History of LiveCD/4.4/BTS/10 (No. 3)

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  • 1 (2009-02-26 (Thu) 09:03:35)
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  • 3 (2009-03-23 (Mon) 18:35:31)
  • 4 (2009-03-23 (Mon) 23:22:42)
  • 5 (2010-05-21 (Fri) 18:44:37)
  • 6 (2010-05-21 (Fri) 22:09:04)

negative mfs size at large memory†

• ページ: LiveCD/4.4/BTS
• 投稿者: kaw
• 優先順位: 低
• 状態: 着手
• カテゴリー: malfunction
• 投稿日: 2009-02-26 (木) 09:03:35
• バージョン:

メッセージ†

more than 2^31 bytes are displayed as negative value.
Because ksh can handle integer range of -2^31 ... 2^31-1

On ksh, this is like this;

$ echo $((2147483647))     # 2^31-1
2147483647
$ echo $((2147483647+1))   # 2^31
-2147483648

Here's a concept code to check two strings representing big non-negative integer values.

#!/bin/ksh

function isgreater {
    # check presence of arguments
    #
    [ $# -lt 2 ] && return -- -1

    x=$1
    y=$2

    # Are arguments both form of positive integer?
    #
    # !!! INCOMPLETE: not checking correct pattern!!!
    #
    case "XX${x}YY${y}ZZ" in
        XX[0-9]*YY[0-9]*ZZ)
            : # ok, do nothing
            ;;
        *)
            return -- -2 # ng, string is not positive integer
            ;;
    esac

    # Compare it
    #
    if [ ${#x} -gt ${#y} ]; then
        return 0
    elif [ ${#x} -eq ${#y} ]; then
        if [ $x -gt $y ]; then
            return 0
        else
            return 1
        fi
    else
        return 1
    fi
}

isgreater $1 $2
case $? in
    0) echo $1 is greater than $2. ;;
    1) echo $1 is NOT greater than $2. ;;
    *) echo argument format error ;;
esac

Note

• This is needed by very early stage of boot time, so only ksh built-ins can be used.
• Codes marked as "INCOMPLETE" should check either if given two strings both $x and $y match the pattern /^[0-9]+$/ .