如何使用ceil，floor和round bcmath數字？

Question

我需要模仿的ceil()，floor()和round()功能的具體功能上bcmath時數，I've already found a very similar question可惜the answer provided isn't good enough for me因爲它缺乏負數和圓形的精度參數（）函數是缺少支持。

我想知道是否有人能想出一個相當簡短和優雅的解決方案來解決這個問題。

所有的輸入讚賞，謝謝！

Answer 1

經過一夜失去試圖解決這個問題，我相信我已經找到了一個比較簡單的解決方案，那就是：

function bcceil($number) 
{ 
    if (strpos($number, '.') !== false) { 
     if (preg_match("~\.[0]+$~", $number)) return bcround($number, 0); 
     if ($number[0] != '-') return bcadd($number, 1, 0); 
     return bcsub($number, 0, 0); 
    } 
    return $number; 
} 

function bcfloor($number) 
{ 
    if (strpos($number, '.') !== false) { 
     if (preg_match("~\.[0]+$~", $number)) return bcround($number, 0); 
     if ($number[0] != '-') return bcadd($number, 0, 0); 
     return bcsub($number, 1, 0); 
    } 
    return $number; 
} 

function bcround($number, $precision = 0) 
{ 
    if (strpos($number, '.') !== false) { 
     if ($number[0] != '-') return bcadd($number, '0.' . str_repeat('0', $precision) . '5', $precision); 
     return bcsub($number, '0.' . str_repeat('0', $precision) . '5', $precision); 
    } 
    return $number; 
} 

我覺得我沒有錯過任何東西，如果有人能發現任何錯誤，請讓我知道。下面是一些測試：

assert(bcceil('4') == ceil('4')); // true 
assert(bcceil('4.3') == ceil('4.3')); // true 
assert(bcceil('9.999') == ceil('9.999')); // true 
assert(bcceil('-3.14') == ceil('-3.14')); // true 

assert(bcfloor('4') == floor('4')); // true 
assert(bcfloor('4.3') == floor('4.3')); // true 
assert(bcfloor('9.999') == floor('9.999')); // true 
assert(bcfloor('-3.14') == floor('-3.14')); // true 

assert(bcround('3', 0) == number_format('3', 0)); // true 
assert(bcround('3.4', 0) == number_format('3.4', 0)); // true 
assert(bcround('3.5', 0) == number_format('3.5', 0)); // true 
assert(bcround('3.6', 0) == number_format('3.6', 0)); // true 
assert(bcround('1.95583', 2) == number_format('1.95583', 2)); // true 
assert(bcround('5.045', 2) == number_format('5.045', 2)); // true 
assert(bcround('5.055', 2) == number_format('5.055', 2)); // true 
assert(bcround('9.999', 2) == number_format('9.999', 2)); // true 

Answer 2

以下是支持舍入的負數和精度參數的示例。

function bcceil($val) { 
    if (($pos = strpos($val, '.')) !== false) { 
     if ($val[$pos+1] != 0 && $val[0] != '-') 
      return bcadd(substr($val, 0, $pos), 1, 0); 
     else 
      return substr($val, 0, $pos); 
    } 
    return $val; 
} 

function bcfloor($val) { 
    if (($pos = strpos($val, '.')) !== false) { 
     if ($val[$pos+1] != 0 && $val[0] == '-') 
      return bcsub(substr($val, 0, $pos), 1, 0); 
     else 
      return substr($val, 0, $pos); 
    } 
    return $val; 
} 

function bcround($val, $precision = 0) { 
    if (($pos = strpos($val, '.')) !== false) { 
     if ($precision > 0) { 
      $int = substr($val, 0, $pos); 
      $pos2 = ++$pos+$precision; 
      if ($pos2 < strlen($val)) { 
       $val2 = sprintf('%s.%s', substr($val, $pos, $pos2-$pos), substr($val, $pos2)); 
       $val2 = $val2[0] >= 5 ? bcceil($val2) : bcfloor($val2); 
       if (strlen($val2) > $precision) 
        return bcadd($int, $val[0] == '-' ? -1 : 1, 0); 
       else 
        return sprintf('%s.%s', $int, rtrim($val2, '0')); 
      } 
      return $val; 
     } else { 
      if ($val[$pos+1] >= 5) 
       return ($val[0] == '-' ? bcfloor($val) : bcceil($val)); 
      else 
       return ($val[0] == '-' ? bcceil($val) : bcfloor($val)); 
     } 
    } 
    return $val; 
} 

Answer 3

function getBcRound($number, $precision = 0) 
{ 
    $precision = ($precision < 0) 
       ? 0 
       : (int) $precision; 
    if (strcmp(bcadd($number, '0', $precision), bcadd($number, '0', $precision+1)) == 0) { 
     return bcadd($number, '0', $precision); 
    } 
    if (getBcPresion($number) - $precision > 1) { 
     $number = getBcRound($number, $precision + 1); 
    } 
    $t = '0.' . str_repeat('0', $precision) . '5'; 
    return $number < 0 
      ? bcsub($number, $t, $precision) 
      : bcadd($number, $t, $precision); 
} 

function getBcPresion($number) { 
    $dotPosition = strpos($number, '.'); 
    if ($dotPosition === false) { 
     return 0; 
    } 
    return strlen($number) - strpos($number, '.') - 1; 
} 

var_dump(getBcRound('3', 0) == number_format('3', 0)); 
var_dump(getBcRound('3.4', 0) == number_format('3.4', 0)); 
var_dump(getBcRound('3.56', 0) == number_format('3.6', 0)); 
var_dump(getBcRound('1.95583', 2) == number_format('1.95583', 2)); 
var_dump(getBcRound('5.045', 2) == number_format('5.045', 2)); 
var_dump(getBcRound('5.055', 2) == number_format('5.055', 2)); 
var_dump(getBcRound('9.999', 2) == number_format('9.999', 2)); 
var_dump(getBcRound('5.0445', 5) == number_format('5.044500', 5)); 
var_dump(getBcRound('5.0445', 4) == number_format('5.04450', 4)); 
var_dump(getBcRound('5.0445', 3) == number_format('5.0445', 3)); 
var_dump(getBcRound('5.0445', 2) == number_format('5.045', 2)); 
var_dump(getBcRound('5.0445', 1) == number_format('5.05', 1)); 
var_dump(getBcRound('5.0445', 0) == number_format('5.0', 0));// 
var_dump(getBcRound('5.04455', 2) == number_format('5.045', 2)); 
var_dump(getBcRound('99.999', 2) == number_format('100.000', 2)); 
var_dump(getBcRound('99.999') == number_format('99.999', 0)); 
var_dump(getBcRound('99.999', 'a') == number_format('99.999', 0)); 
var_dump(getBcRound('99.999', -1.5) == number_format('99.999', 0)); 
var_dump(getBcRound('-0.00001', 2) == number_format('-0.000', 2)); 
var_dump(getBcRound('-0.0000', 2) == number_format('0', 2)); 
var_dump(getBcRound('-4.44455', 2) == number_format('-4.445', 2)); 
var_dump(getBcRound('-4.44555', 0) == number_format('-4.5', 0)); 
var_dump(getBcRound('-4.444444444444444444444444444444444444444444445', 0) == number_format('-4.5', 0));