Use std::swap to swap values

src/exchange_buffer.cpp

 #include "float3DTensorT.hpp"
 #include <cstring>
 #include <stddef.h>
+#include <utility> // swap
 
 // Choose default method to push and pop data to the buffer
 // available methods: OPENMP, MEMCPY
@@ -17,21 +18,9 @@ int buffer_push(
     int i3_start, int i3_end,
     int buffer_counter)
 {
-    if (i1_end < i1_start) {
-        int swap = i1_start;
-        i1_start = i1_end;
-        i1_end = swap;
-    }
-    if (i2_end < i2_start) {
-        int swap = i2_start;
-        i2_start = i2_end;
-        i2_end = swap;
-    }
-    if (i3_end < i3_start) {
-        int swap = i3_start;
-        i3_start = i3_end;
-        i3_end = swap;
-    }
+    if (i1_end < i1_start) std::swap(i1_start, i1_end);
+    if (i2_end < i2_start) std::swap(i2_start, i2_end);
+    if (i3_end < i3_start) std::swap(i3_start, i3_end);
     for (int i1 = i1_start; i1 <= i1_end; i1++) {
         for (int i2 = i2_start; i2 <= i2_end; i2++) {
             #pragma omp simd
@@ -50,21 +39,9 @@ int buffer_pop(
     int i3_start, int i3_end,
     int buffer_counter)
 {
-    if (i1_end < i1_start) {
-        int swap = i1_start;
-        i1_start = i1_end;
-        i1_end = swap;
-    }
-    if (i2_end < i2_start) {
-        int swap = i2_start;
-        i2_start = i2_end;
-        i2_end = swap;
-    }
-    if (i3_end < i3_start) {
-        int swap = i3_start;
-        i3_start = i3_end;
-        i3_end = swap;
-    }
+    if (i1_end < i1_start) std::swap(i1_start, i1_end);
+    if (i2_end < i2_start) std::swap(i2_start, i2_end);
+    if (i3_end < i3_start) std::swap(i3_start, i3_end);
     for (int i1 = i1_start; i1 <= i1_end; i1++) {
         for (int i2 = i2_start; i2 <= i2_end; i2++) {
             #pragma omp simd
@@ -85,21 +62,9 @@ int buffer_push(
     int i3_start, int i3_end,
     int buffer_counter)
 {
-    if (i1_end < i1_start) {
-        int swap = i1_start;
-        i1_start = i1_end;
-        i1_end = swap;
-    }
-    if (i2_end < i2_start) {
-        int swap = i2_start;
-        i2_start = i2_end;
-        i2_end = swap;
-    }
-    if (i3_end < i3_start) {
-        int swap = i3_start;
-        i3_start = i3_end;
-        i3_end = swap;
-    }
+    if (i1_end < i1_start) std::swap(i1_start, i1_end);
+    if (i2_end < i2_start) std::swap(i2_start, i2_end);
+    if (i3_end < i3_start) std::swap(i3_start, i3_end);
     const size_t vec_len = i3_end - i3_start + 1;
     for (int i1 = i1_start; i1 <= i1_end; i1++) {
         for (int i2 = i2_start; i2 <= i2_end; i2++) {
@@ -117,21 +82,9 @@ int buffer_pop(
     int i3_start, int i3_end,
     int buffer_counter)
 {
-    if (i1_end < i1_start) {
-        int swap = i1_start;
-        i1_start = i1_end;
-        i1_end = swap;
-    }
-    if (i2_end < i2_start) {
-        int swap = i2_start;
-        i2_start = i2_end;
-        i2_end = swap;
-    }
-    if (i3_end < i3_start) {
-        int swap = i3_start;
-        i3_start = i3_end;
-        i3_end = swap;
-    }
+    if (i1_end < i1_start) std::swap(i1_start, i1_end);
+    if (i2_end < i2_start) std::swap(i2_start, i2_end);
+    if (i3_end < i3_start) std::swap(i3_start, i3_end);
     const size_t vec_len = i3_end - i3_start + 1;
     for (int i1 = i1_start; i1 <= i1_end; i1++) {
         for (int i2 = i2_start; i2 <= i2_end; i2++) {