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Diffstat (limited to 'src/runtime/string.c')
| -rw-r--r-- | src/runtime/string.c | 226 |
1 files changed, 226 insertions, 0 deletions
diff --git a/src/runtime/string.c b/src/runtime/string.c new file mode 100644 index 000000000..ed5debc33 --- /dev/null +++ b/src/runtime/string.c @@ -0,0 +1,226 @@ +// Copyright 2009 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +#include "runtime.h" +#include "arch_GOARCH.h" +#include "malloc.h" +#include "race.h" +#include "textflag.h" + +String runtime·emptystring; + +#pragma textflag NOSPLIT +intgo +runtime·findnull(byte *s) +{ + intgo l; + + if(s == nil) + return 0; + for(l=0; s[l]!=0; l++) + ; + return l; +} + +intgo +runtime·findnullw(uint16 *s) +{ + intgo l; + + if(s == nil) + return 0; + for(l=0; s[l]!=0; l++) + ; + return l; +} + +uintptr runtime·maxstring = 256; // a hint for print + +#pragma textflag NOSPLIT +String +runtime·gostringnocopy(byte *str) +{ + String s; + uintptr ms; + + s.str = str; + s.len = runtime·findnull(str); + while(true) { + ms = runtime·maxstring; + if(s.len <= ms || runtime·casp((void**)&runtime·maxstring, (void*)ms, (void*)s.len)) + return s; + } +} + +// TODO: move this elsewhere +enum +{ + Bit1 = 7, + Bitx = 6, + Bit2 = 5, + Bit3 = 4, + Bit4 = 3, + Bit5 = 2, + + 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 */ + + 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 */ + + Maskx = (1<<Bitx)-1, /* 0011 1111 */ + + Runeerror = 0xFFFD, + + SurrogateMin = 0xD800, + SurrogateMax = 0xDFFF, + + Runemax = 0x10FFFF, /* maximum rune value */ +}; + +static int32 +runetochar(byte *str, int32 rune) /* note: in original, arg2 was pointer */ +{ + /* Runes are signed, so convert to unsigned for range check. */ + uint32 c; + + /* + * one character sequence + * 00000-0007F => 00-7F + */ + c = rune; + if(c <= Rune1) { + str[0] = c; + return 1; + } + + /* + * two character sequence + * 0080-07FF => T2 Tx + */ + if(c <= Rune2) { + str[0] = T2 | (c >> 1*Bitx); + str[1] = Tx | (c & Maskx); + return 2; + } + + /* + * If the Rune is out of range or a surrogate half, 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; + if (SurrogateMin <= c && c <= SurrogateMax) + c = Runeerror; + + /* + * three character sequence + * 0800-FFFF => T3 Tx Tx + */ + if (c <= Rune3) { + str[0] = T3 | (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 | (c >> 3*Bitx); + str[1] = Tx | ((c >> 2*Bitx) & Maskx); + str[2] = Tx | ((c >> 1*Bitx) & Maskx); + str[3] = Tx | (c & Maskx); + return 4; +} + +String runtime·gostringsize(intgo); + +String +runtime·gostringw(uint16 *str) +{ + intgo n1, n2, i; + byte buf[8]; + String s; + + n1 = 0; + for(i=0; str[i]; i++) + n1 += runetochar(buf, str[i]); + s = runtime·gostringsize(n1+4); + n2 = 0; + for(i=0; str[i]; i++) { + // check for race + if(n2 >= n1) + break; + n2 += runetochar(s.str+n2, str[i]); + } + s.len = n2; + s.str[s.len] = 0; + return s; +} + +int32 +runtime·strcmp(byte *s1, byte *s2) +{ + uintptr i; + byte c1, c2; + + for(i=0;; i++) { + c1 = s1[i]; + c2 = s2[i]; + if(c1 < c2) + return -1; + if(c1 > c2) + return +1; + if(c1 == 0) + return 0; + } +} + +int32 +runtime·strncmp(byte *s1, byte *s2, uintptr n) +{ + uintptr i; + byte c1, c2; + + for(i=0; i<n; i++) { + c1 = s1[i]; + c2 = s2[i]; + if(c1 < c2) + return -1; + if(c1 > c2) + return +1; + if(c1 == 0) + break; + } + return 0; +} + +byte* +runtime·strstr(byte *s1, byte *s2) +{ + byte *sp1, *sp2; + + if(*s2 == 0) + return s1; + for(; *s1; s1++) { + if(*s1 != *s2) + continue; + sp1 = s1; + sp2 = s2; + for(;;) { + if(*sp2 == 0) + return s1; + if(*sp1++ != *sp2++) + break; + } + } + return nil; +} |