Move WrapDimMinimal to c10

Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/14793

Reviewed By: ezyang

Differential Revision: D13336841

fbshipit-source-id: 4365a799e1856cc68dd94a273e97663fee5f51db

1 files changed, 23 insertions, 0 deletions

diff --git a/c10/core/WrapDimMinimal.h b/c10/core/WrapDimMinimal.h
new file mode 100644
index 0000000000..bebd24a043
--- /dev/null
+++ b/c10/core/WrapDimMinimal.h
@@ -0,0 +1,23 @@
+#pragma once
+
+#include <c10/util/Exception.h>
+
+namespace c10 {
+
+static inline int64_t maybe_wrap_dim(int64_t dim, int64_t dim_post_expr, bool wrap_scalar=true) {
+  if (dim_post_expr <= 0) {
+    AT_CHECK(wrap_scalar, "dimension specified as ", dim, " but tensor has no dimensions");
+    dim_post_expr = 1; // this will make range [-1, 0]
+  }
+
+  int64_t min = -dim_post_expr;
+  int64_t max = dim_post_expr - 1;
+  AT_CHECK(
+      dim >= min && dim <= max,
+      "Dimension out of range (expected to be in range of [",
+      min, ", ", max, "], but got ", dim, ")");
+  if (dim < 0) dim += dim_post_expr;
+  return dim;
+}
+
+}