rot13.c

#include <stdio.h>
#include <string.h>
#include <CL/cl.h>
const char rot13_cl[] = "                         \
__kernel void rot13                               \
    (   __global    const   char*    in           \
    ,   __global            char*    out          \
    )                                             \
{                                                 \
    const uint index = get_global_id(0);          \
                                                  \
    char c=in[index];                             \
    if (c<'A' || c>'z' || (c>'Z' && c<'a')) {     \
        out[index] = in[index];                   \
    } else {                                      \
        if (c>'m' || (c>'M' && c<'a')) {          \
          out[index] = in[index]-13;              \
        } else {                                  \
          out[index] = in[index]+13;              \
        }                                         \
    }                                             \
}                                                 \
";
void rot13 (char *buf) {
  int index=0;
  char c=buf[index];
  while (c!=0) {
    if (c<'A' || c>'z' || (c>'Z' && c<'a')) {
      buf[index] = buf[index];
    } else {
      if (c>'m' || (c>'M' && c<'a')) {
        buf[index] = buf[index]-13;
      } else {
        buf[index] = buf[index]+13;
      }
    }
    c=buf[++index];
  }
}
int main() {
  char buf[]="Hello, World!";
  size_t srcsize, worksize=strlen(buf);
  cl_int error;
  cl_platform_id platform;
  cl_device_id device;
  cl_uint platforms, devices;
  error=clGetPlatformIDs(1, &platform, &platforms);
  error=clGetDeviceIDs(platform, CL_DEVICE_TYPE_ALL, 1, &device, &devices);
  cl_context_properties properties[]={
          CL_CONTEXT_PLATFORM, (cl_context_properties)platform,
          0};
  cl_context context=clCreateContext(properties, 1, &device, NULL, NULL, &error);
  cl_command_queue cq = clCreateCommandQueue(context, device, 0, &error);
  rot13(buf);
  const char *src=rot13_cl;
  srcsize=strlen(rot13_cl);
  const char *srcptr[]={src};
  cl_program prog=clCreateProgramWithSource(context,
          1, srcptr, &srcsize, &error);
  error=clBuildProgram(prog, 0, NULL, "", NULL, NULL);
  if (error == CL_BUILD_PROGRAM_FAILURE) {
    size_t logsize;
    clGetProgramBuildInfo(prog, device, CL_PROGRAM_BUILD_LOG, 0, NULL, &logsize);
    char *log=(char *)malloc(logsize);
    clGetProgramBuildInfo(prog, device, CL_PROGRAM_BUILD_LOG, logsize, log, NULL);
    fprintf(stderr, "%s\n", log);
    free(log);
    return 1;
  }
  cl_mem mem1, mem2;
  mem1=clCreateBuffer(context, CL_MEM_READ_ONLY, worksize, NULL, &error);
  mem2=clCreateBuffer(context, CL_MEM_WRITE_ONLY, worksize, NULL, &error);
  cl_kernel k_rot13=clCreateKernel(prog, "rot13", &error);
  clSetKernelArg(k_rot13, 0, sizeof(mem1), &mem1);
  clSetKernelArg(k_rot13, 1, sizeof(mem2), &mem2);
  char buf2[sizeof buf];
  buf2[0]='?';
  buf2[worksize]=0;
  error=clEnqueueWriteBuffer(cq, mem1, CL_FALSE, 0, worksize, buf, 0, NULL, NULL);
  error=clEnqueueNDRangeKernel(cq, k_rot13, 1, NULL, &worksize, &worksize, 0, NULL, NULL);
  error=clEnqueueReadBuffer(cq, mem2, CL_FALSE, 0, worksize, buf2, 0, NULL, NULL);
  error=clFinish(cq);
  puts(buf2);
}