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---------------------------------------------------------------------------
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/** @file  ValidateDataStructure.cpp
 *  @brief Implementation of the post processing step to validate
 *    the data structure returned by Assimp.
 */



// internal headers
#include "ValidateDataStructure.h"
#include "BaseImporter.h"
#include "fast_atof.h"
#include "ProcessHelper.h"
#include <memory>

// CRT headers
#include <stdarg.h>

using namespace Assimp;

// ------------------------------------------------------------------------------------------------
// Constructor to be privately used by Importer
ValidateDSProcess::ValidateDSProcess() :
    mScene()
{}

// ------------------------------------------------------------------------------------------------
// Destructor, private as well
ValidateDSProcess::~ValidateDSProcess()
{}

// ------------------------------------------------------------------------------------------------
// Returns whether the processing step is present in the given flag field.
bool ValidateDSProcess::IsActive( unsigned int pFlags) const
{
    return (pFlags & aiProcess_ValidateDataStructure) != 0;
}
// ------------------------------------------------------------------------------------------------
AI_WONT_RETURN void ValidateDSProcess::ReportError(const char* msg,...)
{
    ai_assert(NULL != msg);

    va_list args;
    va_start(args,msg);

    char szBuffer[3000];
    const int iLen = vsprintf(szBuffer,msg,args);
    ai_assert(iLen > 0);

    va_end(args);
#ifdef ASSIMP_BUILD_DEBUG
    ai_assert( false );
#endif
    throw DeadlyImportError("Validation failed: " + std::string(szBuffer,iLen));
}
// ------------------------------------------------------------------------------------------------
void ValidateDSProcess::ReportWarning(const char* msg,...)
{
    ai_assert(NULL != msg);

    va_list args;
    va_start(args,msg);

    char szBuffer[3000];
    const int iLen = vsprintf(szBuffer,msg,args);
    ai_assert(iLen > 0);

    va_end(args);
    DefaultLogger::get()->warn("Validation warning: " + std::string(szBuffer,iLen));
}

// ------------------------------------------------------------------------------------------------
inline int HasNameMatch(const aiString& in, aiNode* node)
{
    int result = (node->mName == in ? 1 : 0 );
    for (unsigned int i = 0; i < node->mNumChildren;++i)    {
        result += HasNameMatch(in,node->mChildren[i]);
    }
    return result;
}

// ------------------------------------------------------------------------------------------------
template <typename T>
inline void ValidateDSProcess::DoValidation(T** parray, unsigned int size,
    const char* firstName, const char* secondName)
{
    // validate all entries
    if (size)
    {
        if (!parray)
        {
            ReportError("aiScene::%s is NULL (aiScene::%s is %i)",
                firstName, secondName, size);
        }
        for (unsigned int i = 0; i < size;++i)
        {
            if (!parray[i])
            {
                ReportError("aiScene::%s[%i] is NULL (aiScene::%s is %i)",
                    firstName,i,secondName,size);
            }
            Validate(parray[i]);
        }
    }
}

// ------------------------------------------------------------------------------------------------
template <typename T>
inline void ValidateDSProcess::DoValidationEx(T** parray, unsigned int size,
    const char* firstName, const char* secondName)
{
    // validate all entries
    if (size)
    {
        if (!parray)    {
            ReportError("aiScene::%s is NULL (aiScene::%s is %i)",
                firstName, secondName, size);
        }
        for (unsigned int i = 0; i < size;++i)
        {
            if (!parray[i])
            {
                ReportError("aiScene::%s[%i] is NULL (aiScene::%s is %i)",
                    firstName,i,secondName,size);
            }
            Validate(parray[i]);

            // check whether there are duplicate names
            for (unsigned int a = i+1; a < size;++a)
            {
                if (parray[i]->mName == parray[a]->mName)
                {
                    this->ReportError("aiScene::%s[%i] has the same name as "
                        "aiScene::%s[%i]",firstName, i,secondName, a);
                }
            }
        }
    }
}

// ------------------------------------------------------------------------------------------------
template <typename T>
inline void ValidateDSProcess::DoValidationWithNameCheck(T** array,
    unsigned int size, const char* firstName,
    const char* secondName)
{
    // validate all entries
    DoValidationEx(array,size,firstName,secondName);

    for (unsigned int i = 0; i < size;++i)
    {
        int res = HasNameMatch(array[i]->mName,mScene->mRootNode);
        if (!res)   {
            ReportError("aiScene::%s[%i] has no corresponding node in the scene graph (%s)",
                firstName,i,array[i]->mName.data);
        }
        else if (1 != res)  {
            ReportError("aiScene::%s[%i]: there are more than one nodes with %s as name",
                firstName,i,array[i]->mName.data);
        }
    }
}

// ------------------------------------------------------------------------------------------------
// Executes the post processing step on the given imported data.
void ValidateDSProcess::Execute( aiScene* pScene)
{
    this->mScene = pScene;
    DefaultLogger::get()->debug("ValidateDataStructureProcess begin");

    // validate the node graph of the scene
    Validate(pScene->mRootNode);

    // validate all meshes
    if (pScene->mNumMeshes) {
        DoValidation(pScene->mMeshes,pScene->mNumMeshes,"mMeshes","mNumMeshes");
    }
    else if (!(mScene->mFlags & AI_SCENE_FLAGS_INCOMPLETE)) {
        ReportError("aiScene::mNumMeshes is 0. At least one mesh must be there");
    }
    else if (pScene->mMeshes)   {
        ReportError("aiScene::mMeshes is non-null although there are no meshes");
    }

    // validate all animations
    if (pScene->mNumAnimations) {
        DoValidation(pScene->mAnimations,pScene->mNumAnimations,
            "mAnimations","mNumAnimations");
    }
    else if (pScene->mAnimations)   {
        ReportError("aiScene::mAnimations is non-null although there are no animations");
    }

    // validate all cameras
    if (pScene->mNumCameras) {
        DoValidationWithNameCheck(pScene->mCameras,pScene->mNumCameras,
            "mCameras","mNumCameras");
    }
    else if (pScene->mCameras)  {
        ReportError("aiScene::mCameras is non-null although there are no cameras");
    }

    // validate all lights
    if (pScene->mNumLights) {
        DoValidationWithNameCheck(pScene->mLights,pScene->mNumLights,
            "mLights","mNumLights");
    }
    else if (pScene->mLights)   {
        ReportError("aiScene::mLights is non-null although there are no lights");
    }

    // validate all textures
    if (pScene->mNumTextures) {
        DoValidation(pScene->mTextures,pScene->mNumTextures,
            "mTextures","mNumTextures");
    }
    else if (pScene->mTextures) {
        ReportError("aiScene::mTextures is non-null although there are no textures");
    }

    // validate all materials
    if (pScene->mNumMaterials) {
        DoValidation(pScene->mMaterials,pScene->mNumMaterials,"mMaterials","mNumMaterials");
    }
#if 0
    // NOTE: ScenePreprocessor generates a default material if none is there
    else if (!(mScene->mFlags & AI_SCENE_FLAGS_INCOMPLETE)) {
        ReportError("aiScene::mNumMaterials is 0. At least one material must be there");
    }
#endif
    else if (pScene->mMaterials)    {
        ReportError("aiScene::mMaterials is non-null although there are no materials");
    }

//  if (!has)ReportError("The aiScene data structure is empty");
    DefaultLogger::get()->debug("ValidateDataStructureProcess end");
}

// ------------------------------------------------------------------------------------------------
void ValidateDSProcess::Validate( const aiLight* pLight)
{
    if (pLight->mType == aiLightSource_UNDEFINED)
        ReportWarning("aiLight::mType is aiLightSource_UNDEFINED");

    if (!pLight->mAttenuationConstant &&
        !pLight->mAttenuationLinear   &&
        !pLight->mAttenuationQuadratic) {
        ReportWarning("aiLight::mAttenuationXXX - all are zero");
    }

    if (pLight->mAngleInnerCone > pLight->mAngleOuterCone)
        ReportError("aiLight::mAngleInnerCone is larger than aiLight::mAngleOuterCone");

    if (pLight->mColorDiffuse.IsBlack() && pLight->mColorAmbient.IsBlack()
        && pLight->mColorSpecular.IsBlack())
    {
        ReportWarning("aiLight::mColorXXX - all are black and won't have any influence");
    }
}

// ------------------------------------------------------------------------------------------------
void ValidateDSProcess::Validate( const aiCamera* pCamera)
{
    if (pCamera->mClipPlaneFar <= pCamera->mClipPlaneNear)
        ReportError("aiCamera::mClipPlaneFar must be >= aiCamera::mClipPlaneNear");

    // FIX: there are many 3ds files with invalid FOVs. No reason to
    // reject them at all ... a warning is appropriate.
    if (!pCamera->mHorizontalFOV || pCamera->mHorizontalFOV >= (float)AI_MATH_PI)
        ReportWarning("%f is not a valid value for aiCamera::mHorizontalFOV",pCamera->mHorizontalFOV);
}

// ------------------------------------------------------------------------------------------------
void ValidateDSProcess::Validate( const aiMesh* pMesh)
{
    // validate the material index of the mesh
    if (mScene->mNumMaterials && pMesh->mMaterialIndex >= mScene->mNumMaterials)
    {
        ReportError("aiMesh::mMaterialIndex is invalid (value: %i maximum: %i)",
            pMesh->mMaterialIndex,mScene->mNumMaterials-1);
    }

    Validate(&pMesh->mName);

    for (unsigned int i = 0; i < pMesh->mNumFaces; ++i)
    {
        aiFace& face = pMesh->mFaces[i];

        if (pMesh->mPrimitiveTypes)
        {
            switch (face.mNumIndices)
            {
            case 0:
                ReportError("aiMesh::mFaces[%i].mNumIndices is 0",i);
            case 1:
                if (0 == (pMesh->mPrimitiveTypes & aiPrimitiveType_POINT))
                {
                    ReportError("aiMesh::mFaces[%i] is a POINT but aiMesh::mPrimtiveTypes "
                        "does not report the POINT flag",i);
                }
                break;
            case 2:
                if (0 == (pMesh->mPrimitiveTypes & aiPrimitiveType_LINE))
                {
                    ReportError("aiMesh::mFaces[%i] is a LINE but aiMesh::mPrimtiveTypes "
                        "does not report the LINE flag",i);
                }
                break;
            case 3:
                if (0 == (pMesh->mPrimitiveTypes & aiPrimitiveType_TRIANGLE))
                {
                    ReportError("aiMesh::mFaces[%i] is a TRIANGLE but aiMesh::mPrimtiveTypes "
                        "does not report the TRIANGLE flag",i);
                }
                break;
            default:
                if (0 == (pMesh->mPrimitiveTypes & aiPrimitiveType_POLYGON))
                {
                    this->ReportError("aiMesh::mFaces[%i] is a POLYGON but aiMesh::mPrimtiveTypes "
                        "does not report the POLYGON flag",i);
                }
                break;
            };
        }

        if (!face.mIndices)
            ReportError("aiMesh::mFaces[%i].mIndices is NULL",i);
    }

    // positions must always be there ...
    if (!pMesh->mNumVertices || (!pMesh->mVertices && !mScene->mFlags)) {
        ReportError("The mesh contains no vertices");
    }

    if (pMesh->mNumVertices > AI_MAX_VERTICES) {
        ReportError("Mesh has too many vertices: %u, but the limit is %u",pMesh->mNumVertices,AI_MAX_VERTICES);
    }
    if (pMesh->mNumFaces > AI_MAX_FACES) {
        ReportError("Mesh has too many faces: %u, but the limit is %u",pMesh->mNumFaces,AI_MAX_FACES);
    }

    // if tangents are there there must also be bitangent vectors ...
    if ((pMesh->mTangents != NULL) != (pMesh->mBitangents != NULL)) {
        ReportError("If there are tangents, bitangent vectors must be present as well");
    }

    // faces, too
    if (!pMesh->mNumFaces || (!pMesh->mFaces && !mScene->mFlags))   {
        ReportError("Mesh contains no faces");
    }

    // now check whether the face indexing layout is correct:
    // unique vertices, pseudo-indexed.
    std::vector<bool> abRefList;
    abRefList.resize(pMesh->mNumVertices,false);
    for (unsigned int i = 0; i < pMesh->mNumFaces;++i)
    {
        aiFace& face = pMesh->mFaces[i];
        if (face.mNumIndices > AI_MAX_FACE_INDICES) {
            ReportError("Face %u has too many faces: %u, but the limit is %u",i,face.mNumIndices,AI_MAX_FACE_INDICES);
        }

        for (unsigned int a = 0; a < face.mNumIndices;++a)
        {
            if (face.mIndices[a] >= pMesh->mNumVertices)    {
                ReportError("aiMesh::mFaces[%i]::mIndices[%i] is out of range",i,a);
            }
            // the MSB flag is temporarily used by the extra verbose
            // mode to tell us that the JoinVerticesProcess might have
            // been executed already.
			if ( !(this->mScene->mFlags & AI_SCENE_FLAGS_NON_VERBOSE_FORMAT ) && !(this->mScene->mFlags & AI_SCENE_FLAGS_ALLOW_SHARED) &&
				abRefList[face.mIndices[a]])
            {
                ReportError("aiMesh::mVertices[%i] is referenced twice - second "
                    "time by aiMesh::mFaces[%i]::mIndices[%i]",face.mIndices[a],i,a);
            }
            abRefList[face.mIndices[a]] = true;
        }
    }

    // check whether there are vertices that aren't referenced by a face
    bool b = false;
    for (unsigned int i = 0; i < pMesh->mNumVertices;++i)   {
        if (!abRefList[i])b = true;
    }
    abRefList.clear();
    if (b)ReportWarning("There are unreferenced vertices");

    // texture channel 2 may not be set if channel 1 is zero ...
    {
        unsigned int i = 0;
        for (;i < AI_MAX_NUMBER_OF_TEXTURECOORDS;++i)
        {
            if (!pMesh->HasTextureCoords(i))break;
        }
        for (;i < AI_MAX_NUMBER_OF_TEXTURECOORDS;++i)
            if (pMesh->HasTextureCoords(i))
            {
                ReportError("Texture coordinate channel %i exists "
                    "although the previous channel was NULL.",i);
            }
    }
    // the same for the vertex colors
    {
        unsigned int i = 0;
        for (;i < AI_MAX_NUMBER_OF_COLOR_SETS;++i)
        {
            if (!pMesh->HasVertexColors(i))break;
        }
        for (;i < AI_MAX_NUMBER_OF_COLOR_SETS;++i)
            if (pMesh->HasVertexColors(i))
            {
                ReportError("Vertex color channel %i is exists "
                    "although the previous channel was NULL.",i);
            }
    }


    // now validate all bones
    if (pMesh->mNumBones)
    {
        if (!pMesh->mBones)
        {
            ReportError("aiMesh::mBones is NULL (aiMesh::mNumBones is %i)",
                pMesh->mNumBones);
        }
        std::unique_ptr<float[]> afSum(nullptr);
        if (pMesh->mNumVertices)
        {
            afSum.reset(new float[pMesh->mNumVertices]);
            for (unsigned int i = 0; i < pMesh->mNumVertices;++i)
                afSum[i] = 0.0f;
        }

        // check whether there are duplicate bone names
        for (unsigned int i = 0; i < pMesh->mNumBones;++i)
        {
            const aiBone* bone = pMesh->mBones[i];
            if (bone->mNumWeights > AI_MAX_BONE_WEIGHTS) {
                ReportError("Bone %u has too many weights: %u, but the limit is %u",i,bone->mNumWeights,AI_MAX_BONE_WEIGHTS);
            }

            if (!pMesh->mBones[i])
            {
                ReportError("aiMesh::mBones[%i] is NULL (aiMesh::mNumBones is %i)",
                    i,pMesh->mNumBones);
            }
            Validate(pMesh,pMesh->mBones[i],afSum.get());

            for (unsigned int a = i+1; a < pMesh->mNumBones;++a)
            {
                if (pMesh->mBones[i]->mName == pMesh->mBones[a]->mName)
                {
                    ReportError("aiMesh::mBones[%i] has the same name as "
                        "aiMesh::mBones[%i]",i,a);
                }
            }
        }
        // check whether all bone weights for a vertex sum to 1.0 ...
        for (unsigned int i = 0; i < pMesh->mNumVertices;++i)
        {
            if (afSum[i] && (afSum[i] <= 0.94 || afSum[i] >= 1.05)) {
                ReportWarning("aiMesh::mVertices[%i]: bone weight sum != 1.0 (sum is %f)",i,afSum[i]);
            }
        }
    }
    else if (pMesh->mBones)
    {
        ReportError("aiMesh::mBones is non-null although there are no bones");
    }
}

// ------------------------------------------------------------------------------------------------
void ValidateDSProcess::Validate( const aiMesh* pMesh,
    const aiBone* pBone,float* afSum)
{
    this->Validate(&pBone->mName);

    if (!pBone->mNumWeights)    {
        ReportError("aiBone::mNumWeights is zero");
    }

    // check whether all vertices affected by this bone are valid
    for (unsigned int i = 0; i < pBone->mNumWeights;++i)
    {
        if (pBone->mWeights[i].mVertexId >= pMesh->mNumVertices)    {
            ReportError("aiBone::mWeights[%i].mVertexId is out of range",i);
        }
        else if (!pBone->mWeights[i].mWeight || pBone->mWeights[i].mWeight > 1.0f)  {
            ReportWarning("aiBone::mWeights[%i].mWeight has an invalid value",i);
        }
        afSum[pBone->mWeights[i].mVertexId] += pBone->mWeights[i].mWeight;
    }
}

// ------------------------------------------------------------------------------------------------
void ValidateDSProcess::Validate( const aiAnimation* pAnimation)
{
    Validate(&pAnimation->mName);

    // validate all materials
    if (pAnimation->mNumChannels)
    {
        if (!pAnimation->mChannels) {
            ReportError("aiAnimation::mChannels is NULL (aiAnimation::mNumChannels is %i)",
                pAnimation->mNumChannels);
        }
        for (unsigned int i = 0; i < pAnimation->mNumChannels;++i)
        {
            if (!pAnimation->mChannels[i])
            {
                ReportError("aiAnimation::mChannels[%i] is NULL (aiAnimation::mNumChannels is %i)",
                    i, pAnimation->mNumChannels);
            }
            Validate(pAnimation, pAnimation->mChannels[i]);
        }
    }
    else ReportError("aiAnimation::mNumChannels is 0. At least one node animation channel must be there.");

    // Animation duration is allowed to be zero in cases where the anim contains only a single key frame.
    // if (!pAnimation->mDuration)this->ReportError("aiAnimation::mDuration is zero");
}

// ------------------------------------------------------------------------------------------------
void ValidateDSProcess::SearchForInvalidTextures(const aiMaterial* pMaterial,
    aiTextureType type)
{
    const char* szType = TextureTypeToString(type);

    // ****************************************************************************
    // Search all keys of the material ...
    // textures must be specified with ascending indices
    // (e.g. diffuse #2 may not be specified if diffuse #1 is not there ...)
    // ****************************************************************************

    int iNumIndices = 0;
    int iIndex = -1;
    for (unsigned int i = 0; i < pMaterial->mNumProperties;++i)
    {
        aiMaterialProperty* prop = pMaterial->mProperties[i];
        if (!::strcmp(prop->mKey.data,"$tex.file") && prop->mSemantic == type)  {
            iIndex = std::max(iIndex, (int) prop->mIndex);
            ++iNumIndices;

            if (aiPTI_String != prop->mType)
                ReportError("Material property %s is expected to be a string",prop->mKey.data);
        }
    }
    if (iIndex +1 != iNumIndices)   {
        ReportError("%s #%i is set, but there are only %i %s textures",
            szType,iIndex,iNumIndices,szType);
    }
    if (!iNumIndices)return;
    std::vector<aiTextureMapping> mappings(iNumIndices);

    // Now check whether all UV indices are valid ...
    bool bNoSpecified = true;
    for (unsigned int i = 0; i < pMaterial->mNumProperties;++i)
    {
        aiMaterialProperty* prop = pMaterial->mProperties[i];
        if (prop->mSemantic != type)continue;

        if ((int)prop->mIndex >= iNumIndices)
        {
            ReportError("Found texture property with index %i, although there "
                "are only %i textures of type %s",
                prop->mIndex, iNumIndices, szType);
        }

        if (!::strcmp(prop->mKey.data,"$tex.mapping"))  {
            if (aiPTI_Integer != prop->mType || prop->mDataLength < sizeof(aiTextureMapping))
            {
                ReportError("Material property %s%i is expected to be an integer (size is %i)",
                    prop->mKey.data,prop->mIndex,prop->mDataLength);
            }
            mappings[prop->mIndex] = *((aiTextureMapping*)prop->mData);
        }
        else if (!::strcmp(prop->mKey.data,"$tex.uvtrafo")) {
            if (aiPTI_Float != prop->mType || prop->mDataLength < sizeof(aiUVTransform))
            {
                ReportError("Material property %s%i is expected to be 5 floats large (size is %i)",
                    prop->mKey.data,prop->mIndex, prop->mDataLength);
            }
            mappings[prop->mIndex] = *((aiTextureMapping*)prop->mData);
        }
        else if (!::strcmp(prop->mKey.data,"$tex.uvwsrc")) {
            if (aiPTI_Integer != prop->mType || sizeof(int) > prop->mDataLength)
            {
                ReportError("Material property %s%i is expected to be an integer (size is %i)",
                    prop->mKey.data,prop->mIndex,prop->mDataLength);
            }
            bNoSpecified = false;

            // Ignore UV indices for texture channels that are not there ...

            // Get the value
            iIndex = *((unsigned int*)prop->mData);

            // Check whether there is a mesh using this material
            // which has not enough UV channels ...
            for (unsigned int a = 0; a < mScene->mNumMeshes;++a)
            {
                aiMesh* mesh = this->mScene->mMeshes[a];
                if(mesh->mMaterialIndex == (unsigned int)i)
                {
                    int iChannels = 0;
                    while (mesh->HasTextureCoords(iChannels))++iChannels;
                    if (iIndex >= iChannels)
                    {
                        ReportWarning("Invalid UV index: %i (key %s). Mesh %i has only %i UV channels",
                            iIndex,prop->mKey.data,a,iChannels);
                    }
                }
            }
        }
    }
    if (bNoSpecified)
    {
        // Assume that all textures are using the first UV channel
        for (unsigned int a = 0; a < mScene->mNumMeshes;++a)
        {
            aiMesh* mesh = mScene->mMeshes[a];
            if(mesh->mMaterialIndex == (unsigned int)iIndex && mappings[0] == aiTextureMapping_UV)
            {
                if (!mesh->mTextureCoords[0])
                {
                    // This is a special case ... it could be that the
                    // original mesh format intended the use of a special
                    // mapping here.
                    ReportWarning("UV-mapped texture, but there are no UV coords");
                }
            }
        }
    }
}
// ------------------------------------------------------------------------------------------------
void ValidateDSProcess::Validate( const aiMaterial* pMaterial)
{
    // check whether there are material keys that are obviously not legal
    for (unsigned int i = 0; i < pMaterial->mNumProperties;++i)
    {
        const aiMaterialProperty* prop = pMaterial->mProperties[i];
        if (!prop)  {
            ReportError("aiMaterial::mProperties[%i] is NULL (aiMaterial::mNumProperties is %i)",
                i,pMaterial->mNumProperties);
        }
        if (!prop->mDataLength || !prop->mData) {
            ReportError("aiMaterial::mProperties[%i].mDataLength or "
                "aiMaterial::mProperties[%i].mData is 0",i,i);
        }
        // check all predefined types
        if (aiPTI_String == prop->mType)    {
            // FIX: strings are now stored in a less expensive way, but we can't use the
            // validation routine for 'normal' aiStrings
            if (prop->mDataLength < 5 || prop->mDataLength < 4 + (*reinterpret_cast<uint32_t*>(prop->mData)) + 1)   {
                ReportError("aiMaterial::mProperties[%i].mDataLength is "
                    "too small to contain a string (%i, needed: %i)",
                    i,prop->mDataLength,sizeof(aiString));
            }
            if(prop->mData[prop->mDataLength-1]) {
                ReportError("Missing null-terminator in string material property");
            }
        //  Validate((const aiString*)prop->mData);
        }
        else if (aiPTI_Float == prop->mType)    {
            if (prop->mDataLength < sizeof(float))  {
                ReportError("aiMaterial::mProperties[%i].mDataLength is "
                    "too small to contain a float (%i, needed: %i)",
                    i,prop->mDataLength,sizeof(float));
            }
        }
        else if (aiPTI_Integer == prop->mType)  {
            if (prop->mDataLength < sizeof(int))    {
                ReportError("aiMaterial::mProperties[%i].mDataLength is "
                    "too small to contain an integer (%i, needed: %i)",
                    i,prop->mDataLength,sizeof(int));
            }
        }
        // TODO: check whether there is a key with an unknown name ...
    }

    // make some more specific tests
    ai_real fTemp;
    int iShading;
    if (AI_SUCCESS == aiGetMaterialInteger( pMaterial,AI_MATKEY_SHADING_MODEL,&iShading))   {
        switch ((aiShadingMode)iShading)
        {
        case aiShadingMode_Blinn:
        case aiShadingMode_CookTorrance:
        case aiShadingMode_Phong:

            if (AI_SUCCESS != aiGetMaterialFloat(pMaterial,AI_MATKEY_SHININESS,&fTemp)) {
                ReportWarning("A specular shading model is specified but there is no "
                    "AI_MATKEY_SHININESS key");
            }
            if (AI_SUCCESS == aiGetMaterialFloat(pMaterial,AI_MATKEY_SHININESS_STRENGTH,&fTemp) && !fTemp)  {
                ReportWarning("A specular shading model is specified but the value of the "
                    "AI_MATKEY_SHININESS_STRENGTH key is 0.0");
            }
            break;
        default: ;
        };
    }

    if (AI_SUCCESS == aiGetMaterialFloat( pMaterial,AI_MATKEY_OPACITY,&fTemp) && (!fTemp || fTemp > 1.01)) {
        ReportWarning("Invalid opacity value (must be 0 < opacity < 1.0)");
    }

    // Check whether there are invalid texture keys
    // TODO: that's a relict of the past, where texture type and index were baked
    // into the material string ... we could do that in one single pass.
    SearchForInvalidTextures(pMaterial,aiTextureType_DIFFUSE);
    SearchForInvalidTextures(pMaterial,aiTextureType_SPECULAR);
    SearchForInvalidTextures(pMaterial,aiTextureType_AMBIENT);
    SearchForInvalidTextures(pMaterial,aiTextureType_EMISSIVE);
    SearchForInvalidTextures(pMaterial,aiTextureType_OPACITY);
    SearchForInvalidTextures(pMaterial,aiTextureType_SHININESS);
    SearchForInvalidTextures(pMaterial,aiTextureType_HEIGHT);
    SearchForInvalidTextures(pMaterial,aiTextureType_NORMALS);
    SearchForInvalidTextures(pMaterial,aiTextureType_DISPLACEMENT);
    SearchForInvalidTextures(pMaterial,aiTextureType_LIGHTMAP);
    SearchForInvalidTextures(pMaterial,aiTextureType_REFLECTION);
}

// ------------------------------------------------------------------------------------------------
void ValidateDSProcess::Validate( const aiTexture* pTexture)
{
    // the data section may NEVER be NULL
    if (!pTexture->pcData)  {
        ReportError("aiTexture::pcData is NULL");
    }
    if (pTexture->mHeight)
    {
        if (!pTexture->mWidth)ReportError("aiTexture::mWidth is zero "
            "(aiTexture::mHeight is %i, uncompressed texture)",pTexture->mHeight);
    }
    else
    {
        if (!pTexture->mWidth) {
            ReportError("aiTexture::mWidth is zero (compressed texture)");
        }
        if ('\0' != pTexture->achFormatHint[3]) {
            ReportWarning("aiTexture::achFormatHint must be zero-terminated");
        }
        else if ('.'  == pTexture->achFormatHint[0])    {
            ReportWarning("aiTexture::achFormatHint should contain a file extension "
                "without a leading dot (format hint: %s).",pTexture->achFormatHint);
        }
    }

    const char* sz = pTexture->achFormatHint;
    if ((sz[0] >= 'A' && sz[0] <= 'Z') ||
        (sz[1] >= 'A' && sz[1] <= 'Z') ||
        (sz[2] >= 'A' && sz[2] <= 'Z') ||
        (sz[3] >= 'A' && sz[3] <= 'Z')) {
        ReportError("aiTexture::achFormatHint contains non-lowercase letters");
    }
}

// ------------------------------------------------------------------------------------------------
void ValidateDSProcess::Validate( const aiAnimation* pAnimation,
     const aiNodeAnim* pNodeAnim)
{
    Validate(&pNodeAnim->mNodeName);

    if (!pNodeAnim->mNumPositionKeys && !pNodeAnim->mScalingKeys && !pNodeAnim->mNumRotationKeys)
        ReportError("Empty node animation channel");

    // otherwise check whether one of the keys exceeds the total duration of the animation
    if (pNodeAnim->mNumPositionKeys)
    {
        if (!pNodeAnim->mPositionKeys)
        {
            this->ReportError("aiNodeAnim::mPositionKeys is NULL (aiNodeAnim::mNumPositionKeys is %i)",
                pNodeAnim->mNumPositionKeys);
        }
        double dLast = -10e10;
        for (unsigned int i = 0; i < pNodeAnim->mNumPositionKeys;++i)
        {
            // ScenePreprocessor will compute the duration if still the default value
            // (Aramis) Add small epsilon, comparison tended to fail if max_time == duration,
            //  seems to be due the compilers register usage/width.
            if (pAnimation->mDuration > 0. && pNodeAnim->mPositionKeys[i].mTime > pAnimation->mDuration+0.001)
            {
                ReportError("aiNodeAnim::mPositionKeys[%i].mTime (%.5f) is larger "
                    "than aiAnimation::mDuration (which is %.5f)",i,
                    (float)pNodeAnim->mPositionKeys[i].mTime,
                    (float)pAnimation->mDuration);
            }
            if (i && pNodeAnim->mPositionKeys[i].mTime <= dLast)
            {
                ReportWarning("aiNodeAnim::mPositionKeys[%i].mTime (%.5f) is smaller "
                    "than aiAnimation::mPositionKeys[%i] (which is %.5f)",i,
                    (float)pNodeAnim->mPositionKeys[i].mTime,
                    i-1, (float)dLast);
            }
            dLast = pNodeAnim->mPositionKeys[i].mTime;
        }
    }
    // rotation keys
    if (pNodeAnim->mNumRotationKeys)
    {
        if (!pNodeAnim->mRotationKeys)
        {
            this->ReportError("aiNodeAnim::mRotationKeys is NULL (aiNodeAnim::mNumRotationKeys is %i)",
                pNodeAnim->mNumRotationKeys);
        }
        double dLast = -10e10;
        for (unsigned int i = 0; i < pNodeAnim->mNumRotationKeys;++i)
        {
            if (pAnimation->mDuration > 0. && pNodeAnim->mRotationKeys[i].mTime > pAnimation->mDuration+0.001)
            {
                ReportError("aiNodeAnim::mRotationKeys[%i].mTime (%.5f) is larger "
                    "than aiAnimation::mDuration (which is %.5f)",i,
                    (float)pNodeAnim->mRotationKeys[i].mTime,
                    (float)pAnimation->mDuration);
            }
            if (i && pNodeAnim->mRotationKeys[i].mTime <= dLast)
            {
                ReportWarning("aiNodeAnim::mRotationKeys[%i].mTime (%.5f) is smaller "
                    "than aiAnimation::mRotationKeys[%i] (which is %.5f)",i,
                    (float)pNodeAnim->mRotationKeys[i].mTime,
                    i-1, (float)dLast);
            }
            dLast = pNodeAnim->mRotationKeys[i].mTime;
        }
    }
    // scaling keys
    if (pNodeAnim->mNumScalingKeys)
    {
        if (!pNodeAnim->mScalingKeys)   {
            ReportError("aiNodeAnim::mScalingKeys is NULL (aiNodeAnim::mNumScalingKeys is %i)",
                pNodeAnim->mNumScalingKeys);
        }
        double dLast = -10e10;
        for (unsigned int i = 0; i < pNodeAnim->mNumScalingKeys;++i)
        {
            if (pAnimation->mDuration > 0. && pNodeAnim->mScalingKeys[i].mTime > pAnimation->mDuration+0.001)
            {
                ReportError("aiNodeAnim::mScalingKeys[%i].mTime (%.5f) is larger "
                    "than aiAnimation::mDuration (which is %.5f)",i,
                    (float)pNodeAnim->mScalingKeys[i].mTime,
                    (float)pAnimation->mDuration);
            }
            if (i && pNodeAnim->mScalingKeys[i].mTime <= dLast)
            {
                ReportWarning("aiNodeAnim::mScalingKeys[%i].mTime (%.5f) is smaller "
                    "than aiAnimation::mScalingKeys[%i] (which is %.5f)",i,
                    (float)pNodeAnim->mScalingKeys[i].mTime,
                    i-1, (float)dLast);
            }
            dLast = pNodeAnim->mScalingKeys[i].mTime;
        }
    }

    if (!pNodeAnim->mNumScalingKeys && !pNodeAnim->mNumRotationKeys &&
        !pNodeAnim->mNumPositionKeys)
    {
        ReportError("A node animation channel must have at least one subtrack");
    }
}

// ------------------------------------------------------------------------------------------------
void ValidateDSProcess::Validate( const aiNode* pNode)
{
    if (!pNode)ReportError("A node of the scenegraph is NULL");
    if (pNode != mScene->mRootNode && !pNode->mParent)
        this->ReportError("A node has no valid parent (aiNode::mParent is NULL)");

    this->Validate(&pNode->mName);

    // validate all meshes
    if (pNode->mNumMeshes)
    {
        if (!pNode->mMeshes)
        {
            ReportError("aiNode::mMeshes is NULL (aiNode::mNumMeshes is %i)",
                pNode->mNumMeshes);
        }
        std::vector<bool> abHadMesh;
        abHadMesh.resize(mScene->mNumMeshes,false);
        for (unsigned int i = 0; i < pNode->mNumMeshes;++i)
        {
            if (pNode->mMeshes[i] >= mScene->mNumMeshes)
            {
                ReportError("aiNode::mMeshes[%i] is out of range (maximum is %i)",
                    pNode->mMeshes[i],mScene->mNumMeshes-1);
            }
            if (abHadMesh[pNode->mMeshes[i]])
            {
                ReportError("aiNode::mMeshes[%i] is already referenced by this node (value: %i)",
                    i,pNode->mMeshes[i]);
            }
            abHadMesh[pNode->mMeshes[i]] = true;
        }
    }
    if (pNode->mNumChildren)
    {
        if (!pNode->mChildren)  {
            ReportError("aiNode::mChildren is NULL (aiNode::mNumChildren is %i)",
                pNode->mNumChildren);
        }
        for (unsigned int i = 0; i < pNode->mNumChildren;++i)   {
            Validate(pNode->mChildren[i]);
        }
    }
}

// ------------------------------------------------------------------------------------------------
void ValidateDSProcess::Validate( const aiString* pString)
{
    if (pString->length > MAXLEN)
    {
        this->ReportError("aiString::length is too large (%i, maximum is %i)",
            pString->length,MAXLEN);
    }
    const char* sz = pString->data;
    while (true)
    {
        if ('\0' == *sz)
        {
            if (pString->length != (unsigned int)(sz-pString->data))
                ReportError("aiString::data is invalid: the terminal zero is at a wrong offset");
            break;
        }
        else if (sz >= &pString->data[MAXLEN])
            ReportError("aiString::data is invalid. There is no terminal character");
        ++sz;
    }
}
