ref: 2f4516ba69e49b93de2f844c5e772112ff58a31e
dir: /libmp/strtomp.c/
#include "os.h" #include <mp.h> #include <libsec.h> #include "dat.h" static struct { int inited; uchar t64[256]; uchar t32[256]; uchar t16[256]; uchar t10[256]; } tab; enum { INVAL= 255 }; static char set64[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; static char set32[] = "23456789abcdefghijkmnpqrstuvwxyz"; static char set16[] = "0123456789ABCDEF0123456789abcdef"; static char set10[] = "0123456789"; static void init(void) { char *p; memset(tab.t64, INVAL, sizeof(tab.t64)); memset(tab.t32, INVAL, sizeof(tab.t32)); memset(tab.t16, INVAL, sizeof(tab.t16)); memset(tab.t10, INVAL, sizeof(tab.t10)); for(p = set64; *p; p++) tab.t64[(uchar)*p] = p-set64; for(p = set32; *p; p++) tab.t32[(uchar)*p] = p-set32; for(p = set16; *p; p++) tab.t16[(uchar)*p] = (p-set16)%16; for(p = set10; *p; p++) tab.t10[(uchar)*p] = (p-set10); tab.inited = 1; } static char* from16(char *a, mpint *b) { char *p, *next; int i; mpdigit x; b->top = 0; for(p = a; *p; p++) if(tab.t16[(uchar)*p] == INVAL) break; mpbits(b, (p-a)*4); b->top = 0; next = p; while(p > a){ x = 0; for(i = 0; i < Dbits; i += 4){ if(p <= a) break; x |= tab.t16[(uchar)*--p]<<i; } b->p[b->top++] = x; } return next; } static ulong mppow10[] = { 1, 10, 100, 1000, 10000, 100000, 1000000, 10000000, 100000000, 1000000000 }; static char* from10(char *a, mpint *b) { ulong x, y; mpint *pow, *r; int i; pow = mpnew(0); r = mpnew(0); b->top = 0; for(;;){ // do a billion at a time in native arithmetic x = 0; for(i = 0; i < 9; i++){ y = tab.t10[(uchar)*a]; if(y == INVAL) break; a++; x *= 10; x += y; } if(i == 0) break; // accumulate into mpint uitomp(mppow10[i], pow); uitomp(x, r); mpmul(b, pow, b); mpadd(b, r, b); if(i != 9) break; } mpfree(pow); mpfree(r); return a; } static char* from64(char *a, mpint *b) { char *buf = a; uchar *p; int n, m; for(; tab.t64[(uchar)*a] != INVAL; a++) ; n = a-buf; mpbits(b, n*6); p = malloc(n); if(p == nil) return a; m = dec64(p, n, buf, n); betomp(p, m, b); free(p); return a; } static char* from32(char *a, mpint *b) { char *buf = a; uchar *p; int n, m; for(; tab.t64[(uchar)*a] != INVAL; a++) ; n = a-buf; mpbits(b, n*5); p = malloc(n); if(p == nil) return a; m = dec32(p, n, buf, n); betomp(p, m, b); free(p); return a; } mpint* strtomp(char *a, char **pp, int base, mpint *b) { int sign; char *e; if(b == nil) b = mpnew(0); if(tab.inited == 0) init(); while(*a==' ' || *a=='\t') a++; sign = 1; for(;; a++){ switch(*a){ case '-': sign *= -1; continue; } break; } switch(base){ case 10: e = from10(a, b); break; default: case 16: e = from16(a, b); break; case 32: e = from32(a, b); break; case 64: e = from64(a, b); break; } // if no characters parsed, there wasn't a number to convert if(e == a) return nil; mpnorm(b); b->sign = sign; if(pp != nil) *pp = e; return b; }