ObjectArchiveKit

A Swift library for parsing Unix ar archives (for example static libraries like .a) and reading member/symbol metadata.

The parser supports multiple archive layouts used by toolchains such as GNU, BSD, Darwin, and COFF.

Features

• Parse archive magic headers (!<arch>\n, !<thin>\n, !<bout>\n)
• Enumerate archive members and resolve member names (including long-name formats)
• Detect archive kind (gnu, gnu64, bsd, darwin64, coff)
• Read GNU symbol table (/) and string table (//)
• Read BSD/Darwin64 symbol tables (__.SYMDEF*) and map symbols to members
• Read COFF string table entries

Installation

Swift Package Manager

Add ObjectArchiveKit to your Package.swift dependencies.

dependencies: [
    .package(url: "https://github.com/p-x9/ObjectArchiveKit.git", branch: "main")
]

Then add the product to your target.

targets: [
    .target(
        name: "YourTarget",
        dependencies: [
            .product(name: "ObjectArchiveKit", package: "ObjectArchiveKit")
        ]
    )
]

Usage

Load from file

import Foundation
import ObjectArchiveKit

let url = URL(fileURLWithPath: "/path/to/libSomething.a")
let archive = try ArchiveFile(url: url)

print("Magic:", archive.magic)
print("Kind:", archive.kind)
print("Members:", archive.members.count)

Enumerate members

for (index, member) in archive.members.enumerated() {
    print("[\(index)]", member.name(in: archive))
    print("  offset:", member.offset)
    print("  size:", member.header.size)
}

Read symbol tables

switch archive.kind {
case .gnu, .gnu64:
    if let table = archive.gnuSymbolTable {
        print("GNU symbol count:", table.count)
        if let names = try table.names(in: archive) {
            for entry in names {
                print(entry.offset, entry.string)
            }
        }
    }

case .bsd:
    if let table = archive.bsdSymbolTable {
        print("BSD symbol count:", table.count)
        for symbol in try table.entries(in: archive) {
            let name = try table.name(for: symbol, in: archive) ?? "unknown"
            print(name, symbol.stringOffset, symbol.headerOffset)
        }
    }

case .darwin64:
    if let table = archive.darwin64SymbolTable {
        print("Darwin64 symbol count:", table.count)
        for symbol in try table.entries(in: archive) {
            let name = try table.name(for: symbol, in: archive) ?? "unknown"
            print(name, symbol.stringOffset, symbol.headerOffset)
        }
    }

case .coff:
    if let strings = archive.coffStrings {
        for entry in strings {
            print(entry.offset, entry.string)
        }
    }
}

Parse an archive region in a larger file

If an archive starts at a non-zero offset, use the designated initializer:

let archive = try ArchiveFile(
    url: url,
    headerStartOffset: 0x1000,
    size: 0x20000
)

Example Codes

Basic print-style examples are available in:

• ObjectArchiveKitTests

License

This repository currently does not include a LICENSE file.