Smalltalk【1】 语言二进制流实战：读取 EXE【2】 文件的头部信息
Smalltalk 是一种面向对象的编程语言，以其简洁、优雅和动态性【3】著称。在软件开发过程中，我们经常需要与二进制文件【4】进行交互，例如读取、解析和修改。本文将围绕 Smalltalk 语言，通过实战演示如何读取 EXE 文件的头部信息。
EXE 文件头部信息【5】概述
EXE 文件是 Windows 操作系统上可执行文件的格式。EXE 文件头部包含了文件的基本信息，如文件大小、入口点地址【6】等。了解这些信息对于逆向工程【7】和软件开发具有重要意义。
Smalltalk 环境准备
在开始编写代码之前，我们需要准备一个 Smalltalk 环境。这里以 Pharo Smalltalk【8】 为例，它是一个开源的 Smalltalk 实现，具有丰富的库和工具。
1. 下载 Pharo Smalltalk：https://www.pharo.org/
2. 安装 Pharo Smalltalk：按照官方文档进行安装。
3. 运行 Pharo Smalltalk：打开 Pharo Smalltalk，开始编写代码。
读取 EXE 文件头部信息
以下是一个使用 Smalltalk 读取 EXE 文件头部信息的示例代码：
smalltalk
| file header |
file := File newNamed: 'example.exe'.
file openRead.
header := file readBytes: 512.
file close.
header at: 0 to: 4 do: [ :byte |
(byte asInteger) printNl.
].
header at: 28 to: 32 do: [ :byte |
(byte asInteger) printNl.
].
header at: 52 to: 56 do: [ :byte |
(byte asInteger) printNl.
].
header at: 60 to: 64 do: [ :byte |
(byte asInteger) printNl.
].
header at: 68 to: 72 do: [ :byte |
(byte asInteger) printNl.
].
header at: 76 to: 80 do: [ :byte |
(byte asInteger) printNl.
].
header at: 84 to: 88 do: [ :byte |
(byte asInteger) printNl.
].
header at: 92 to: 96 do: [ :byte |
(byte asInteger) printNl.
].
header at: 100 to: 104 do: [ :byte |
(byte asInteger) printNl.
].
header at: 108 to: 112 do: [ :byte |
(byte asInteger) printNl.
].
header at: 116 to: 120 do: [ :byte |
(byte asInteger) printNl.
].
header at: 124 to: 128 do: [ :byte |
(byte asInteger) printNl.
].
header at: 132 to: 136 do: [ :byte |
(byte asInteger) printNl.
].
header at: 140 to: 144 do: [ :byte |
(byte asInteger) printNl.
].
header at: 148 to: 152 do: [ :byte |
(byte asInteger) printNl.
].
header at: 156 to: 160 do: [ :byte |
(byte asInteger) printNl.
].
header at: 164 to: 168 do: [ :byte |
(byte asInteger) printNl.
].
header at: 172 to: 176 do: [ :byte |
(byte asInteger) printNl.
].
header at: 180 to: 184 do: [ :byte |
(byte asInteger) printNl.
].
header at: 188 to: 192 do: [ :byte |
(byte asInteger) printNl.
].
header at: 196 to: 200 do: [ :byte |
(byte asInteger) printNl.
].
header at: 204 to: 208 do: [ :byte |
(byte asInteger) printNl.
].
header at: 212 to: 216 do: [ :byte |
(byte asInteger) printNl.
].
header at: 220 to: 224 do: [ :byte |
(byte asInteger) printNl.
].
header at: 228 to: 232 do: [ :byte |
(byte asInteger) printNl.
].
header at: 236 to: 240 do: [ :byte |
(byte asInteger) printNl.
].
header at: 244 to: 248 do: [ :byte |
(byte asInteger) printNl.
].
header at: 252 to: 256 do: [ :byte |
(byte asInteger) printNl.
].
header at: 260 to: 264 do: [ :byte |
(byte asInteger) printNl.
].
header at: 268 to: 272 do: [ :byte |
(byte asInteger) printNl.
].
header at: 276 to: 280 do: [ :byte |
(byte asInteger) printNl.
].
header at: 284 to: 288 do: [ :byte |
(byte asInteger) printNl.
].
header at: 292 to: 296 do: [ :byte |
(byte asInteger) printNl.
].
header at: 300 to: 304 do: [ :byte |
(byte asInteger) printNl.
].
header at: 308 to: 312 do: [ :byte |
(byte asInteger) printNl.
].
header at: 316 to: 320 do: [ :byte |
(byte asInteger) printNl.
].
header at: 324 to: 328 do: [ :byte |
(byte asInteger) printNl.
].
header at: 332 to: 336 do: [ :byte |
(byte asInteger) printNl.
].
header at: 340 to: 344 do: [ :byte |
(byte asInteger) printNl.
].
header at: 348 to: 352 do: [ :byte |
(byte asInteger) printNl.
].
header at: 356 to: 360 do: [ :byte |
(byte asInteger) printNl.
].
header at: 364 to: 368 do: [ :byte |
(byte asInteger) printNl.
].
header at: 372 to: 376 do: [ :byte |
(byte asInteger) printNl.
].
header at: 380 to: 384 do: [ :byte |
(byte asInteger) printNl.
].
header at: 388 to: 392 do: [ :byte |
(byte asInteger) printNl.
].
header at: 396 to: 400 do: [ :byte |
(byte asInteger) printNl.
].
header at: 404 to: 408 do: [ :byte |
(byte asInteger) printNl.
].
header at: 412 to: 416 do: [ :byte |
(byte asInteger) printNl.
].
header at: 420 to: 424 do: [ :byte |
(byte asInteger) printNl.
].
header at: 428 to: 432 do: [ :byte |
(byte asInteger) printNl.
].
header at: 436 to: 440 do: [ :byte |
(byte asInteger) printNl.
].
header at: 444 to: 448 do: [ :byte |
(byte asInteger) printNl.
].
header at: 452 to: 456 do: [ :byte |
(byte asInteger) printNl.
].
header at: 460 to: 464 do: [ :byte |
(byte asInteger) printNl.
].
header at: 468 to: 472 do: [ :byte |
(byte asInteger) printNl.
].
header at: 476 to: 480 do: [ :byte |
(byte asInteger) printNl.
].
header at: 484 to: 488 do: [ :byte |
(byte asInteger) printNl.
].
header at: 492 to: 496 do: [ :byte |
(byte asInteger) printNl.
].
header at: 500 to: 504 do: [ :byte |
(byte asInteger) printNl.
].
代码解析
1. 创建一个 `File` 对象，并指定要读取的 EXE 文件名。
2. 使用 `openRead【9】` 方法打开文件，以便读取。
3. 使用 `readBytes【10】` 方法读取文件的前 512 个字节，这些字节包含了 EXE 文件头部信息。
4. 使用 `close` 方法关闭文件。
5. 使用 `do:` 循环遍历文件头部信息，并打印出每个字节的值。
总结
本文通过 Smalltalk 语言展示了如何读取 EXE 文件的头部信息。在实际应用中，我们可以根据需要解析文件头部信息中的各个字段，以获取更多关于文件的信息。Smalltalk 语言在处理二进制文件方面具有强大的功能，可以方便地实现各种二进制文件操作。
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