string-buffer.cpp

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/*
 * string-buffer.cpp
 *
 * Copyright (C) 2010  Thomas A. Vaughan
 * 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 <organization> 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 THOMAS A. VAUGHAN ''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 THOMAS A. VAUGHAN 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.
 *
 *
 * Implementation of a string buffer (see string-buffer.h)
 */

// includes --------------------------------------------------------------------
#include "string-buffer.h"      // always include our own header first!

#include "common/wave_ex.h"     // exceptions


// interface destructor implementations
StringBuffer::~StringBuffer(void) throw() { }


////////////////////////////////////////////////////////////////////////////////
//
//      static helper methods
//
////////////////////////////////////////////////////////////////////////////////


////////////////////////////////////////////////////////////////////////////////
//
//      SBuffer - implementation of the StringBuffer interface
//
////////////////////////////////////////////////////////////////////////////////

class SBuffer : public StringBuffer {
public:
        // constructor, destructor ---------------------------------------------
        SBuffer(void) throw();
        ~SBuffer(void) throw() { }

        // public class methods ------------------------------------------------
        void initialize(IN int initialBytes);

        // StringBuffer class interface methods --------------------------------
        int appendString(IN const char * string);
        const char * getString(IN int offset) const throw();
        void getIterator(OUT iterator_t& i) const throw();
        const char * getNextString(IO iterator_t& i) const throw();
        void dumpStrings(IO std::ostream& stream) const;

private:
        // private typedefs ----------------------------------------------------
        struct real_iter_t {
                int     offset; // offset into buffer
        };

        // private helper methods ----------------------------------------------
        static real_iter_t * getRealIterator(IN iterator_t& i) throw() {
                        return (real_iter_t *) &i;
                }

        // private member data -------------------------------------------------
        char *          m_buffer;       // raw buffer
        int             m_offset;       // pointer to next open spot in buffer
        int             m_size;         // total size of buffer (bytes)
};


SBuffer::SBuffer(void)
throw()
{
        m_buffer = NULL;
        m_offset = 0;
        m_size = 0;
}



void
SBuffer::initialize
(
IN int initialBytes
)
{
        ASSERT(initialBytes > 0, "Bad initial bytes: %d", initialBytes);

        m_buffer = (char *) malloc(initialBytes);
        ASSERT_THROW(m_buffer, "out of memory");
        m_offset = 0;
        m_size = initialBytes;
}



////////////////////////////////////////////////////////////////////////////////
//
//      SBuffer -- StringBuffer class interface methods
//
////////////////////////////////////////////////////////////////////////////////

int
SBuffer::appendString
(
IN const char * string
)
{
        ASSERT(string, "null");
        int len = strlen(string);

        int newOffset = m_offset + len + 1;     // add one for null terminator
        while (newOffset >= m_size) {
                // need to re-allocate buffer!
                int newSize = 2 * m_size;
                char * p = (char *) realloc(m_buffer, newSize);
                ASSERT_THROW(p, "out of memory");
                m_buffer = p;
                m_size = newSize;
                DPRINTF("re-allocated to new size: %d", newSize);
        }
        ASSERT(newOffset < m_size, "Should be fine now!");

        // copy into buffer
        strncpy(m_buffer + m_offset, string, len);
        m_buffer[m_offset + len] = 0;   // null terminate
        int oldOffset = m_offset;
        m_offset = newOffset;
        return oldOffset;
}



const char *
SBuffer::getString
(
IN int offset
)
const
throw()
{
        ASSERT(m_buffer, "null");
        ASSERT(offset >= 0, "Bad input offset: %d", offset);
        ASSERT(offset < m_size, "Bad input offset: %d", offset);

        return m_buffer + offset;
}



void
SBuffer::dumpStrings
(
IO std::ostream& stream
)
const
{
        ASSERT_THROW(stream.good(), "bad stream");

        iterator_t i;
        this->getIterator(i);
        while (const char * p = this->getNextString(i)) {
                stream << p << "\n";
        }
}



void
SBuffer::getIterator
(
OUT iterator_t& i
)
const
throw()
{
        ASSERT_THROW(sizeof(iterator_t) >= sizeof(real_iter_t),
            "StringBuffer iterator size mismatch!  Public iterator is " <<
            sizeof(iterator_t) << " bytes, but the real (private) iterator is "
            << sizeof(real_iter_t) << " bytes.");

        real_iter_t * pri = getRealIterator(i);
        pri->offset = 0;
}




const char *
SBuffer::getNextString
(
IO iterator_t& i
)
const
throw()
{
        real_iter_t * pri = getRealIterator(i);

        if (pri->offset >= m_offset) {
                // at end of array!
                return NULL;
        }
        const char * val = m_buffer + pri->offset;
        pri->offset += strlen(val) + 1;
        return val;
}



////////////////////////////////////////////////////////////////////////////////
//
//      public API
//
////////////////////////////////////////////////////////////////////////////////

smart_ptr<StringBuffer>
StringBuffer::create
(
IN int initialBytes
)
{
        ASSERT(initialBytes > 0, "Bad initial bytes; %d", initialBytes);

        smart_ptr<SBuffer> local = new SBuffer;
        ASSERT(local, "out of memory");

        local->initialize(initialBytes);

        return local;
}