//
//	地名検索サーバ
//
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

main()
{
  readdata();
  server();
}

//
//  曖昧検索ルーチン (1998年2月号「asearch」と同じもの)
//  makepat(パタン,曖昧度);
//  match(テキスト);
//
int mismatch;
unsigned int epsilon, acceptpat;
unsigned int shiftpat[0x100];

void makepat(unsigned char *pat, int m)
{
  int i;
  unsigned int mask = 0x4000;

  mismatch = (m <= 0 ? 0 : m <= 3 ? m : 3);
  epsilon = 0;

  for(i=0;i<0x100;i++) shiftpat[i] = 0;
  for(;*pat;pat++){
    if(*pat == ' '){ // ワイルドカード文字
      epsilon |= mask;
    }
    else {
      shiftpat[*pat] |= mask;
      mask >>= 1;
    }
  }
  acceptpat = mask;
}

int match(register unsigned char *text)
{
  unsigned int i0 = 0x4000, i1=0, i2=0, i3=0;
  unsigned int mask;
  unsigned int e = epsilon;

  for(;*text;text++){
    mask = shiftpat[*text];
    i3 = (i3 & e) | ((i3 & mask) >> 1) | (i2 >> 1) | i2;
    i2 = (i2 & e) | ((i2 & mask) >> 1) | (i1 >> 1) | i1;
    i1 = (i1 & e) | ((i1 & mask) >> 1) | (i0 >> 1) | i0;
    i0 = (i0 & e) | ((i0 & mask) >> 1);
    i1 |= (i0 >> 1);
    i2 |= (i1 >> 1);
    i3 |= (i2 >> 1);
  }
  switch(mismatch){
    case 0: return (i0 & acceptpat);
    case 1: return (i1 & acceptpat);
    case 2: return (i2 & acceptpat);
    case 3: return (i3 & acceptpat);
    default: return 0;
  }
}

//
//  郵便番号辞書読み込み
//
#define ZIPFILE "./loclist"

#define MAXWORDS 120000
unsigned char *address[MAXWORDS];
unsigned char *addressyomi[MAXWORDS];
unsigned char *zip[MAXWORDS];
int nlines = 0;

#define MAXLEN 1000

readdata()
{
  unsigned char buf[MAXLEN];
  unsigned char s1[MAXLEN],s2[MAXLEN],s3[8];
  FILE *f;

  if((f = fopen(ZIPFILE,"r")) == NULL){
    fprintf(stderr,"Can't open ZIP file %s\n",ZIPFILE);
    exit(0);
  }
  while(fgets(buf,1000,f)){
    int len = strlen(buf);
    if(buf[len-1] == '\n') buf[len-1] = '\0';
    sscanf(buf,"%s %s %s",s1,s2,s3);
    address[nlines] = (unsigned char*)strdup(s1);
    addressyomi[nlines] = (unsigned char*)strdup(s2);
    zip[nlines] = (unsigned char*)strdup(s3);
    nlines++;
  }
}

//
//  検索サーバメインルーチン
//

#include  <ctype.h>
#include  <sys/types.h>
#include  <sys/ioctl.h>
#include  <sys/socket.h>
#include  <netinet/in.h>
#include  <netdb.h>

#define MAXDTAB  20
#define MAXCLIENT 32  // 最大接続数
#define  BUFSIZE 512  // リクエストの最大サイズ

#define  MAXQUE 5

#define ZIPSERVERPORT  5560

int initsock;     // 要求待ちsocket
int clientfd[MAXCLIENT]; // 各クライアント用socket
int nclients = 0;

server()
{
  int i;
  int len;
  struct sockaddr_in sin;
  struct sockaddr_in from;
  struct servent *sp;

  fd_set readfds, writefds, exceptfds;
  fd_set getrfds();
  
  bzero((char*)&sin, sizeof(sin));

  sin.sin_family = AF_INET;
  sin.sin_addr.s_addr = htonl(INADDR_ANY);

  sin.sin_port = htons(ZIPSERVERPORT); 

  if((initsock = socket(PF_INET,SOCK_STREAM,0))<0){
    fprintf(stderr,"socket: can't create a socket");
    exit(0);
  }
  if(bind(initsock, struct sockaddr*)&sin,sizeof(sin))<0){
    fprintf(stderr,"bind: socket already used");
    exit(0);
  }
  if(listen(initsock,MAXQUE)<0){
    fprintf(stderr,"listen:");
    exit(0);
  }

  FD_ZERO(&writefds);
  FD_ZERO(&exceptfds);
  for(;;){
    FD_ZERO(&readfds);
    FD_SET(initsock,&readfds);
    for (i = 0; i < nclients; i ++)
      FD_SET(clientfd[i], &readfds);
    if (select(MAXDTAB,&readfds,&writefds,&exceptfds,NULL)<0){
      fprintf(stderr,"select:");
    }
    if (FD_ISSET(initsock, &readfds)) {
      len = sizeof(from);
      if((clientfd[nclients++] = accept(initsock,&from,&len)) < 0){
        fprintf(stderr,"accept:");
      }
      if(nclients >= MAXDTAB-3) {
        write(clientfd[--nclients],"F",1);
        close(clientfd[nclients]);
      }
    }
    for(i=0;i<nclients;i++){
      if (FD_ISSET(clientfd[i],&readfds)) {
        if (process(clientfd[i]) < 0) { 
            /* -1 means client closed the connection */
          close(clientfd[i]);
          clientfd[i] = clientfd[nclients-1];
          nclients--;
        }
      }
    }
  }
}

//  クライアントからの要求と返答
//  C  "S0abc\n"  "abc"を曖昧度0で検索
//  S  "123\n"    123個マッチ
//  C  "C2"    2番目の項目内容を要求
//  S  "大きな"  項目内容を返す

#define MAXCANDS 100  // 最大候補数
int candindex[MAXCLIENT][MAXCANDS];
int ncands[MAXCLIENT];  // 検索結果の候補数

process(int fd)
{  
  unsigned char buf[BUFSIZE];
  int n;
  int i;
  unsigned char retbuf[MAXLEN+10];

  if((n=read(fd,&buf[0],BUFSIZE))<=0){
    fprintf(stderr,"read error; transmission between processes\n");
    return -1;
  }
  else { // サ=バへの要求
    // 行末の改行文字の除去
    for(;n>0 && (buf[n-1]=='\n' || buf[n-1]=='\r');n--);
    buf[n] = '\0';
    if(buf[0]=='S'){ // 検索要求 "S1 emerald ", etc.
      makepat(&buf[2],buf[1]-'0');
      for(i=n=0;i<nlines && n<MAXCANDS;i++){
        if(match(addressyomi[i]) || match(zip[i])){
          candindex[fd][n] = i;
          n++;
        }
      }
      ncands[fd] = n;
      sprintf(retbuf,"%d\n",n);
      if(write(fd,retbuf,strlen(retbuf))<0){
        fprintf(stderr,"error in writing to socket\n");
        return -1;
      }
    }
    else if(buf[0]=='C'){ // "C1", "C2,4", "C2,10,2", etc.
      int start=0,end=-1,skip=1;
      n = sscanf(buf+1,"%d,%d,%d",&start,&end,&skip);
      switch(n){
        case 1:  end = start;
        case 2:  skip = 1;
        case 3:  break;
        default:
          start=0; end = -1;
      }
      for(i=start;i<=end && i<ncands[fd];i+=skip){
        strcpy(retbuf,address[candindex[fd][i]]);
        strcat(retbuf," ");
        strcat(retbuf,zip[candindex[fd][i]]);
        strcat(retbuf,"\n");
        if(write(fd, retbuf, strlen(retbuf)) < 0){
          fprintf(stderr,"error in writing to socket\n");
          return -1;
        }
      }
    }
    else if(buf[0] == 'Q'){ // クライアント切断要求
      return -1;
    }
    else if(buf[0] == 'X'){ // サーバ中止要求
      close(initsock);
      close(fd);
      exit(0);
    }
  }
  return 0;
}