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Request #79153 function to copy arrays
Submitted: 2020-01-21 22:04 UTC Modified: 2021-09-16 21:31 UTC
From: flip101 at gmail dot com Assigned:
Status: Open Package: FFI (PECL)
PHP Version: 7.4.1 OS:
Private report: No CVE-ID: None
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 [2020-01-21 22:04 UTC] flip101 at gmail dot com
Description:
------------
On example #5 in https://www.php.net/manual/en/ffi.examples-basic.php it says "work with it like with a regular PHP array".

But when i assign values directly
$a = [1, 2, 3, 4];

The type seems to change from `FFI\CData` to PHP `array`. It would be useful to have an array copy method so a copy loop (which seems?? the only way for the moment) doesn't need to be done in php itself. Although pack() could be used as well, but is that the best way?


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 [2020-01-21 22:38 UTC] flip101 at gmail dot com
I wrote this piece of code, not saying it's the best. But perhaps some of the logic here is better implemented in C.

function arrayCreate(string $type, array $source) {
  $size = count($source);

  if ('char' === $type) {
    $format = 'c'; $bytes_multiplier = 1;
  } elseif ('unsigned char' === $type) {
    $format = 'C'; $bytes_multiplier = 1;
  } elseif ('short' === $type) {
    $format = 's'; $bytes_multiplier = 2;
  } elseif ('unsigned short' === $type) {
    $format = 'S'; $bytes_multiplier = 2;
  } elseif ('int' === $type) {
    $format = 'i'; $bytes_multiplier = 4; // assumption: https://stackoverflow.com/a/11438838/1833322
  } elseif ('unsigned int' === $type) {
    $format = 'I'; $bytes_multiplier = 4;
  } elseif ('long' === $type) {
    $format = 'l'; $bytes_multiplier = 4;
  } elseif ('unsigned long' === $type) {
    $format = 'L'; $bytes_multiplier = 4;
  } elseif ('long long' === $type) {
    $format = 'q'; $bytes_multiplier = 8;
  } elseif ('unsigned long long' === $type) {
    $format = 'Q'; $bytes_multiplier = 8;
  } elseif ('float' === $type) {
    $format = 'f'; $bytes_multiplier = 4;
  } elseif ('double' === $type) {
    $format = 'd'; $bytes_multiplier = 8;
  } else {
    throw new \InvalidArgumentException('type');
  }

  $first_type = gettype(reset($source));
  if (! array_reduce($source, function($c, $i) use ($first_type) { return $c && gettype($i) === $first_type; }, true)) {
    throw new \InvalidArgumentException('source');
  }

  $array = FFI::new($type . '[' . $size . ']');

  FFI::memcpy($array, pack($format . '*', ...$source), $size * $bytes_multiplier);

  return $array;
}
 [2020-01-23 13:33 UTC] sjon@php.net
-Package: ffi +Package: *Extensibility Functions
 [2021-09-16 21:31 UTC] cmb@php.net
-Package: *Extensibility Functions +Package: FFI
 
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