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utf8: use a more verbose mask test name

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This commit is contained in:
Danny Robson 2017-10-02 15:40:23 +11:00
parent 7ecaaacd93
commit 45e2477e1b
1 changed files with 22 additions and 19 deletions
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41
utf8.cpp
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@ -21,21 +21,25 @@
template <typename T> template <typename T>
struct test { struct test {
constexpr constexpr
test (T _mask, T _value, T _shift): test (T _mask, T _bits) noexcept:
mask (_mask), mask (_mask),
value (_value), bits (_bits)
shift (_shift)
{ ; } { ; }
constexpr bool constexpr bool
operator() (T t) const valid (T t) const noexcept
{ {
return (t & mask) == value; return (t & mask) == bits;
}
constexpr T
value (T t) const noexcept
{
return t & ~mask;
} }
T mask; T mask;
T value; T bits;
T shift;
}; };
@ -44,8 +48,7 @@ static constexpr test<uint32_t>
operator"" _test (const char *str, size_t len) operator"" _test (const char *str, size_t len)
{ {
uint32_t mask = 0; uint32_t mask = 0;
uint32_t value = 0; uint32_t bits = 0;
uint32_t shift = 0;
if (str[0] != '0' || str[1] != 'b') if (str[0] != '0' || str[1] != 'b')
throw std::invalid_argument ("invalid bit test prefix"); throw std::invalid_argument ("invalid bit test prefix");
@ -53,20 +56,20 @@ operator"" _test (const char *str, size_t len)
for (size_t i = 2; i < len; ++i) { for (size_t i = 2; i < len; ++i) {
auto c = str[i]; auto c = str[i];
mask <<= 1; mask <<= 1;
value <<= 1; bits <<= 1;
switch (c) { switch (c) {
case '0': mask |= 0x1; value |= 0x0; break; case '0': mask |= 0x1; bits |= 0x0; break;
case '1': mask |= 0x1; value |= 0x1; break; case '1': mask |= 0x1; bits |= 0x1; break;
case 'x': mask |= 0x0; value |= 0x0; ++shift; break; case 'x': mask |= 0x0; bits |= 0x0; break;
default: default:
throw std::invalid_argument ("invalid bit test character"); throw std::invalid_argument ("invalid bit test character");
} }
} }
return { mask, value, shift }; return { mask, bits };
} }
@ -88,10 +91,10 @@ util::utf8::decode (view<const std::byte*> src)
for (auto cursor = src.cbegin (); cursor != src.cend (); ++cursor) { for (auto cursor = src.cbegin (); cursor != src.cend (); ++cursor) {
codepoint_t c = std::to_integer<codepoint_t> (*cursor); codepoint_t c = std::to_integer<codepoint_t> (*cursor);
int len = TESTS[0] (c) ? 0 : int len = TESTS[0].valid (c) ? 0 :
TESTS[1] (c) ? 1 : TESTS[1].valid (c) ? 1 :
TESTS[2] (c) ? 2 : TESTS[2].valid (c) ? 2 :
TESTS[3] (c) ? 3 : TESTS[3].valid (c) ? 3 :
throw malformed_error {}; throw malformed_error {};
if (cursor + len >= src.cend ()) if (cursor + len >= src.cend ())