#include "./def.h"#include <sys/types.h>#include "bencode.h"#ifndef WINDOWS#include <unistd.h>#include <fcntl.h>#include <stdio.h>#include <limits.h>#endif#include <stdio.h>#include <stdlib.h>#include <string.h>#include <ctype.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_long(const char *b,size_t len,char beginchar,char endchar,int64_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 = strtoll(b + 1,(char**) 0,10);    else  *pi=strtoll(b,(char**) 0,10);  }  return (size_t)( p - b + 1 );}size_t buf_int(const char *b,size_t len,char beginchar,char endchar,size_t *pi){  size_t r;  if( pi ){    int64_t pl;    r = buf_long(b,len,beginchar,endchar,&pl);    *pi = (size_t) pl;  }else{    r = buf_long(b,len,beginchar,endchar,(int64_t*) 0);  }  return r;}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_long(b,len,'i','e',(int64_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,int64_t *pl,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;  case QUERY_LONG: return(buf_long(b + pos,len - pos, 'i', 'e', pl));  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)];#ifndef WINDOWS  if( !b ) return 0;#endif  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, PATH_SP);    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 = PATH_SP, pathname++;} else break;  }  *pathname = '\0';  return (pb - b + 1);}