chore: import upstream snapshot with attribution

paddle/phi/kernels/strings/case_utils.h

@@ -0,0 +1,74 @@
+/* Copyright (c) 2022 PaddlePaddle Authors. All Rights Reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License. */
+
+#pragma once
+#include <string>
+
+#include "paddle/phi/common/pstring.h"
+#include "paddle/phi/kernels/strings/unicode.h"
+#if defined(__NVCC__) || defined(__HIPCC__)
+#include <thrust/device_vector.h>
+#include <thrust/execution_policy.h>
+
+#include "paddle/phi/backends/gpu/gpu_context.h"
+#endif
+
+namespace phi {
+namespace strings {
+
+using pstring = dtype::pstring;
+struct AsciiToLower {
+  HOSTDEVICE char operator()(char in) const {
+    return ('A' <= in && in <= 'Z') ? in - ('Z' - 'z') : in;
+  }
+};
+
+struct AsciiToUpper {
+  HOSTDEVICE char operator()(char in) const {
+    return ('a' <= in && in <= 'z') ? in ^ 0x20 : in;
+  }
+};
+
+template <typename Context>
+struct UTF8ToLower {
+  HOSTDEVICE UTF8ToLower(const uint8_t* unicode_flag_map,
+                         const uint16_t* cases_map)
+      : unicode_flag_map_(unicode_flag_map), cases_map_(cases_map) {}
+
+  HOSTDEVICE uint32_t operator()(uint32_t in) const {
+    uint32_t flg = (in <= 0x00FFFF ? unicode_flag_map_[in] : 0);
+    return (strings::IsUpper(flg) ? cases_map_[in] : in);
+  }
+
+  const uint8_t* unicode_flag_map_;
+  const uint16_t* cases_map_;
+};
+
+template <typename Context>
+struct UTF8ToUpper {
+  HOSTDEVICE UTF8ToUpper(const uint8_t* unicode_flag_map,
+                         const uint16_t* cases_map)
+      : unicode_flag_map_(unicode_flag_map), cases_map_(cases_map) {}
+
+  HOSTDEVICE uint32_t operator()(uint32_t in) const {
+    uint32_t flg = (in <= 0x00FFFF ? unicode_flag_map_[in] : 0);
+    return (strings::IsLower(flg) ? cases_map_[in] : in);
+  }
+
+  const uint8_t* unicode_flag_map_;
+  const uint16_t* cases_map_;
+};
+
+}  // namespace strings
+}  // namespace phi