stdlib.cpp

MONA是为数不多的C++语言编写的一个很小的操作系统

/*!
  \file   MlcStdlib.cpp
  \brief  mona c standard library

  Copyright (c) 2002-2004 shadow
  All rights reserved.<BR>
  \b License NYSL<BR>
  \b Create 2004/02/29
  \author  shadow

  $Revision: 1.4 $
  $Date: 2004/10/17 08:45:26 $
*/
#include <monalibc.h>
#include <monapi/string.h>

int uitos(char* s, unsigned int n, int real_width, unsigned int base, char flag);
int uitosn(char* s, int max_width, unsigned int n, int real_width, unsigned int base, char flag);


/*!
  \brief string to long int

  \param s      string to be converted
  \param endptr pointer after string converted
  \param base   radix of string to be converted
  \return  result of the conversion
*/
long int strtol(const char *s, char **endptr, int base){
  return strtoi(s, endptr, base, 0, S_FORMAT_LONG);
}

/*!
  \brief string to unsigned long int

  \param s      string to be converted
  \param endptr pointer after string converted
  \param base   radix of string to be converted
  \return  result of the conversion
*/
unsigned long int strtoul(const char *s, char **endptr, int base){
  return strtoi(s, endptr, base, 0, S_FORMAT_LONG | S_FORMAT_UNSIGNED);
}


/*!
  \brief string to int

  \param s      string to be converted
  \param endptr pointer after string converted
  \param base   radix of string to be converted
  \param width  size of string to be converted
  \param flag   conversion using flag
  \return  result of the conversion
*/
size_t strtoi(const char *s, char **endptr, int base, int width, char flag){
  const char *tmp = s;
  const char *head;
  unsigned long int result = 0;
  int mflag = 1;
  unsigned long int max;

  if(s == NULL) return result;
  if(base > 36) base = 36; /* check base */
  if(base < 0) base = 0;
  while(isspace(*s)) s++; /* skip spaces */
  if(*s == '+'){ /* init Minus flag */
    s++;
  } else if(*s == '-'){
    mflag = -1;
    s++;
  }
  if(*s == '0'){ /* modify base using s */
    s++;
    if(*s == 'X' || *s == 'x'){
      if((base == 0) || (base == 16)){
        base = 16;
        s++;
      }
    } else if(*s >= '1' && *s <= '7'){
      if(base == 0) base = 8;
    } else {
      if(base == 0) base = 10;
    }
  } else if(base == 0){
    base = 10;
  }
  head = s;
  if(width == 0) width = INT_MAX;
  width -= (int)(head - tmp);
  if(flag & S_FORMAT_UNSIGNED){
    mflag = 1;
    if(flag & S_FORMAT_LONG){
      max = ULONG_MAX;
    } else {
      max = UINT_MAX;
    }
  } else {
    if(flag & S_FORMAT_LONG){
      max = LONG_MAX;
    } else {
      max = INT_MAX;
    }
  }

  while(width-- > 0){ /* conversion */
    long int value;

    if(!isalnum(*s)) break;
    if(isdigit(*s)){
      value = *s - '0';
    } else {
      value = toupper(*s) - ('A' - 10);
    }
    if(value >= base) break;
    if(result == max){
      s++;
      continue;
    } else if(result > (max - value)/base){
      result = max;
      s++;
      continue;
    }
    result = result*base + value;
    s++;
  }

  if(endptr != NULL){ /* set endptr */
    if(s == head){
      *endptr = (char *)tmp;
    } else {
      *endptr = (char *)s;
    }
  }

  return result * (long)mflag;
}


/*!
  \brief ascii of decimal to int

  \param s string to be converted
  \return  result of the conversion
*/
int atoi(const char *s){
  int result;
  int mflag;

  if(s == NULL) return 0;
  mflag = 1;
  result = 0;

  while(isspace(*s)) s++;

  if(*s == '+'){
    mflag = 1;
    s++;
  } else if(*s == '-'){
    mflag = -1;
    s++;
  }
  
  while((*s >= '0') && (*s <= '9')){
    result = result*10 + (int)(*s - '0');
    s++;
  }

  return result*mflag;
}

/*!
  \brief int to string

  \param s     string buffer printed characters
  \param n     number converted
  \param width minimum field width of number to be converted
  \param base  radix of number to be converted
  \param flag  conversion using flag
  \return size of characters printed to buffer
*/
int itos(char *s, int n, int width, unsigned int base, char flag){
  return itosn(s, -1, n, width, base, flag);
}

/*!
  \brief unsigned int to string

  \param s         string buffer printed characters
  \param max_width maximum field width of number to be converted
                   (nearly equal string buffer size), 0< : infinity
  \param n         number converted
  \param width     minimum field width of number to be converted
  \param base      radix of number to be converted
  \param flag      conversion using flag
  \return size of characters printed to buffer
*/
int itosn(char *s, int max_width, int n, int width, unsigned int base, char flag){
  int num;
  int real_width;
  int i;
  int j = 0;
  char charP = '+';
  
  if((s == NULL) || (max_width == 0) || (base == 0) || (base > 36)){
    return 0;
  }

  if((max_width > 0) && (max_width < width)) width = max_width;

  if(!(flag & P_FORMAT_UNSIGNED) && (n < 0)){/* negative number */
    flag |= P_FORMAT_PLUS;
    charP = '-';
    n = n * -1;
  }
  num = n;

  if((flag & P_FORMAT_SPACE) && !(flag & P_FORMAT_PLUS)){
    flag |= P_FORMAT_PLUS;
    charP = ' ';
  }

  for(real_width = 0; num != 0; real_width++){
    num /= base;
  }
  
  if((flag & P_FORMAT_ZERO) && (real_width >= width)){
    flag &= ~P_FORMAT_ZERO;
  }

  if(flag & P_FORMAT_PLUS){
    if(flag & P_FORMAT_MINUS){
      s[j] = charP;
      j++;
      j += uitosn(&s[j], max_width - j, n, real_width, base, flag);
      for(i = 0; j < width; i++){
        s[j] = ' ';
         j++;
      }
    } else if(flag & P_FORMAT_ZERO){
      s[j] = charP;
      j++;
      for(i = 0; j < width - real_width; i++){
        s[j] = '0';
         j++;
      }
      j += uitosn(&s[j], max_width - j, n, real_width, base, flag);
    } else {
      for(i = 0; j < width - real_width - 1; i++){
        s[j] = ' ';
         j++;
      }
      s[j] = charP;
      j++;
      j += uitosn(&s[j], max_width - j, n, real_width, base, flag);
    }
  } else {
    if(flag & P_FORMAT_MINUS){
      j += uitosn(&s[j], max_width - j, n, real_width, base, flag);
      for(i = 0; j < width; i++){
        s[j] = ' ';
         j++;
      }
    } else if(flag & P_FORMAT_ZERO){
      for(i = 0; j < width - real_width; i++){
        s[j] = '0';
         j++;
      }
      j += uitosn(&s[j], max_width - j, n, real_width, base, flag);
    } else {
      for(i = 0; j < width - real_width; i++){
        s[j] = ' ';
         j++;
      }
      j += uitosn(&s[j], max_width - j, n, real_width, base, flag);
    }
  }
  if(flag & P_FORMAT_TERMINATE){
    s[j] = 0;
    j++;
  }
  return j;
}

/*!
  \brief unsigned int to string

  \param s          string buffer printed characters
  \param n          number converted
  \param real_width width of number to be converted
  \param base       radix of number to be converted
  \param flag       conversion using flag
  \return size of characters printed to buffer
*/
int uitos(char* s, unsigned int n, int real_width, unsigned int base, char flag){
  return uitosn(s, -1, n, real_width, base, flag);
}

/*!
  \brief unsigned int to string with max size n

  \param s          string buffer printed characters
  \param max_width  maximum field width of number to be converted
                    (nearly equal string buffer size), 0< : infinity
  \param n          number converted
  \param real_width width of number to be converted
  \param base       radix of number to be converted
  \param flag       conversion using flag
  \return size of characters printed to buffer
*/
int uitosn(char* s, int max_width, unsigned int n, int real_width, unsigned int base, char flag){
  int j = 0;
  int i;
  size_t ch;
  char basechar = 'a';

  if((s == NULL) || (max_width == 0)) return 0;

  if(flag & P_FORMAT_CAPITAL){
    basechar = 'A';
  }

  for(i = real_width -1; i >= 0; i--){
    ch = n / __power(base, i);
    n %= __power(base, i);

    if (ch > 9){
      s[j] = (basechar + ch -10);
      j++;
    } else {
      s[j] = ('0' + ch);
      j++;
    }
    if((max_width - j) == 0) break;
  }

  return j;
}

/*!
  \brief double to string

  \param s          string buffer printed characters
  \param n          number converted
  \param real_width width of number to be converted before decimal-point
  \param precision  width of number to be converted after decimal-point
  \param flag       conversion using flag
  \return size of characters printed to buffer
*/
int ftos(char *s, double n, int width, int precision, char flag){
  int num, fraction;
  int j = 0;
  char tmpflag = 0;

  if(s == NULL){
    return 0;
  }

  num = (int)n;
  fraction = (int)((n - (double)num)*__power(10, precision));
  if(precision > 0){
    if(flag & P_FORMAT_TERMINATE){
      flag &= ~P_FORMAT_TERMINATE;
      tmpflag = P_FORMAT_TERMINATE;
    }
    if(num != 0){
     width -= (precision + 1);
     j += itos(s, num, width, 10, flag);
     s[j] = '.';
     j++;
     if(fraction < 0) fraction *= -1;
     j += itos(&s[j], fraction, precision, 10, tmpflag);
    } else { /* num == 0 */
      if(fraction >= 0){
       s[j++] = '0';
       s[j++] = '.';
       j += itos(&s[j], fraction, precision, 10, tmpflag);
      } else { /* num == 0 && fraction < 0 */
       s[j++] = '-';
       s[j++] = '0';
       s[j++] = '.';
       fraction *= -1;
       j += itos(&s[j], fraction, precision, 10, tmpflag);
      }
    }
  } else { /* precision <= 0 */
    j += itos(s, num, width, 10, flag);
  }

  return j;
}