#include "stdafx.h"
#include "bencode.h"
static const char* next_key(const char *keylist)
{
for(; *keylist && *keylist != KEY_SP; ++keylist);
if(*keylist)
++keylist;
return keylist;
}
static size_t compare_key(const char *key,size_t keylen,const char *keylist)
{
for(;keylen && *keylist && *key==*keylist; keylen--,key++,keylist++);
if(!keylen)
if(*keylist && *keylist!=KEY_SP)
return 1;
return keylen;
}
size_t buf_int(const char *b,size_t len,char beginchar,char endchar,size_t *pi)
{
const char *p = b;
const char *psave;
if(2 > len)
return 0; /* buffer too small */
if( beginchar )
{
if(*p != beginchar)
return 0;
p++; len--;
}
for(psave = p; len && isdigit(*p); p++,len--) ;
if(!len || MAX_INT_SIZ < (p - psave) || *p != endchar) return 0;
if( pi )
{
if( beginchar )
*pi = (size_t)strtol(b + 1,(char**) 0,10);
else
*pi=(size_t)strtol(b,(char**) 0,10);
}
return (size_t)( p - b + 1 );
}
size_t buf_str(const char *b,size_t len,const char **pstr,size_t* slen)
{
size_t rl,sl;
rl = buf_int(b,len,0,':',&sl);
if( !rl )
return 0;
if(len < rl + sl)
return 0;
if(pstr) *pstr = b + rl;
if(slen) *slen = sl;
return( rl + sl );
}
size_t decode_int(const char *b,size_t len)
{
return(buf_int(b,len,'i','e',(size_t*) 0));
}
size_t decode_str(const char *b,size_t len)
{
return (buf_str(b,len,(const char**) 0,(size_t*) 0));
}
size_t decode_dict(const char *b,size_t len,const char *keylist)
{
size_t rl,dl,nl;
const char *pkey;
dl = 0;
if(2 > len || *b != 'd')
return 0;
dl++; len--;
for(;len && *(b + dl) != 'e';)
{
rl = buf_str(b + dl,len,&pkey,&nl);
if( !rl || KEYNAME_SIZ < nl)
return 0;
dl += rl;
len -= rl;
if(keylist && compare_key(pkey,nl,keylist) == 0)
{
pkey = next_key(keylist);
if(! *pkey )
return dl;
rl = decode_dict(b + dl,len, pkey);
if( !rl )
return 0;
return dl + rl;
}
rl = decode_rev(b + dl,len,(const char*) 0);
if( !rl )
return 0;
dl += rl;len -= rl;
}
if( !len || keylist) return 0;
return dl + 1; /* add the last char 'e' */
}
size_t decode_list(const char *b,size_t len,const char *keylist)
{
size_t ll,rl;
ll = 0;
if(2 > len || *b != 'l')
return 0;
len--; ll++;
for(;len && *(b + ll) != 'e';)
{
rl = decode_rev(b + ll,len,keylist);
if( !rl ) return 0;
ll += rl; len -= rl;
}
if( !len )
return 0;
return ll + 1; /* add last char 'e' */
}
size_t decode_rev(const char *b,size_t len,const char *keylist)
{
if( !b ) return 0;
switch( *b )
{
case 'i': return decode_int(b,len);
case 'd': return decode_dict(b,len,keylist);
case 'l': return decode_list(b,len,keylist);
default: return decode_str(b,len);
}
}
size_t decode_query(const char *b,size_t len,const char *keylist,const char **ps,size_t *pi,int method)
{
size_t pos;
char kl[KEYNAME_LISTSIZ];
strcpy(kl,keylist);
pos = decode_rev(b, len, kl);
if( !pos ) return 0;
switch(method)
{
case QUERY_STR:
return(buf_str(b + pos,len - pos, ps, pi));
case QUERY_INT:
return(buf_int(b + pos,len - pos, 'i', 'e', pi));
case QUERY_POS:
if(pi) *pi = decode_rev(b + pos, len - pos, (const char*) 0);
return pos;
default:
return 0;
}
}
size_t bencode_buf(const char *buf,size_t len,FILE *fp)
{
char slen[MAX_INT_SIZ];
char *b;
if( MAX_INT_SIZ <= _snprintf(slen, MAX_INT_SIZ, "%u:", len) )
return 0;
if( fwrite( slen, strlen(slen), 1, fp) != 1)
return 0;
b = new char[len + strlen(slen)];
if( fwrite(buf, len, 1, fp) != 1 )
{
delete []b;
return 0;
}
delete []b;
return 1;
}
size_t bencode_str(const char *str, FILE *fp)
{
return bencode_buf(str, strlen(str), fp);
}
size_t bencode_int(const int integer, FILE *fp)
{
char buf[MAX_INT_SIZ];
if( EOF == fputc('i', fp))
return 0;
if( MAX_INT_SIZ <= _snprintf(buf, MAX_INT_SIZ, "%u", integer) )
return 0;
if( fwrite(buf, strlen(buf), 1, fp) != 1 )
return 0;
return ( EOF == fputc('e', fp)) ? 0: 1;
}
size_t bencode_begin_dict(FILE *fp)
{
return (EOF == fputc('d',fp)) ? 0 : 1;
}
size_t bencode_begin_list(FILE *fp)
{
return (EOF == fputc('l',fp)) ? 0 : 1;
}
size_t bencode_end_dict_list(FILE *fp)
{
return (EOF == fputc('e',fp)) ? 0 : 1;
}
size_t bencode_path2list(const char *pathname, FILE *fp)
{
char *pn;
const char *p = pathname;
if( bencode_begin_list(fp) != 1 ) return 0;
for(; *p;)
{
pn = strchr(p, '\\');
if( pn )
{
if( bencode_buf(p, pn - p, fp) != 1) return 0;
p = pn + 1;
}
else
{
if( bencode_str(p, fp) != 1) return 0;
break;
}
}
return bencode_end_dict_list(fp);
}
size_t decode_list2path(const char *b, size_t n, char *pathname)
{
const char *pb = b;
const char *s = (char *) 0;
size_t r,q;
if( 'l' != *pb ) return 0;
pb++;
n--;
if( !n ) return 0;
for(; n;)
{
if(!(r = buf_str(pb, n, &s, &q)) ) return 0;
memcpy(pathname, s, q);
pathname += q;
pb += r; n -= r;
if( 'e' != *pb ){*pathname = '\\', pathname++;} else break;
}
*pathname = '\0';
return (pb - b + 1);
}
