minimal_expect.c

#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>

char cmd_str[] = \
    "$ te\\x4Ast\\r\\n\r\n"
    "> OK\r\n"
    "$ hoge\\r\\n\r\n"
    "> ERROR\r\n"
    "$ error\\r\\n\r\n";

char read_cmd(){
  static char *cmd_p = cmd_str;
  return *(cmd_p++);
}

char read_res(){
  return (char)getchar();
}

void send_char(char c){
  putchar(c);
}

void run(){
  enum {
    INIT,
    BEFORE_SEND,
    SENDING,
    SENDING_ESCAPE,
    SENDING_ESCAPE_HEX1,
    SENDING_ESCAPE_HEX2,
    BEFORE_EXPECT,
    EXPECTING,
    EXPECT_FAILED,
    IGNORE_LINE,
  } state = INIT;

  char c;
  char buf[8];
  unsigned char buf_length, expect_index;

  while(c = read_cmd()){
    unsigned char is_endline = ((c == '\r') || (c == '\n'));
    switch(state){
      case INIT:
        if(c == '$'){
          state = BEFORE_SEND;
        }else if(c == '>'){
          state = BEFORE_EXPECT;
          buf_length = expect_index = 0;
          while(c = read_res()){
            if(c == '\r' || c == '\n'){
              if(buf_length > 0){break;}
            }else if(buf_length < sizeof(buf)){
              buf[buf_length++] = c;
            }
          }
        }else if(!isspace(c)){
          state = IGNORE_LINE;
        }
        break;
      case BEFORE_SEND:
        if(is_endline){
          state = INIT;
          break;
        }else if(isspace(c)){break;}
        state = SENDING;
      case SENDING:
        if(is_endline){
          state = INIT;
        }else if(c == '\\'){ // escape char
          state = SENDING_ESCAPE;
        }else{
          send_char(c);
        }
        break;
      case SENDING_ESCAPE:
        if(c == 'x'){
          state = SENDING_ESCAPE_HEX1;
          break;
        }
        switch(c){
          case 'n': c = '\r'; break;
          case 'r': c = '\n'; break;
          case '\\': c = '\\'; break;
        }
        send_char(c);
        state = SENDING;
        break;
      case SENDING_ESCAPE_HEX1:
        buf[0] = ((c & 0x0F) + (c >= 'A' ? 10 : 0)) << 4;
        state = SENDING_ESCAPE_HEX2;
        break;
      case SENDING_ESCAPE_HEX2:
        buf[0] += ((c & 0x0F) + (c >= 'A' ? 10 : 0));
        send_char(buf[0]);
        state = SENDING;
        break;
      case BEFORE_EXPECT:
        if(is_endline){ // match any
          state = INIT;
          break;
        }else if(isspace(c)){break;}
        state = EXPECTING;
      case EXPECTING:
        if(is_endline){
          state = INIT;
        }else if((expect_index < buf_length) && (c == buf[expect_index])){
          expect_index++;
        }else{
          state = EXPECT_FAILED;
        }
        break;
      case IGNORE_LINE:
        if(is_endline){state = INIT;}
        break;
    }
  }
}

int main(){

  printf("%s\r\n", cmd_str);

  run();

  return 0;
}