[2312] Added utility class to write data of various types to a buffer.

src/lib/dhcp/Makefile.am

@@ -21,7 +21,7 @@ libb10_dhcp___la_SOURCES += iface_mgr_linux.cc
 libb10_dhcp___la_SOURCES += iface_mgr_sun.cc
 libb10_dhcp___la_SOURCES += libdhcp++.cc libdhcp++.h
 libb10_dhcp___la_SOURCES += option.cc option.h
-libb10_dhcp___la_SOURCES += option_data_types.h
+libb10_dhcp___la_SOURCES += option_data_types.cc option_data_types.h
 libb10_dhcp___la_SOURCES += option_definition.cc option_definition.h
 libb10_dhcp___la_SOURCES += option_custom.cc option_custom.h
 libb10_dhcp___la_SOURCES += option6_ia.cc option6_ia.h

src/lib/dhcp/option_data_types.cc

@@ -0,0 +1,85 @@
+// Copyright (C) 2012 Internet Systems Consortium, Inc. ("ISC")
+//
+// Permission to use, copy, modify, and/or distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice appear in all copies.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
+// REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+// AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
+// INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+// LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
+// OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+// PERFORMANCE OF THIS SOFTWARE.
+
+#include <dhcp/option_data_types.h>
+#include <util/encode/hex.h>
+
+namespace isc {
+namespace dhcp {
+
+void
+OptionDataTypeUtil::writeBinary(const std::string& hex_str,
+                                std::vector<uint8_t>& buf) {
+    // Binary value means that the value is encoded as a string
+    // of hexadecimal deigits. We need to decode this string
+    // to the binary format here.
+    OptionBuffer binary;
+    try {
+        util::encode::decodeHex(hex_str, binary);
+    } catch (const Exception& ex) {
+        isc_throw(BadDataTypeCast, "unable to cast " << hex_str
+                  << " to binary data type: " << ex.what());
+    }
+    // Decode was successful so append decoded binary value
+    // to the buffer.
+    buf.insert(buf.end(), binary.begin(), binary.end());
+}
+
+void
+OptionDataTypeUtil::writeBool(const bool value,
+                              std::vector<uint8_t>& buf) {
+    if (value) {
+        buf.push_back(static_cast<uint8_t>(1));
+    } else {
+        buf.push_back(static_cast<uint8_t>(0));
+    }
+}
+
+void
+OptionDataTypeUtil::writeAddress(const asiolink::IOAddress& address,
+                                 std::vector<uint8_t>& buf) {
+    if (address.getAddress().is_v4()) {
+        asio::ip::address_v4::bytes_type addr_bytes =
+            address.getAddress().to_v4().to_bytes();
+        // Increase the buffer size by the size of IPv4 address.
+        buf.resize(buf.size() + addr_bytes.size());
+        std::copy_backward(addr_bytes.begin(), addr_bytes.end(),
+                           buf.end());
+    } else if (address.getAddress().is_v6()) {
+        asio::ip::address_v6::bytes_type addr_bytes =
+            address.getAddress().to_v6().to_bytes();
+        // Incresase the buffer size by the size of IPv6 address.
+        buf.resize(buf.size() + addr_bytes.size());
+        std::copy_backward(addr_bytes.begin(), addr_bytes.end(),
+                           buf.end());
+    } else {
+        isc_throw(BadDataTypeCast, "the address " << address.toText()
+                  << " is neither valid IPv4 not IPv6 address.");
+    }
+}
+
+void
+OptionDataTypeUtil::writeString(const std::string& value,
+                                std::vector<uint8_t>& buf) {
+    if (value.size() > 0) {
+        // Increase the size of the storage by the size of the string.
+        buf.resize(buf.size() + value.size());
+        // Assuming that the string is already UTF8 encoded.
+        std::copy_backward(value.c_str(), value.c_str() + value.size(),
+                           buf.end());
+    }
+}
+
+} // end of isc::dhcp namespace
+} // end of isc namespace

src/lib/dhcp/option_data_types.h

@@ -16,7 +16,9 @@
 #define OPTION_DATA_TYPES_H
 
 #include <asiolink/io_address.h>
+#include <dhcp/option.h>
 #include <exceptions/exceptions.h>
+#include <util/io_utilities.h>
 
 #include <stdint.h>
 
@@ -172,6 +174,74 @@ struct OptionDataTypeTraits<std::string> {
     static const OptionDataType type = OPT_STRING_TYPE;
 };
 
+/// @brief Utility class to write/read data to/from a buffer.
+class OptionDataTypeUtil {
+public:
+    /// @brief Write IPv4 or IPv6 address into a buffer.
+    ///
+    /// @param address IPv4 or IPv6 address.
+    /// @param [out] buf output buffer.
+    static void writeAddress(const asiolink::IOAddress& address,
+                                     std::vector<uint8_t>& buf);
+
+    /// @brief Write hex-encoded binary values into a buffer.
+    ///
+    /// @param hex_str string representing a binary value encoded
+    /// with hexadecimal digits (without 0x prefix).
+    /// @param [out] output buffer.
+    static void writeBinary(const std::string& hex_str,
+                                    std::vector<uint8_t>& buf);
+
+    /// @brief Write boolean value into a buffer.
+    ///
+    /// The bool value is encoded in a buffer in such a way that
+    /// "1" means "true" and "0" means "false".
+    ///
+    /// @param boolean value to be written.
+    /// @param [out] buf output buffer.
+    static void writeBool(const bool value, std::vector<uint8_t>& buf);
+
+    /// @brief Write integer or unsiged integer value into a buffer.
+    ///
+    /// @param value an integer value to be written into a buffer.
+    /// @param [out] buf output buffer.
+    /// @tparam data type of the value.
+    template<typename T>
+    static void writeInt(const T value,
+                         std::vector<uint8_t>& buf) {
+        if (!OptionDataTypeTraits<T>::is_integer) {
+            isc_throw(InvalidDataType, "provided data type is not the supported.");
+        }
+        switch (OptionDataTypeTraits<T>::len) {
+        case 1:
+            buf.push_back(static_cast<uint8_t>(value));
+            break;
+        case 2:
+            buf.resize(buf.size() + 2);
+            isc::util::writeUint16(static_cast<uint16_t>(value), &buf[buf.size() - 2]);
+            break;
+        case 4:
+            buf.resize(buf.size() + 4);
+            isc::util::writeUint32(static_cast<uint32_t>(value), &buf[buf.size() - 4]);
+            break;
+        default:
+            // The cases above cover whole range of possible data lengths because
+            // we check at the beginning of this function that given data type is
+            // a supported integer type which can be only 1,2 or 4 bytes long.
+            ;
+        }
+    }
+
+    /// @brief Write utf8-encoded string into a buffer.
+    ///
+    /// @param value string value to be written into a buffer.
+    /// @param [out] buf output buffer.
+    static void writeString(const std::string& value,
+                            std::vector<uint8_t>& buf);
+
+};
+
+
 } // isc::dhcp namespace
 } // isc namespace