diff options
Diffstat (limited to 'src/base')
-rw-r--r-- | src/base/string/raw/asint.c | 86 |
1 files changed, 86 insertions, 0 deletions
diff --git a/src/base/string/raw/asint.c b/src/base/string/raw/asint.c new file mode 100644 index 0000000..6751146 --- /dev/null +++ b/src/base/string/raw/asint.c @@ -0,0 +1,86 @@ +#include <u.h> +#include <base.h> + +long +strĀ·asint(char *s, char **end, int base) +{ + char *p; + vlong n, nn, m; + int c, ovfl, v, neg, ndig; + + p = s; + neg = 0; + n = 0; + ndig = 0; + ovfl = 0; + + /* White space */ + for(;; p++){ + switch(*p){ + case ' ': + case '\t': + case '\n': + case '\f': + case '\r': + case '\v': + continue; + } + break; + } + + /* Sign */ + if(*p=='-' || *p=='+') + if(*p++ == '-') + neg = 1; + + /* Base */ + if(base==0){ + base=10; + if(*p == '0'){ + base = 8; + if(p[1]=='x'||p[1]=='X'){ + p += 2; + base = 16; + } + } + }else if(base==16 && *p=='0'){ + if(p[1]=='x' || p[1]=='X') + p += 2; + }else if(base<0 || 36<base) + goto Return; + + /* Non-empty sequence of digits */ + m = LONG_MAX/base; + for(;; p++,ndig++){ + c = *p; + v = base; + if('0'<=c && c<='9') + v = c - '0'; + else if('a'<=c && c<='z') + v = c - 'a' + 10; + else if('A'<=c && c<='Z') + v = c - 'A' + 10; + if(v >= base) + break; + if(n > m) + ovfl = 1; + nn = n*base + v; + if(nn < n) + ovfl = 1; + n = nn; + } + +Return: + if(ndig == 0) + p = s; + if(end) + *end = p; + if(ovfl){ + if(neg) + return LONG_MIN; + return LONG_MAX; + } + if(neg) + return -n; + return n; +} |