Merge branch 'add-clFFT_GetSize-MR' into 'master'

Add clFFT_GetSize() for getting the estimated size of a plan

See merge request !5

include/clFFT.h

@@ -194,6 +194,8 @@ cl_int clFFT_1DTwistPlannar(clFFT_Plan Plan, cl_command_queue queue, cl_mem arra
 
 void clFFT_DumpPlan( clFFT_Plan plan, FILE *file);
 
+cl_int clFFT_GetSize(clFFT_Plan Plan, size_t* workSize, cl_uint batchSize);
+
 #ifdef __cplusplus
 }
 #endif

src/fft_setup.cpp

@@ -526,3 +526,25 @@ void clFFT_DumpPlan( clFFT_Plan Plan, FILE *file)
     }
     fprintf(out, "%s\n", plan->kernel_string->c_str());
 }
+
+cl_int
+clFFT_GetSize(clFFT_Plan Plan, size_t* workSize, cl_uint batchSize)
+{
+  if ( workSize == NULL ) {
+      return CL_INVALID_VALUE;
+  }
+  cl_fft_plan *plan = (cl_fft_plan *) Plan;
+  *workSize = 0;
+  // from precomputeSinCosLUTs() called in clFFT_CreatePlanAdv()
+  if (plan->twiddleMethod == clFFT_TaylorLUT || plan->twiddleMethod == clFFT_BigLUT) {
+      *workSize += ( plan->N1 + plan->N2 ) * 2 * sizeof(float);
+  }
+  // Additional alloc's from allocateTemporaryBufferInterleaved(), called in clFFT_ExecuteInterleaved()
+  // or allocateTemporaryBufferPlannar() called in clFFT_ExecutePlannar()
+  if(plan->temp_buffer_needed) {
+      size_t tmpLength = plan->n.x * plan->n.y * plan->n.z * batchSize * 2 * sizeof(cl_float);
+      *workSize += tmpLength;
+  }
+
+  return CL_SUCCESS;
+}