diff options
Diffstat (limited to 'src/third_party/re2/dist/util/rune.cc')
| -rw-r--r-- | src/third_party/re2/dist/util/rune.cc | 260 |
1 files changed, 260 insertions, 0 deletions
diff --git a/src/third_party/re2/dist/util/rune.cc b/src/third_party/re2/dist/util/rune.cc new file mode 100644 index 00000000000..4f625ea380f --- /dev/null +++ b/src/third_party/re2/dist/util/rune.cc @@ -0,0 +1,260 @@ +/* + * 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 |