/*
 * Copyright 1993-2015 NVIDIA Corporation.  All rights reserved.
 *
 * Please refer to the NVIDIA end user license agreement (EULA) associated
 * with this source code for terms and conditions that govern your use of
 * this software. Any use, reproduction, disclosure, or distribution of
 * this software and related documentation outside the terms of the EULA
 * is strictly prohibited.
 *
 */

/* Vector addition: C = A + B.
 *
 * This sample is a very basic sample that implements element by element
 * vector addition. It is the same as the sample illustrating Chapter 3
 * of the programming guide with some additions like error checking.
 *
 */

// Includes
#include <stdio.h>
#include <string.h>
#include <iostream>
#include <cstring>
#include <math.h>

// includes, project
#include <driver_types.h>
#include <cuda_runtime.h>
#include <cuda.h>
#include "helper_cuda.h"

// includes, CUDA
#include <builtin_types.h>

#define PTX_FILE "vectorAdd_kernel.ptx"


using namespace std;

// Variables
CUdevice cuDevice;
CUcontext cuContext;
CUmodule cuModule;
CUfunction vecAdd_kernel;
float *h_A;
float *h_B;
float *h_C;
CUdeviceptr d_A;
CUdeviceptr d_B;
CUdeviceptr d_C;
bool noprompt = false;

// Functions
void Cleanup(bool);
CUresult CleanupNoFailure();
void RandomInit(float *, int);
bool findModulePath(const char *, string &, char **, string &);
void ParseArguments(int, char **);

int *pArgc = NULL;
char **pArgv = NULL;


// Host code
int main(int argc, char **argv)
{
    pArgc = &argc;
    pArgv = argv;

    printf("Vector Addition (Driver API)\n");
    int N = 50000, devID = 0;
    size_t  size = N * sizeof(float);

    ParseArguments(argc, argv);

    // Initialize
    checkCudaErrors(cuInit(0));

    // This assumes that the user is attempting to specify a explicit device -device=n
    if (argc > 1)
    {
        bool bFound = false;

        for (int param=0; param < argc; param++)
        {
            int string_start = 0;

            while (argv[param][string_start] == '-')
            {
                string_start++;
            }

            char *string_argv = &argv[param][string_start];

            if (!strncmp(string_argv, "device", 6))
            {
                int len=(int)strlen(string_argv);

                while (string_argv[len] != '=')
                {
                    len--;
                }

                devID = atoi(&string_argv[++len]);
                bFound = true;
            }

            if (bFound)
            {
                break;
            }
        }
    }

    // Get number of devices supporting CUDA
    int deviceCount = 0;
    checkCudaErrors(cuDeviceGetCount(&deviceCount));
    if (deviceCount == 0)
    {
        printf("There is no device supporting CUDA.\n");
        Cleanup(false);
    }

    if (devID < 0)
    {
        devID = 0;
    }

    if (devID > deviceCount-1)
    {
        fprintf(stderr, "(Device=%d) invalid GPU device.  %d GPU device(s) detected.\nexiting...\n", devID, deviceCount);
        CleanupNoFailure();
        exit(EXIT_SUCCESS);
    }
    else
    {
        int major, minor;
        char deviceName[100];
        checkCudaErrors(cuDeviceComputeCapability(&major, &minor, devID));
        checkCudaErrors(cuDeviceGetName(deviceName, 256, devID));
        printf("> Using Device %d: \"%s\" with Compute %d.%d capability\n", devID, deviceName, major, minor);
    }

    // pick up device with zero ordinal (default, or devID)
    checkCudaErrors(cuDeviceGet(&cuDevice, devID));
    // Create context
    checkCudaErrors(cuCtxCreate(&cuContext, 0, cuDevice));
    // first search for the module path before we load the results
    string module_path, ptx_source;

    if (!findModulePath(PTX_FILE, module_path, argv, ptx_source))
    {
        if (!findModulePath("vectorAdd_kernel.cubin", module_path, argv, ptx_source))
        {
            printf("> findModulePath could not find <vectorAdd> ptx or cubin\n");
            Cleanup(false);
        }
    }
    else
    {
        printf("> initCUDA loading module: <%s>\n", module_path.c_str());
    }

    // Create module from binary file (PTX or CUBIN)
    if (module_path.rfind("ptx") != string::npos)
    {
        // in this branch we use compilation with parameters
        const unsigned int jitNumOptions = 3;
        CUjit_option *jitOptions = new CUjit_option[jitNumOptions];
        void **jitOptVals = new void *[jitNumOptions];

        // set up size of compilation log buffer
        jitOptions[0] = CU_JIT_INFO_LOG_BUFFER_SIZE_BYTES;
        int jitLogBufferSize = 1024;
        jitOptVals[0] = (void *)(size_t)jitLogBufferSize;

        // set up pointer to the compilation log buffer
        jitOptions[1] = CU_JIT_INFO_LOG_BUFFER;
        char *jitLogBuffer = new char[jitLogBufferSize];
        jitOptVals[1] = jitLogBuffer;

        // set up pointer to set the Maximum # of registers for a particular kernel
        jitOptions[2] = CU_JIT_MAX_REGISTERS;
        int jitRegCount = 32;
        jitOptVals[2] = (void *)(size_t)jitRegCount;

        checkCudaErrors(cuModuleLoadDataEx(&cuModule, ptx_source.c_str(), jitNumOptions, jitOptions, (void **)jitOptVals));

        printf("> PTX JIT log:\n%s\n", jitLogBuffer);
    }
    else
    {
        checkCudaErrors(cuModuleLoad(&cuModule, module_path.c_str()));
    }

    // Get function handle from module
    checkCudaErrors(cuModuleGetFunction(&vecAdd_kernel, cuModule, "VecAdd_kernel"));

    // Allocate input vectors h_A and h_B in host memory
    h_A = (float *)malloc(size);
    if (h_A == 0) { Cleanup(false); }

    h_B = (float *)malloc(size);
    if (h_B == 0) { Cleanup(false); }

    h_C = (float *)malloc(size);
    if (h_C == 0) { Cleanup(false); }

    // Initialize input vectors
    RandomInit(h_A, N);
    RandomInit(h_B, N);

    // Allocate vectors in device memory
    checkCudaErrors(cuMemAlloc(&d_A, size));
    checkCudaErrors(cuMemAlloc(&d_B, size));
    checkCudaErrors(cuMemAlloc(&d_C, size));

    // Copy vectors from host memory to device memory
    checkCudaErrors(cuMemcpyHtoD(d_A, h_A, size));
    checkCudaErrors(cuMemcpyHtoD(d_B, h_B, size));

#if 1

    if (1)
    {
        // This is the new CUDA 4.0 API for Kernel Parameter Passing and Kernel Launch (simpler method)

        // Grid/Block configuration
        int threadsPerBlock = 256;
        int blocksPerGrid   = (N + threadsPerBlock - 1) / threadsPerBlock;

        void *args[] = { &d_A, &d_B, &d_C, &N };

        // Launch the CUDA kernel
        checkCudaErrors(cuLaunchKernel(vecAdd_kernel,  blocksPerGrid, 1, 1,
                               threadsPerBlock, 1, 1,
                               0,
                               NULL, args, NULL));
    }
    else
    {
        // This is the new CUDA 4.0 API for Kernel Parameter Passing and Kernel Launch (advanced method)
        int offset = 0;
        void *argBuffer[16];
        *((CUdeviceptr *)&argBuffer[offset]) = d_A;
        offset += sizeof(d_A);
        *((CUdeviceptr *)&argBuffer[offset]) = d_B;
        offset += sizeof(d_B);
        *((CUdeviceptr *)&argBuffer[offset]) = d_C;
        offset += sizeof(d_C);
        *((int *)&argBuffer[offset]) = N;
        offset += sizeof(N);

        // Grid/Block configuration
        int threadsPerBlock = 256;
        int blocksPerGrid   = (N + threadsPerBlock - 1) / threadsPerBlock;

        // Launch the CUDA kernel
        checkCudaErrors(cuLaunchKernel(vecAdd_kernel,  blocksPerGrid, 1, 1,
                               threadsPerBlock, 1, 1,
                               0,
                               NULL, NULL, argBuffer));
    }

#else
    {
        char argBuffer[256];

        // pass in launch parameters (not actually de-referencing CUdeviceptr).  CUdeviceptr is
        // storing the value of the parameters
        *((CUdeviceptr *)&argBuffer[offset]) = d_A;
        offset += sizeof(d_A);
        *((CUdeviceptr *)&argBuffer[offset]) = d_B;
        offset += sizeof(d_B);
        *((CUdeviceptr *)&argBuffer[offset]) = d_C;
        offset += sizeof(d_C);
        *((int *)&argBuffer[offset]) = N;
        offset += sizeof(N);

        void *kernel_launch_config[5] =
        {
            CU_LAUNCH_PARAM_BUFFER_POINTER, argBuffer,
            CU_LAUNCH_PARAM_BUFFER_SIZE,    &offset,
            CU_LAUNCH_PARAM_END
        };

        // Grid/Block configuration
        int threadsPerBlock = 256;
        int blocksPerGrid   = (N + threadsPerBlock - 1) / threadsPerBlock;

        // Launch the CUDA kernel
        checkCudaErrors(cuLaunchKernel(vecAdd_kernel,  blocksPerGrid, 1, 1,
                               threadsPerBlock, 1, 1,
                               0, 0,
                               NULL, (void **)&kernel_launch_config));
    }
#endif

#ifdef _DEBUG
    checkCudaErrors(cuCtxSynchronize());
#endif

    // Copy result from device memory to host memory
    // h_C contains the result in host memory
    checkCudaErrors(cuMemcpyDtoH(h_C, d_C, size));

    // Verify result
    int i;

    for (i = 0; i < N; ++i)
    {
        float sum = h_A[i] + h_B[i];

        if (fabs(h_C[i] - sum) > 1e-7f)
        {
            break;
        }
    }

    printf("%s\n", (i==N) ? "Result = PASS" : "Result = FAIL");

    exit((i==N) ? EXIT_SUCCESS : EXIT_FAILURE);
}

CUresult CleanupNoFailure()
{
    CUresult error;

    // Free device memory
    if (d_A)
    {
        error = cuMemFree(d_A);
    }

    if (d_B)
    {
        error = cuMemFree(d_B);
    }

    if (d_C)
    {
        error = cuMemFree(d_C);
    }

    // Free host memory
    if (h_A)
    {
        free(h_A);
    }

    if (h_B)
    {
        free(h_B);
    }

    if (h_C)
    {
        free(h_C);
    }

    error = cuCtxDestroy(cuContext);

    return error;
}

void Cleanup(bool noError)
{
    CUresult error;
    error = CleanupNoFailure();

    if (!noError || error != CUDA_SUCCESS)
    {
        printf("Function call failed\nFAILED\n");
        exit(EXIT_FAILURE);
    }

    if (!noprompt)
    {
        printf("\nPress ENTER to exit...\n");
        fflush(stdout);
        fflush(stderr);
        getchar();
    }
}


// Allocates an array with random float entries.
void RandomInit(float *data, int n)
{
    for (int i = 0; i < n; ++i)
    {
        data[i] = rand() / (float)RAND_MAX;
    }
}

bool inline
findModulePath(const char *module_file, string &module_path, char **argv, string &ptx_source)
{
    char *actual_path = sdkFindFilePath(module_file, argv[0]);

    if (actual_path)
    {
        module_path = actual_path;
    }
    else
    {
        printf("> findModulePath file not found: <%s> \n", module_file);
        return false;
    }

    if (module_path.empty())
    {
        printf("> findModulePath could not find file: <%s> \n", module_file);
        return false;
    }
    else
    {
        printf("> findModulePath found file at <%s>\n", module_path.c_str());

        if (module_path.rfind(".ptx") != string::npos)
        {
            FILE *fp = fopen(module_path.c_str(), "rb");
            fseek(fp, 0, SEEK_END);
            int file_size = ftell(fp);
            char *buf = new char[file_size+1];
            fseek(fp, 0, SEEK_SET);
            fread(buf, sizeof(char), file_size, fp);
            fclose(fp);
            buf[file_size] = '\0';
            ptx_source = buf;
            delete[] buf;
        }

        return true;
    }
}

// Parse program arguments
void ParseArguments(int argc, char **argv)
{
    for (int i = 0; i < argc; ++i)
    {
        if (strcmp(argv[i], "--noprompt") == 0 ||
            strcmp(argv[i], "-noprompt") == 0)
        {
            noprompt = true;
            break;
        }
    }
}