my_vsnprintf.c

/* Copyright (c) 2000, 2011, Oracle and/or its affiliates. All rights reserved.

   This program 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; version 2 of the License.

   This program 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 this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA */

#include <my_global.h>
#include <m_string.h>
#include <stdarg.h>
#include <m_ctype.h>


#define MAX_ARGS 32                           /* max positional args count*/
#define MAX_PRINT_INFO 32                     /* max print position count */

#define LENGTH_ARG     1
#define WIDTH_ARG      2
#define PREZERO_ARG    4
#define ESCAPED_ARG    8 

typedef struct pos_arg_info ARGS_INFO;
typedef struct print_info PRINT_INFO;

struct pos_arg_info
{
  char arg_type;                              /* argument type */
  uint have_longlong;                         /* used from integer values */
  char *str_arg;                              /* string value of the arg */
  longlong longlong_arg;                      /* integer value of the arg */
  double double_arg;                          /* double value of the arg */
};


struct print_info
{
  char arg_type;                              /* argument type */
  size_t arg_idx;                             /* index of the positional arg */
  size_t length;                              /* print width or arg index */
  size_t width;                               /* print width or arg index */
  uint flags;
  const char *begin;                          
  const char *end;                            
};


static const char *get_length(const char *fmt, size_t *length, uint *pre_zero)
{
  for (; my_isdigit(&my_charset_latin1, *fmt); fmt++)
  {
    *length= *length * 10 + (uint)(*fmt - '0');
    if (!*length)
      *pre_zero|= PREZERO_ARG;                  /* first digit was 0 */
  }
  return fmt;
}


static const char *get_width(const char *fmt, size_t *width)
{
  for (; my_isdigit(&my_charset_latin1, *fmt); fmt++)
  {
    *width= *width * 10 + (uint)(*fmt - '0');
  }
  return fmt;
}

static const char *check_longlong(const char *fmt, uint *have_longlong)
{
  *have_longlong= 0;
  if (*fmt == 'l')
  {
    fmt++;
    if (*fmt != 'l')
      *have_longlong= (sizeof(long) == sizeof(longlong));
    else
    {
      fmt++;
      *have_longlong= 1;
    }
  }
  else if (*fmt == 'z')
  {
    fmt++;
    *have_longlong= (sizeof(size_t) == sizeof(longlong));
  }
  return fmt;
}


static char *backtick_string(const CHARSET_INFO *cs, char *to, char *end,
                             char *par, size_t par_len, char quote_char)
{
  uint char_len;
  char *start= to;
  char *par_end= par + par_len;
  size_t buff_length= (size_t) (end - to);

  if (buff_length <= par_len)
    goto err;
  *start++= quote_char;

  for ( ; par < par_end; par+= char_len)
  {
    uchar c= *(uchar *) par;
    if (!(char_len= my_mbcharlen(cs, c)))
      char_len= 1;
    if (char_len == 1 && c == (uchar) quote_char )
    {
      if (start + 1 >= end)
        goto err;
      *start++= quote_char;
    }
    if (start + char_len >= end)
      goto err;
    start= strnmov(start, par, char_len);
  }
    
  if (start + 1 >= end)
    goto err;
  *start++= quote_char;
  return start;

err:
    *to='\0';
  return to;
}


static char *process_str_arg(const CHARSET_INFO *cs, char *to, char *end,
                             size_t width, char *par, uint print_type)
{
  int well_formed_error;
  size_t plen, left_len= (size_t) (end - to) + 1;
  if (!par)
    par = (char*) "(null)";

  plen= strnlen(par, width);
  if (left_len <= plen)
    plen = left_len - 1;
  plen= cs->cset->well_formed_len(cs, par, par + plen,
                                  width, &well_formed_error);
  if (print_type & ESCAPED_ARG)
    to= backtick_string(cs, to, end, par, plen, '`');
  else
    to= strnmov(to,par,plen);
  return to;
}


static char *process_bin_arg(char *to, char *end, size_t width, char *par)
{
  DBUG_ASSERT(to <= end);
  if (to + width + 1 > end)
    width= end - to - 1;  /* sign doesn't matter */
  memmove(to, par, width);
  to+= width;
  return to;
}


static char *process_dbl_arg(char *to, char *end, size_t width,
                             double par, char arg_type)
{
  if (width == SIZE_T_MAX)
    width= FLT_DIG; /* width not set, use default */
  else if (width >= NOT_FIXED_DEC)
    width= NOT_FIXED_DEC - 1; /* max.precision for my_fcvt() */
  width= MY_MIN(width, (size_t)(end-to) - 1);
  
  if (arg_type == 'f')
    to+= my_fcvt(par, (int)width , to, NULL);
  else
    to+= my_gcvt(par, MY_GCVT_ARG_DOUBLE, (int) width , to, NULL);
  return to;
}


static char *process_int_arg(char *to, char *end, size_t length,
                             longlong par, char arg_type, uint print_type)
{
  size_t res_length, to_length;
  char *store_start= to, *store_end;
  char buff[32];

  if ((to_length= (size_t) (end-to)) < 16 || length)
    store_start= buff;

  if (arg_type == 'd' || arg_type == 'i')
    store_end= longlong10_to_str(par, store_start, -10);
  else if (arg_type == 'u')
    store_end= longlong10_to_str(par, store_start, 10);
  else if (arg_type == 'p')
  {
    store_start[0]= '0';
    store_start[1]= 'x';
    store_end= ll2str(par, store_start + 2, 16, 0);
  }
  else if (arg_type == 'o')
  {
    store_end= ll2str(par, store_start, 8, 0);
  }
  else
  {
    DBUG_ASSERT(arg_type == 'X' || arg_type =='x');
    store_end= ll2str(par, store_start, 16, (arg_type == 'X'));
  }

  if ((res_length= (size_t) (store_end - store_start)) > to_length)
    return to;                           /* num doesn't fit in output */
  /* If %#d syntax was used, we have to pre-zero/pre-space the string */
  if (store_start == buff)
  {
    length= MY_MIN(length, to_length);
    if (res_length < length)
    {
      size_t diff= (length- res_length);
      memset(to, (print_type & PREZERO_ARG) ? '0' : ' ', diff);
      if (arg_type == 'p' && print_type & PREZERO_ARG)
      {
        if (diff > 1)
          to[1]= 'x';
        else
          store_start[0]= 'x';
        store_start[1]= '0';
      }
      to+= diff;
    }
    bmove(to, store_start, res_length);
  }
  to+= res_length;
  return to;
}


static char *process_args(const CHARSET_INFO *cs, char *to, char *end,
                          const char* fmt, size_t arg_index, va_list ap)
{
  ARGS_INFO args_arr[MAX_ARGS];
  PRINT_INFO print_arr[MAX_PRINT_INFO];
  uint idx= 0, arg_count= arg_index;

start:
  /* Here we are at the beginning of positional argument, right after $ */
  arg_index--;
  print_arr[idx].flags= 0;
  if (*fmt == '`')
  {
    print_arr[idx].flags|= ESCAPED_ARG;
    fmt++;
  }
  if (*fmt == '-')
    fmt++;
  print_arr[idx].length= print_arr[idx].width= 0;
  /* Get print length */
  if (*fmt == '*')
  {          
    fmt++;
    fmt= get_length(fmt, &print_arr[idx].length, &print_arr[idx].flags);
    print_arr[idx].length--;    
    DBUG_ASSERT(*fmt == '$' && print_arr[idx].length < MAX_ARGS);
    args_arr[print_arr[idx].length].arg_type= 'd';
    args_arr[print_arr[idx].length].have_longlong= 0;
    print_arr[idx].flags|= LENGTH_ARG;
    arg_count= MY_MAX(arg_count, print_arr[idx].length + 1);
    fmt++;
  }
  else
    fmt= get_length(fmt, &print_arr[idx].length, &print_arr[idx].flags);
  
  if (*fmt == '.')
  {
    fmt++;
    /* Get print width */
    if (*fmt == '*')
    {
      fmt++;
      fmt= get_width(fmt, &print_arr[idx].width);
      print_arr[idx].width--;
      DBUG_ASSERT(*fmt == '$' && print_arr[idx].width < MAX_ARGS);
      args_arr[print_arr[idx].width].arg_type= 'd';
      args_arr[print_arr[idx].width].have_longlong= 0;
      print_arr[idx].flags|= WIDTH_ARG;
      arg_count= MY_MAX(arg_count, print_arr[idx].width + 1);
      fmt++;
    }
    else
      fmt= get_width(fmt, &print_arr[idx].width);
  }
  else
    print_arr[idx].width= SIZE_T_MAX;

  fmt= check_longlong(fmt, &args_arr[arg_index].have_longlong);
  if (*fmt == 'p')
    args_arr[arg_index].have_longlong= (sizeof(void *) == sizeof(longlong));
  args_arr[arg_index].arg_type= print_arr[idx].arg_type= *fmt;
  
  print_arr[idx].arg_idx= arg_index;
  print_arr[idx].begin= ++fmt;

  while (*fmt && *fmt != '%')
    fmt++;

  if (!*fmt)                                  /* End of format string */
  {
    uint i;
    print_arr[idx].end= fmt;
    /* Obtain parameters from the list */
    for (i= 0 ; i < arg_count; i++)
    {
      switch (args_arr[i].arg_type) {
      case 's':
      case 'b':
        args_arr[i].str_arg= va_arg(ap, char *);
        break;
      case 'f':
      case 'g':
        args_arr[i].double_arg= va_arg(ap, double);
        break;
      case 'd':
      case 'i':
      case 'u':
      case 'x':
      case 'X':
      case 'o':
      case 'p':
        if (args_arr[i].have_longlong)
          args_arr[i].longlong_arg= va_arg(ap,longlong);
        else if (args_arr[i].arg_type == 'd' || args_arr[i].arg_type == 'i')
          args_arr[i].longlong_arg= va_arg(ap, int);
        else
          args_arr[i].longlong_arg= va_arg(ap, uint);
        break;
      case 'c':
        args_arr[i].longlong_arg= va_arg(ap, int);
        break;
      default:
        DBUG_ASSERT(0);
      }
    }
    /* Print result string */
    for (i= 0; i <= idx; i++)
    {
      size_t width= 0, length= 0;
      switch (print_arr[i].arg_type) {
      case 's':
      {
        char *par= args_arr[print_arr[i].arg_idx].str_arg;
        width= (print_arr[i].flags & WIDTH_ARG)
          ? (size_t)args_arr[print_arr[i].width].longlong_arg
          : print_arr[i].width;
        to= process_str_arg(cs, to, end, width, par, print_arr[i].flags);
        break;
      }
      case 'b':
      {
        char *par = args_arr[print_arr[i].arg_idx].str_arg;
        width= (print_arr[i].flags & WIDTH_ARG)
          ? (size_t)args_arr[print_arr[i].width].longlong_arg
          : print_arr[i].width;
        to= process_bin_arg(to, end, width, par);
        break;
      }
      case 'c':
      {
        if (to == end)
          break;
        *to++= (char) args_arr[print_arr[i].arg_idx].longlong_arg;
        break;
      }
      case 'f':
      case 'g':
      {
        double d= args_arr[print_arr[i].arg_idx].double_arg;
        width= (print_arr[i].flags & WIDTH_ARG) ?
          (uint)args_arr[print_arr[i].width].longlong_arg : print_arr[i].width;
        to= process_dbl_arg(to, end, width, d, print_arr[i].arg_type);
        break;
      }
      case 'd':
      case 'i':
      case 'u':
      case 'x':
      case 'X':
      case 'o':
      case 'p':
      {
        /* Integer parameter */
        longlong larg;
        length= (print_arr[i].flags & LENGTH_ARG)
          ? (size_t)args_arr[print_arr[i].length].longlong_arg
          : print_arr[i].length;

        if (args_arr[print_arr[i].arg_idx].have_longlong)
          larg = args_arr[print_arr[i].arg_idx].longlong_arg;
        else if (print_arr[i].arg_type == 'd' || print_arr[i].arg_type == 'i' )
          larg = (int) args_arr[print_arr[i].arg_idx].longlong_arg;
        else
          larg= (uint) args_arr[print_arr[i].arg_idx].longlong_arg;

        to= process_int_arg(to, end, length, larg, print_arr[i].arg_type,
                            print_arr[i].flags);
        break;
      }
      default:
        break;
      }

      if (to == end)
        break;

      length= MY_MIN(end - to , print_arr[i].end - print_arr[i].begin);
      if (to + length < end)
        length++;
      to= strnmov(to, print_arr[i].begin, length);
    }
    DBUG_ASSERT(to <= end);
    *to='\0';                           /* End of errmessage */
    return to;
  }
  else
  {
    /* Process next positional argument*/
    DBUG_ASSERT(*fmt == '%');
    print_arr[idx].end= fmt - 1;
    idx++;
    fmt++;
    arg_index= 0;
    fmt= get_width(fmt, &arg_index);
    DBUG_ASSERT(*fmt == '$');
    fmt++;
    arg_count= MY_MAX(arg_count, arg_index);
    goto start;
  }

  return 0;
}



size_t my_vsnprintf_ex(const CHARSET_INFO *cs, char *to, size_t n,
                       const char* fmt, va_list ap)
{
  char *start=to, *end=to+n-1;
  size_t length, width;
  uint print_type, have_longlong;

  for (; *fmt ; fmt++)
  {
    if (*fmt != '%')
    {
      if (to == end)                            /* End of buffer */
        break;
      *to++= *fmt;                            /* Copy ordinary char */
      continue;
    }
    fmt++;                                      /* skip '%' */

    length= width= 0;
    print_type= 0;

    /* Read max fill size (only used with %d and %u) */
    if (my_isdigit(&my_charset_latin1, *fmt))
    {
      fmt= get_length(fmt, &length, &print_type);
      if (*fmt == '$')
      {
        to= process_args(cs, to, end, (fmt+1), length, ap);
        return (size_t) (to - start);
      }
    }
    else
    {
      if (*fmt == '`')
      {
        print_type|= ESCAPED_ARG;
        fmt++;
      }
      if (*fmt == '-')
        fmt++;
      if (*fmt == '*')
      {
        fmt++;
        length= va_arg(ap, int);
      }
      else
        fmt= get_length(fmt, &length, &print_type);
    }

    if (*fmt == '.')
    {
      fmt++;
      if (*fmt == '*')
      {
        fmt++;
        width= va_arg(ap, int);
      }
      else
        fmt= get_width(fmt, &width);
    }
    else
      width= SIZE_T_MAX;   

    fmt= check_longlong(fmt, &have_longlong);

    if (*fmt == 's')                            /* String parameter */
    {
      reg2 char *par= va_arg(ap, char *);
      to= process_str_arg(cs, to, end, width, par, print_type);
      continue;
    }
    else if (*fmt == 'b')                               /* Buffer parameter */
    {
      char *par = va_arg(ap, char *);
      to= process_bin_arg(to, end, width, par);
      continue;
    }
    else if (*fmt == 'f' || *fmt == 'g')
    {
      double d= va_arg(ap, double);
      to= process_dbl_arg(to, end, width, d, *fmt);
      continue;
    }
    else if (*fmt == 'd' || *fmt == 'i' || *fmt == 'u' || *fmt == 'x' || 
             *fmt == 'X' || *fmt == 'p' || *fmt == 'o')
    {
      /* Integer parameter */
      longlong larg;
      if (*fmt == 'p')
        have_longlong= (sizeof(void *) == sizeof(longlong));

      if (have_longlong)
        larg = va_arg(ap,longlong);
      else if (*fmt == 'd' || *fmt == 'i')
        larg = va_arg(ap, int);
      else
        larg= va_arg(ap, uint);

      to= process_int_arg(to, end, length, larg, *fmt, print_type);
      continue;
    }
    else if (*fmt == 'c')                       /* Character parameter */
    {
      register int larg;
      if (to == end)
        break;
      larg = va_arg(ap, int);
      *to++= (char) larg;
      continue;
    }

    /* We come here on '%%', unknown code or too long parameter */
    if (to == end)
      break;
    *to++='%';                          /* % used as % or unknown code */
  }
  DBUG_ASSERT(to <= end);
  *to='\0';                             /* End of errmessage */
  return (size_t) (to - start);
}


/*
  Limited snprintf() implementations

  exported to plugins as a service, see the detailed documentation
  around my_snprintf_service_st
*/

size_t my_vsnprintf(char *to, size_t n, const char* fmt, va_list ap)
{
  return my_vsnprintf_ex(&my_charset_latin1, to, n, fmt, ap);
}


size_t my_snprintf(char* to, size_t n, const char* fmt, ...)
{
  size_t result;
  va_list args;
  va_start(args,fmt);
  result= my_vsnprintf(to, n, fmt, args);
  va_end(args);
  return result;
}