ref: 26e00d014cebde8bc07725700b5ac9c0cade8171
dir: /sys/src/cmd/ip/cifsd/pack.c/
#include <u.h> #include <libc.h> #include "dat.h" #include "fns.h" int unpack(uchar *b, uchar *p, uchar *e, char *f, ...) { va_list a; int r; va_start(a, f); r = vunpack(b, p, e, f, a); va_end(a); return r; } int pack(uchar *b, uchar *p, uchar *e, char *f, ...) { va_list a; int r; va_start(a, f); r = vpack(b, p, e, f, a); va_end(a); return r; } int vunpack(uchar *b, uchar *p, uchar *e, char *f, va_list a) { struct { void *prev; int o, c, i; uchar *e; uchar **ap, **ae; } sub[8], *sp, *sa; int (*funpack)(uchar *, uchar *, uchar *, void *); char c, ff[2]; int i, x, n; uchar *t; memset(sub, 0, sizeof(sub)); for(sp = sub; sp < sub+nelem(sub); sp++){ sp->o = -1; sp->c = -1; sp->i = 1; } t = p; sp = nil; sa = sub; while(c = *f++){ switch(c){ case '_': case 'b': if(p >= e) return 0; if(c == 'b') *va_arg(a, int*) = *p; p++; break; case 'w': if(p+1 >= e) return 0; *va_arg(a, int*) = (int)p[1]<<8 | (int)p[0]; p+=2; break; case 'l': if(p+3 >= e) return 0; *va_arg(a, int*) = (int)p[3]<<24 | (int)p[2]<<16 | (int)p[1]<<8 | (int)p[0]; p+=4; break; case 'v': if(p+7 >= e) return 0; *va_arg(a, vlong*) = (vlong)p[7]<<56 | (vlong)p[6]<<48 | (vlong)p[5]<<40 | (vlong)p[4]<<32 | (vlong)p[3]<<24 | (vlong)p[2]<<16 | (vlong)p[1]<<8 | (vlong)p[0]; p += 8; break; case '%': x = *f++ - '0'; while((p - b) % x) p++; break; case 'f': funpack = va_arg(a, void*); if((n = funpack(b, p, e, va_arg(a, void*))) == 0) return 0; p += n; break; case '#': case '@': x = *f++ - '0'; ff[0] = *f++; ff[1] = 0; if((n = unpack(b, p, e, ff, &i)) == 0) return 0; p += n; if(c == '#'){ sub[x].c = i; } else { sub[x].o = i; } break; case '{': case '[': sa->prev = sp; sp = sa++; if(*f == '*'){ sp->i = f[1]-'0'; f += 2; } if(sp->o >= 0 && b + sp->o > p) if(b + sp->o <= e || *f != '?') p = b + sp->o; if(*f == '?') f++; sp->o = p - b; sp->e = e; if(sp->c >= 0){ e = p + sp->c * sp->i; if(e > sp->e) return 0; } if(c == '['){ sp->ap = va_arg(a, uchar**); sp->ae = va_arg(a, uchar**); } break; case '}': case ']': e = sp->e; if(sp->c < 0) sp->c = ((p - (b + sp->o))+sp->i-1)/sp->i; p = b + sp->o + sp->c * sp->i; if(p > e) return 0; if(sp->ap) *sp->ap = b + sp->o; if(sp->ae) *sp->ae = p; sp = sp->prev; break; case '.': *va_arg(a, uchar**) = p; break; } if(p > e) return 0; } return p - t; } vpack(uchar *b, uchar *p, uchar *e, char *f, va_list a) { struct { void *prev; int o, i; uchar *wc, *wo, wcf, wof; } sub[8], *sp, *sa; int (*fpack)(uchar *, uchar *, uchar *, void *); char c, ff[2]; int i, x, n; vlong v; uchar *t; memset(sub, 0, sizeof(sub)); for(sp = sub; sp < sub+nelem(sub); sp++){ sp->o = -1; sp->i = 1; } t = p; sp = nil; sa = sub; while(c = *f++){ switch(c){ case '_': case 'b': if(p >= e) return 0; if(c == 'b') *p++ = va_arg(a, int); else *p++ = 0; break; case 'w': if(p+1 >= e) return 0; i = va_arg(a, int); *p++ = i & 0xFF; *p++ = i>>8 & 0xFF; break; case 'l': if(p+3 >= e) return 0; i = va_arg(a, int); *p++ = i & 0xFF; *p++ = i>>8 & 0xFF; *p++ = i>>16 & 0xFF; *p++ = i>>24 & 0xFF; break; case 'v': if(p+7 >= e) return 0; v = va_arg(a, vlong); *p++ = v & 0xFF; *p++ = v>>8 & 0xFF; *p++ = v>>16 & 0xFF; *p++ = v>>24 & 0xFF; *p++ = v>>32 & 0xFF; *p++ = v>>40 & 0xFF; *p++ = v>>48 & 0xFF; *p++ = v>>56 & 0xFF; break; case '%': x = *f++ - '0'; while((p - b) % x){ if(p >= e) return 0; *p++ = 0; } break; case 'f': fpack = va_arg(a, void*); if((n = fpack(b, p, e, va_arg(a, void*))) == 0) return 0; p += n; break; case '#': case '@': x = *f++ - '0'; ff[0] = *f++; ff[1] = 0; if((n = pack(b, p, e, ff, 0)) == 0) return 0; if(c == '#'){ sub[x].wc = p; sub[x].wcf = ff[0]; } else { sub[x].wo = p; sub[x].wof = ff[0]; } p += n; break; case '{': case '[': sa->prev = sp; sp = sa++; if(*f == '*'){ sp->i = f[1]-'0'; f += 2; } if(*f == '?') f++; sp->o = p - b; if(c == '['){ uchar *s, *se; s = va_arg(a, uchar*); se = va_arg(a, uchar*); n = se - s; if(n < 0 || p + n > e) return 0; if(p != s) memmove(p, s, n); p += n; } break; case '}': case ']': n = ((p - (b + sp->o))+sp->i-1)/sp->i; p = b + sp->o + n * sp->i; if(sp->wc){ ff[0] = sp->wcf; ff[1] = 0; pack(b, sp->wc, e, ff, n); } if(sp->wo){ ff[0] = sp->wof; ff[1] = 0; pack(b, sp->wo, e, ff, sp->o); } sp = sp->prev; break; case '.': *va_arg(a, uchar**) = p; break; } if(p > e) return 0; } return p - t; }