//
//Copyright (C) 2002-2005  3Dlabs Inc. Ltd.
//Copyright (C) 2013 LunarG, Inc.
//
//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 3Dlabs Inc. Ltd. 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 THE COPYRIGHT HOLDERS AND CONTRIBUTORS
//"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 THE
//COPYRIGHT HOLDERS OR CONTRIBUTORS 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.
//

// this only applies to the standalone wrapper, not the front end in general
#define _CRT_SECURE_NO_WARNINGS

#include "ResourceLimits.h"
#include "Worklist.h"
#include "./../glslang/Include/ShHandle.h"
#include "./../glslang/Include/revision.h"
#include "./../glslang/Public/ShaderLang.h"
#include "../SPIRV/GlslangToSpv.h"
#include "../SPIRV/GLSL.std.450.h"
#include "../SPIRV/doc.h"
#include "../SPIRV/disassemble.h"
#include <string.h>
#include <stdlib.h>
#include <math.h>

#include "../glslang/OSDependent/osinclude.h"

extern "C" {
    SH_IMPORT_EXPORT void ShOutputHtml();
}

// Command-line options
enum TOptions {
    EOptionNone               = 0,
    EOptionIntermediate       = (1 <<  0),
    EOptionSuppressInfolog    = (1 <<  1),
    EOptionMemoryLeakMode     = (1 <<  2),
    EOptionRelaxedErrors      = (1 <<  3),
    EOptionGiveWarnings       = (1 <<  4),
    EOptionLinkProgram        = (1 <<  5),
    EOptionMultiThreaded      = (1 <<  6),
    EOptionDumpConfig         = (1 <<  7),
    EOptionDumpReflection     = (1 <<  8),
    EOptionSuppressWarnings   = (1 <<  9),
    EOptionDumpVersions       = (1 << 10),
    EOptionSpv                = (1 << 11),
    EOptionHumanReadableSpv   = (1 << 12),
    EOptionVulkanRules        = (1 << 13),
    EOptionDefaultDesktop     = (1 << 14),
    EOptionOutputPreprocessed = (1 << 15),
    EOptionOutputHexadecimal  = (1 << 16),
    EOptionReadHlsl           = (1 << 17),
    EOptionCascadingErrors    = (1 << 18),
};

//
// Return codes from main/exit().
//
enum TFailCode {
    ESuccess = 0,
    EFailUsage,
    EFailCompile,
    EFailLink,
    EFailCompilerCreate,
    EFailThreadCreate,
    EFailLinkerCreate
};

//
// Forward declarations.
//
EShLanguage FindLanguage(const std::string& name);
void CompileFile(const char* fileName, ShHandle);
void usage();
void FreeFileData(char** data);
char** ReadFileData(const char* fileName);
void InfoLogMsg(const char* msg, const char* name, const int num);

// Globally track if any compile or link failure.
bool CompileFailed = false;
bool LinkFailed = false;

// Use to test breaking up a single shader file into multiple strings.
// Set in ReadFileData().
int NumShaderStrings;

TBuiltInResource Resources;
std::string ConfigFile;

//
// Parse either a .conf file provided by the user or the default from glslang::DefaultTBuiltInResource
//
void ProcessConfigFile()
{
    char** configStrings = 0;
    char* config = 0;
    if (ConfigFile.size() > 0) {
        configStrings = ReadFileData(ConfigFile.c_str());
        if (configStrings)
            config = *configStrings;
        else {
            printf("Error opening configuration file; will instead use the default configuration\n");
            usage();
        }
    }

    if (config == 0) {
        Resources = glslang::DefaultTBuiltInResource;
        return;
    }

    glslang::DecodeResourceLimits(&Resources,  config);

    if (configStrings)
        FreeFileData(configStrings);
    else
        delete[] config;
}

// thread-safe list of shaders to asynchronously grab and compile
glslang::TWorklist Worklist;

// array of unique places to leave the shader names and infologs for the asynchronous compiles
glslang::TWorkItem** Work = 0;
int NumWorkItems = 0;

int Options = 0;
const char* ExecutableName = nullptr;
const char* binaryFileName = nullptr;
const char* entryPointName = nullptr;

//
// Create the default name for saving a binary if -o is not provided.
//
const char* GetBinaryName(EShLanguage stage)
{
    const char* name;
    if (binaryFileName == nullptr) {
        switch (stage) {
        case EShLangVertex:          name = "vert.spv";    break;
        case EShLangTessControl:     name = "tesc.spv";    break;
        case EShLangTessEvaluation:  name = "tese.spv";    break;
        case EShLangGeometry:        name = "geom.spv";    break;
        case EShLangFragment:        name = "frag.spv";    break;
        case EShLangCompute:         name = "comp.spv";    break;
        default:                     name = "unknown";     break;
        }
    } else
        name = binaryFileName;

    return name;
}

//
// *.conf => this is a config file that can set limits/resources
//
bool SetConfigFile(const std::string& name)
{
    if (name.size() < 5)
        return false;

    if (name.compare(name.size() - 5, 5, ".conf") == 0) {
        ConfigFile = name;
        return true;
    }

    return false;
}

//
// Give error and exit with failure code.
//
void Error(const char* message)
{
    printf("%s: Error %s (use -h for usage)\n", ExecutableName, message);
    exit(EFailUsage);
}

//
// Do all command-line argument parsing.  This includes building up the work-items
// to be processed later, and saving all the command-line options.
//
// Does not return (it exits) if command-line is fatally flawed.
//
void ProcessArguments(int argc, char* argv[])
{
    ExecutableName = argv[0];
    NumWorkItems = argc;  // will include some empties where the '-' options were, but it doesn't matter, they'll be 0
    Work = new glslang::TWorkItem*[NumWorkItems];
    for (int w = 0; w < NumWorkItems; ++w)
        Work[w] = 0;

    argc--;
    argv++;    
    for (; argc >= 1; argc--, argv++) {
        if (argv[0][0] == '-') {
            switch (argv[0][1]) {
            case 'H':
                Options |= EOptionHumanReadableSpv;
                if ((Options & EOptionSpv) == 0) {
                    // default to Vulkan
                    Options |= EOptionSpv;
                    Options |= EOptionVulkanRules;
                    Options |= EOptionLinkProgram;
                }
                break;
            case 'V':
                Options |= EOptionSpv;
                Options |= EOptionVulkanRules;
                Options |= EOptionLinkProgram;
                break;
            case 'G':
                Options |= EOptionSpv;
                Options |= EOptionLinkProgram;
                // undo a -H default to Vulkan
                Options &= ~EOptionVulkanRules;
                break;
            case 'E':
                Options |= EOptionOutputPreprocessed;
                break;
            case 'c':
                Options |= EOptionDumpConfig;
                break;
            case 'C':
                Options |= EOptionCascadingErrors;
                break;
            case 'd':
                Options |= EOptionDefaultDesktop;
                break;
            case 'D':
                Options |= EOptionReadHlsl;
                break;
            case 'e':
                // HLSL todo: entry point handle needs much more sophistication.
                // This is okay for one compilation unit with one entry point.
                entryPointName = argv[1];
                if (argc > 0) {
                    argc--;
                    argv++;
                } else
                    Error("no <entry-point> provided for -e");
                break;
            case 'h':
                usage();
                break;
            case 'i':
                Options |= EOptionIntermediate;
                break;
            case 'l':
                Options |= EOptionLinkProgram;
                break;
            case 'm':
                Options |= EOptionMemoryLeakMode;
                break;
            case 'o':
                binaryFileName = argv[1];
                if (argc > 0) {
                    argc--;
                    argv++;
                } else
                    Error("no <file> provided for -o");
                break;
            case 'q':
                Options |= EOptionDumpReflection;
                break;
            case 'r':
                Options |= EOptionRelaxedErrors;
                break;
            case 's':
                Options |= EOptionSuppressInfolog;
                break;
            case 't':
                #ifdef _WIN32
                    Options |= EOptionMultiThreaded;
                #endif
                break;
            case 'v':
                Options |= EOptionDumpVersions;
                break;
            case 'w':
                Options |= EOptionSuppressWarnings;
                break;
            case 'x':
                Options |= EOptionOutputHexadecimal;
                break;
            default:
                usage();
                break;
            }
        } else {
            std::string name(argv[0]);
            if (! SetConfigFile(name)) {
                Work[argc] = new glslang::TWorkItem(name);
                Worklist.add(Work[argc]);
            }
        }
    }

    // Make sure that -E is not specified alongside linking (which includes SPV generation)
    if ((Options & EOptionOutputPreprocessed) && (Options & EOptionLinkProgram))
        Error("can't use -E when linking is selected");

    // -o or -x makes no sense if there is no target binary
    if (binaryFileName && (Options & EOptionSpv) == 0)
        Error("no binary generation requested (e.g., -V)");
}

//
// Translate the meaningful subset of command-line options to parser-behavior options.
//
void SetMessageOptions(EShMessages& messages)
{
    if (Options & EOptionRelaxedErrors)
        messages = (EShMessages)(messages | EShMsgRelaxedErrors);
    if (Options & EOptionIntermediate)
        messages = (EShMessages)(messages | EShMsgAST);
    if (Options & EOptionSuppressWarnings)
        messages = (EShMessages)(messages | EShMsgSuppressWarnings);
    if (Options & EOptionSpv)
        messages = (EShMessages)(messages | EShMsgSpvRules);
    if (Options & EOptionVulkanRules)
        messages = (EShMessages)(messages | EShMsgVulkanRules);
    if (Options & EOptionOutputPreprocessed)
        messages = (EShMessages)(messages | EShMsgOnlyPreprocessor);
    if (Options & EOptionReadHlsl)
        messages = (EShMessages)(messages | EShMsgReadHlsl);
    if (Options & EOptionCascadingErrors)
        messages = (EShMessages)(messages | EShMsgCascadingErrors);
}

//
// Thread entry point, for non-linking asynchronous mode.
//
// Return 0 for failure, 1 for success.
//
unsigned int CompileShaders(void*)
{
    glslang::TWorkItem* workItem;
    while (Worklist.remove(workItem)) {
        ShHandle compiler = ShConstructCompiler(FindLanguage(workItem->name), Options);
        if (compiler == 0)
            return 0;

        CompileFile(workItem->name.c_str(), compiler);

        if (! (Options & EOptionSuppressInfolog))
            workItem->results = ShGetInfoLog(compiler);

        ShDestruct(compiler);
    }

    return 0;
}

// Outputs the given string, but only if it is non-null and non-empty.
// This prevents erroneous newlines from appearing.
void PutsIfNonEmpty(const char* str)
{
    if (str && str[0]) {
        puts(str);
    }
}

// Outputs the given string to stderr, but only if it is non-null and non-empty.
// This prevents erroneous newlines from appearing.
void StderrIfNonEmpty(const char* str)
{
    if (str && str[0]) {
      fprintf(stderr, "%s\n", str);
    }
}

// Simple bundling of what makes a compilation unit for ease in passing around,
// and separation of handling file IO versus API (programmatic) compilation.
struct ShaderCompUnit {
    EShLanguage stage;
    std::string fileName;
    char** text;           // memory owned/managed externally
};

//
// For linking mode: Will independently parse each compilation unit, but then put them
// in the same program and link them together, making at most one linked module per
// pipeline stage.
//
// Uses the new C++ interface instead of the old handle-based interface.
//

void CompileAndLinkShaderUnits(std::vector<ShaderCompUnit> compUnits)
{
    // keep track of what to free
    std::list<glslang::TShader*> shaders;

    EShMessages messages = EShMsgDefault;
    SetMessageOptions(messages);

    //
    // Per-shader processing...
    //

    glslang::TProgram& program = *new glslang::TProgram;
    for (auto it = compUnits.cbegin(); it != compUnits.cend(); ++it) {
        const auto &compUnit = *it;
        glslang::TShader* shader = new glslang::TShader(compUnit.stage);
        shader->setStrings(compUnit.text, 1);
        if (entryPointName) // HLSL todo: this needs to be tracked per compUnits
            shader->setEntryPoint(entryPointName);
        shaders.push_back(shader);

        const int defaultVersion = Options & EOptionDefaultDesktop? 110: 100;

        if (Options & EOptionOutputPreprocessed) {
            std::string str;
            glslang::TShader::ForbidInclude includer;
            if (shader->preprocess(&Resources, defaultVersion, ENoProfile, false, false,
                                   messages, &str, includer)) {
                PutsIfNonEmpty(str.c_str());
            } else {
                CompileFailed = true;
            }
            StderrIfNonEmpty(shader->getInfoLog());
            StderrIfNonEmpty(shader->getInfoDebugLog());
            continue;
        }
        if (! shader->parse(&Resources, defaultVersion, false, messages))
            CompileFailed = true;

        program.addShader(shader);

        if (! (Options & EOptionSuppressInfolog) &&
            ! (Options & EOptionMemoryLeakMode)) {
            PutsIfNonEmpty(compUnit.fileName.c_str());
            PutsIfNonEmpty(shader->getInfoLog());
            PutsIfNonEmpty(shader->getInfoDebugLog());
        }
    }

    //
    // Program-level processing...
    //

    // Link
    if (! (Options & EOptionOutputPreprocessed) && ! program.link(messages))
        LinkFailed = true;

    // Report
    if (! (Options & EOptionSuppressInfolog) &&
        ! (Options & EOptionMemoryLeakMode)) {
        PutsIfNonEmpty(program.getInfoLog());
        PutsIfNonEmpty(program.getInfoDebugLog());
    }

    // Reflect
    if (Options & EOptionDumpReflection) {
        program.buildReflection();
        program.dumpReflection();
    }

    // Dump SPIR-V
    if (Options & EOptionSpv) {
        if (CompileFailed || LinkFailed)
            printf("SPIR-V is not generated for failed compile or link\n");
        else {
            for (int stage = 0; stage < EShLangCount; ++stage) {
                if (program.getIntermediate((EShLanguage)stage)) {
                    std::vector<unsigned int> spirv;
                    std::string warningsErrors;
                    spv::SpvBuildLogger logger;
                    glslang::GlslangToSpv(*program.getIntermediate((EShLanguage)stage), spirv, &logger);

                    // Dump the spv to a file or stdout, etc., but only if not doing
                    // memory/perf testing, as it's not internal to programmatic use.
                    if (! (Options & EOptionMemoryLeakMode)) {
                        printf("%s", logger.getAllMessages().c_str());
                        if (Options & EOptionOutputHexadecimal) {
                            glslang::OutputSpvHex(spirv, GetBinaryName((EShLanguage)stage));
                        } else {
                            glslang::OutputSpvBin(spirv, GetBinaryName((EShLanguage)stage));
                        }
                        if (Options & EOptionHumanReadableSpv) {
                            spv::Disassemble(std::cout, spirv);
                        }
                    }
                }
            }
        }
    }

    // Free everything up, program has to go before the shaders
    // because it might have merged stuff from the shaders, and
    // the stuff from the shaders has to have its destructors called
    // before the pools holding the memory in the shaders is freed.
    delete &program;
    while (shaders.size() > 0) {
        delete shaders.back();
        shaders.pop_back();
    }
}

//
// Do file IO part of compile and link, handing off the pure
// API/programmatic mode to CompileAndLinkShaderUnits(), which can
// be put in a loop for testing memory footprint and performance.
//
// This is just for linking mode: meaning all the shaders will be put into the
// the same program linked together.
//
// This means there are a limited number of work items (not multi-threading mode)
// and that the point is testing at the linking level. Hence, to enable
// performance and memory testing, the actual compile/link can be put in
// a loop, independent of processing the work items and file IO.
//
void CompileAndLinkShaderFiles()
{
    std::vector<ShaderCompUnit> compUnits;

    // Transfer all the work items from to a simple list of
    // of compilation units.  (We don't care about the thread
    // work-item distribution properties in this path, which
    // is okay due to the limited number of shaders, know since
    // they are all getting linked together.)
    glslang::TWorkItem* workItem;
    while (Worklist.remove(workItem)) {
        ShaderCompUnit compUnit = {
            FindLanguage(workItem->name),
            workItem->name,
            ReadFileData(workItem->name.c_str())
        };

        if (! compUnit.text) {
            usage();
            return;
        }

        compUnits.push_back(compUnit);
    }

    // Actual call to programmatic processing of compile and link,
    // in a loop for testing memory and performance.  This part contains
    // all the perf/memory that a programmatic consumer will care about.
    for (int i = 0; i < ((Options & EOptionMemoryLeakMode) ? 100 : 1); ++i) {
        for (int j = 0; j < ((Options & EOptionMemoryLeakMode) ? 100 : 1); ++j)
           CompileAndLinkShaderUnits(compUnits);

        if (Options & EOptionMemoryLeakMode)
            glslang::OS_DumpMemoryCounters();
    }

    for (auto it = compUnits.begin(); it != compUnits.end(); ++it)
        FreeFileData(it->text);
}

int C_DECL main(int argc, char* argv[])
{
    ProcessArguments(argc, argv);

    if (Options & EOptionDumpConfig) {
        printf("%s", glslang::GetDefaultTBuiltInResourceString().c_str());
        if (Worklist.empty())
            return ESuccess;
    }

    if (Options & EOptionDumpVersions) {
        printf("Glslang Version: %s %s\n", GLSLANG_REVISION, GLSLANG_DATE);
        printf("ESSL Version: %s\n", glslang::GetEsslVersionString());
        printf("GLSL Version: %s\n", glslang::GetGlslVersionString());
        std::string spirvVersion;
        glslang::GetSpirvVersion(spirvVersion);
        printf("SPIR-V Version %s\n", spirvVersion.c_str());
        printf("GLSL.std.450 Version %d, Revision %d\n", GLSLstd450Version, GLSLstd450Revision);
        printf("Khronos Tool ID %d\n", glslang::GetKhronosToolId());
        printf("GL_KHR_vulkan_glsl version %d\n", 100);
        printf("ARB_GL_gl_spirv version %d\n", 100);
        if (Worklist.empty())
            return ESuccess;
    }

    if (Worklist.empty()) {
        usage();
    }

    ProcessConfigFile();

    //
    // Two modes:
    // 1) linking all arguments together, single-threaded, new C++ interface
    // 2) independent arguments, can be tackled by multiple asynchronous threads, for testing thread safety, using the old handle interface
    //
    if (Options & EOptionLinkProgram ||
        Options & EOptionOutputPreprocessed) {
        glslang::InitializeProcess();
        CompileAndLinkShaderFiles();
        glslang::FinalizeProcess();
        for (int w = 0; w < NumWorkItems; ++w) {
          if (Work[w]) {
            delete Work[w];
          }
        }
    } else {
        ShInitialize();

        bool printShaderNames = Worklist.size() > 1;

        if (Options & EOptionMultiThreaded) {
            const int NumThreads = 16;
            void* threads[NumThreads];
            for (int t = 0; t < NumThreads; ++t) {
                threads[t] = glslang::OS_CreateThread(&CompileShaders);
                if (! threads[t]) {
                    printf("Failed to create thread\n");
                    return EFailThreadCreate;
                }
            }
            glslang::OS_WaitForAllThreads(threads, NumThreads);
        } else
            CompileShaders(0);

        // Print out all the resulting infologs
        for (int w = 0; w < NumWorkItems; ++w) {
            if (Work[w]) {
                if (printShaderNames || Work[w]->results.size() > 0)
                    PutsIfNonEmpty(Work[w]->name.c_str());
                PutsIfNonEmpty(Work[w]->results.c_str());
                delete Work[w];
            }
        }

        ShFinalize();
    }

    delete[] Work;

    if (CompileFailed)
        return EFailCompile;
    if (LinkFailed)
        return EFailLink;

    return 0;
}

//
//   Deduce the language from the filename.  Files must end in one of the
//   following extensions:
//
//   .vert = vertex
//   .tesc = tessellation control
//   .tese = tessellation evaluation
//   .geom = geometry
//   .frag = fragment
//   .comp = compute
//
EShLanguage FindLanguage(const std::string& name)
{
    size_t ext = name.rfind('.');
    if (ext == std::string::npos) {
        usage();
        return EShLangVertex;
    }

    std::string suffix = name.substr(ext + 1, std::string::npos);
    if (suffix == "vert")
        return EShLangVertex;
    else if (suffix == "tesc")
        return EShLangTessControl;
    else if (suffix == "tese")
        return EShLangTessEvaluation;
    else if (suffix == "geom")
        return EShLangGeometry;
    else if (suffix == "frag")
        return EShLangFragment;
    else if (suffix == "comp")
        return EShLangCompute;

    usage();
    return EShLangVertex;
}

//
// Read a file's data into a string, and compile it using the old interface ShCompile, 
// for non-linkable results.
//
void CompileFile(const char* fileName, ShHandle compiler)
{
    int ret = 0;
    char** shaderStrings = ReadFileData(fileName);
    if (! shaderStrings) {
        usage();
    }

    int* lengths = new int[NumShaderStrings];

    // move to length-based strings, rather than null-terminated strings
    for (int s = 0; s < NumShaderStrings; ++s)
        lengths[s] = (int)strlen(shaderStrings[s]);

    if (! shaderStrings) {
        CompileFailed = true;
        return;
    }

    EShMessages messages = EShMsgDefault;
    SetMessageOptions(messages);
    
    for (int i = 0; i < ((Options & EOptionMemoryLeakMode) ? 100 : 1); ++i) {
        for (int j = 0; j < ((Options & EOptionMemoryLeakMode) ? 100 : 1); ++j) {
            //ret = ShCompile(compiler, shaderStrings, NumShaderStrings, lengths, EShOptNone, &Resources, Options, (Options & EOptionDefaultDesktop) ? 110 : 100, false, messages);
            ret = ShCompile(compiler, shaderStrings, NumShaderStrings, nullptr, EShOptNone, &Resources, Options, (Options & EOptionDefaultDesktop) ? 110 : 100, false, messages);
            //const char* multi[12] = { "# ve", "rsion", " 300 e", "s", "\n#err", 
            //                         "or should be l", "ine 1", "string 5\n", "float glo", "bal", 
            //                         ";\n#error should be line 2\n void main() {", "global = 2.3;}" };
            //const char* multi[7] = { "/", "/", "\\", "\n", "\n", "#", "version 300 es" };
            //ret = ShCompile(compiler, multi, 7, nullptr, EShOptNone, &Resources, Options, (Options & EOptionDefaultDesktop) ? 110 : 100, false, messages);
        }

        if (Options & EOptionMemoryLeakMode)
            glslang::OS_DumpMemoryCounters();
    }

    delete [] lengths;
    FreeFileData(shaderStrings);

    if (ret == 0)
        CompileFailed = true;
}

//
//   print usage to stdout
//
void usage()
{
    printf("Usage: glslangValidator [option]... [file]...\n"
           "\n"
           "Where: each 'file' ends in .<stage>, where <stage> is one of\n"
           "    .conf   to provide an optional config file that replaces the default configuration\n"
           "            (see -c option below for generating a template)\n"
           "    .vert   for a vertex shader\n"
           "    .tesc   for a tessellation control shader\n"
           "    .tese   for a tessellation evaluation shader\n"
           "    .geom   for a geometry shader\n"
           "    .frag   for a fragment shader\n"
           "    .comp   for a compute shader\n"
           "\n"
           "Compilation warnings and errors will be printed to stdout.\n"
           "\n"
           "To get other information, use one of the following options:\n"
           "Each option must be specified separately.\n"
           "  -V          create SPIR-V binary, under Vulkan semantics; turns on -l;\n"
           "              default file name is <stage>.spv (-o overrides this)\n"
           "  -G          create SPIR-V binary, under OpenGL semantics; turns on -l;\n"
           "              default file name is <stage>.spv (-o overrides this)\n"
           "  -H          print human readable form of SPIR-V; turns on -V\n"
           "  -E          print pre-processed GLSL; cannot be used with -l;\n"
           "              errors will appear on stderr.\n"
           "  -c          configuration dump;\n"
           "              creates the default configuration file (redirect to a .conf file)\n"
           "  -C          cascading errors; risks crashes from accumulation of error recoveries\n"
           "  -d          default to desktop (#version 110) when there is no shader #version\n"
           "              (default is ES version 100)\n"
           "  -D          input is HLSL\n"
           "  -e          specify entry-point name\n"
           "  -h          print this usage message\n"
           "  -i          intermediate tree (glslang AST) is printed out\n"
           "  -l          link all input files together to form a single module\n"
           "  -m          memory leak mode\n"
           "  -o  <file>  save binary to <file>, requires a binary option (e.g., -V)\n"
           "  -q          dump reflection query database\n"
           "  -r          relaxed semantic error-checking mode\n"
           "  -s          silent mode\n"
           "  -t          multi-threaded mode\n"
           "  -v          print version strings\n"
           "  -w          suppress warnings (except as required by #extension : warn)\n"
           "  -x          save 32-bit hexadecimal numbers as text, requires a binary option (e.g., -V)\n"
           );

    exit(EFailUsage);
}

#if !defined _MSC_VER && !defined MINGW_HAS_SECURE_API

#include <errno.h>

int fopen_s(
   FILE** pFile,
   const char* filename,
   const char* mode
)
{
   if (!pFile || !filename || !mode) {
      return EINVAL;
   }

   FILE* f = fopen(filename, mode);
   if (! f) {
      if (errno != 0) {
         return errno;
      } else {
         return ENOENT;
      }
   }
   *pFile = f;

   return 0;
}

#endif

//
//   Malloc a string of sufficient size and read a string into it.
//
char** ReadFileData(const char* fileName) 
{
    FILE *in = nullptr;
    int errorCode = fopen_s(&in, fileName, "r");

    int count = 0;
    const int maxSourceStrings = 5;  // for testing splitting shader/tokens across multiple strings
    char** return_data = (char**)malloc(sizeof(char *) * (maxSourceStrings+1)); // freed in FreeFileData()

    if (errorCode || in == nullptr)
        Error("unable to open input file");
    
    while (fgetc(in) != EOF)
        count++;

    fseek(in, 0, SEEK_SET);

    char *fdata = (char*)malloc(count+2); // freed before return of this function
    if (! fdata)
        Error("can't allocate memory");

    if ((int)fread(fdata, 1, count, in) != count) {
        free(fdata);
        Error("can't read input file");
    }

    fdata[count] = '\0';
    fclose(in);

    if (count == 0) {
        // recover from empty file
        return_data[0] = (char*)malloc(count+2);  // freed in FreeFileData()
        return_data[0][0]='\0';
        NumShaderStrings = 0;
        free(fdata);

        return return_data;
    } else
        NumShaderStrings = 1;  // Set to larger than 1 for testing multiple strings

    // compute how to split up the file into multiple strings, for testing multiple strings
    int len = (int)(ceil)((float)count/(float)NumShaderStrings);
    int ptr_len = 0;
    int i = 0;
    while (count > 0) {
        return_data[i] = (char*)malloc(len + 2);  // freed in FreeFileData()
        memcpy(return_data[i], fdata + ptr_len, len);
        return_data[i][len] = '\0';
        count -= len;
        ptr_len += len;
        if (count < len) {
            if (count == 0) {
               NumShaderStrings = i + 1;
               break;
            }
            len = count;
        }  
        ++i;
    }

    free(fdata);

    return return_data;
}

void FreeFileData(char** data)
{
    for(int i = 0; i < NumShaderStrings; i++)
        free(data[i]);

    free(data);
}

void InfoLogMsg(const char* msg, const char* name, const int num)
{
    if (num >= 0 )
        printf("#### %s %s %d INFO LOG ####\n", msg, name, num);
    else
        printf("#### %s %s INFO LOG ####\n", msg, name);
}