c Minus Scanner 소스, c마이너스 스캐너 예제 (C++ Lex 응용)

c Minus Scanner 소스, c마이너스 스캐너 예제 (C++ Lex 응용)

c Minus Scanner 스캐너 소스 소개하기에 앞서, 먼저 C Minus의 어휘 규칙을 설명합니다.

C Minus의 어휘 규칙.

키워드

else if int return void while

특수 심볼

+ - * / < <= > >= == != = ; , ( ) [ ] { } /- *-

문자

소문자와 대문자는 서로 다른 문자로 취급

공백 문자

빈자리, 줄바꿈, 탭이 존재하며 보통은 무시하나 ID와 NUM 가운데 공백 문자가 있어야 분리됨

주석

/-와 *-로 둘러싸며, 한 줄 이상이어도 되지만 중첩될 수는 없음

첨부 파일 : c-minus scanner.c

아래는 위 첨부 파일(c마이너스 스캐너)의 전체 소스입니다.

[c마이너스 스캐너 소스] 이런 스캐너 제품과는 관련이 없습니다.

/*
  Copyright (c) 2008-2009 LordZen
 
  This file is part of tinycalc.
 
  tinycalc is free software: you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation, either version 3 of the License, or
  (at your option) any later version.
 
  tinycalc is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.
 
  You should have received a copy of the GNU General Public License
  along with tinycalc.  If not, see <http://www.gnu.org/licenses/>.
*/
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <math.h>
 
#include "config.h"
#include "debug.h"
#include "lex.h"
#include "convert.h"
#include "parser.h"
 
void usage(char *progname)
{
  printf("\n:: Tiny Calculator %s ::\n",PACKAGE_VERSION);
  printf("Copyright (c) 2008-2009 LordZen\n\n");
  printf("USAGE: %s <expression>\n",progname);
  printf("SAMPLE EXPRESSION: 0x2f+57-(0b1100001/4)\n\n");
  exit(0);
}
 
void show_debug(char *s)
{
#ifdef DEBUG
  printf("[*] DEBUG: %s\n",s);
#endif
}
 
void show_error(char *s)
{
  printf("\n[**] FATAL: %s\n\n",s);
  exit(-1);
}
 
long hex2dec(char *num)
{
  //skip 0x
  int i = 2;
  int pos = strlen(num) - 3;
 
  long curr_num = 0;
  long tot = 0;
 
  while(num[i] != '\0')
  {
    switch(num[i])
    {
      case '0':
            curr_num = 0;
            break;
      case '1':
            curr_num = 1;
            break;
      case '2':
            curr_num = 2;
            break;
      case '3':
            curr_num = 3;
            break;
      case '4':
            curr_num = 4;
            break;
      case '5':
            curr_num = 5;
            break;
      case '6':
            curr_num = 6;
            break;
      case '7':
            curr_num = 7;
            break;
      case '8':
            curr_num = 8;
            break;
      case '9':
            curr_num = 9;
            break;
      case 'a':
      case 'A':
            curr_num = 10;
            break;
      case 'b':
      case 'B':
            curr_num = 11;
            break;
      case 'c':
      case 'C':
            curr_num = 12;
            break;
      case 'd':
      case 'D':
            curr_num = 13;
            break;
      case 'e':
      case 'E':
            curr_num = 14;
            break;
      case 'f':
      case 'F':
            curr_num = 15;
            break;
    }
    tot += curr_num * pow(16,pos--);
    i++;
  }
 
  return tot;
}
 
long bin2dec(char *num)
{
  //skip 0b
  int i = 2;
  int pos = strlen(num) - 3;
 
  long curr_num = 0;
  long tot = 0;
 
  while(num[i] != '\0')
  {
    switch(num[i])
    {
      case '0':
            curr_num = 0;
            break;
      case '1':
            curr_num = 1;
            break;
    }
    tot += curr_num * pow(2,pos--);
    i++;
  }
 
  return tot;
}
 
void dec2bin(unsigned long num,char *bin)
{
  int i = 0;
  char buffer[MAX_BIT_BIN+1];
 
  //pointer to the end of buffer
  char *pbuf = buffer + sizeof(buffer) - 1;
  
  *pbuf-- = '\0';
  
  for(i=0; i<sizeof(num)*8; ++i)
  {
    unsigned long bit = (unsigned int)1 << i;
    *pbuf-- = ((num & bit)? '1' : '0');
  }
 
  *pbuf = ' ';
  
  //skip leading spaces and zeros
  while(*pbuf == '0' || *pbuf == ' ')
    pbuf++;
  
  strcpy(bin,pbuf);
}
 
void dec2hex(unsigned long num,char *hex)
{
  char buffer[MAX_BIT_HEX+1];
  
  //pointer to the end of buffer
  char *pbuf = buffer +sizeof(buffer) - 1;
  
  *pbuf-- = '\0';
  
  while(num != 0)
  {
    switch(num % 16)
    {
      case 0:
    *pbuf-- = '0';
    break;
      case 1:
    *pbuf-- = '1';
    break;
      case 2:
    *pbuf-- = '2';
    break;
      case 3:
    *pbuf-- = '3';
    break;
      case 4:
    *pbuf-- = '4';
    break;
      case 5:
    *pbuf-- = '5';
    break;
      case 6:
    *pbuf-- = '6';
    break;
      case 7:
    *pbuf-- = '7';
    break;
      case 8:
    *pbuf-- = '8';
    break;
      case 9:
    *pbuf-- = '9';
    break;
      case 10:
    *pbuf-- = 'a';
    break;
      case 11:
    *pbuf-- = 'b';
    break;
      case 12:
    *pbuf-- = 'c';
    break;
      case 13:
    *pbuf-- = 'd';
    break;
      case 14:
    *pbuf-- = 'e';
    break;
      case 15:
    *pbuf-- = 'f';
    break;
    }
    num /= 16;
  }
 
  pbuf++;
  
  strcpy(hex,pbuf);
}
 
int main(int argc,char *argv[])
{
  int decres = 0;
  char binres[MAX_BIT_BIN+1];
  char hexres[MAX_BIT_HEX+1];
 
  if(argc != 2)
    usage(argv[0]);
 
  Lex *lex = lex_init(argv[1]);
 
  if(lex == NULL)
    show_error("syntax analizator not initialized");
 
  decres = parse(lex);
 
  lex_free(lex);
 
  //convert result in binary format
  dec2bin((unsigned int)abs(decres),binres);
 
  //convert result in esadecimal format
  dec2hex((unsigned int)abs(decres),hexres);
  
  //print the result
  if(decres < 0)
    printf("\n\t%d\t\t\t-0x%s\t\t\t-0b%s\n\n",decres,hexres,binres);
  else
    printf("\n\t%d\t\t\t0x%s\t\t\t0b%s\n\n",decres,hexres,binres);
 
  return 0;
}

c Minus Scanner 소스, c마이너스 스캐너 예제 (C++ Lex 응용)