Use Apple's PUA Unicode data

oops

stdlib/public/stubs/Unicode/UnicodeNormalization.cpp

@@ -0,0 +1,116 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2021 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+#if defined(__APPLE__)
+#include "Apple/NormalizationData.h"
+#else
+#include "Common/NormalizationData.h"
+#endif
+
+#include "../SwiftShims/UnicodeData.h"
+#include <limits>
+
+SWIFT_RUNTIME_STDLIB_INTERNAL
+__swift_uint16_t _swift_stdlib_getNormData(__swift_uint32_t scalar) {
+  // Fast Path: ASCII and some latiny scalars are very basic and have no
+  // normalization properties.
+  if (scalar < 0xC0) {
+    return 0;
+  }
+
+  auto dataIdx = _swift_stdlib_getScalarBitArrayIdx(scalar,
+                                                    _swift_stdlib_normData,
+                                                  _swift_stdlib_normData_ranks);
+
+  // If we don't have an index into the data indices, then this scalar has no
+  // normalization information.
+  if (dataIdx == std::numeric_limits<__swift_intptr_t>::max()) {
+    return 0;
+  }
+
+  auto scalarDataIdx = _swift_stdlib_normData_data_indices[dataIdx];
+  return _swift_stdlib_normData_data[scalarDataIdx];
+}
+
+SWIFT_RUNTIME_STDLIB_INTERNAL
+const __swift_uint8_t * const _swift_stdlib_nfd_decompositions = _swift_stdlib_nfd_decomp;
+
+SWIFT_RUNTIME_STDLIB_INTERNAL
+__swift_uint32_t _swift_stdlib_getDecompositionEntry(__swift_uint32_t scalar) {
+  auto levelCount = NFD_DECOMP_LEVEL_COUNT;
+  __swift_intptr_t decompIdx = _swift_stdlib_getMphIdx(scalar, levelCount,
+                                                  _swift_stdlib_nfd_decomp_keys,
+                                                  _swift_stdlib_nfd_decomp_ranks,
+                                                  _swift_stdlib_nfd_decomp_sizes);
+
+  return _swift_stdlib_nfd_decomp_indices[decompIdx];
+}
+
+SWIFT_RUNTIME_STDLIB_INTERNAL
+__swift_uint32_t _swift_stdlib_getComposition(__swift_uint32_t x,
+                                            __swift_uint32_t y) {
+  auto levelCount = NFC_COMP_LEVEL_COUNT;
+  __swift_intptr_t compIdx = _swift_stdlib_getMphIdx(y, levelCount,
+                                                  _swift_stdlib_nfc_comp_keys,
+                                                  _swift_stdlib_nfc_comp_ranks,
+                                                  _swift_stdlib_nfc_comp_sizes);
+  auto array = _swift_stdlib_nfc_comp_indices[compIdx];
+
+  // Ensure that the first element in this array is equal to our y scalar.
+  auto realY = (array[0] << 11) >> 11;
+
+  if (y != realY) {
+    return std::numeric_limits<__swift_uint32_t>::max();
+  }
+
+  auto count = array[0] >> 21;
+
+  __swift_uint32_t low = 1;
+  __swift_uint32_t high = count - 1;
+
+  while (high >= low) {
+    auto idx = low + (high - low) / 2;
+  
+    auto entry = array[idx];
+  
+    // Shift the range count out of the scalar.
+    auto lower = (entry << 15) >> 15;
+  
+    bool isNegative = entry >> 31;
+    auto rangeCount = (entry << 1) >> 18;
+  
+    if (isNegative) {
+      rangeCount = -rangeCount;
+    }
+  
+    auto composed = lower + rangeCount;
+  
+    if (x == lower) {
+      return composed;
+    }
+  
+    if (x > lower) {
+      low = idx + 1;
+      continue;
+    }
+  
+    if (x < lower) {
+      high = idx - 1;
+      continue;
+    }
+  }
+
+  // If we made it out here, then our scalar was not found in the composition
+  // array.
+  // Return the max here to indicate that we couldn't find one.
+  return std::numeric_limits<__swift_uint32_t>::max();
+}