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Unified Diff: src/runtime/runtime-strings.cc

Issue 2533033003: Fix the uppercasing of U+00E7(ç) and U+00F7(÷) (Closed)
Patch Set: a bit more tweaks + tests Created 4 years ago
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Index: src/runtime/runtime-strings.cc
diff --git a/src/runtime/runtime-strings.cc b/src/runtime/runtime-strings.cc
index 328bdceb376c469e90c103c9464732415ba527e4..205b1898c40faa1b604d071fe63477fcf66f9669 100644
--- a/src/runtime/runtime-strings.cc
+++ b/src/runtime/runtime-strings.cc
@@ -679,122 +679,6 @@ MUST_USE_RESULT static Object* ConvertCaseHelper(
}
}
-
-static const uintptr_t kOneInEveryByte = kUintptrAllBitsSet / 0xFF;
-static const uintptr_t kAsciiMask = kOneInEveryByte << 7;
-
-// Given a word and two range boundaries returns a word with high bit
-// set in every byte iff the corresponding input byte was strictly in
-// the range (m, n). All the other bits in the result are cleared.
-// This function is only useful when it can be inlined and the
-// boundaries are statically known.
-// Requires: all bytes in the input word and the boundaries must be
-// ASCII (less than 0x7F).
-static inline uintptr_t AsciiRangeMask(uintptr_t w, char m, char n) {
- // Use strict inequalities since in edge cases the function could be
- // further simplified.
- DCHECK(0 < m && m < n);
- // Has high bit set in every w byte less than n.
- uintptr_t tmp1 = kOneInEveryByte * (0x7F + n) - w;
- // Has high bit set in every w byte greater than m.
- uintptr_t tmp2 = w + kOneInEveryByte * (0x7F - m);
- return (tmp1 & tmp2 & (kOneInEveryByte * 0x80));
-}
-
-
-#ifdef DEBUG
-static bool CheckFastAsciiConvert(char* dst, const char* src, int length,
- bool changed, bool is_to_lower) {
- bool expected_changed = false;
- for (int i = 0; i < length; i++) {
- if (dst[i] == src[i]) continue;
- expected_changed = true;
- if (is_to_lower) {
- DCHECK('A' <= src[i] && src[i] <= 'Z');
- DCHECK(dst[i] == src[i] + ('a' - 'A'));
- } else {
- DCHECK('a' <= src[i] && src[i] <= 'z');
- DCHECK(dst[i] == src[i] - ('a' - 'A'));
- }
- }
- return (expected_changed == changed);
-}
-#endif
-
-
-template <class Converter>
-static bool FastAsciiConvert(char* dst, const char* src, int length,
- bool* changed_out) {
-#ifdef DEBUG
- char* saved_dst = dst;
- const char* saved_src = src;
-#endif
- DisallowHeapAllocation no_gc;
- // We rely on the distance between upper and lower case letters
- // being a known power of 2.
- DCHECK('a' - 'A' == (1 << 5));
- // Boundaries for the range of input characters than require conversion.
- static const char lo = Converter::kIsToLower ? 'A' - 1 : 'a' - 1;
- static const char hi = Converter::kIsToLower ? 'Z' + 1 : 'z' + 1;
- bool changed = false;
- uintptr_t or_acc = 0;
- const char* const limit = src + length;
-
- // dst is newly allocated and always aligned.
- DCHECK(IsAligned(reinterpret_cast<intptr_t>(dst), sizeof(uintptr_t)));
- // Only attempt processing one word at a time if src is also aligned.
- if (IsAligned(reinterpret_cast<intptr_t>(src), sizeof(uintptr_t))) {
- // Process the prefix of the input that requires no conversion one aligned
- // (machine) word at a time.
- while (src <= limit - sizeof(uintptr_t)) {
- const uintptr_t w = *reinterpret_cast<const uintptr_t*>(src);
- or_acc |= w;
- if (AsciiRangeMask(w, lo, hi) != 0) {
- changed = true;
- break;
- }
- *reinterpret_cast<uintptr_t*>(dst) = w;
- src += sizeof(uintptr_t);
- dst += sizeof(uintptr_t);
- }
- // Process the remainder of the input performing conversion when
- // required one word at a time.
- while (src <= limit - sizeof(uintptr_t)) {
- const uintptr_t w = *reinterpret_cast<const uintptr_t*>(src);
- or_acc |= w;
- uintptr_t m = AsciiRangeMask(w, lo, hi);
- // The mask has high (7th) bit set in every byte that needs
- // conversion and we know that the distance between cases is
- // 1 << 5.
- *reinterpret_cast<uintptr_t*>(dst) = w ^ (m >> 2);
- src += sizeof(uintptr_t);
- dst += sizeof(uintptr_t);
- }
- }
- // Process the last few bytes of the input (or the whole input if
- // unaligned access is not supported).
- while (src < limit) {
- char c = *src;
- or_acc |= c;
- if (lo < c && c < hi) {
- c ^= (1 << 5);
- changed = true;
- }
- *dst = c;
- ++src;
- ++dst;
- }
-
- if ((or_acc & kAsciiMask) != 0) return false;
-
- DCHECK(CheckFastAsciiConvert(saved_dst, saved_src, length, changed,
- Converter::kIsToLower));
-
- *changed_out = changed;
- return true;
-}
-
-
template <class Converter>
MUST_USE_RESULT static Object* ConvertCase(
Handle<String> s, Isolate* isolate,
@@ -818,7 +702,7 @@ MUST_USE_RESULT static Object* ConvertCase(
String::FlatContent flat_content = s->GetFlatContent();
DCHECK(flat_content.IsFlat());
bool has_changed_character = false;
- bool is_ascii = FastAsciiConvert<Converter>(
+ bool is_ascii = FastAsciiConvert<Converter::kIsToLower>(
reinterpret_cast<char*>(result->GetChars()),
reinterpret_cast<const char*>(flat_content.ToOneByteVector().start()),
length, &has_changed_character);
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