Function to encode *valid* UTF-32 to UTF-8
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@ -413,6 +413,50 @@ dchar decodeValidUTF8NoGC(const(char[]) str, ref size_t index)
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assert(false, invalidUTFMsg);
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assert(false, invalidUTFMsg);
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}
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}
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/// @nogc version of std.utf.endoce() for char[], but assumes c is a valid UTF-32 char.
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///
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/// The caller $(B must) handle ASCII (< 0x80) characters manually; this is asserted to
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/// force code using this function to be efficient.
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///
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/// Params:
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///
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/// buf = Buffer to write the encoded result to.
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/// c = Character to encode. Must be valid UTF-32, otherwise undefined behavior
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/// $(D will) occur.
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///
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/// Returns: Number of bytes the encoded character takes up in buf.
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size_t encodeValidCharNoGC(ref char[4] buf, dchar c) @safe pure nothrow @nogc
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{
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assert(isValidDchar(c));
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// Force the caller to optimize ASCII (the 1-byte case)
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assert(c >= 0x80, "Caller should explicitly handle ASCII chars");
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if (c <= 0x7FF)
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{
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buf[0] = cast(char)(0xC0 | (c >> 6));
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buf[1] = cast(char)(0x80 | (c & 0x3F));
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return 2;
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}
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if (c <= 0xFFFF)
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{
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assert(0xD800 > c || c > 0xDFFF,
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"Supposedly valid code point is a surrogate code point");
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buf[0] = cast(char)(0xE0 | (c >> 12));
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buf[1] = cast(char)(0x80 | ((c >> 6) & 0x3F));
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buf[2] = cast(char)(0x80 | (c & 0x3F));
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return 3;
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}
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if (c <= 0x10FFFF)
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{
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buf[0] = cast(char)(0xF0 | (c >> 18));
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buf[1] = cast(char)(0x80 | ((c >> 12) & 0x3F));
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buf[2] = cast(char)(0x80 | ((c >> 6) & 0x3F));
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buf[3] = cast(char)(0x80 | (c & 0x3F));
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return 4;
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}
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assert(false, "This should not be reached for valid dchars");
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}
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/// @nogc version of std.utf.isValidDchar
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/// @nogc version of std.utf.isValidDchar
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bool isValidDchar(dchar c) @safe pure nothrow @nogc
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bool isValidDchar(dchar c) @safe pure nothrow @nogc
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{
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{
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