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//
// utf8.h - UTF8 helper functions
//
#ifndef UTF8__H
#define UTF8__H
#define UTF8_MAXCHARLEN 4
//
// Return the location of the next character or UTF8 codepoint.
// (i.e. skip forward one codepoint at a time, not one byte at a time)
//
__attribute__((nonnull, pure))
static inline const char *next_char(file_t *f, const char *str)
{
if (__builtin_expect(str+1 <= f->end && (str[0] & 0x80) == 0x0, 1))
return str+1;
if (__builtin_expect(str+2 <= f->end && (str[0] & 0xe0) == 0xc0, 1))
return str+2;
if (__builtin_expect(str+3 <= f->end && (str[0] & 0xf0) == 0xe0, 1))
return str+3;
if (__builtin_expect(str+4 <= f->end && (str[0] & 0xf8) == 0xf0, 1))
return str+4;
return __builtin_expect(str+1 <= f->end, 1) ? str+1 : f->end;
}
//
// Return the location of the previous character or UTF8 codepoint.
// (i.e. skip backwards one codepoint at a time, not one byte at a time)
//
__attribute__((nonnull, pure))
static inline const char *prev_char(file_t *f, const char *str)
{
if (__builtin_expect(str-1 >= f->contents && (str[-1] & 0x80) == 0x0, 1))
return str-1;
if (__builtin_expect(str-2 >= f->contents && (str[-2] & 0xe0) == 0xc0, 1))
return str-2;
if (__builtin_expect(str-3 >= f->contents && (str[-3] & 0xf0) == 0xe0, 1))
return str-3;
if (__builtin_expect(str-4 >= f->contents && (str[-4] & 0xf8) == 0xf0, 1))
return str-4;
return __builtin_expect(str-1 >= f->contents, 1) ? str-1 : f->contents;
}
#endif
// vim: ts=4 sw=0 et cino=L2,l1,(0,W4,m1
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