| /* |
| * The authors of this software are Rob Pike and Ken Thompson. |
| * Copyright (c) 2002 by Lucent Technologies. |
| * Permission to use, copy, modify, and distribute this software for any |
| * purpose without fee is hereby granted, provided that this entire notice |
| * is included in all copies of any software which is or includes a copy |
| * or modification of this software and in all copies of the supporting |
| * documentation for such software. |
| * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR IMPLIED |
| * WARRANTY. IN PARTICULAR, NEITHER THE AUTHORS NOR LUCENT TECHNOLOGIES MAKE ANY |
| * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE MERCHANTABILITY |
| * OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR PURPOSE. |
| */ |
| |
| #include <stdarg.h> |
| #include <string.h> |
| |
| #include "util/utf.h" |
| |
| namespace re2 { |
| |
| enum |
| { |
| Bit1 = 7, |
| Bitx = 6, |
| Bit2 = 5, |
| Bit3 = 4, |
| Bit4 = 3, |
| Bit5 = 2, |
| |
| T1 = ((1<<(Bit1+1))-1) ^ 0xFF, /* 0000 0000 */ |
| Tx = ((1<<(Bitx+1))-1) ^ 0xFF, /* 1000 0000 */ |
| T2 = ((1<<(Bit2+1))-1) ^ 0xFF, /* 1100 0000 */ |
| T3 = ((1<<(Bit3+1))-1) ^ 0xFF, /* 1110 0000 */ |
| T4 = ((1<<(Bit4+1))-1) ^ 0xFF, /* 1111 0000 */ |
| T5 = ((1<<(Bit5+1))-1) ^ 0xFF, /* 1111 1000 */ |
| |
| Rune1 = (1<<(Bit1+0*Bitx))-1, /* 0000 0000 0111 1111 */ |
| Rune2 = (1<<(Bit2+1*Bitx))-1, /* 0000 0111 1111 1111 */ |
| Rune3 = (1<<(Bit3+2*Bitx))-1, /* 1111 1111 1111 1111 */ |
| Rune4 = (1<<(Bit4+3*Bitx))-1, |
| /* 0001 1111 1111 1111 1111 1111 */ |
| |
| Maskx = (1<<Bitx)-1, /* 0011 1111 */ |
| Testx = Maskx ^ 0xFF, /* 1100 0000 */ |
| |
| Bad = Runeerror, |
| }; |
| |
| int |
| chartorune(Rune *rune, const char *str) |
| { |
| int c, c1, c2, c3; |
| long l; |
| |
| /* |
| * one character sequence |
| * 00000-0007F => T1 |
| */ |
| c = *(unsigned char*)str; |
| if(c < Tx) { |
| *rune = c; |
| return 1; |
| } |
| |
| /* |
| * two character sequence |
| * 0080-07FF => T2 Tx |
| */ |
| c1 = *(unsigned char*)(str+1) ^ Tx; |
| if(c1 & Testx) |
| goto bad; |
| if(c < T3) { |
| if(c < T2) |
| goto bad; |
| l = ((c << Bitx) | c1) & Rune2; |
| if(l <= Rune1) |
| goto bad; |
| *rune = l; |
| return 2; |
| } |
| |
| /* |
| * three character sequence |
| * 0800-FFFF => T3 Tx Tx |
| */ |
| c2 = *(unsigned char*)(str+2) ^ Tx; |
| if(c2 & Testx) |
| goto bad; |
| if(c < T4) { |
| l = ((((c << Bitx) | c1) << Bitx) | c2) & Rune3; |
| if(l <= Rune2) |
| goto bad; |
| *rune = l; |
| return 3; |
| } |
| |
| /* |
| * four character sequence (21-bit value) |
| * 10000-1FFFFF => T4 Tx Tx Tx |
| */ |
| c3 = *(unsigned char*)(str+3) ^ Tx; |
| if (c3 & Testx) |
| goto bad; |
| if (c < T5) { |
| l = ((((((c << Bitx) | c1) << Bitx) | c2) << Bitx) | c3) & Rune4; |
| if (l <= Rune3) |
| goto bad; |
| *rune = l; |
| return 4; |
| } |
| |
| /* |
| * Support for 5-byte or longer UTF-8 would go here, but |
| * since we don't have that, we'll just fall through to bad. |
| */ |
| |
| /* |
| * bad decoding |
| */ |
| bad: |
| *rune = Bad; |
| return 1; |
| } |
| |
| int |
| runetochar(char *str, const Rune *rune) |
| { |
| /* Runes are signed, so convert to unsigned for range check. */ |
| unsigned long c; |
| |
| /* |
| * one character sequence |
| * 00000-0007F => 00-7F |
| */ |
| c = *rune; |
| if(c <= Rune1) { |
| str[0] = static_cast<char>(c); |
| return 1; |
| } |
| |
| /* |
| * two character sequence |
| * 0080-07FF => T2 Tx |
| */ |
| if(c <= Rune2) { |
| str[0] = T2 | static_cast<char>(c >> 1*Bitx); |
| str[1] = Tx | (c & Maskx); |
| return 2; |
| } |
| |
| /* |
| * If the Rune is out of range, convert it to the error rune. |
| * Do this test here because the error rune encodes to three bytes. |
| * Doing it earlier would duplicate work, since an out of range |
| * Rune wouldn't have fit in one or two bytes. |
| */ |
| if (c > Runemax) |
| c = Runeerror; |
| |
| /* |
| * three character sequence |
| * 0800-FFFF => T3 Tx Tx |
| */ |
| if (c <= Rune3) { |
| str[0] = T3 | static_cast<char>(c >> 2*Bitx); |
| str[1] = Tx | ((c >> 1*Bitx) & Maskx); |
| str[2] = Tx | (c & Maskx); |
| return 3; |
| } |
| |
| /* |
| * four character sequence (21-bit value) |
| * 10000-1FFFFF => T4 Tx Tx Tx |
| */ |
| str[0] = T4 | static_cast<char>(c >> 3*Bitx); |
| str[1] = Tx | ((c >> 2*Bitx) & Maskx); |
| str[2] = Tx | ((c >> 1*Bitx) & Maskx); |
| str[3] = Tx | (c & Maskx); |
| return 4; |
| } |
| |
| int |
| runelen(Rune rune) |
| { |
| char str[10]; |
| |
| return runetochar(str, &rune); |
| } |
| |
| int |
| fullrune(const char *str, int n) |
| { |
| if (n > 0) { |
| int c = *(unsigned char*)str; |
| if (c < Tx) |
| return 1; |
| if (n > 1) { |
| if (c < T3) |
| return 1; |
| if (n > 2) { |
| if (c < T4 || n > 3) |
| return 1; |
| } |
| } |
| } |
| return 0; |
| } |
| |
| |
| int |
| utflen(const char *s) |
| { |
| int c; |
| long n; |
| Rune rune; |
| |
| n = 0; |
| for(;;) { |
| c = *(unsigned char*)s; |
| if(c < Runeself) { |
| if(c == 0) |
| return n; |
| s++; |
| } else |
| s += chartorune(&rune, s); |
| n++; |
| } |
| return 0; |
| } |
| |
| char* |
| utfrune(const char *s, Rune c) |
| { |
| long c1; |
| Rune r; |
| int n; |
| |
| if(c < Runesync) /* not part of utf sequence */ |
| return strchr((char*)s, c); |
| |
| for(;;) { |
| c1 = *(unsigned char*)s; |
| if(c1 < Runeself) { /* one byte rune */ |
| if(c1 == 0) |
| return 0; |
| if(c1 == c) |
| return (char*)s; |
| s++; |
| continue; |
| } |
| n = chartorune(&r, s); |
| if(r == c) |
| return (char*)s; |
| s += n; |
| } |
| return 0; |
| } |
| |
| } // namespace re2 |