ref: 479a31ae8f4a361b101aa203aa1c0822137708d7
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;
}
int
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;
}