snprintf.c

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/* @(#)root/clib:$Id: snprintf.c 23600 2008-04-28 19:47:05Z pcanal $ */
/* Author: Tomi Salo & Fons Rademakers */

/*
   Portable snprintf and vsnprintf implementation.

   Format:
      snprintf(holder, sizeof_holder, format, ...)
      vsnprintf(holder, sizeof_holder, format, args)

   Return values:
      number of characters written or -1 if truncated or -2 if there is an
      error in format specification

   Author:
      Tomi Salo
         Original code

   Modified:
      Fons Rademakers
         Return -1 in case of truncation
         Added test program.
      M.Asokan
         Return -2 in case of error in format specification
         Distinguish between missing precision and a specified precision of 0

   To test snprintf and vsnprintf compile this file with:
      cc -g -DSNTEST `root-config --cflags` snprintf.c -o snprintf
*/

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

#include "RConfig.h"            /* for NEED_SNPRINTF */

#if defined(NEED_SNPRINTF) || defined(SNTEST)

/* to be able to test this code on machines that have snprintf */
#ifndef NEED_SNPRINTF
#define snprintf  r__snprintf
#define vsnprintf r__vsnprintf
#endif

#if defined(R__WIN32) && !defined(__CINT__)
typedef __int64            Long64_t;  /* Portable signed long integer 8 bytes */
typedef unsigned __int64   ULong64_t; /* Portable unsigned long integer 8 bytes */
#else
typedef long long          Long64_t;  /* Portable signed long integer 8 bytes */
typedef unsigned long long ULong64_t; /* Portable unsigned long integer 8 bytes */
#endif

#undef isdigit
#define isdigit(ch) ((ch) >= '0' && (ch) <= '9')

#define MINUS_FLAG 0x1
#define PLUS_FLAG 0x2
#define SPACE_FLAG 0x4
#define HASH_FLAG 0x8
#define CONV_TO_SHORT 0x10
#define IS_LONG_INT 0x20
#define IS_LONG_DOUBLE 0x40
#define X_UPCASE 0x80
#define IS_NEGATIVE 0x100
#define UNSIGNED_DEC 0x200
#define ZERO_PADDING 0x400
#define IS_LONG_LONG_INT 0x800

#ifndef DONTNEED_VSNPRINTF

/* Extract a formatting directive from str. Str must point to a '%'.
   Returns number of characters used or zero if extraction failed. */

static int snprintf_get_directive(const char *str, int *flags, int *width,
                                  int *precision, char *format_char,
                                  va_list *ap)
{
   int length, value;
   const char *orig_str = str;

   *flags = 0;
   *width = 0;
   *precision = -1; /* Assume unspecified */
   *format_char = (char) 0;

   if (*str == '%') {
      /* Get the flags */
      str++;
      while (*str == '-' || *str == '+' || *str == ' '
             || *str == '#' || *str == '0') {
         switch (*str) {
         case '-':
            *flags |= MINUS_FLAG;
            break;
         case '+':
            *flags |= PLUS_FLAG;
            break;
         case ' ':
            *flags |= SPACE_FLAG;
            break;
         case '#':
            *flags |= HASH_FLAG;
            break;
         case '0':
            *flags |= ZERO_PADDING;
            break;
         }
         str++;
      }

      /* Don't pad left-justified numbers withs zeros */
      if ((*flags & MINUS_FLAG) && (*flags & ZERO_PADDING))
         *flags &= ~ZERO_PADDING;

      /* Is width field present? */
      if (isdigit(*str)) {
         for (value = 0; *str && isdigit(*str); str++)
            value = 10 * value + *str - '0';
         *width = value;
      } else if (*str == '*') {
         *width = va_arg(*ap, int);
         str++;
      }

      /* Is the precision field present? */
      if (*str == '.') {
         str++;
         if (isdigit(*str)) {
            for (value = 0; *str && isdigit(*str); str++)
               value = 10 * value + *str - '0';
            *precision = value;
         } else if (*str == '*') {
            *precision = va_arg(*ap, int);
            str++;
         } else
            *precision = 0;
      }

      /* Get the optional type character */
      if (*str == 'h') {
         *flags |= CONV_TO_SHORT;
         str++;
      } else {
         if (*str == 'l') {
            if (*(str+1)=='l') {
               *flags |= IS_LONG_LONG_INT;
               str++;
            } else {
               *flags |= IS_LONG_INT;
            }
            str++;
         } else {
            /* Support Win32 I64 type specifier, i.e. %I64d or %I64u */
            if (*str == 'I' && *(str+1)=='6' && *(str+2)=='4') {
               *flags |= IS_LONG_LONG_INT;
               str += 3;
            } else if (*str == 'L') {
               *flags |= IS_LONG_DOUBLE;
               str++;
            }
         }
      }

      /* Get and check the formatting character */

      *format_char = *str;
      str++;
      length = str - orig_str;

      switch (*format_char) {
      case 'i':
      case 'd':
      case 'o':
      case 'u':
      case 'x':
      case 'X':
      case 'f':
      case 'e':
      case 'E':
      case 'g':
      case 'G':
      case 'c':
      case 's':
      case 'p':
      case 'n':
         if (*format_char == 'X')
            *flags |= X_UPCASE;
         if (*format_char == 'o')
            *flags |= UNSIGNED_DEC;
         return length;

      default:
         return 0;
      }
   } else {
      return 0;
   }
}

/*
   Convert a integer from unsigned long int representation
   to string representation. This will insert prefixes if needed
   (leading zero for octal and 0x or 0X for hexadecimal) and
   will write at most buf_size characters to buffer.
   tmp_buf is used because we want to get correctly truncated
   results.
*/
static int snprintf_convert_ulong(char *buffer, size_t buf_size, int base,
                                  char *digits, ULong64_t ulong_val,
                                  int flags, int width, int precision)
{
   int tmp_buf_len = 100 + width, len;
   char *tmp_buf, *tmp_buf_ptr, prefix[2];
   tmp_buf = malloc(tmp_buf_len);

   prefix[0] = '\0';
   prefix[1] = '\0';

   /* Make tmp_buf_ptr point just past the last char of buffer */
   tmp_buf_ptr = tmp_buf + tmp_buf_len;

   /* Main conversion loop */
   do {
      *--tmp_buf_ptr = digits[ulong_val % base];
      ulong_val /= base;
      precision--;
   }
   while ((ulong_val != 0 || precision > 0) && tmp_buf_ptr > tmp_buf);

   /* Get the prefix */
   if (!(flags & IS_NEGATIVE)) {
      if (base == 16 && (flags & HASH_FLAG)) {
         if (flags && X_UPCASE) {
            prefix[0] = 'x';
            prefix[1] = '0';
         } else {
            prefix[0] = 'X';
            prefix[1] = '0';
         }
      }

      if (base == 8 && (flags & HASH_FLAG))
         prefix[0] = '0';

      if (base == 10 && !(flags & UNSIGNED_DEC) && (flags & PLUS_FLAG))
         prefix[0] = '+';
      else
          if (base == 10 && !(flags & UNSIGNED_DEC)
              && (flags & SPACE_FLAG)) prefix[0] = ' ';
   } else
      prefix[0] = '-';

   if (prefix[0] != '\0' && tmp_buf_ptr > tmp_buf) {
      *--tmp_buf_ptr = prefix[0];
      if (prefix[1] != '\0' && tmp_buf_ptr > tmp_buf)
         *--tmp_buf_ptr = prefix[1];
   }

   len = (tmp_buf + tmp_buf_len) - tmp_buf_ptr;

   if (len <= (int)buf_size) {
      if (len < width) {
         if (width > (tmp_buf_ptr - tmp_buf))
            width = (tmp_buf_ptr - tmp_buf);
         if (flags & MINUS_FLAG) {
            memcpy(buffer, tmp_buf_ptr, len);
            memset(buffer + len, (flags & ZERO_PADDING) ? '0' : ' ',
                   width - len);
            len = width;
         } else {
            memset(buffer, (flags & ZERO_PADDING) ? '0' : ' ',
                   width - len);
            memcpy(buffer + width - len, tmp_buf_ptr, len);
            len = width;
         }
      } else {
         memcpy(buffer, tmp_buf_ptr, len);
      }
      free(tmp_buf);
      return len;
   } else {
      memcpy(buffer, tmp_buf_ptr, buf_size);
      free(tmp_buf);
      return buf_size;
   }
}


static int snprintf_convert_float(char *buffer, size_t buf_size,
                                  double dbl_val, int flags, int width,
                                  int precision, char format_char)
{
   char print_buf[160], print_buf_len = 0;
   char format_str[80], *format_str_ptr;

   format_str_ptr = format_str;

   if (width > 155)
      width = 155;
   if (precision <= 0)
      precision = 6;
   if (precision > 120)
      precision = 120;

   /* Construct the formatting string and let system's sprintf
      do the real work. */

   *format_str_ptr++ = '%';

   if (flags & MINUS_FLAG)
      *format_str_ptr++ = '-';
   if (flags & PLUS_FLAG)
      *format_str_ptr++ = '+';
   if (flags & SPACE_FLAG)
      *format_str_ptr++ = ' ';
   if (flags & ZERO_PADDING)
      *format_str_ptr++ = '0';
   if (flags & HASH_FLAG)
      *format_str_ptr++ = '#';

   sprintf(format_str_ptr, "%d.%d", width, precision);
   format_str_ptr += strlen(format_str_ptr);

   if (flags & IS_LONG_DOUBLE)
      *format_str_ptr++ = 'L';
   *format_str_ptr++ = format_char;
   *format_str_ptr++ = '\0';

   sprintf(print_buf, format_str, dbl_val);
   print_buf_len = strlen(print_buf);

   if (print_buf_len > (int)buf_size)
      print_buf_len = buf_size;
   strncpy(buffer, print_buf, print_buf_len);
   return print_buf_len;
}

int vsnprintf(char *str, size_t size, const char *format, va_list ap)
{
   int status, left = (int) size - 1;
   const char *format_ptr = format;
   int flags, width, precision, i;
   char format_char, *orig_str = str;
   int *int_ptr;
   Long64_t long_val;
   ULong64_t ulong_val;
   char *str_val;
   double dbl_val;
   int precision_specified = 0;

  if (size <= 0 || str == NULL || format == NULL)
    return -1;

   flags = 0;
   while (format_ptr < format + strlen(format)) {
      if (*format_ptr == '%') {
         if (format_ptr[1] == '%' && left > 0) {
            *str++ = '%';
            left--;
            format_ptr += 2;
         } else {
            if (left <= 0) {
               *str = '\0';
               return -1;   /* size; */
            } else {
               status = snprintf_get_directive(format_ptr, &flags, &width,
                                               &precision, &format_char,
                                               &ap);
               if (status == 0) {
                  *str = '\0';
                  return -2;
               } else {
                  if (precision >= 0) {
                     precision_specified = 1;
                  } else {
                     precision_specified = 0;
                     precision = 0;
                  }
                  format_ptr += status;
                  /* Print a formatted argument */
                  switch (format_char) {
                  case 'i':
                  case 'd':
                     /* Convert to unsigned long int before
                        actual conversion to string */
                     if (flags & IS_LONG_LONG_INT)
                        long_val = va_arg(ap, Long64_t);
                     else if (flags & IS_LONG_INT)
                        long_val = (Long64_t) va_arg(ap, long int);
                     else
                        long_val = (Long64_t) va_arg(ap, int);

                     if (long_val < 0) {
                        ulong_val = (ULong64_t) -long_val;
                        flags |= IS_NEGATIVE;
                     } else {
                        ulong_val = (ULong64_t) long_val;
                     }
                     status = snprintf_convert_ulong(str, left, 10,
                                                     "0123456789",
                                                     ulong_val, flags,
                                                     width, precision);
                     str += status;
                     left -= status;
                     break;

                  case 'x':
                     if (flags & IS_LONG_LONG_INT)
                        ulong_val = va_arg(ap, ULong64_t);
                     else if (flags & IS_LONG_INT)
                        ulong_val = (ULong64_t) va_arg(ap, unsigned long int);
                     else
                        ulong_val = (ULong64_t) va_arg(ap, unsigned int);

                     status = snprintf_convert_ulong(str, left, 16,
                                                     "0123456789abcdef",
                                                     ulong_val, flags,
                                                     width, precision);
                     str += status;
                     left -= status;
                     break;

                  case 'X':
                     if (flags & IS_LONG_LONG_INT)
                        ulong_val = va_arg(ap, ULong64_t);
                     else if (flags & IS_LONG_INT)
                        ulong_val = (ULong64_t) va_arg(ap, unsigned long int);
                     else
                        ulong_val = (ULong64_t) va_arg(ap, unsigned int);

                     status = snprintf_convert_ulong(str, left, 16,
                                                     "0123456789ABCDEF",
                                                     ulong_val, flags,
                                                     width, precision);
                     str += status;
                     left -= status;
                     break;

                  case 'o':
                     if (flags & IS_LONG_LONG_INT)
                        ulong_val = va_arg(ap, ULong64_t);
                     else if (flags & IS_LONG_INT)
                        ulong_val = (ULong64_t) va_arg(ap, unsigned long int);
                     else
                        ulong_val = (ULong64_t) va_arg(ap, unsigned int);

                     status = snprintf_convert_ulong(str, left, 8,
                                                     "01234567",
                                                     ulong_val, flags,
                                                     width, precision);
                     str += status;
                     left -= status;
                     break;

                  case 'u':
                     if (flags & IS_LONG_LONG_INT)
                        ulong_val = va_arg(ap, ULong64_t);
                     else if (flags & IS_LONG_INT)
                        ulong_val = (ULong64_t) va_arg(ap, unsigned long int);
                     else
                        ulong_val = (ULong64_t) va_arg(ap, unsigned int);

                     status = snprintf_convert_ulong(str, left, 10,
                                                     "0123456789",
                                                     ulong_val, flags,
                                                     width, precision);
                     str += status;
                     left -= status;
                     break;

                  case 'p':
                     *str++ = '0';
                     *str++ = 'x';
                     ulong_val = (ULong64_t) va_arg(ap, unsigned long int);

                     status = snprintf_convert_ulong(str, left, 16,
                                                     "0123456789abcdef",
                                                     ulong_val, flags,
                                                     width, precision);
                     str += status;
                     left -= status;
                     break;

                  case 'c':
                     if (flags & IS_LONG_LONG_INT)
                        ulong_val = va_arg(ap, ULong64_t);
                     else if (flags & IS_LONG_INT)
                        ulong_val = (ULong64_t) va_arg(ap, unsigned long int);
                     else
                        ulong_val = (ULong64_t) va_arg(ap, unsigned int);

                     if (width==0) {
                        *str++ = (unsigned char) ulong_val;
                        --left;
                     } else {
                        if (width > left)
                           width = left;
                        i = width - 1;

                        if (flags & MINUS_FLAG) {
                           *str = (unsigned char) ulong_val;
                           memset(str + 1,
                                  (flags & ZERO_PADDING) ? '0' : ' ', i);
                        } else {
                           memset(str, (flags & ZERO_PADDING) ? '0' : ' ', i);
                           *(str+i) = (unsigned char) ulong_val;
                        }
                        str += width;
                        left -= width;
                     }
                     break;

                  case 's':
                     str_val = va_arg(ap, char *);

                     if (str_val == NULL || ((long)str_val) == -1)
                        str_val = "(null)";

                     if (!precision_specified)
                        precision = strlen(str_val);
                     else {
                        if (memchr(str_val, 0, precision) != NULL)
                           precision = strlen(str_val);
                     }
                     if (precision > left)
                        precision = left;

                     if (width > left)
                        width = left;
                     if (width < precision)
                        width = precision;
                     i = width - precision;

                     if (flags & MINUS_FLAG) {
                        strncpy(str, str_val, precision);
                        memset(str + precision,
                               (flags & ZERO_PADDING) ? '0' : ' ', i);
                     } else {
                        memset(str, (flags & ZERO_PADDING) ? '0' : ' ', i);
                        strncpy(str + i, str_val, precision);
                     }
                     str += width;
                     left -= width;
                     break;

                  case 'n':
                     int_ptr = va_arg(ap, int *);
                     *int_ptr = str - orig_str;
                     break;

                  case 'f':
                  case 'e':
                  case 'E':
                  case 'g':
                  case 'G':
                     if (flags & IS_LONG_DOUBLE)
                        dbl_val = (double) va_arg(ap, long double);
                     else
                        dbl_val = va_arg(ap, double);
                     status =
                         snprintf_convert_float(str, left, dbl_val, flags,
                                                width, precision,
                                                format_char);
                     str += status;
                     left -= status;
                     break;

                  default:
                     break;
                  }
               }
            }
         }
      } else {
         if (left > 0) {
            *str++ = *format_ptr++;
            left--;
         } else {
            *str = '\0';
            return -1;  /* size; */
         }
      }
   }
   *str = '\0';

   if (left <= 0)
      return -1;

   return size - left - 1;
}
#endif

int snprintf(char *str, size_t size, const char *format, ...)
{
   int ret;
   va_list ap;
   va_start(ap, format);
   ret = vsnprintf(str, size, format, ap);
   va_end(ap);

   return ret;
}



#ifdef SNTEST

#include <stdio.h>

/* set of small tests for snprintf() */
int main()
{
   char holder[100];
   int i;

/*
   printf("Suite of test for snprintf:\n");
   printf("a_format\n");
   printf("printf() format\n");
   printf("snprintf() format\n\n");
*/

   /* Checking the field widths */
   printf("/%%d/, 336\n");
   snprintf(holder, sizeof holder, "/%d/\n", 336);
   printf("/%d/\n", 336);
   printf("%s\n", holder);

   printf("/%%2d/, 336\n");
   snprintf(holder, sizeof holder, "/%2d/\n", 336);
   printf("/%2d/\n", 336);
   printf("%s\n", holder);

   printf("/%%10d/, 336\n");
   snprintf(holder, sizeof holder, "/%10d/\n", 336);
   printf("/%10d/\n", 336);
   printf("%s\n", holder);

   printf("/%%-10d/, 336\n");
   snprintf(holder, sizeof holder, "/%-10d/\n", 336);
   printf("/%-10d/\n", 336);
   printf("%s\n", holder);

   /* floating points */
   printf("/%%f/, 1234.56\n");
   snprintf(holder, sizeof holder, "/%f/\n", 1234.56);
   printf("/%f/\n", 1234.56);
   printf("%s\n", holder);

   printf("/%%e/, 1234.56\n");
   snprintf(holder, sizeof holder, "/%e/\n", 1234.56);
   printf("/%e/\n", 1234.56);
   printf("%s\n", holder);

   printf("/%%4.2f/, 1234.56\n");
   snprintf(holder, sizeof holder, "/%4.2f/\n", 1234.56);
   printf("/%4.2f/\n", 1234.56);
   printf("%s\n", holder);

   printf("/%%3.1f/, 1234.56\n");
   snprintf(holder, sizeof holder, "/%3.1f/\n", 1234.56);
   printf("/%3.1f/\n", 1234.56);
   printf("%s\n", holder);

   printf("/%%10.3f/, 1234.56\n");
   snprintf(holder, sizeof holder, "/%10.3f/\n", 1234.56);
   printf("/%10.3f/\n", 1234.56);
   printf("%s\n", holder);

   printf("/%%10.3e/, 1234.56\n");
   snprintf(holder, sizeof holder, "/%10.3e/\n", 1234.56);
   printf("/%10.3e/\n", 1234.56);
   printf("%s\n", holder);

   printf("/%%+4.2f/, 1234.56\n");
   snprintf(holder, sizeof holder, "/%+4.2f/\n", 1234.56);
   printf("/%+4.2f/\n", 1234.56);
   printf("%s\n", holder);

   printf("/%%010.2f/, 1234.56\n");
   snprintf(holder, sizeof holder, "/%010.2f/\n", 1234.56);
   printf("/%010.2f/\n", 1234.56);
   printf("%s\n", holder);

#define BLURB "Outstanding acting !"
   /* strings precisions */
   printf("/%%2s/, \"%s\"\n", BLURB);
   snprintf(holder, sizeof holder, "/%2s/\n", BLURB);
   printf("/%2s/\n", BLURB);
   printf("%s\n", holder);

   printf("/%%22s/ %s\n", BLURB);
   snprintf(holder, sizeof holder, "/%22s/\n", BLURB);
   printf("/%22s/\n", BLURB);
   printf("%s\n", holder);

   printf("/%%22.5s/ %s\n", BLURB);
   snprintf(holder, sizeof holder, "/%22.5s/\n", BLURB);
   printf("/%22.5s/\n", BLURB);
   printf("%s\n", holder);

   printf("/%%-22.5s/ %s\n", BLURB);
   snprintf(holder, sizeof holder, "/%-22.5s/\n", BLURB);
   printf("/%-22.5s/\n", BLURB);
   printf("%s\n", holder);

   /* see some flags */
   printf("%%x %%X %%#x, 31, 31, 31\n");
   snprintf(holder, sizeof holder, "%x %X %#x\n", 31, 31, 31);
   printf("%x %X %#x\n", 31, 31, 31);
   printf("%s\n", holder);

   printf("**%%d**%% d**%% d**, 42, 42, -42\n");
   snprintf(holder, sizeof holder, "**%d**% d**% d**\n", 42, 42, -42);
   printf("**%d**% d**% d**\n", 42, 42, -42);
   printf("%s\n", holder);

   /* other flags */
   printf("/%%g/, 31.4\n");
   snprintf(holder, sizeof holder, "/%g/\n", 31.4);
   printf("/%g/\n", 31.4);
   printf("%s\n", holder);

   printf("/%%.6g/, 31.4\n");
   snprintf(holder, sizeof holder, "/%.6g/\n", 31.4);
   printf("/%.6g/\n", 31.4);
   printf("%s\n", holder);

   printf("/%%.1G/, 31.4\n");
   snprintf(holder, sizeof holder, "/%.1G/\n", 31.4);
   printf("/%.1G/\n", 31.4);
   printf("%s\n", holder);

   printf("abc%%n\n");
   printf("abc%n", &i);
   printf("%d\n", i);
   snprintf(holder, sizeof holder, "abc%n", &i);
   printf("%s", holder);
   printf("%d\n\n", i);

   printf("%%*.*s --> 10.10\n");
   snprintf(holder, sizeof holder, "%*.*s\n", 10, 10, BLURB);
   printf("%*.*s\n", 10, 10, BLURB);
   printf("%s\n", holder);

   printf("%%%%%%%%\n");
   snprintf(holder, sizeof holder, "%%%%\n");
   printf("%%%%\n");
   printf("%s\n", holder);

#define BIG "Hello this is a too big string for the buffer"
   /* printf("A buffer of size 10, trying to put this:\n");*/
   printf("<%%s>, %s\n", BIG);
   i = snprintf(holder, 10, "%s", BIG);
   printf("<%s>\n", BIG);
   printf("<%s> i = %d\n", holder, i);
   i = snprintf(holder, sizeof holder, "%s", BIG);
   printf("<%s> i = %d\n", holder, i);

   return 0;
}
#endif

#endif /* defined(NEED_SNPRINTF) || defined(SNTEST) */

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