/*
---------------------------------------------------------------------------
Open Asset Import Library (assimp)
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  following disclaimer.

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*/

/** @file Implementation of the XFile parser helper class */

#ifndef ASSIMP_BUILD_NO_X_IMPORTER

#include "XFileParser.h"
#include "XFileHelper.h"
#include <assimp/ByteSwapper.h>
#include <assimp/Exceptional.h>
#include <assimp/StringUtils.h>
#include <assimp/TinyFormatter.h>
#include <assimp/fast_atof.h>
#include <assimp/DefaultLogger.hpp>

using namespace Assimp;
using namespace Assimp::XFile;
using namespace Assimp::Formatter;

#ifndef ASSIMP_BUILD_NO_COMPRESSED_X

#include "Common/Compression.h"

// Magic identifier for MSZIP compressed data
constexpr unsigned int MSZIP_MAGIC = 0x4B43;
constexpr size_t MSZIP_BLOCK = 32786l;

#endif // !! ASSIMP_BUILD_NO_COMPRESSED_X

// ------------------------------------------------------------------------------------------------
// Throws an exception with a line number and the given text.
template<typename... T>
AI_WONT_RETURN void XFileParser::ThrowException(T&&... args) {
    if (mIsBinaryFormat) {
        throw DeadlyImportError(args...);
    } else {
        throw DeadlyImportError("Line ", mLineNumber, ": ", args...);
    }
}

// ------------------------------------------------------------------------------------------------
// Constructor. Creates a data structure out of the XFile given in the memory block.
XFileParser::XFileParser(const std::vector<char> &pBuffer) :
        mMajorVersion(0), mMinorVersion(0), mIsBinaryFormat(false), mBinaryNumCount(0), mP(nullptr), mEnd(nullptr), mLineNumber(0), mScene(nullptr) {
    // vector to store uncompressed file for INFLATE'd X files
    std::vector<char> uncompressed;

    // set up memory pointers
    mP = &pBuffer.front();
    mEnd = mP + pBuffer.size() - 1;

    // check header
    if (0 != strncmp(mP, "xof ", 4)) {
        throw DeadlyImportError("Header mismatch, file is not an XFile.");
    }

    // read version. It comes in a four byte format such as "0302"
    mMajorVersion = (unsigned int)(mP[4] - 48) * 10 + (unsigned int)(mP[5] - 48);
    mMinorVersion = (unsigned int)(mP[6] - 48) * 10 + (unsigned int)(mP[7] - 48);

    bool compressed = false;

    // txt - pure ASCII text format
    if (strncmp(mP + 8, "txt ", 4) == 0)
        mIsBinaryFormat = false;

    // bin - Binary format
    else if (strncmp(mP + 8, "bin ", 4) == 0)
        mIsBinaryFormat = true;

    // tzip - Inflate compressed text format
    else if (strncmp(mP + 8, "tzip", 4) == 0) {
        mIsBinaryFormat = false;
        compressed = true;
    }
    // bzip - Inflate compressed binary format
    else if (strncmp(mP + 8, "bzip", 4) == 0) {
        mIsBinaryFormat = true;
        compressed = true;
    } else
        ThrowException("Unsupported x-file format '", mP[8], mP[9], mP[10], mP[11], "'");

    // float size
    mBinaryFloatSize = (unsigned int)(mP[12] - 48) * 1000 + (unsigned int)(mP[13] - 48) * 100 + (unsigned int)(mP[14] - 48) * 10 + (unsigned int)(mP[15] - 48);

    if (mBinaryFloatSize != 32 && mBinaryFloatSize != 64)
        ThrowException("Unknown float size ", mBinaryFloatSize, " specified in x-file header.");

    // The x format specifies size in bits, but we work in bytes
    mBinaryFloatSize /= 8;

    mP += 16;

    // If this is a compressed X file, apply the inflate algorithm to it
    if (compressed) {
#ifdef ASSIMP_BUILD_NO_COMPRESSED_X
        throw DeadlyImportError("Assimp was built without compressed X support");
#else
        /* ///////////////////////////////////////////////////////////////////////
         * COMPRESSED X FILE FORMAT
         * ///////////////////////////////////////////////////////////////////////
         *    [xhead]
         *    2 major
         *    2 minor
         *    4 type    // bzip,tzip
         *    [mszip_master_head]
         *    4 unkn    // checksum?
         *    2 unkn    // flags? (seems to be constant)
         *    [mszip_head]
         *    2 ofs     // offset to next section
         *    2 magic   // 'CK'
         *    ... ofs bytes of data
         *    ... next mszip_head
         *
         *  http://www.kdedevelopers.org/node/3181 has been very helpful.
         * ///////////////////////////////////////////////////////////////////////
         */

        // skip unknown data (checksum, flags?)
        mP += 6;

        // First find out how much storage we'll need. Count sections.
        const char *P1 = mP;
        unsigned int est_out = 0;

        while (P1 + 3 < mEnd) {
            // read next offset
            uint16_t ofs = *((uint16_t *)P1);
            AI_SWAP2(ofs);
            P1 += 2;

            if (ofs >= MSZIP_BLOCK)
                throw DeadlyImportError("X: Invalid offset to next MSZIP compressed block");

            // check magic word
            uint16_t magic = *((uint16_t *)P1);
            AI_SWAP2(magic);
            P1 += 2;

            if (magic != MSZIP_MAGIC)
                throw DeadlyImportError("X: Unsupported compressed format, expected MSZIP header");

            // and advance to the next offset
            P1 += ofs;
            est_out += MSZIP_BLOCK; // one decompressed block is 327861 in size
        }

        // Allocate storage and terminating zero and do the actual uncompressing
        Compression compression;
        uncompressed.resize(est_out + 1);
        char *out = &uncompressed.front();
        if (compression.open(mIsBinaryFormat ? Compression::Format::Binary : Compression::Format::ASCII,
                Compression::FlushMode::SyncFlush, -Compression::MaxWBits)) {
            while (mP + 3 < mEnd) {
                uint16_t ofs = *((uint16_t *)mP);
                AI_SWAP2(ofs);
                mP += 4;

                if (mP + ofs > mEnd + 2) {
                    throw DeadlyImportError("X: Unexpected EOF in compressed chunk");
                }
                out += compression.decompressBlock(mP, ofs, out, MSZIP_BLOCK);
                mP += ofs;
            }
            compression.close();
        }

        // ok, update pointers to point to the uncompressed file data
        mP = &uncompressed[0];
        mEnd = out;

        // FIXME: we don't need the compressed data anymore, could release
        // it already for better memory usage. Consider breaking const-co.
        ASSIMP_LOG_INFO("Successfully decompressed MSZIP-compressed file");
#endif // !! ASSIMP_BUILD_NO_COMPRESSED_X
    } else {
        // start reading here
        ReadUntilEndOfLine();
    }

    mScene = new Scene;
    ParseFile();

    // filter the imported hierarchy for some degenerated cases
    if (mScene->mRootNode) {
        FilterHierarchy(mScene->mRootNode);
    }
}

// ------------------------------------------------------------------------------------------------
// Destructor. Destroys all imported data along with it
XFileParser::~XFileParser() {
    // kill everything we created
    delete mScene;
}

// ------------------------------------------------------------------------------------------------
void XFileParser::ParseFile() {
    bool running = true;
    while (running) {
        // read name of next object
        std::string objectName = GetNextToken();
        if (objectName.length() == 0) {
            break;
        }

        // parse specific object
        if (objectName == "template") {
            ParseDataObjectTemplate();
        } else if (objectName == "Frame") {
            ParseDataObjectFrame(nullptr);
        } else if (objectName == "Mesh") {
            // some meshes have no frames at all
            Mesh *mesh = new Mesh;
            ParseDataObjectMesh(mesh);
            mScene->mGlobalMeshes.push_back(mesh);
        } else if (objectName == "AnimTicksPerSecond")
            ParseDataObjectAnimTicksPerSecond();
        else if (objectName == "AnimationSet")
            ParseDataObjectAnimationSet();
        else if (objectName == "Material") {
            // Material outside of a mesh or node
            Material material;
            ParseDataObjectMaterial(&material);
            mScene->mGlobalMaterials.push_back(material);
        } else if (objectName == "}") {
            // whatever?
            ASSIMP_LOG_WARN("} found in dataObject");
        } else {
            // unknown format
            ASSIMP_LOG_WARN("Unknown data object in animation of .x file");
            ParseUnknownDataObject();
        }
    }
}

// ------------------------------------------------------------------------------------------------
void XFileParser::ParseDataObjectTemplate() {
    // parse a template data object. Currently not stored.
    std::string name;
    readHeadOfDataObject(&name);

    // read GUID
    std::string guid = GetNextToken();

    // read and ignore data members
    bool running = true;
    while (running) {
        std::string s = GetNextToken();

        if (s == "}") {
            break;
        }

        if (s.length() == 0) {
            ThrowException("Unexpected end of file reached while parsing template definition");
        }
    }
}

// ------------------------------------------------------------------------------------------------
void XFileParser::ParseDataObjectFrame(Node *pParent) {
    // A coordinate frame, or "frame of reference." The Frame template
    // is open and can contain any object. The Direct3D extensions (D3DX)
    // mesh-loading functions recognize Mesh, FrameTransformMatrix, and
    // Frame template instances as child objects when loading a Frame
    // instance.
    std::string name;
    readHeadOfDataObject(&name);

    // create a named node and place it at its parent, if given
    Node *node = new Node(pParent);
    node->mName = name;
    if (pParent) {
        pParent->mChildren.push_back(node);
    } else {
        // there might be multiple root nodes
        if (mScene->mRootNode != nullptr) {
            // place a dummy root if not there
            if (mScene->mRootNode->mName != "$dummy_root") {
                Node *exroot = mScene->mRootNode;
                mScene->mRootNode = new Node(nullptr);
                mScene->mRootNode->mName = "$dummy_root";
                mScene->mRootNode->mChildren.push_back(exroot);
                exroot->mParent = mScene->mRootNode;
            }
            // put the new node as its child instead
            mScene->mRootNode->mChildren.push_back(node);
            node->mParent = mScene->mRootNode;
        } else {
            // it's the first node imported. place it as root
            mScene->mRootNode = node;
        }
    }

    // Now inside a frame.
    // read tokens until closing brace is reached.
    bool running = true;
    while (running) {
        std::string objectName = GetNextToken();
        if (objectName.size() == 0)
            ThrowException("Unexpected end of file reached while parsing frame");

        if (objectName == "}")
            break; // frame finished
        else if (objectName == "Frame")
            ParseDataObjectFrame(node); // child frame
        else if (objectName == "FrameTransformMatrix")
            ParseDataObjectTransformationMatrix(node->mTrafoMatrix);
        else if (objectName == "Mesh") {
            Mesh *mesh = new Mesh(name);
            node->mMeshes.push_back(mesh);
            ParseDataObjectMesh(mesh);
        } else {
            ASSIMP_LOG_WARN("Unknown data object in frame in x file");
            ParseUnknownDataObject();
        }
    }
}

// ------------------------------------------------------------------------------------------------
void XFileParser::ParseDataObjectTransformationMatrix(aiMatrix4x4 &pMatrix) {
    // read header, we're not interested if it has a name
    readHeadOfDataObject();

    // read its components
    pMatrix.a1 = ReadFloat();
    pMatrix.b1 = ReadFloat();
    pMatrix.c1 = ReadFloat();
    pMatrix.d1 = ReadFloat();
    pMatrix.a2 = ReadFloat();
    pMatrix.b2 = ReadFloat();
    pMatrix.c2 = ReadFloat();
    pMatrix.d2 = ReadFloat();
    pMatrix.a3 = ReadFloat();
    pMatrix.b3 = ReadFloat();
    pMatrix.c3 = ReadFloat();
    pMatrix.d3 = ReadFloat();
    pMatrix.a4 = ReadFloat();
    pMatrix.b4 = ReadFloat();
    pMatrix.c4 = ReadFloat();
    pMatrix.d4 = ReadFloat();

    // trailing symbols
    CheckForSemicolon();
    CheckForClosingBrace();
}

// ------------------------------------------------------------------------------------------------
void XFileParser::ParseDataObjectMesh(Mesh *pMesh) {
    std::string name;
    readHeadOfDataObject(&name);

    // read vertex count
    unsigned int numVertices = ReadInt();
    pMesh->mPositions.resize(numVertices);

    // read vertices
    for (unsigned int a = 0; a < numVertices; a++)
        pMesh->mPositions[a] = ReadVector3();

    // read position faces
    unsigned int numPosFaces = ReadInt();
    pMesh->mPosFaces.resize(numPosFaces);
    for (unsigned int a = 0; a < numPosFaces; ++a) {
        // read indices
        unsigned int numIndices = ReadInt();
        Face &face = pMesh->mPosFaces[a];
        for (unsigned int b = 0; b < numIndices; ++b) {
            const int idx(ReadInt());
            if (static_cast<unsigned int>(idx) <= numVertices) {
                face.mIndices.push_back(idx);
            }
        }
        TestForSeparator();
    }

    // here, other data objects may follow
    bool running = true;
    while (running) {
        std::string objectName = GetNextToken();

        if (objectName.empty())
            ThrowException("Unexpected end of file while parsing mesh structure");
        else if (objectName == "}")
            break; // mesh finished
        else if (objectName == "MeshNormals")
            ParseDataObjectMeshNormals(pMesh);
        else if (objectName == "MeshTextureCoords")
            ParseDataObjectMeshTextureCoords(pMesh);
        else if (objectName == "MeshVertexColors")
            ParseDataObjectMeshVertexColors(pMesh);
        else if (objectName == "MeshMaterialList")
            ParseDataObjectMeshMaterialList(pMesh);
        else if (objectName == "VertexDuplicationIndices")
            ParseUnknownDataObject(); // we'll ignore vertex duplication indices
        else if (objectName == "XSkinMeshHeader")
            ParseDataObjectSkinMeshHeader(pMesh);
        else if (objectName == "SkinWeights")
            ParseDataObjectSkinWeights(pMesh);
        else {
            ASSIMP_LOG_WARN("Unknown data object in mesh in x file");
            ParseUnknownDataObject();
        }
    }
}

// ------------------------------------------------------------------------------------------------
void XFileParser::ParseDataObjectSkinWeights(Mesh *pMesh) {
    if (nullptr == pMesh) {
        return;
    }
    readHeadOfDataObject();

    std::string transformNodeName;
    GetNextTokenAsString(transformNodeName);

    pMesh->mBones.emplace_back();
    Bone &bone = pMesh->mBones.back();
    bone.mName = transformNodeName;

    // read vertex weights
    unsigned int numWeights = ReadInt();
    bone.mWeights.reserve(numWeights);

    for (unsigned int a = 0; a < numWeights; a++) {
        BoneWeight weight = {};
        weight.mVertex = ReadInt();
        bone.mWeights.push_back(weight);
    }

    // read vertex weights
    for (unsigned int a = 0; a < numWeights; a++)
        bone.mWeights[a].mWeight = ReadFloat();

    // read matrix offset
    bone.mOffsetMatrix.a1 = ReadFloat();
    bone.mOffsetMatrix.b1 = ReadFloat();
    bone.mOffsetMatrix.c1 = ReadFloat();
    bone.mOffsetMatrix.d1 = ReadFloat();
    bone.mOffsetMatrix.a2 = ReadFloat();
    bone.mOffsetMatrix.b2 = ReadFloat();
    bone.mOffsetMatrix.c2 = ReadFloat();
    bone.mOffsetMatrix.d2 = ReadFloat();
    bone.mOffsetMatrix.a3 = ReadFloat();
    bone.mOffsetMatrix.b3 = ReadFloat();
    bone.mOffsetMatrix.c3 = ReadFloat();
    bone.mOffsetMatrix.d3 = ReadFloat();
    bone.mOffsetMatrix.a4 = ReadFloat();
    bone.mOffsetMatrix.b4 = ReadFloat();
    bone.mOffsetMatrix.c4 = ReadFloat();
    bone.mOffsetMatrix.d4 = ReadFloat();

    CheckForSemicolon();
    CheckForClosingBrace();
}

// ------------------------------------------------------------------------------------------------
void XFileParser::ParseDataObjectSkinMeshHeader(Mesh * /*pMesh*/) {
    readHeadOfDataObject();

    /*unsigned int maxSkinWeightsPerVertex =*/ReadInt();
    /*unsigned int maxSkinWeightsPerFace =*/ReadInt();
    /*unsigned int numBonesInMesh = */ ReadInt();

    CheckForClosingBrace();
}

// ------------------------------------------------------------------------------------------------
void XFileParser::ParseDataObjectMeshNormals(Mesh *pMesh) {
    readHeadOfDataObject();

    // read count
    unsigned int numNormals = ReadInt();
    pMesh->mNormals.resize(numNormals);

    // read normal vectors
    for (unsigned int a = 0; a < numNormals; ++a) {
        pMesh->mNormals[a] = ReadVector3();
    }

    // read normal indices
    unsigned int numFaces = ReadInt();
    if (numFaces != pMesh->mPosFaces.size()) {
        ThrowException("Normal face count does not match vertex face count.");
    }

    // do not crah when no face definitions are there
    if (numFaces > 0) {
        // normal face creation
        pMesh->mNormFaces.resize(numFaces);
        for (unsigned int a = 0; a < numFaces; ++a) {
            unsigned int numIndices = ReadInt();
            pMesh->mNormFaces[a] = Face();
            Face &face = pMesh->mNormFaces[a];
            for (unsigned int b = 0; b < numIndices; ++b) {
                face.mIndices.push_back(ReadInt());
            }

            TestForSeparator();
        }
    }

    CheckForClosingBrace();
}

// ------------------------------------------------------------------------------------------------
void XFileParser::ParseDataObjectMeshTextureCoords(Mesh *pMesh) {
    readHeadOfDataObject();
    if (pMesh->mNumTextures + 1 > AI_MAX_NUMBER_OF_TEXTURECOORDS)
        ThrowException("Too many sets of texture coordinates");

    std::vector<aiVector2D> &coords = pMesh->mTexCoords[pMesh->mNumTextures++];

    unsigned int numCoords = ReadInt();
    if (numCoords != pMesh->mPositions.size())
        ThrowException("Texture coord count does not match vertex count");

    coords.resize(numCoords);
    for (unsigned int a = 0; a < numCoords; a++)
        coords[a] = ReadVector2();

    CheckForClosingBrace();
}

// ------------------------------------------------------------------------------------------------
void XFileParser::ParseDataObjectMeshVertexColors(Mesh *pMesh) {
    readHeadOfDataObject();
    if (pMesh->mNumColorSets + 1 > AI_MAX_NUMBER_OF_COLOR_SETS)
        ThrowException("Too many colorsets");
    std::vector<aiColor4D> &colors = pMesh->mColors[pMesh->mNumColorSets++];

    unsigned int numColors = ReadInt();
    if (numColors != pMesh->mPositions.size())
        ThrowException("Vertex color count does not match vertex count");

    colors.resize(numColors, aiColor4D(0, 0, 0, 1));
    for (unsigned int a = 0; a < numColors; a++) {
        unsigned int index = ReadInt();
        if (index >= pMesh->mPositions.size())
            ThrowException("Vertex color index out of bounds");

        colors[index] = ReadRGBA();
        // HACK: (thom) Maxon Cinema XPort plugin puts a third separator here, kwxPort puts a comma.
        // Ignore gracefully.
        if (!mIsBinaryFormat) {
            FindNextNoneWhiteSpace();
            if (*mP == ';' || *mP == ',')
                mP++;
        }
    }

    CheckForClosingBrace();
}

// ------------------------------------------------------------------------------------------------
void XFileParser::ParseDataObjectMeshMaterialList(Mesh *pMesh) {
    readHeadOfDataObject();

    // read material count
    /*unsigned int numMaterials =*/ReadInt();
    // read non triangulated face material index count
    unsigned int numMatIndices = ReadInt();

    // some models have a material index count of 1... to be able to read them we
    // replicate this single material index on every face
    if (numMatIndices != pMesh->mPosFaces.size() && numMatIndices != 1)
        ThrowException("Per-Face material index count does not match face count.");

    // read per-face material indices
    for (unsigned int a = 0; a < numMatIndices; a++)
        pMesh->mFaceMaterials.push_back(ReadInt());

    // in version 03.02, the face indices end with two semicolons.
    // commented out version check, as version 03.03 exported from blender also has 2 semicolons
    if (!mIsBinaryFormat) // && MajorVersion == 3 && MinorVersion <= 2)
    {
        if (mP < mEnd && *mP == ';')
            ++mP;
    }

    // if there was only a single material index, replicate it on all faces
    while (pMesh->mFaceMaterials.size() < pMesh->mPosFaces.size())
        pMesh->mFaceMaterials.push_back(pMesh->mFaceMaterials.front());

    // read following data objects
    bool running = true;
    while (running) {
        std::string objectName = GetNextToken();
        if (objectName.size() == 0)
            ThrowException("Unexpected end of file while parsing mesh material list.");
        else if (objectName == "}")
            break; // material list finished
        else if (objectName == "{") {
            // template materials
            std::string matName = GetNextToken();
            Material material;
            material.mIsReference = true;
            material.mName = matName;
            pMesh->mMaterials.push_back(material);

            CheckForClosingBrace(); // skip }
        } else if (objectName == "Material") {
            pMesh->mMaterials.emplace_back();
            ParseDataObjectMaterial(&pMesh->mMaterials.back());
        } else if (objectName == ";") {
            // ignore
        } else {
            ASSIMP_LOG_WARN("Unknown data object in material list in x file");
            ParseUnknownDataObject();
        }
    }
}

// ------------------------------------------------------------------------------------------------
void XFileParser::ParseDataObjectMaterial(Material *pMaterial) {
    std::string matName;
    readHeadOfDataObject(&matName);
    if (matName.empty())
        matName = std::string("material") + ai_to_string(mLineNumber);
    pMaterial->mName = matName;
    pMaterial->mIsReference = false;

    // read material values
    pMaterial->mDiffuse = ReadRGBA();
    pMaterial->mSpecularExponent = ReadFloat();
    pMaterial->mSpecular = ReadRGB();
    pMaterial->mEmissive = ReadRGB();

    // read other data objects
    bool running = true;
    while (running) {
        std::string objectName = GetNextToken();
        if (objectName.size() == 0)
            ThrowException("Unexpected end of file while parsing mesh material");
        else if (objectName == "}")
            break; // material finished
        else if (objectName == "TextureFilename" || objectName == "TextureFileName") {
            // some exporters write "TextureFileName" instead.
            std::string texname;
            ParseDataObjectTextureFilename(texname);
            pMaterial->mTextures.emplace_back(texname);
        } else if (objectName == "NormalmapFilename" || objectName == "NormalmapFileName") {
            // one exporter writes out the normal map in a separate filename tag
            std::string texname;
            ParseDataObjectTextureFilename(texname);
            pMaterial->mTextures.emplace_back(texname, true);
        } else {
            ASSIMP_LOG_WARN("Unknown data object in material in x file");
            ParseUnknownDataObject();
        }
    }
}

// ------------------------------------------------------------------------------------------------
void XFileParser::ParseDataObjectAnimTicksPerSecond() {
    readHeadOfDataObject();
    mScene->mAnimTicksPerSecond = ReadInt();
    CheckForClosingBrace();
}

// ------------------------------------------------------------------------------------------------
void XFileParser::ParseDataObjectAnimationSet() {
    std::string animName;
    readHeadOfDataObject(&animName);

    Animation *anim = new Animation;
    mScene->mAnims.push_back(anim);
    anim->mName = animName;

    bool running = true;
    while (running) {
        std::string objectName = GetNextToken();
        if (objectName.length() == 0)
            ThrowException("Unexpected end of file while parsing animation set.");
        else if (objectName == "}")
            break; // animation set finished
        else if (objectName == "Animation")
            ParseDataObjectAnimation(anim);
        else {
            ASSIMP_LOG_WARN("Unknown data object in animation set in x file");
            ParseUnknownDataObject();
        }
    }
}

// ------------------------------------------------------------------------------------------------
void XFileParser::ParseDataObjectAnimation(Animation *pAnim) {
    readHeadOfDataObject();
    AnimBone *banim = new AnimBone;
    pAnim->mAnims.push_back(banim);

    bool running = true;
    while (running) {
        std::string objectName = GetNextToken();

        if (objectName.length() == 0)
            ThrowException("Unexpected end of file while parsing animation.");
        else if (objectName == "}")
            break; // animation finished
        else if (objectName == "AnimationKey")
            ParseDataObjectAnimationKey(banim);
        else if (objectName == "AnimationOptions")
            ParseUnknownDataObject(); // not interested
        else if (objectName == "{") {
            // read frame name
            banim->mBoneName = GetNextToken();
            CheckForClosingBrace();
        } else {
            ASSIMP_LOG_WARN("Unknown data object in animation in x file");
            ParseUnknownDataObject();
        }
    }
}

// ------------------------------------------------------------------------------------------------
void XFileParser::ParseDataObjectAnimationKey(AnimBone *pAnimBone) {
    readHeadOfDataObject();

    // read key type
    unsigned int keyType = ReadInt();

    // read number of keys
    unsigned int numKeys = ReadInt();

    for (unsigned int a = 0; a < numKeys; a++) {
        // read time
        unsigned int time = ReadInt();

        // read keys
        switch (keyType) {
        case 0: // rotation quaternion
        {
            // read count
            if (ReadInt() != 4)
                ThrowException("Invalid number of arguments for quaternion key in animation");

            aiQuatKey key;
            key.mTime = double(time);
            key.mValue.w = ReadFloat();
            key.mValue.x = ReadFloat();
            key.mValue.y = ReadFloat();
            key.mValue.z = ReadFloat();
            pAnimBone->mRotKeys.push_back(key);

            CheckForSemicolon();
            break;
        }

        case 1: // scale vector
        case 2: // position vector
        {
            // read count
            if (ReadInt() != 3)
                ThrowException("Invalid number of arguments for vector key in animation");

            aiVectorKey key;
            key.mTime = double(time);
            key.mValue = ReadVector3();

            if (keyType == 2)
                pAnimBone->mPosKeys.push_back(key);
            else
                pAnimBone->mScaleKeys.push_back(key);

            break;
        }

        case 3: // combined transformation matrix
        case 4: // denoted both as 3 or as 4
        {
            // read count
            if (ReadInt() != 16)
                ThrowException("Invalid number of arguments for matrix key in animation");

            // read matrix
            MatrixKey key;
            key.mTime = double(time);
            key.mMatrix.a1 = ReadFloat();
            key.mMatrix.b1 = ReadFloat();
            key.mMatrix.c1 = ReadFloat();
            key.mMatrix.d1 = ReadFloat();
            key.mMatrix.a2 = ReadFloat();
            key.mMatrix.b2 = ReadFloat();
            key.mMatrix.c2 = ReadFloat();
            key.mMatrix.d2 = ReadFloat();
            key.mMatrix.a3 = ReadFloat();
            key.mMatrix.b3 = ReadFloat();
            key.mMatrix.c3 = ReadFloat();
            key.mMatrix.d3 = ReadFloat();
            key.mMatrix.a4 = ReadFloat();
            key.mMatrix.b4 = ReadFloat();
            key.mMatrix.c4 = ReadFloat();
            key.mMatrix.d4 = ReadFloat();
            pAnimBone->mTrafoKeys.push_back(key);

            CheckForSemicolon();
            break;
        }

        default:
            ThrowException("Unknown key type ", keyType, " in animation.");
        } // end switch

        // key separator
        CheckForSeparator();
    }

    CheckForClosingBrace();
}

// ------------------------------------------------------------------------------------------------
void XFileParser::ParseDataObjectTextureFilename(std::string &pName) {
    readHeadOfDataObject();
    GetNextTokenAsString(pName);
    CheckForClosingBrace();

    // FIX: some files (e.g. AnimationTest.x) have "" as texture file name
    if (!pName.length()) {
        ASSIMP_LOG_WARN("Length of texture file name is zero. Skipping this texture.");
    }

    // some exporters write double backslash paths out. We simply replace them if we find them
    while (pName.find("\\\\") != std::string::npos)
        pName.replace(pName.find("\\\\"), 2, "\\");
}

// ------------------------------------------------------------------------------------------------
void XFileParser::ParseUnknownDataObject() {
    // find opening delimiter
    bool running = true;
    while (running) {
        std::string t = GetNextToken();
        if (t.length() == 0)
            ThrowException("Unexpected end of file while parsing unknown segment.");

        if (t == "{")
            break;
    }

    unsigned int counter = 1;

    // parse until closing delimiter
    while (counter > 0) {
        std::string t = GetNextToken();

        if (t.length() == 0)
            ThrowException("Unexpected end of file while parsing unknown segment.");

        if (t == "{")
            ++counter;
        else if (t == "}")
            --counter;
    }
}

// ------------------------------------------------------------------------------------------------
//! checks for closing curly brace
void XFileParser::CheckForClosingBrace() {
    if (GetNextToken() != "}")
        ThrowException("Closing brace expected.");
}

// ------------------------------------------------------------------------------------------------
//! checks for one following semicolon
void XFileParser::CheckForSemicolon() {
    if (mIsBinaryFormat)
        return;

    if (GetNextToken() != ";")
        ThrowException("Semicolon expected.");
}

// ------------------------------------------------------------------------------------------------
//! checks for a separator char, either a ',' or a ';'
void XFileParser::CheckForSeparator() {
    if (mIsBinaryFormat)
        return;

    std::string token = GetNextToken();
    if (token != "," && token != ";")
        ThrowException("Separator character (';' or ',') expected.");
}

// ------------------------------------------------------------------------------------------------
// tests and possibly consumes a separator char, but does nothing if there was no separator
void XFileParser::TestForSeparator() {
    if (mIsBinaryFormat)
        return;

    FindNextNoneWhiteSpace();
    if (mP >= mEnd)
        return;

    // test and skip
    if (*mP == ';' || *mP == ',')
        mP++;
}

// ------------------------------------------------------------------------------------------------
void XFileParser::readHeadOfDataObject(std::string *poName) {
    std::string nameOrBrace = GetNextToken();
    if (nameOrBrace != "{") {
        if (poName)
            *poName = nameOrBrace;

        if (GetNextToken() != "{") {
            delete mScene;
            ThrowException("Opening brace expected.");
        }
    }
}

// ------------------------------------------------------------------------------------------------
std::string XFileParser::GetNextToken() {
    std::string s;

    // process binary-formatted file
    if (mIsBinaryFormat) {
        // in binary mode it will only return NAME and STRING token
        // and (correctly) skip over other tokens.
        if (mEnd - mP < 2) {
            return s;
        }
        unsigned int tok = ReadBinWord();
        unsigned int len;

        // standalone tokens
        switch (tok) {
        case 1: {
            // name token
            if (mEnd - mP < 4) {
                return s;
            }
            len = ReadBinDWord();
            const int bounds = int(mEnd - mP);
            const int iLen = int(len);
            if (iLen < 0) {
                return s;
            }
            if (bounds < iLen) {
                return s;
            }
            s = std::string(mP, len);
            mP += len;
        }
            return s;

        case 2:
            // string token
            if (mEnd - mP < 4) return s;
            len = ReadBinDWord();
            if (mEnd - mP < int(len)) return s;
            s = std::string(mP, len);
            mP += (len + 2);
            return s;
        case 3:
            // integer token
            mP += 4;
            return "<integer>";
        case 5:
            // GUID token
            mP += 16;
            return "<guid>";
        case 6:
            if (mEnd - mP < 4) return s;
            len = ReadBinDWord();
            mP += (len * 4);
            return "<int_list>";
        case 7:
            if (mEnd - mP < 4) return s;
            len = ReadBinDWord();
            mP += (len * mBinaryFloatSize);
            return "<flt_list>";
        case 0x0a:
            return "{";
        case 0x0b:
            return "}";
        case 0x0c:
            return "(";
        case 0x0d:
            return ")";
        case 0x0e:
            return "[";
        case 0x0f:
            return "]";
        case 0x10:
            return "<";
        case 0x11:
            return ">";
        case 0x12:
            return ".";
        case 0x13:
            return ",";
        case 0x14:
            return ";";
        case 0x1f:
            return "template";
        case 0x28:
            return "WORD";
        case 0x29:
            return "DWORD";
        case 0x2a:
            return "FLOAT";
        case 0x2b:
            return "DOUBLE";
        case 0x2c:
            return "CHAR";
        case 0x2d:
            return "UCHAR";
        case 0x2e:
            return "SWORD";
        case 0x2f:
            return "SDWORD";
        case 0x30:
            return "void";
        case 0x31:
            return "string";
        case 0x32:
            return "unicode";
        case 0x33:
            return "cstring";
        case 0x34:
            return "array";
        }
    }
    // process text-formatted file
    else {
        FindNextNoneWhiteSpace();
        if (mP >= mEnd)
            return s;

        while ((mP < mEnd) && !isspace((unsigned char)*mP)) {
            // either keep token delimiters when already holding a token, or return if first valid char
            if (*mP == ';' || *mP == '}' || *mP == '{' || *mP == ',') {
                if (!s.size())
                    s.append(mP++, 1);
                break; // stop for delimiter
            }
            s.append(mP++, 1);
        }
    }
    return s;
}

// ------------------------------------------------------------------------------------------------
void XFileParser::FindNextNoneWhiteSpace() {
    if (mIsBinaryFormat)
        return;

    bool running = true;
    while (running) {
        while (mP < mEnd && isspace((unsigned char)*mP)) {
            if (*mP == '\n')
                mLineNumber++;
            ++mP;
        }

        if (mP >= mEnd)
            return;

        // check if this is a comment
        if ((mP[0] == '/' && mP[1] == '/') || mP[0] == '#')
            ReadUntilEndOfLine();
        else
            break;
    }
}

// ------------------------------------------------------------------------------------------------
void XFileParser::GetNextTokenAsString(std::string &poString) {
    if (mIsBinaryFormat) {
        poString = GetNextToken();
        return;
    }

    FindNextNoneWhiteSpace();
    if (mP >= mEnd) {
        delete mScene;
        ThrowException("Unexpected end of file while parsing string");
    }

    if (*mP != '"') {
        delete mScene;
        ThrowException("Expected quotation mark.");
    }
    ++mP;

    while (mP < mEnd && *mP != '"')
        poString.append(mP++, 1);

    if (mP >= mEnd - 1) {
        delete mScene;
        ThrowException("Unexpected end of file while parsing string");
    }

    if (mP[1] != ';' || mP[0] != '"') {
        delete mScene;
        ThrowException("Expected quotation mark and semicolon at the end of a string.");
    }
    mP += 2;
}

// ------------------------------------------------------------------------------------------------
void XFileParser::ReadUntilEndOfLine() {
    if (mIsBinaryFormat)
        return;

    while (mP < mEnd) {
        if (*mP == '\n' || *mP == '\r') {
            ++mP;
            mLineNumber++;
            return;
        }

        ++mP;
    }
}

// ------------------------------------------------------------------------------------------------
unsigned short XFileParser::ReadBinWord() {
    ai_assert(mEnd - mP >= 2);
    const unsigned char *q = (const unsigned char *)mP;
    unsigned short tmp = q[0] | (q[1] << 8);
    mP += 2;
    return tmp;
}

// ------------------------------------------------------------------------------------------------
unsigned int XFileParser::ReadBinDWord() {
    ai_assert(mEnd - mP >= 4);

    const unsigned char *q = (const unsigned char *)mP;
    unsigned int tmp = q[0] | (q[1] << 8) | (q[2] << 16) | (q[3] << 24);
    mP += 4;
    return tmp;
}

// ------------------------------------------------------------------------------------------------
unsigned int XFileParser::ReadInt() {
    if (mIsBinaryFormat) {
        if (mBinaryNumCount == 0 && mEnd - mP >= 2) {
            unsigned short tmp = ReadBinWord(); // 0x06 or 0x03
            if (tmp == 0x06 && mEnd - mP >= 4) // array of ints follows
                mBinaryNumCount = ReadBinDWord();
            else // single int follows
                mBinaryNumCount = 1;
        }

        --mBinaryNumCount;
        const size_t len(mEnd - mP);
        if (len >= 4) {
            return ReadBinDWord();
        } else {
            mP = mEnd;
            return 0;
        }
    } else {
        FindNextNoneWhiteSpace();

        // TODO: consider using strtol10 instead???

        // check preceding minus sign
        bool isNegative = false;
        if (*mP == '-') {
            isNegative = true;
            mP++;
        }

        // at least one digit expected
        if (!isdigit((unsigned char)*mP))
            ThrowException("Number expected.");

        // read digits
        unsigned int number = 0;
        while (mP < mEnd) {
            if (!isdigit((unsigned char)*mP))
                break;
            number = number * 10 + (*mP - 48);
            mP++;
        }

        CheckForSeparator();

        return isNegative ? ((unsigned int)-int(number)) : number;
    }
}

// ------------------------------------------------------------------------------------------------
ai_real XFileParser::ReadFloat() {
    if (mIsBinaryFormat) {
        if (mBinaryNumCount == 0 && mEnd - mP >= 2) {
            unsigned short tmp = ReadBinWord(); // 0x07 or 0x42
            if (tmp == 0x07 && mEnd - mP >= 4) // array of floats following
                mBinaryNumCount = ReadBinDWord();
            else // single float following
                mBinaryNumCount = 1;
        }

        --mBinaryNumCount;
        if (mBinaryFloatSize == 8) {
            if (mEnd - mP >= 8) {
                double res;
                ::memcpy(&res, mP, 8);
                mP += 8;
                const ai_real result(static_cast<ai_real>(res));
                return result;
            } else {
                mP = mEnd;
                return 0;
            }
        } else {
            if (mEnd - mP >= 4) {
                ai_real result;
                ::memcpy(&result, mP, 4);
                mP += 4;
                return result;
            } else {
                mP = mEnd;
                return 0;
            }
        }
    }

    // text version
    FindNextNoneWhiteSpace();
    // check for various special strings to allow reading files from faulty exporters
    // I mean you, Blender!
    // Reading is safe because of the terminating zero
    if (strncmp(mP, "-1.#IND00", 9) == 0 || strncmp(mP, "1.#IND00", 8) == 0) {
        mP += 9;
        CheckForSeparator();
        return 0.0;
    } else if (strncmp(mP, "1.#QNAN0", 8) == 0) {
        mP += 8;
        CheckForSeparator();
        return 0.0;
    }

    ai_real result = 0.0;
    mP = fast_atoreal_move(mP, result);

    CheckForSeparator();

    return result;
}

// ------------------------------------------------------------------------------------------------
aiVector2D XFileParser::ReadVector2() {
    aiVector2D vector;
    vector.x = ReadFloat();
    vector.y = ReadFloat();
    TestForSeparator();

    return vector;
}

// ------------------------------------------------------------------------------------------------
aiVector3D XFileParser::ReadVector3() {
    aiVector3D vector;
    vector.x = ReadFloat();
    vector.y = ReadFloat();
    vector.z = ReadFloat();
    TestForSeparator();

    return vector;
}

// ------------------------------------------------------------------------------------------------
aiColor4D XFileParser::ReadRGBA() {
    aiColor4D color;
    color.r = ReadFloat();
    color.g = ReadFloat();
    color.b = ReadFloat();
    color.a = ReadFloat();
    TestForSeparator();

    return color;
}

// ------------------------------------------------------------------------------------------------
aiColor3D XFileParser::ReadRGB() {
    aiColor3D color;
    color.r = ReadFloat();
    color.g = ReadFloat();
    color.b = ReadFloat();
    TestForSeparator();

    return color;
}

// ------------------------------------------------------------------------------------------------
// Filters the imported hierarchy for some degenerated cases that some exporters produce.
void XFileParser::FilterHierarchy(XFile::Node *pNode) {
    // if the node has just a single unnamed child containing a mesh, remove
    // the anonymous node between. The 3DSMax kwXport plugin seems to produce this
    // mess in some cases
    if (pNode->mChildren.size() == 1 && pNode->mMeshes.empty()) {
        XFile::Node *child = pNode->mChildren.front();
        if (child->mName.length() == 0 && child->mMeshes.size() > 0) {
            // transfer its meshes to us
            for (unsigned int a = 0; a < child->mMeshes.size(); a++)
                pNode->mMeshes.push_back(child->mMeshes[a]);
            child->mMeshes.clear();

            // transfer the transform as well
            pNode->mTrafoMatrix = pNode->mTrafoMatrix * child->mTrafoMatrix;

            // then kill it
            delete child;
            pNode->mChildren.clear();
        }
    }

    // recurse
    for (unsigned int a = 0; a < pNode->mChildren.size(); a++)
        FilterHierarchy(pNode->mChildren[a]);
}

#endif // !! ASSIMP_BUILD_NO_X_IMPORTER
