Stdlib: pack()/unpack() — machine-endian integer formats (P/p/I/i/L/l/Q/q/J/j/V/v) and @ alignment (ext/standard/pack.c)

[PurHur]

Category

stdlib

Problem

After basic pack() / unpack() exist, this build must match Zend for machine-dependent and explicitly sized integer formats and the @ alignment specifier. Float codes d/e/f/g are tracked in #4662; this issue covers integer / endian / padding codes from pack.c.

Typical gaps when not using host pack(): wrong endianness, wrong sizeof for P/p, @ skip misaligned, Q/J 64-bit layout.

php-src reference

• php/php-src ext/standard/pack.c — pack_template, php_pack, php_unpack, endianness, @ handling

Repro

<?php
// 32-bit little-endian unsigned (format N) vs machine (I)
$bin = pack('Nn', 0x11223344, 0x5566);
var_export(unpack('Nn', $bin));
echo "\n";
// padding / alignment
var_export(strlen(pack('I@4I', 1, 2)));
echo "\n";
// 64-bit (platform-dependent width for J/Q on 64-bit PHP)
var_export(unpack('P', pack('P', 0x1234)));

Compare Zend vs this compiler (VM):

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh
php repro_pack_int.php
php bin/vm.php repro_pack_int.php
'

Scope (this repo)

• ext/standard/VmPack.php (or native port from bootstrap issue)
• lib/AOT/runtime/ — __compiler_pack / __compiler_unpack
• ext/standard/JitPack.php, ext/standard/JitUnpack.php
• Compliance: test/compliance/cases/stdlib/pack_integer_endian.phpt

Done when

• VM returns Zend-identical binary strings and unpack() arrays for c/C, s/S, n/N, v/V, i/I, l/L, q/Q, j/J, p/P on the CI target arch
• @ alignment and x/X/Z padding bytes match pack.c
• Invalid specifier warnings/false return follow #4532
• JIT/AOT use the same encoder/decoder as VM

Related

• #4662 float/double formats
• #4673 bootstrap native pack (prerequisite if VmPack still delegates)
• #4204 numeric-string length params on other builtins

[PurHur]

claim: cursor-agent-lane-b — starting this run

Trust gates (this host): bootstrap-inventory OK 5388/5388; release-readiness user_release_ready: yes (north-star5-fast + vm-driver-probe ok).

Issue repro already matches Zend on VM for Nn / I@4I / P round-trip; adding pack_integer_endian.phpt (and closing Done-when).

[PurHur]

merged: #20051

Verification:

• Issue repro Zend ≡ VM for Nn / I@4I / P round-trip
• vendor/bin/phpunit --filter pack_integer_endian → OK (4 tests)
• Compliance: pack_integer_endian.phpt + JIT twin

Note: Zend 8.2 in docker also rejects j/p format codes; matched as php-src-strict.