python处理二进制数据的方法

#!/usr/env/env python 
#-*- coding: cp936 -*- 
''''' 
add Head Infomation for pcm file 
''' 
import sys 
import struct 
import os 
__author__ = 'bob_hu, hewitt924@gmail.com' 
__date__ = 'Dec 19,2011' 
__update__ = 'Dec 19,2011' 
def geneHeadInfo(sampleRate,bits,sampleNum): 
 ''''' 
 生成头信息，需要采样率，每个采样的位数，和整个wav的采样的字节数 
 ''' 
 rHeadInfo = 'x52x49x46x46' 
 fileLength = struct.pack('i',sampleNum + 36) 
 rHeadInfo += fileLength 
 rHeadInfo += 'x57x41x56x45x66x6Dx74x20x10x00x00x00x01x00x01x00' 
 rHeadInfo += struct.pack('i',sampleRate) 
 rHeadInfo += struct.pack('i',sampleRate * bits / 8) 
 rHeadInfo += 'x02x00' 
 rHeadInfo += struct.pack('H',bits) 
 rHeadInfo += 'xx61x74x61' 
 rHeadInfo += struct.pack('i',sampleNum) 
 return rHeadInfo 
if __name__ == '__main__': 
 if len(sys.argv) != 5: 
 print "usage: python %s inFile sampleRate bits outFile" % sys.argv[0] 
 sys.exit(1) 
 fout = open(sys.argv[4],'wb') #用二进制的写入模式 
 #fout.write(struct.pack('4s','x66x6Dx74x20'))
 #写入一个长度为4的串，这个串的二进制内容为 66 6D 74 20 
 #Riff_flag,afd,fad,afdd, = struct.unpack('4c',fin.read(4))
 #读入四个字节，每一个都解析成一个字母 
 #open(sys.argv[4],'wb').write(struct.pack('4s','fmt '))
 #将字符串解析成二进制后再写入 
 #open(sys.argv[4],'wb').write('x3Cx9Cx00x00x57')
 #直接写入二进制内容：3C 9C 00 00 57 
 #fout.write(struct.pack('i',6000)) #写入6000的二进制形式 
 #check whether inFile has head-Info 
 fin = open(sys.argv[1],'rb') 
 Riff_flag, = struct.unpack('4s',fin.read(4)) 
 if Riff_flag == 'RIFF': 
 print "%s 有头信息" % sys.argv[1] 
 fin.close() 
 sys.exit(0) 
 else: 
 print "%s 没有头信息" % sys.argv[1] 
 fin.close() 
 #采样率 
 sampleRate = int(sys.argv[2]) 
 #bit位 
 bits = int(sys.argv[3]) 
 fin = open(sys.argv[1],'rb') 
 startPos = fin.tell() 
 fin.seek(0,os.SEEK_END) 
 endPos = fin.tell() 
 sampleNum = (endPos - startPos) 
 print sampleNum 
 headInfo = geneHeadInfo(sampleRate,bits,sampleNum) 
 fout.write(headInfo) 
 fin.seek(os.SEEK_SET) 
 fout.write(fin.read()) 
 fin.close() 
 fout.close()

希望本文所述对大家的Python程序设计有所帮助。