57 lines
2.8 KiB
C
57 lines
2.8 KiB
C
// UTF8.h -- Interface definition for conversions between Unicode and the UTF8 representation
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#ifndef __UTF8_H__
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#define __UTF8_H__
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// UTF8 is a multibyte encoding of 16-bit Unicode characters. Its primary purpose
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// is to provide a transmission form to take Unicode text through host environments
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// that assume all text is ASCII text.In particular many of those environments will
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// interpret a zero byte as marking the end of a text string.
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//
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// The UTF8 encoding guarantees that the ASCII section of Unicode (0x0000 - 0x007F)
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// is represented by 8-bit ASCII codes (0x00 - 0x7F). Thus any environment which
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// expects to see ASCII characters will see no difference when those ASCII characters
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// appear in a UTF8 stream.
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//
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// Those are the only single-byte encodings in UTF8. All other Unicode values are
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// represented with two or three byte codes. In those encodings all the byte values
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// values have their high bit set. Thus the appearance of a byte in the range
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// 0x00-0x7F always represents an ASCII character.
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//
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// Values in the range 0x0080 through 0x07FF are encoded in two bytes, while values
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// in the range 0x0x0800 through 0xFFFF are encoded with three bytes. The first byte
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// in an encoding defines the length of the encoding by the number of high order bits
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// set to one. Thus a two byte code has a first byte value of the form 110xxxxx and
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// the first byte of a three byte code has the form 1110xxxx. Trailing bytes always
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// have the form 10xxxxxx so they won't be mistaken for ASCII characters.
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//
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// Note that two byte codes represent values that have zeroes in the five high-order
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// bit positions. That means they can be represented in 11 bits. So we store those
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// eleven bits with the high order five bits in the first encoding byte, and we store
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// the low order six bits in the second byte of the code.
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//
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// Similarly for a three-byte code we store the high-order four-bits in the first byte,
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// we put the next six bits in the second code, and we store the low order six bits
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// in the third code.
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#define MAX_UTF8_PATH (MAX_PATH*3 - 2) // Worst case expansion from Unicode
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// path to UTF-8 encoded path.
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int WideCharToUTF8
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(LPCWSTR lpWideCharStr, // address of wide-character string
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int cchWideChar, // number of characters in string
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LPSTR lpMultiByteStr, // address of buffer for new string
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int cchMultiByte // size of buffer
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);
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int UTF8ToWideChar
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(LPCSTR lpMultiByteStr, // address of string to map
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int cchMultiByte, // number of characters in string
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LPWSTR lpWideCharStr, // address of wide-character buffer
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int cchWideChar // size of buffer
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);
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UINT BuildAKey(const WCHAR *pwcImage, UINT cwcImage, PCHAR pchKeyBuffer, UINT cchKeyBuffer);
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#endif // __UTF8_H__
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