Python实现Linux命令xxd -i功能
一. Linux xxd -i功能
Linux系统xxd命令使用二进制或十六进制格式显示文件内容。若未指定outfile参数，则将结果显示在终端屏幕上；否则输出到outfile中。详细的用法可参考linux命令xxd。
本文主要关注xxd命令-i选项。使用该选项可输出以inputfile为名的C语言数组定义。例如，执行echo 12345 > test和xxd -i test命令后，输出为：
unsigned char test[] = {
0x31, 0x32, 0x33, 0x34, 0x35, 0x0a
};
unsigned int test_len = 6;可见，数组名即输入文件名(若有后缀名则点号替换为下划线)。注意，0x0a表示换行符LF，即'\n'。
二. xxd -i常见用途
当设备没有文件系统或不支持动态内存管理时，有时会将二进制文件(如引导程序和固件)内容存储在C代码静态数组内。此时，借助xxd命令就可自动生成版本数组。举例如下：
1) 使用Linux命令xdd将二进制文件VdslBooter.bin转换为16进制文件DslBooter.txt：
xxd -i < VdslBooter.bin > DslBooter.txt
其中，'-i'选项表示输出为C包含文件的风格(数组方式)。重定向符号'<'将VdslBooter.bin文件内容重定向到标准输入，该处理可剔除数组声明和长度变量定义，使输出仅包含16进制数值。
2) 在C代码源文件内定义相应的静态数组：
static const uint8 bootImageArray[] = {
#include " ../../DslBooter.txt"
};
TargetImage bootImage = {
(uint8 *) bootImageArray,
sizeof(bootImageArray) / sizeof(bootImageArray[0])
};编译源码时，DslBooter.txt文件的内容会自动展开到上述数组内。通过巧用#include预处理指令，可免去手工拷贝数组内容的麻烦。
三. 类xxd -i功能的Python实现
本节将使用Python2.7语言实现类似xxd -i的功能。
因为作者处于学习阶段，代码中存在许多写法不同但功能相同或相近的地方，旨在提供不同的语法参考，敬请谅解。
首先，请看一段短小却完整的程序(保存为xddi.py)：
#!/usr/bin/python
#coding=utf-8
#判断是否C语言关键字
CKeywords = ("auto", "break", "case", "char", "const", "continue", "default",
"do","double","else","enum","extern","float","for",
"goto","if","int","long","register","return","short",
"signed","static","sizeof","struct","switch","typedef","union",
"unsigned","void","volatile","while", "_Bool") #_Bool为C99新关键字
def IsCKeywords(name):
for x in CKeywords:
if cmp(x, name) == 0:
return True
return False
if __name__ == '__main__':
print IsCKeywords('const')
#Xxdi()这段代码判断给定的字符串是否为C语言关键字。在Windows系统cmd命令提示符下输入E:\PyTest>python xxdi.py，执行结果为True。
接下来的代码片段将省略头部的脚本和编码声明，以及尾部的'main'段。
生成C数组前，应确保数组名合法。C语言标识符只能由字母、数字和下划线组成，且不能以数字开头。此外，关键字不能用作标识符。所有，需要对非法字符做处理，其规则参见代码注释：
import re
def GenerateCArrayName(inFile):
#字母数字下划线以外的字符均转为下划线
#'int $=5;'的定义在Gcc 4.1.2可编译通过，但此处仍视为非法标识符
inFile = re.sub('[^0-9a-zA-Z\_]', '_', inFile) #'_'改为''可剔除非法字符
#数字开头加双下划线
if inFile[0].isdigit() == True:
inFile = '__' + inFile
#若输入文件名为C语言关键字，则将其大写并加下划线后缀作为数组名
#不能仅仅大写或加下划线前，否则易于用户自定义名冲突
if IsCKeywords(inFile) is True:
inFile = '%s_' %inFile.upper()
return inFile以print GenerateCArrayName('1a$if1#1_4.txt')执行时，入参字符串将被转换为__1a_if1_1_4_txt。类似地，_Bool被转换为_BOOL_。
为了尽可能模拟Linux命令风格，还需提供命令行选项和参数。解析模块选用optionparser，其用法详见python命令行解析。类xxd -i功能的命令行实现如下：
#def ParseOption(base, cols, strip, inFile, outFile):
def ParseOption(base = 16, cols = 12, strip = False, inFile = '', outFile = None):
from optparse import OptionParser
custUsage = '\n xxdi(.py) [options] inFile [outFile]'
parser = OptionParser(usage=custUsage)
parser.add_option('-b', '--base', dest='base',
help='represent values according to BASE(default:16)')
parser.add_option('-c', '--column', dest='col',
help='COL octets per line(default:12)')
parser.add_option('-s', '--strip', action='store_true', dest='strip',
help='only output C array elements')
(options, args) = parser.parse_args()
if options.base is not None:
base = int(options.base)
if options.col is not None:
cols = int(options.col)
if options.strip is not None:
strip = True
if len(args) == 0:
print 'No argument, at least one(inFile)!\nUsage:%s' %custUsage
if len(args) >= 1:
inFile = args[0]
if len(args) >= 2:
outFile = args[1]
return ([base, cols, strip], [inFile, outFile])被注释掉的def ParseOption(...)原本是以下面的方式调用：
base = 16; cols = 12; strip = False; inFile = ''; outFile = '' ([base, cols, strip], [inFile, outFile]) = ParseOption(base, cols, strip, inFile, outFile)
其意图是同时修改base、cols、strip等参数值。但这种写法非常别扭，改用缺省参数的函数定义方式，调用时只需要写ParseOption()即可。若读者知道更好的写法，望不吝赐教。
以-h选项调出命令提示，可见非常接近Linux风格：
E:\PyTest>python xxdi.py -h Usage: xxdi(.py) [options] inFile [outFile] Options: -h, --help show this help message and exit -b BASE, --base=BASE represent values according to BASE(default:16) -c COL, --column=COL COL octets per line(default:12) -s, --strip only output C array elements
基于上述练习，接着完成本文的重头戏：
def Xxdi():
#解析命令行选项及参数
([base, cols, strip], [inFile, outFile]) = ParseOption()
import os
if os.path.isfile(inFile) is False:
print ''''%s' is not a file!''' %inFile
return
with open(inFile, 'rb') as file: #必须以'b'模式访问二进制文件
#file = open(inFile, 'rb') #Python2.5以下版本不支持with...as语法
#if True:
#不用for line in file或readline(s)，以免遇'0x0a'换行
content = file.read()
#将文件内容"打散"为字节数组
if base is 16: #Hexadecimal
content = map(lambda x: hex(ord(x)), content)
elif base is 10: #Decimal
content = map(lambda x: str(ord(x)), content)
elif base is 8: #Octal
content = map(lambda x: oct(ord(x)), content)
else:
print '[%s]: Invalid base or radix for C language!' %base
return
#构造数组定义头及长度变量
cArrayName = GenerateCArrayName(inFile)
if strip is False:
cArrayHeader = 'unsigned char %s[] = {' %cArrayName
else:
cArrayHeader = ''
cArrayTailer = '};\nunsigned int %s_len = %d;' %(cArrayName, len(content))
if strip is True: cArrayTailer = ''
#print会在每行输出后自动换行
if outFile is None:
print cArrayHeader
for i in range(0, len(content), cols):
line = ', '.join(content[i:i+cols])
print ' ' + line + ','
print cArrayTailer
return
with open(outFile, 'w') as file:
#file = open(outFile, 'w') #Python2.5以下版本不支持with...as语法
#if True:
file.write(cArrayHeader + '\n')
for i in range(0, len(content), cols):
line = reduce(lambda x,y: ', '.join([x,y]), content[i:i+cols])
file.write(' %s,\n' %line)
file.flush()
file.write(cArrayTailer)Python2.5以下版本不支持with...as语法，而作者调试所用的Linux系统仅装有Python2.4.3。因此，要在Linux系统中运行xddi.py，只能写为file = open(...。但这需要处理文件的关闭和异常，详见理解Python中的with…as…语法。注意，Python2.5中使用with...as语法时需要声明from __future__ import with_statement。
可通过platform.python_version()获取Python版本号。例如：
import platform
#判断Python是否为major.minor及以上版本
def IsForwardPyVersion(major, minor):
#python_version()返回'major.minor.patchlevel'，如'2.7.11'
ver = platform.python_version().split('.')
if int(ver[0]) >= major and int(ver[1]) >= minor:
return True
return False经过Windows和Linux系统双重检验后，Xddi()工作基本符合预期。以123456789ABCDEF.txt文件(内容为'123456789ABCDEF')为例，测试结果如下：
E:\PyTest>python xxdi.py -c 5 -b 2 -s 123456789ABCDEF.txt
[2]: Invalid base or radix for C language!
E:\Pytest>python xxdi.py -c 5 -b 10 -s 123456789ABCDEF.txt
49, 50, 51, 52, 53,
54, 55, 56, 57, 65,
66, 67, 68, 69, 70,
E:\PyTest>python xxdi.py -c 5 -b 10 123456789ABCDEF.txt
unsigned char __123456789ABCDEF_txt[] = {
49, 50, 51, 52, 53,
54, 55, 56, 57, 65,
66, 67, 68, 69, 70,
};
unsigned int __123456789ABCDEF_txt_len = 15;
E:\PyTest>python xxdi.py -c 5 -b 8 123456789ABCDEF.txt
unsigned char __123456789ABCDEF_txt[] = {
061, 062, 063, 064, 065,
066, 067, 070, 071, 0101,
0102, 0103, 0104, 0105, 0106,
};
unsigned int __123456789ABCDEF_txt_len = 15;
E:\PyTest>python xxdi.py 123456789ABCDEF.txt
unsigned char __123456789ABCDEF_txt[] = {
0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x41, 0x42, 0x43,
0x44, 0x45, 0x46,
};
unsigned int __123456789ABCDEF_txt_len = 15;再以稍大的二级制文件为例，执行 python xxdi.py VdslBooter.bin booter.c后，booter.c文件内容如下(截取首尾)：
unsigned char VdslBooter_bin[] = {
0xff, 0x31, 0x0, 0xb, 0xff, 0x3, 0x1f, 0x5a, 0x0, 0x0, 0x0, 0x0,
//... ... ... ...
0x0, 0x0, 0x0, 0x0, 0xff, 0xff, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
};
unsigned int VdslBooter_bin_len = 53588;综上可见，作者实现的xxdi模块与Linux xxd -i功能非常接近，且各有优劣。xxdi优点在于对数组名合法性校验更充分(关键字检查)，数组内容表现形式更丰富(8进制和10进制)；缺点在于不支持重定向，且数值宽度不固定(如0xb和0xff)。当然，这些缺点并不难消除。例如，用'0x%02x'%val代替hex(val)即可控制输出位宽。只是，再加完善难免提高代码复杂度，也许会事倍功半。
以上所述是小编给大家介绍的Python实现Linux命令xxd -i功能，希望对大家以上帮助！
Hot AI Tools
Undresser.AI Undress
AI-powered app for creating realistic nude photos
AI Clothes Remover
Online AI tool for removing clothes from photos.
Undress AI Tool
Undress images for free
Clothoff.io
AI clothes remover
Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!
Hot Article
Hot Tools
Notepad++7.3.1
Easy-to-use and free code editor
SublimeText3 Chinese version
Chinese version, very easy to use
Zend Studio 13.0.1
Powerful PHP integrated development environment
Dreamweaver CS6
Visual web development tools
SublimeText3 Mac version
God-level code editing software (SublimeText3)
Hot Topics
1677
14
1431
52
1334
25
1279
29
1257
24
Python vs. C : Learning Curves and Ease of Use
Apr 19, 2025 am 12:20 AM
Python is easier to learn and use, while C is more powerful but complex. 1. Python syntax is concise and suitable for beginners. Dynamic typing and automatic memory management make it easy to use, but may cause runtime errors. 2.C provides low-level control and advanced features, suitable for high-performance applications, but has a high learning threshold and requires manual memory and type safety management.
Learning Python: Is 2 Hours of Daily Study Sufficient?
Apr 18, 2025 am 12:22 AM
Is it enough to learn Python for two hours a day? It depends on your goals and learning methods. 1) Develop a clear learning plan, 2) Select appropriate learning resources and methods, 3) Practice and review and consolidate hands-on practice and review and consolidate, and you can gradually master the basic knowledge and advanced functions of Python during this period.
Python vs. C : Exploring Performance and Efficiency
Apr 18, 2025 am 12:20 AM
Python is better than C in development efficiency, but C is higher in execution performance. 1. Python's concise syntax and rich libraries improve development efficiency. 2.C's compilation-type characteristics and hardware control improve execution performance. When making a choice, you need to weigh the development speed and execution efficiency based on project needs.
Python vs. C : Understanding the Key Differences
Apr 21, 2025 am 12:18 AM
Python and C each have their own advantages, and the choice should be based on project requirements. 1) Python is suitable for rapid development and data processing due to its concise syntax and dynamic typing. 2)C is suitable for high performance and system programming due to its static typing and manual memory management.
Which is part of the Python standard library: lists or arrays?
Apr 27, 2025 am 12:03 AM
Pythonlistsarepartofthestandardlibrary,whilearraysarenot.Listsarebuilt-in,versatile,andusedforstoringcollections,whereasarraysareprovidedbythearraymoduleandlesscommonlyusedduetolimitedfunctionality.
Python: Automation, Scripting, and Task Management
Apr 16, 2025 am 12:14 AM
Python excels in automation, scripting, and task management. 1) Automation: File backup is realized through standard libraries such as os and shutil. 2) Script writing: Use the psutil library to monitor system resources. 3) Task management: Use the schedule library to schedule tasks. Python's ease of use and rich library support makes it the preferred tool in these areas.
Python for Scientific Computing: A Detailed Look
Apr 19, 2025 am 12:15 AM
Python's applications in scientific computing include data analysis, machine learning, numerical simulation and visualization. 1.Numpy provides efficient multi-dimensional arrays and mathematical functions. 2. SciPy extends Numpy functionality and provides optimization and linear algebra tools. 3. Pandas is used for data processing and analysis. 4.Matplotlib is used to generate various graphs and visual results.
Python for Web Development: Key Applications
Apr 18, 2025 am 12:20 AM
Key applications of Python in web development include the use of Django and Flask frameworks, API development, data analysis and visualization, machine learning and AI, and performance optimization. 1. Django and Flask framework: Django is suitable for rapid development of complex applications, and Flask is suitable for small or highly customized projects. 2. API development: Use Flask or DjangoRESTFramework to build RESTfulAPI. 3. Data analysis and visualization: Use Python to process data and display it through the web interface. 4. Machine Learning and AI: Python is used to build intelligent web applications. 5. Performance optimization: optimized through asynchronous programming, caching and code
