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Diffstat (limited to 'mysql/strings/str2int.c')
| -rw-r--r-- | mysql/strings/str2int.c | 180 |
1 files changed, 0 insertions, 180 deletions
diff --git a/mysql/strings/str2int.c b/mysql/strings/str2int.c deleted file mode 100644 index 44fe836..0000000 --- a/mysql/strings/str2int.c +++ /dev/null @@ -1,180 +0,0 @@ -/* Copyright (c) 2000, 2013, 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 */ - -/* - str2int(src, radix, lower, upper, &val) - converts the string pointed to by src to an integer and stores it in - val. It skips leading spaces and tabs (but not newlines, formfeeds, - backspaces), then it accepts an optional sign and a sequence of digits - in the specified radix. The result should satisfy lower <= *val <= upper. - The result is a pointer to the first character after the number; - trailing spaces will NOT be skipped. - - If an error is detected, the result will be NullS, the value put - in val will be 0, and errno will be set to - EDOM if there are no digits - ERANGE if the result would overflow or otherwise fail to lie - within the specified bounds. - Check that the bounds are right for your machine. - This looks amazingly complicated for what you probably thought was an - easy task. Coping with integer overflow and the asymmetric range of - twos complement machines is anything but easy. - - So that users of atoi and atol can check whether an error occured, - I have taken a wholly unprecedented step: errno is CLEARED if this - call has no problems. -*/ - -#include <my_global.h> -#include "m_string.h" -#include "m_ctype.h" -#include "my_sys.h" /* defines errno */ -#include <errno.h> - -#define char_val(X) (X >= '0' && X <= '9' ? X-'0' :\ - X >= 'A' && X <= 'Z' ? X-'A'+10 :\ - X >= 'a' && X <= 'z' ? X-'a'+10 :\ - '\177') - -char *str2int(const char *src, int radix, long int lower, - long int upper, long int *val) -{ - int sign; /* is number negative (+1) or positive (-1) */ - int n; /* number of digits yet to be converted */ - long limit; /* "largest" possible valid input */ - long scale; /* the amount to multiply next digit by */ - long sofar; /* the running value */ - int d; /* (negative of) next digit */ - char *start; - int digits[32]; /* Room for numbers */ - - /* Make sure *val is sensible in case of error */ - - *val = 0; - - /* Check that the radix is in the range 2..36 */ - -#ifndef DBUG_OFF - if (radix < 2 || radix > 36) { - errno=EDOM; - return NullS; - } -#endif - - /* The basic problem is: how do we handle the conversion of - a number without resorting to machine-specific code to - check for overflow? Obviously, we have to ensure that - no calculation can overflow. We are guaranteed that the - "lower" and "upper" arguments are valid machine integers. - On sign-and-magnitude, twos-complement, and ones-complement - machines all, if +|n| is representable, so is -|n|, but on - twos complement machines the converse is not true. So the - "maximum" representable number has a negative representative. - Limit is set to min(-|lower|,-|upper|); this is the "largest" - number we are concerned with. */ - - /* Calculate Limit using Scale as a scratch variable */ - - if ((limit = lower) > 0) limit = -limit; - if ((scale = upper) > 0) scale = -scale; - if (scale < limit) limit = scale; - - /* Skip leading spaces and check for a sign. - Note: because on a 2s complement machine MinLong is a valid - integer but |MinLong| is not, we have to keep the current - converted value (and the scale!) as *negative* numbers, - so the sign is the opposite of what you might expect. - */ - while (my_isspace(&my_charset_latin1,*src)) src++; - sign = -1; - if (*src == '+') src++; else - if (*src == '-') src++, sign = 1; - - /* Skip leading zeros so that we never compute a power of radix - in scale that we won't have a need for. Otherwise sticking - enough 0s in front of a number could cause the multiplication - to overflow when it neededn't. - */ - start=(char*) src; - while (*src == '0') src++; - - /* Move over the remaining digits. We have to convert from left - to left in order to avoid overflow. Answer is after last digit. - */ - - for (n = 0; (digits[n]=char_val(*src)) < radix && n < 20; n++,src++) ; - - /* Check that there is at least one digit */ - - if (start == src) { - errno=EDOM; - return NullS; - } - - /* The invariant we want to maintain is that src is just - to the right of n digits, we've converted k digits to - sofar, scale = -radix**k, and scale < sofar < 0. Now - if the final number is to be within the original - Limit, we must have (to the left)*scale+sofar >= Limit, - or (to the left)*scale >= Limit-sofar, i.e. the digits - to the left of src must form an integer <= (Limit-sofar)/(scale). - In particular, this is true of the next digit. In our - incremental calculation of Limit, - - IT IS VITAL that (-|N|)/(-|D|) = |N|/|D| - */ - - for (sofar = 0, scale = -1; --n >= 1;) - { - if ((long) -(d=digits[n]) < limit) { - errno=ERANGE; - return NullS; - } - limit = (limit+d)/radix, sofar += d*scale; scale *= radix; - } - if (n == 0) - { - if ((long) -(d=digits[n]) < limit) /* get last digit */ - { - errno=ERANGE; - return NullS; - } - sofar+=d*scale; - } - - /* Now it might still happen that sofar = -32768 or its equivalent, - so we can't just multiply by the sign and check that the result - is in the range lower..upper. All of this caution is a right - pain in the neck. If only there were a standard routine which - says generate thus and such a signal on integer overflow... - But not enough machines can do it *SIGH*. - */ - if (sign < 0) - { - if (sofar < -LONG_MAX || (sofar= -sofar) > upper) - { - errno=ERANGE; - return NullS; - } - } - else if (sofar < lower) - { - errno=ERANGE; - return NullS; - } - *val = sofar; - errno=0; /* indicate that all went well */ - return (char*) src; -} |