CppUnit TDD之探索swf文件头(中)

这一篇，我们来看一下代码。 using System; using System.IO; namespace SwfHeaderReader { /// <summary> /// Summary description for FlashHeaderReader. /// </summary> public class FlashHeaderReader { internal int FrameRate { get { return mFrameRate; } } internal int FrameCount { get { return mFrameCount; } } internal int Width { get { return mWidth; } } internal int Height { get { return mHeight; } } internal bool Error { get {return mbErrorSignature;} } private int mFrameRate=0; private int mFrameCount=0; private int mVersion=0; private bool mIsCompressed=false; private int mWidth=0; private int mHeight=0; private bool mbErrorSignature; // To Parse Header private byte[] data; private int currentIndex; public FlashHeaderReader(String filename) { currentIndex=0; mbErrorSignature=false; FileStream fs = File.OpenRead(filename); data = new byte[fs.Length]; fs.Read (data,data.Length); fs.Close(); ParseHeader(); } /* *Parse the header of the swf format *Format http://www.half-serious.com/swf/format/index.html#header *convert from php : http://www.zend.com/codex.php?id=1382&single=1 */ private void ParseHeader() { ReadSignature(); mVersion=GetNextByte(); ReadFileLength(); ReadFrameSize(); ReadFrameRate(); ReadFrameCount(); } /* * Read first caractere FWS or CWS * File compressed are not supported */ private void ReadSignature() { Byte readingByte=GetNextByte(); if (readingByte=='C') { mIsCompressed=true; // Not supported } if (readingByte!='F' && readingByte!='C') { mbErrorSignature=true; } if (GetNextByte()!='W') mbErrorSignature=true; if (GetNextByte()!='S') mbErrorSignature=true; } /* *Read the RECT Structure : Frame size in twips *This retrieve from byte the size. *the source php is difficult to translate I have made *something working... */ private void ReadFrameSize() { int cByte = GetNextByte(); int NbBits=cByte>>3; cByte&=7; cByte<<=5; int currentBit=2; int currentValue; // Must get all 4 values in the RECT for (int numField=0;numField<4;numField++) { currentValue=0; int bitcount = 0 ; while (bitcount<NbBits) { if ((cByte&128)==128) { currentValue =currentValue + (1<<(NbBits-bitcount-1)) ; } cByte<<=1 ; cByte &= 255 ; currentBit-- ; bitcount++ ; // We will be needing a new byte if we run out of bits if (currentBit<0) { cByte = GetNextByte() ; currentBit = 7 ; } } // TWIPS to PIXELS currentValue/=20; switch (numField) { case 0: mWidth = currentValue ; break ; case 1: mWidth = currentValue - mWidth ; break ; case 2: mHeight = currentValue ; break ; case 3: mHeight = currentValue - mHeight ; break; } } } /* * Read Frame delay in 8.8 fixed number of frames per second */ private void ReadFrameRate() { // Frame rate bytefps_decimal,fps_int ; fps_decimal = GetNextByte(); fps_int =GetNextByte(); mFrameRate=fps_int+(fps_decimal)/100; } private void ReadFrameCount() { for (int i=0;i<2;i++) { mFrameCount+= (GetNextByte()<<(8*i)) ; } } /* *ReadFileLength : Length of entire file in bytes *Not implemented */ private void ReadFileLength() { //Read Size GetNextByte(); GetNextByte(); GetNextByte(); GetNextByte(); } /* *Retrieve one caractere of the buffer. */ private byte GetNextByte() { Byte result; result=data[currentIndex]; currentIndex++; return(result); } } } 哇塞。怎么这么写啊。 private void ParseHeader() { ReadSignature(); mVersion=GetNextByte(); ReadFileLength(); ReadFrameSize(); ReadFrameRate(); ReadFrameCount(); } 在C++里面，我一个File的open一下就读完所有的结构了啊。 还好我前两年看了设计模式，要不还不被人笑死。这个应该算是builder模式吧。 从重构的角度讲，小函数更具灵活性，而且更容易被重用。这点上，最后一个函数GetNextByte()也是深得重构理论真传。 好了，先写个测试读取文件大小的用例吧。 写个读取swf文件的类。 //SwfReader.h #pragma once typedef struct SwfHeader {