src/qpid/amqp/Encoder.h

#ifndef QPID_AMQP_ENCODER_H
#define QPID_AMQP_ENCODER_H

/*
 *
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 *
 */
#include "qpid/sys/IntegerTypes.h"
#include "qpid/amqp/Constructor.h"
#include "qpid/Exception.h"
#include <list>
#include <map>
#include <stddef.h>
#include <string>

namespace qpid {
namespace types {
class Uuid;
class Variant;
}
namespace amqp {
struct CharSequence;
struct Descriptor;

/**
 * Class to help create AMQP encoded data.
 */
class Encoder
{
  public:
    struct Overflow : public Exception { Overflow(); };

    /** Create an encoder that writes into the buffer at data up to size bytes.
     * Write operations throw Overflow if encoding exceeds size bytes.
     */
    QPID_COMMON_EXTERN Encoder(char* data, size_t size);

    /** Create an encoder that manages its own buffer. Buffer grows to accomodate
     * all encoded data. Call getBuffer() to get the buffer.
     */
    QPID_COMMON_EXTERN Encoder();

    void writeCode(uint8_t);

    void write(bool);
    void write(uint8_t);
    void write(uint16_t);
    void write(uint32_t);
    void write(uint64_t);
    void write(int8_t);
    void write(int16_t);
    void write(int32_t);
    void write(int64_t);
    void write(float);
    void write(double);
    void write(const qpid::types::Uuid&);

    void writeNull(const Descriptor* d=0);
    void writeBoolean(bool, const Descriptor* d=0);
    void writeUByte(uint8_t, const Descriptor* d=0);
    void writeUShort(uint16_t, const Descriptor* d=0);
    void writeUInt(uint32_t, const Descriptor* d=0);
    void writeULong(uint64_t, const Descriptor* d=0);
    void writeByte(int8_t, const Descriptor* d=0);
    void writeShort(int16_t, const Descriptor* d=0);
    void writeInt(int32_t, const Descriptor* d=0);
    void writeLong(int64_t, const Descriptor* d=0);
    void writeFloat(float, const Descriptor* d=0);
    void writeDouble(double, const Descriptor* d=0);
    void writeUuid(const qpid::types::Uuid&, const Descriptor* d=0);
    void writeTimestamp(int64_t, const Descriptor* d=0);

    void writeSymbol(const CharSequence&, const Descriptor* d=0);
    void writeSymbol(const std::string&, const Descriptor* d=0);
    void writeString(const CharSequence&, const Descriptor* d=0);
    void writeString(const std::string&, const Descriptor* d=0);
    void writeBinary(const CharSequence&, const Descriptor* d=0);
    QPID_COMMON_EXTERN void writeBinary(const std::string&, const Descriptor* d=0);

    void* startList8(const Descriptor* d=0);
    void* startList32(const Descriptor* d=0);
    void endList8(uint8_t count, void*);
    void endList32(uint32_t count, void*);

    void* startMap8(const Descriptor* d=0);
    void* startMap32(const Descriptor* d=0);
    void endMap8(uint8_t count, void*);
    void endMap32(uint32_t count, void*);

    void* startArray8(const Constructor&, const Descriptor* d=0);
    void* startArray32(const Constructor&, const Descriptor* d=0);
    void endArray8(size_t count, void*);
    void endArray32(size_t count, void*);

    QPID_COMMON_EXTERN void writeValue(const qpid::types::Variant&, const Descriptor* d=0);
    QPID_COMMON_EXTERN void writeMap(const std::map<std::string, qpid::types::Variant>& value, const Descriptor* d=0, bool large=true);
    QPID_COMMON_EXTERN void writeList(const std::list<qpid::types::Variant>& value, const Descriptor* d=0, bool large=true);

    void writeDescriptor(const Descriptor&);
    QPID_COMMON_EXTERN size_t getPosition();
    void resetPosition(size_t p);
    char* skip(size_t);
    void writeBytes(const char* bytes, size_t count);
    virtual ~Encoder() {}

    /** Return the total size of the buffer. */
    size_t getSize() const;

    /** Return the growable buffer. */
    std::string getBuffer();

    /** Return the unused portion of the buffer. */
    char* getData();

  private:
    char* data;
    size_t size;
    size_t position;
    bool grow;
    std::string buffer;

    void write(const CharSequence& v, std::pair<uint8_t, uint8_t> codes, const Descriptor* d);
    void write(const std::string& v, std::pair<uint8_t, uint8_t> codes, const Descriptor* d);
    void check(size_t);

    template<typename T> void write(T value, uint8_t code, const Descriptor* d)
    {
        if (d) writeDescriptor(*d);
        writeCode(code);
        write(value);
    }

    template<typename T> void write(T value, std::pair<uint8_t, uint8_t> codes, const Descriptor* d)
    {
        if (value < 256) {
            write((uint8_t) value, codes.first, d);
        } else {
            write(value, codes.second, d);
        }
    }

    template<typename T> void* start(uint8_t code, const Descriptor* d)
    {
        if (d) writeDescriptor(*d);
        writeCode(code);
        //skip size and count, will backfill on end
        return skip(sizeof(T)/*size*/ + sizeof(T)/*count*/);
    }

    template<typename T> void* startArray(uint8_t code, const Descriptor* d, const Constructor& c)
    {
        void* token = start<T>(code, d);
        if (c.isDescribed) {
            writeDescriptor(c.descriptor);
        }
        check(1);
        writeCode(c.code);
        return token;
    }

};

}} // namespace qpid::amqp

#endif  /*!QPID_AMQP_ENCODER_H*/