload().as_string());
+    EXPECT_EQ(Buffer(payload), message.get_payload());
-    EXPECT_EQ(key, message.get_key().as_string());
+    EXPECT_EQ(Buffer(key), message.get_key());
     EXPECT_EQ(KAFKA_TOPIC, message.get_topic());
     EXPECT_EQ(partition, message.get_partition());
     EXPECT_EQ(0, message.get_error());
@@ -183,9 +183,9 @@ TEST_F(ProducerTest, MultipleMessagesUnassignedPartitions) {
     ASSERT_EQ(message_count, messages.size());
     for (const auto& message : messages) {
         EXPECT_EQ(KAFKA_TOPIC, message.get_topic());
-        EXPECT_EQ(1, payloads.erase(message.get_payload().as_string()));
+        EXPECT_EQ(1, payloads.erase(message.get_payload()));
         EXPECT_EQ(0, message.get_error());
-        EXPECT_EQ("", message.get_key().as_string());
+        EXPECT_FALSE(message.get_key());
         EXPECT_GE(message.get_partition(), 0);
         EXPECT_LT(message.get_partition(), 3);
     }
@@ -205,14 +205,14 @@ TEST_F(ProducerTest, Callbacks) {
     bool deliver_report_called = false;
     Configuration config = make_producer_config();
     config.set_delivery_report_callback([&](Producer&, const Message& msg) {
-        EXPECT_EQ(payload, msg.get_payload().as_string());
+        EXPECT_EQ(Buffer(payload), msg.get_payload());
         deliver_report_called = true;
     });
 
     TopicConfiguration topic_config;
     topic_config.set_partitioner_callback([&](const Topic& topic, const Buffer& msg_key,
                                               int32_t partition_count) {
-        EXPECT_EQ(key, msg_key.as_string());
+        EXPECT_EQ(Buffer(key), msg_key);
         EXPECT_EQ(3, partition_count);
         EXPECT_EQ(KAFKA_TOPIC, topic.get_name());
         return 0;
@@ -227,8 +227,8 @@ TEST_F(ProducerTest, Callbacks) {
     const auto& messages = runner.get_messages();
     ASSERT_EQ(1, messages.size());
     const auto& message = messages[0];
-    EXPECT_EQ(payload, message.get_payload().as_string());
+    EXPECT_EQ(Buffer(payload), message.get_payload());
-    EXPECT_EQ(key, message.get_key().as_string());
+    EXPECT_EQ(Buffer(key), message.get_key());
     EXPECT_EQ(KAFKA_TOPIC, message.get_topic());
     EXPECT_EQ(partition, message.get_partition());
     EXPECT_EQ(0, message.get_error());
@@ -252,7 +252,7 @@ TEST_F(ProducerTest, PartitionerCallbackOnDefaultTopicConfig) {
     TopicConfiguration topic_config;
     topic_config.set_partitioner_callback([&](const Topic& topic, const Buffer& msg_key,
                                               int32_t partition_count) {
-        EXPECT_EQ(key, msg_key.as_string());
+        EXPECT_EQ(Buffer(key), msg_key);
         EXPECT_EQ(3, partition_count);
         EXPECT_EQ(KAFKA_TOPIC, topic.get_name());
         callback_called = true;
@@ -303,8 +303,8 @@ TEST_F(ProducerTest, ConnectUsingZookeeper) {
     const auto& messages = runner.get_messages();
     ASSERT_EQ(1, messages.size());
     const auto& message = messages[0];
-    EXPECT_EQ(payload, message.get_payload().as_string());
+    EXPECT_EQ(Buffer(payload), message.get_payload());
-    EXPECT_EQ(key, message.get_key().as_string());
+    EXPECT_EQ(Buffer(key), message.get_key());
     EXPECT_EQ(KAFKA_TOPIC, message.get_topic());
     EXPECT_EQ(partition, message.get_partition());
     EXPECT_EQ(0, message.get_error());