DXFHelper.h

/*
Open Asset Import Library (assimp)
----------------------------------------------------------------------

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  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
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"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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*/

/** @file  DXFHelper.h
 *  @brief Internal utilities for the DXF loader.
 */

#ifndef INCLUDED_DXFHELPER_H
#define INCLUDED_DXFHELPER_H

#include "LineSplitter.h"
#include "TinyFormatter.h"
#include "StreamReader.h"
#include "fast_atof.h"
#include <vector>
#include <assimp/DefaultLogger.hpp>

namespace Assimp {
    namespace DXF {


// read pairs of lines, parse group code and value and provide utilities
// to convert the data to the target data type.
class LineReader
{

public:

    LineReader(StreamReaderLE& reader)
         // do NOT skip empty lines. In DXF files, they count as valid data.
        : splitter(reader,false,true)
        , groupcode( 0 )
        , value()
        , end()
    {
    }

public:


    // -----------------------------------------
    bool Is(int gc, const char* what) const {
        return groupcode == gc && !strcmp(what,value.c_str());
    }

    // -----------------------------------------
    bool Is(int gc) const {
        return groupcode == gc;
    }

    // -----------------------------------------
    int GroupCode() const {
        return groupcode;
    }

    // -----------------------------------------
    const std::string& Value() const {
        return value;
    }

    // -----------------------------------------
    bool End() const {
        return !((bool)*this);
    }

public:

    // -----------------------------------------
    unsigned int ValueAsUnsignedInt() const {
        return strtoul10(value.c_str());
    }

    // -----------------------------------------
    int ValueAsSignedInt() const {
        return strtol10(value.c_str());
    }

    // -----------------------------------------
    float ValueAsFloat() const {
        return fast_atof(value.c_str());
    }

public:

    // -----------------------------------------
    /** pseudo-iterator increment to advance to the next (groupcode/value) pair */
    LineReader& operator++() {
        if (end) {
            if (end == 1) {
                ++end;
            }
            return *this;
        }

        try {
            groupcode = strtol10(splitter->c_str());
            splitter++;

            value = *splitter;
            splitter++;

            // automatically skip over {} meta blocks (these are for application use
            // and currently not relevant for Assimp).
            if (value.length() && value[0] == '{') {

                size_t cnt = 0;
                for(;splitter->length() && splitter->at(0) != '}'; splitter++, cnt++);

                splitter++;
                DefaultLogger::get()->debug((Formatter::format("DXF: skipped over control group ("),cnt," lines)"));
            }
        } catch(std::logic_error&) {
            ai_assert(!splitter);
        }
        if (!splitter) {
            end = 1;
        }
        return *this;
    }

    // -----------------------------------------
    LineReader& operator++(int) {
        return ++(*this);
    }


    // -----------------------------------------
    operator bool() const {
        return end <= 1;
    }

private:

    LineSplitter splitter;
    int groupcode;
    std::string value;
    int end;
};



// represents a POLYLINE or a LWPOLYLINE. or even a 3DFACE The data is converted as needed.
struct PolyLine
{
    PolyLine()
        : flags()
    {}

    std::vector<aiVector3D> positions;
    std::vector<aiColor4D>  colors;
    std::vector<unsigned int> indices;
    std::vector<unsigned int> counts;
    unsigned int flags;

    std::string layer;
    std::string desc;
};


// reference to a BLOCK. Specifies its own coordinate system.
struct InsertBlock
{
    InsertBlock()
        : scale(1.f,1.f,1.f)
        , angle()
    {}

    aiVector3D pos;
    aiVector3D scale;
    float angle;

    std::string name;
};


// keeps track of all geometry in a single BLOCK.
struct Block
{
    std::vector< std::shared_ptr<PolyLine> > lines;
    std::vector<InsertBlock> insertions;

    std::string name;
    aiVector3D base;
};


struct FileData
{
    // note: the LAST block always contains the stuff from ENTITIES.
    std::vector<Block> blocks;
};





}}
#endif