Bug#6147: Traditional: Assigning a string to a numeric column has unexpected results

The problem was that when converting a string to an exact number,
rounding didn't work, because conversion didn't understand
approximate numbers notation.
Fix: a new function for string-to-number conversion was implemented,
which is aware of approxinate number notation (with decimal point
and exponent, e.g. -19.55e-1)

1 files changed, 337 insertions, 0 deletions

diff --git a/strings/ctype-simple.c b/strings/ctype-simple.c
index 12ef77c59b1..e40a1948dcf 100644
--- a/strings/ctype-simple.c
+++ b/strings/ctype-simple.c
@@ -17,6 +17,7 @@
 #include <my_global.h>
 #include "m_string.h"
 #include "m_ctype.h"
+#include "my_sys.h"  /* Needed for MY_ERRNO_ERANGE */
 #include <errno.h>
 
 #include "stdarg.h"
@@ -1354,6 +1355,341 @@ longlong my_strtoll10_8bit(CHARSET_INFO *cs __attribute__((unused)),
 }
 
 
+#undef  ULONGLONG_MAX
+/*
+  Needed under MetroWerks Compiler, since MetroWerks compiler does not
+  properly handle a constant expression containing a mod operator
+*/
+#if defined(__NETWARE__) && defined(__MWERKS__)
+static ulonglong ulonglong_max= ~(ulonglong) 0;
+#define ULONGLONG_MAX ulonglong_max
+#else
+#define ULONGLONG_MAX           (~(ulonglong) 0)
+#endif /* __NETWARE__ && __MWERKS__ */
+
+    
+#define CUTOFF  (ULONGLONG_MAX / 10)
+#define CUTLIM  (ULONGLONG_MAX % 10)
+#define DIGITS_IN_ULONGLONG 20
+
+static ulonglong d10[DIGITS_IN_ULONGLONG]=
+{
+  1,
+  10,
+  100,
+  1000,
+  10000,
+  100000,
+  1000000,
+  10000000,
+  100000000,
+  1000000000,
+  10000000000ULL,
+  100000000000ULL,
+  1000000000000ULL,
+  10000000000000ULL,
+  100000000000000ULL,
+  1000000000000000ULL,
+  10000000000000000ULL,
+  100000000000000000ULL,
+  1000000000000000000ULL,
+  10000000000000000000ULL
+};
+
+
+/*
+
+  Convert a string to unsigned long long integer value
+  with rounding.
+  
+  SYNOPSYS
+    my_strntoull10_8bit()
+      cs              in      pointer to character set
+      str             in      pointer to the string to be converted
+      length          in      string length
+      unsigned_flag   in      whether the number is unsigned
+      endptr          out     pointer to the stop character
+      error           out     returned error code
+
+  DESCRIPTION
+    This function takes the decimal representation of integer number
+    from string str and converts it to an signed or unsigned
+    long long integer value.
+    Space characters and tab are ignored.
+    A sign character might precede the digit characters.
+    The number may have any number of pre-zero digits.
+    The number may have decimal point and exponent.
+    Rounding is always done in "away from zero" style:
+      0.5  ->   1
+     -0.5  ->  -1
+
+    The function stops reading the string str after "length" bytes
+    or at the first character that is not a part of correct number syntax:
+
+    <signed numeric literal> ::=
+      [ <sign> ] <exact numeric literal> [ E [ <sign> ] <unsigned integer> ]
+
+    <exact numeric literal> ::=
+                        <unsigned integer> [ <period> [ <unsigned integer> ] ]
+                      | <period> <unsigned integer>
+    <unsigned integer>   ::= <digit>...
+     
+  RETURN VALUES
+    Value of string as a signed/unsigned longlong integer
+
+    endptr cannot be NULL. The function will store the end pointer
+    to the stop character here.
+
+    The error parameter contains information how things went:
+    0	     ok
+    ERANGE   If the the value of the converted number is out of range
+    In this case the return value is:
+    - ULONGLONG_MAX if unsigned_flag and the number was too big
+    - 0 if unsigned_flag and the number was negative
+    - LONGLONG_MAX if no unsigned_flag and the number is too big
+    - LONGLONG_MIN if no unsigned_flag and the number it too big negative
+    
+    EDOM If the string didn't contain any digits.
+    In this case the return value is 0.
+*/
+
+ulonglong
+my_strntoull10rnd_8bit(CHARSET_INFO *cs __attribute__((unused)),
+                       const char *str, uint length, int unsigned_flag,
+                       char **endptr, int *error)
+{
+  const char *dot, *end9, *beg, *end= str + length;
+  ulonglong ull;
+  ulong ul;
+  unsigned char ch;
+  int shift= 0, digits= 0, negative, addon;
+
+  /* Skip leading spaces and tabs */
+  for ( ; str < end && (*str == ' ' || *str == '\t') ; str++);
+
+  if (str >= end)
+    goto ret_edom;
+
+  if ((negative= (*str == '-')) || *str=='+') /* optional sign */
+  {
+    if (++str == end)
+      goto ret_edom;
+  }
+
+  beg= str;
+  end9= (str + 9) > end ? end : (str + 9);
+  /* Accumulate small number into ulong, for performance purposes */
+  for (ul= 0 ; str < end9 && (ch= (unsigned char) (*str - '0')) < 10; str++)
+  {
+    ul= ul * 10 + ch;
+  }
+  
+  if (str >= end) /* Small number without dots and expanents */
+  {
+    *endptr= (char*) str;
+    if (negative)
+    {
+      if (unsigned_flag)
+      {
+        *error= ul ? MY_ERRNO_ERANGE : 0;
+        return 0;
+      }
+      else
+      {
+        *error= 0;
+        return (ulonglong) (longlong) (long) -ul;
+      }
+    }
+    else
+    {
+      *error=0;
+      return (ulonglong) ul;
+    }
+  }
+  
+  digits= str - beg;
+
+  /* Continue to accumulate into ulonglong */
+  for (dot= NULL, ull= ul; str < end; str++)
+  {
+    if ((ch= (unsigned char) (*str - '0')) < 10)
+    {
+      if (ull < CUTOFF || (ull == CUTOFF && ch <= CUTLIM))
+      {
+        ull= ull * 10 + ch;
+        digits++;
+        continue;
+      }
+      /*
+        Adding the next digit would overflow.
+        Remember the next digit in "addon", for rounding.
+        Scan all digits with an optional single dot.
+      */
+      if (ull == CUTOFF)
+      {
+        ull= ULONGLONG_MAX;
+        addon= 1;
+        str++;
+      }
+      else
+        addon= (*str >= '5');
+      for ( ; str < end && (ch= (unsigned char) (*str - '0')) < 10; str++)
+      {
+        if (!dot)
+          shift++;
+      }
+      if (str < end && *str == '.' && !dot)
+      {
+        str++;
+        for ( ; str < end && (ch= (unsigned char) (*str - '0')) < 10; str++);
+      }
+      goto exp;
+    }
+    
+    if (*str == '.')
+    {
+      if (dot)
+      {
+        /* The second dot character */
+        addon= 0;
+        goto exp;
+      }
+      else
+      {
+        dot= str + 1;
+      }
+      continue;
+    }
+    
+    /* Unknown character, exit the loop */
+    break; 
+  }
+  shift= dot ? dot - str : 0; /* Right shift */
+  addon= 0;
+
+exp:    /* [ E [ <sign> ] <unsigned integer> ] */
+
+  if (!digits)
+  {
+    str= beg;
+    goto ret_edom;
+  }
+  
+  if (str < end && (*str == 'e' || *str == 'E'))
+  {
+    str++;
+    if (str < end)
+    {
+      int negative_exp, exp;
+      if ((negative_exp= (*str == '-')) || *str=='+')
+      {
+        if (++str == end)
+          goto ret_sign;
+      }
+      for (exp= 0 ;
+           str < end && (ch= (unsigned char) (*str - '0')) < 10;
+           str++)
+      {
+        exp= exp * 10 + ch;
+      }
+      shift+= negative_exp ? -exp : exp;
+    }
+  }
+  
+  if (shift == 0) /* No shift, check addon digit */
+  {
+    if (addon)
+    {
+      if (ull == ULONGLONG_MAX)
+        goto ret_too_big;
+      ull++;
+    }
+    goto ret_sign;
+  }
+
+  if (shift < 0) /* Right shift */
+  {
+    ulonglong d, r;
+    
+    if (-shift >= DIGITS_IN_ULONGLONG)
+      goto ret_zero; /* Exponent is a big negative number, return 0 */
+    
+    d= d10[-shift];
+    r= (ull % d) * 2;
+    ull /= d;
+    if (r >= d)
+      ull++;
+    goto ret_sign;
+  }
+
+  if (shift > DIGITS_IN_ULONGLONG) /* Huge left shift */
+  {
+    if (!ull)
+      goto ret_sign;
+    goto ret_too_big;
+  }
+
+  for ( ; shift > 0; shift--, ull*= 10) /* Left shift */
+  {
+    if (ull > CUTOFF)
+      goto ret_too_big; /* Overflow, number too big */
+  }
+
+ret_sign:
+  *endptr= (char*) str;
+
+  if (!unsigned_flag)
+  {
+    if (negative)
+    {
+      if (ull > (ulonglong) LONGLONG_MIN)
+      {
+        *error= MY_ERRNO_ERANGE;
+        return (ulonglong) LONGLONG_MIN;
+      }
+      *error= 0;
+      return (ulonglong) -ull;
+    }
+    else
+    {
+      if (ull > (ulonglong) LONGLONG_MAX)
+      {
+        *error= MY_ERRNO_ERANGE;
+        return (ulonglong) LONGLONG_MAX;
+      }
+      *error= 0;
+      return ull;
+    }
+  }
+
+  /* Unsigned number */
+  if (negative && ull)
+  {
+    *error= MY_ERRNO_ERANGE;
+    return 0;
+  }
+  *error= 0;
+  return ull;
+
+ret_zero:
+  *endptr= (char*) str;
+  *error= 0;
+  return 0;
+
+ret_edom:
+  *endptr= (char*) str;
+  *error= MY_ERRNO_EDOM;
+  return 0;
+  
+ret_too_big:
+  *endptr= (char*) str;
+  *error= MY_ERRNO_ERANGE;
+  return unsigned_flag ?
+         ULONGLONG_MAX :
+         negative ? (ulonglong) LONGLONG_MIN : (ulonglong) LONGLONG_MAX;
+}
+
+
 /*
   Check if a constant can be propagated
 
@@ -1434,6 +1770,7 @@ MY_CHARSET_HANDLER my_charset_8bit_handler=
     my_strntoull_8bit,
     my_strntod_8bit,
     my_strtoll10_8bit,
+    my_strntoull10rnd_8bit,
     my_scan_8bit
 };