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// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
/**
* Unicode utilities.
*/
#pragma once
#include <cstddef>
#include <cstdint>
#include <sys/types.h>
/** ucs4_t is the type of the 4-byte UCS4 characters */
using ucs4_t = uint32_t;
/**
* Utility class for unicode character handling.
* Used to examine properties of unicode characters, and
* provide fast conversion methods between often used encodings.
*/
class Fast_UnicodeUtil {
private:
/**
* Is true when the tables have been initialized. Is set by
* InitTables, and should be protected by the _initMutex before
* inspection.
*/
/** Two-level lowercase table. 256 pages, 256 elements each.
* This table is defined in unicode-lowercase.cpp, which is
* autogenerated by the extcase application. */
static unsigned short *_compLowerCase[256];
/** Two-level character property table. 256 pages with 256 elements each.
* This table is defined in unicode-charprops.cpp, which is
* autogenerated by the extprop applicatoin. */
static unsigned char *_compCharProps[256];
/** The property bit identificators */
enum {
_spaceProp = 1,
_wordcharProp = 2,
_ideographicProp = 4,
_decimalDigitCharProp = 8,
_ignorableControlCharProp = 16,
_terminalPunctuationCharProp = 32
};
public:
virtual ~Fast_UnicodeUtil() { }
/** Initialize the ISO 8859-1 static tables. */
static void InitTables();
/** Indicates an invalid UTF-8 character sequence. */
enum { _BadUTF8Char = 0xfffffffeu };
/**
* Test for word character. Characters with certain unicode properties
* are recognized as word characters. In addition to this, all
* characters with the custom _FASTWordProp is regarded as a word
* character. The previous range in _privateUseProp is included
* in the _FASTWordProp set of ranges.
* @param testchar the UCS4 character to test.
* @return true if testchar is a word character, i.e. if it has
* one or more of the properties alphabetic, ideographic,
* combining char, decimal digit char, private use, extender.
*/
static bool IsWordChar(ucs4_t testchar) {
return (testchar < 65536 &&
(_compCharProps[testchar >> 8][testchar & 255] &
_wordcharProp) != 0);
}
/**
* Get the next UCS4 character from an UTF-8 string buffer.
* Modify the src pointer to allow future calls.
* @param src The address of a pointer to the current position
* in the UTF-8 string.
* @param length The maximum allowed length of the byte sequence.
* -1 means no check.
* @return The next UCS4 character, or _BadUTF8Char if the
* next character is invalid.
*/
static ucs4_t GetUTF8Char(const unsigned char *& src);
static ucs4_t GetUTF8Char(const char *& src) {
const unsigned char *temp = reinterpret_cast<const unsigned char *>(src);
ucs4_t res = GetUTF8Char(temp);
src = reinterpret_cast<const char *>(temp);
return res;
}
/**
* Put an UCS4 character into a buffer as an UTF-8 representation.
* @param dst The destination buffer.
* @param i The UCS4 character.
* @return Pointer to the next position in dst after the putted byte(s).
*/
static char *utf8cput(char *dst, ucs4_t i) {
if (i < 128)
*dst++ = i;
else if (i < 0x800) {
*dst++ = (i >> 6) | 0xc0;
*dst++ = (i & 63) | 0x80;
} else if (i < 0x10000) {
*dst++ = (i >> 12) | 0xe0;
*dst++ = ((i >> 6) & 63) | 0x80;
*dst++ = (i & 63) | 0x80;
} else if (i < 0x200000) {
*dst++ = (i >> 18) | 0xf0;
*dst++ = ((i >> 12) & 63) | 0x80;
*dst++ = ((i >> 6) & 63) | 0x80;
*dst++ = (i & 63) | 0x80;
} else if (i < 0x4000000) {
*dst++ = (i >> 24) | 0xf8;
*dst++ = ((i >> 18) & 63) | 0x80;
*dst++ = ((i >> 12) & 63) | 0x80;
*dst++ = ((i >> 6) & 63) | 0x80;
*dst++ = (i & 63) | 0x80;
} else {
*dst++ = (i >> 30) | 0xfc;
*dst++ = ((i >> 24) & 63) | 0x80;
*dst++ = ((i >> 18) & 63) | 0x80;
*dst++ = ((i >> 12) & 63) | 0x80;
*dst++ = ((i >> 6) & 63) | 0x80;
*dst++ = (i & 63) | 0x80;
}
return dst;
}
/**
* Copy an UTF-8 string into an UCS4 string.
* @param dst The UCS4 destination buffer.
* @param src The UTF-8 source buffer.
* @return A pointer to the destination string.
*/
static ucs4_t *ucs4copy(ucs4_t *dst, const char *src);
/**
* Get the length of the UTF-8 representation of an UCS4 character.
* @param i The UCS4 character.
* @return The number of bytes required for the UTF-8 representation.
*/
static size_t utf8clen(ucs4_t i) {
if (i < 128)
return 1;
else if (i < 0x800)
return 2;
else if (i < 0x10000)
return 3;
else if (i < 0x200000)
return 4;
else if (i < 0x4000000)
return 5;
else
return 6;
}
/**
* Lowercase an UCS4 character.
* @param testchar The character to lowercase.
* @return The lowercase of the input, if defined. Else the input character.
*/
static ucs4_t ToLower(ucs4_t testchar)
{
ucs4_t ret;
if (testchar < 65536) {
ret = _compLowerCase[testchar >> 8][testchar & 255];
if (ret == 0)
return testchar;
return ret;
} else
return testchar;
}
/** Move forwards or backwards a number of characters within an UTF8 buffer
* Modify pos to yield new position if possible
* @param start A pointer to the start of the UTF8 buffer
* @param length The length of the UTF8 buffer
* @param pos A pointer to the current position within the UTF8 buffer,
* updated to reflect new position upon return
* @param offset An offset (+/-) in number of UTF8 characters.
* Offset 0 means move to the start of the current character.
* @return Number of bytes moved, or -1 if out of range
*/
static int UTF8move(unsigned const char* start, size_t length,
unsigned const char*& pos, off_t offset);
/**
* Find the number of characters in an UCS4 string.
* @param str The UCS4 string.
* @return The number of characters.
*/
static size_t ucs4strlen(const ucs4_t *str);
/**
* Convert UCS4 to UTF-8, bounded by max lengths.
* @param dst The destination buffer for the UTF-8 string.
* @param src The source UCS4 string.
* @param maxdst The maximum number of bytes to put into dst.
* @param maxsrc The maximum number of characters to convert from src.
* @return A pointer to the destination.
*/
static char *utf8ncopy(char *dst, const ucs4_t *src, int maxdst, int maxsrc);
/**
* Compare an UTF-8 string to a UCS4 string, analogous to strcmp(3).
* @param s1 The UTF-8 string.
* @param s2 The UCS4 string.
* @return An integer less than, equal to, or greater than zero,
* if s1 is, respectively, less than, matching, or greater than s2.
* NB Only used in local test
*/
static int utf8cmp(const char *s1, const ucs4_t *s2);
/**
* Test for terminal punctuation.
* @param testchar the UCS4 character to test.
* @return true if testchar is a terminal punctuation character,
* i.e. if it has the terminal punctuation char property.
*/
static bool IsTerminalPunctuationChar(ucs4_t testchar) {
return (testchar < 65536 &&
(_compCharProps[testchar >> 8][testchar & 255] &
_terminalPunctuationCharProp) != 0);
}
/**
* Get the next UCS4 character from an UTF-8 string buffer.
* We assume that the first character in the UTF-8 string is >= 0x80 (non-ascii).
* Modify the src pointer to allow future calls.
* @param src The address of a pointer to the current position
* in the UTF-8 string.
* @return The next UCS4 character, or _BadUTF8Char if the
* next character is invalid.
*/
static ucs4_t GetUTF8CharNonAscii(unsigned const char *&src);
// this is really an alias of the above function
static ucs4_t GetUTF8CharNonAscii(const char *&src) {
unsigned const char *temp = reinterpret_cast<unsigned const char *>(src);
ucs4_t res = GetUTF8CharNonAscii(temp);
src = reinterpret_cast<const char *>(temp);
return res;
}
};
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