From 79f6b161f892f621a909ce1df99b3c680f3682a2 Mon Sep 17 00:00:00 2001
From: Sunil Nimmagadda <sunil@nimmagadda.net>
Date: Fri, 23 Oct 2026 22:43:44 +0530
Subject: Refactor: Move to an elf module.

While here, define a elf.d.lua to help author type check configuration file.
---
 elf/segment.lua | 65 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 65 insertions(+)
 create mode 100644 elf/segment.lua

(limited to 'elf/segment.lua')

diff --git a/elf/segment.lua b/elf/segment.lua
new file mode 100644
index 0000000..da8e9c6
--- /dev/null
+++ b/elf/segment.lua
@@ -0,0 +1,65 @@
+local ec = require("elf.constants")
+local fmt = require("elf.fmt")
+
+local M = {}
+
+---@class Segment
+---@field type SegmentType
+---@field flags integer
+---@field offset integer
+---@field vaddr integer
+---@field paddr integer
+---@field filesz integer
+---@field memsz integer
+---@field align integer
+
+---@param phdr Segment
+---@param endian Endian
+---@return string
+---@nodiscard
+local function pack32(phdr, endian)
+    return string.pack(
+        fmt.endian(endian) .. string.rep(fmt.word(ec.Class.bit32), 8),
+        phdr.type,
+        phdr.offset,
+        phdr.vaddr,
+        phdr.paddr,
+        phdr.filesz,
+        phdr.memsz,
+        phdr.flags,
+        phdr.align)
+end
+
+---@param phdr Segment
+---@param endian Endian
+---@return string
+---@nodiscard
+local function pack64(phdr, endian)
+    return string.pack(
+        fmt.endian(endian) .. "I4I4" .. string.rep(fmt.word(ec.Class.bit64), 6),
+        phdr.type,
+        phdr.flags,
+        phdr.offset,
+        phdr.vaddr,
+        phdr.paddr,
+        phdr.filesz,
+        phdr.memsz,
+        phdr.align)
+end
+
+---@param phdrs Segment[]
+---@param endian Endian
+---@param class Class
+---@return string
+---@nodiscard
+function M.pack(phdrs, endian, class)
+    local p = {}
+    for i, phdr in ipairs(phdrs) do
+        p[i] = (class == ec.Class.bit32) and
+            pack32(phdr, endian) or
+            pack64(phdr, endian)
+    end
+    return table.concat(p)
+end
+
+return M
-- 
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