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#include <stdarg.h>
#include <string.h>
#include "asn1.h"
size_t fmt_asn1generic(char* dest,const char* fmt,...) {
size_t containerstack[100];
size_t curinstack=0;
va_list args;
unsigned long* application=0;
struct string* s;
struct oid* o;
struct string S;
size_t curlen=0;
size_t cursor=0;
size_t seqlen;
unsigned long desttag=0;
unsigned long appstore;
int stringtype;
va_start(args,fmt);
while (*fmt) {
char* realdest=dest?dest+cursor:NULL;
switch (*fmt) {
case '*': // make next tag use APPLICATION with this tag
appstore=va_arg(args,unsigned long);
application=&appstore;
break;
case '0': // UNIVERSAL PRIMITIVE NULL length 0
if (application)
curlen=fmt_asn1tag(realdest,APPLICATION,PRIMITIVE,_NULL);
else
curlen=fmt_asn1tag(realdest,UNIVERSAL,PRIMITIVE,_NULL);
application=NULL;
curlen+=fmt_asn1length(realdest?realdest+curlen:NULL,0);
break;
case 'B': // send boolean
{
int i=va_arg(args,int);
if (i!=0 && i!=1) {
va_end(args);
return 0;
}
if (application)
curlen=fmt_asn1int(realdest,APPLICATION,PRIMITIVE,*application,i);
else
curlen=fmt_asn1int(realdest,UNIVERSAL,PRIMITIVE,BOOLEAN,i);
application=NULL;
break;
}
case 'i': // send integer
{
unsigned long i=va_arg(args,unsigned long);
if (application)
curlen=fmt_asn1int(realdest,APPLICATION,PRIMITIVE,*application,i);
else
curlen=fmt_asn1int(realdest,UNIVERSAL,PRIMITIVE,INTEGER,i);
application=NULL;
break;
}
case 'b': // send BIT_STRING, using struct string* as arg (expect l to be in bits, not bytes)
s=va_arg(args,struct string*);
if (application)
curlen=fmt_asn1bitstring(realdest,APPLICATION,PRIMITIVE,*application,s->s,s->l);
else
curlen=fmt_asn1bitstring(realdest,UNIVERSAL,PRIMITIVE,BIT_STRING,s->s,s->l);
application=NULL;
break;
case 'I':
stringtype=BIT_STRING;
goto stringcopy;
case 'A':
stringtype=IA5String;
goto stringcopy;
case 'P':
stringtype=PrintableString;
goto stringcopy;
case 'S': // send OCTET_STRING, using struct string* as arg
stringtype=OCTET_STRING;
stringcopy:
s=va_arg(args,struct string*);
copystring:
if (application)
curlen=fmt_asn1string(realdest,APPLICATION,PRIMITIVE,*application,s->s,s->l);
else
curlen=fmt_asn1string(realdest,UNIVERSAL,PRIMITIVE,stringtype,s->s,s->l);
application=NULL;
break;
case 't':
stringtype=UTCTIME;
goto stringcopy_alt;
case 'a':
stringtype=IA5String;
goto stringcopy_alt;
case 'p':
stringtype=PrintableString;
goto stringcopy_alt;
case 's': // send OCTET_STRING, using const char* with strlen() as arg
stringtype=OCTET_STRING;
stringcopy_alt:
S.s=va_arg(args,const char*);
S.l=strlen(S.s);
s=&S;
goto copystring;
case 'o': // send OBJECT_IDENTIFIER, using struct oid* as arg
o=va_arg(args,struct oid*);
if (application)
curlen=fmt_asn1OID(realdest,APPLICATION,PRIMITIVE,*application,o->a,o->l);
else
curlen=fmt_asn1OID(realdest,UNIVERSAL,PRIMITIVE,OBJECT_IDENTIFIER,o->a,o->l);
application=NULL;
break;
case 'C': // copy raw ASN.1 DER data, take struct string*
s=va_arg(args,struct string*);
if (realdest) memcpy(realdest,s->s,s->l);
curlen=s->l;
break;
case 'c': // start context specific section
desttag=va_arg(args,unsigned long);
// fall through
case '[': // start SET
case '{': // start SEQUENCE
if (application)
curlen=fmt_asn1tag(realdest,APPLICATION,CONSTRUCTED,*application);
else if (*fmt=='c')
curlen=fmt_asn1tag(realdest,CONTEXT_SPECIFIC,CONSTRUCTED,desttag);
else
curlen=fmt_asn1tag(realdest,UNIVERSAL,CONSTRUCTED,*fmt=='{'?SEQUENCE_OF:SET_OF);
containerstack[curinstack++]=cursor+curlen;
application=NULL;
break;
case ']': // end of SET
case '}': // end of SEQUENCE
/* we just wrote the tag and the sequence. Now that we wrote the
* sequence, we know the length it took, and we need to move the
* sequence data backwards to make room to write the ASN.1 length */
{
char* anfang;
if (!curinstack) {
va_end(args);
return 0;
}
anfang=dest+containerstack[--curinstack];
seqlen=dest+cursor-anfang;
curlen=fmt_asn1length(NULL,seqlen);
if (!dest) break;
memmove(anfang+curlen,anfang,seqlen);
fmt_asn1length(anfang,seqlen);
break;
}
}
cursor+=curlen;
++fmt;
}
va_end(args);
return cursor;
}
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