自行封装的LZMA接口库,用于unity,包括win平台的dll,安卓的so动态库和iOS的.a静态库
LZMA是目前压缩比最高的压缩算法,官方提供了多种语言的版本,unity中可以直接使用C#版,但是实际证明纯C版的压缩速度是C#版的四五倍。
封装工程介绍
LZMA(Xcode)是一个iOS的静态库工程,直接在xcode中run一下即可得到对应的.a静态库,顶层接口封装在LZMALib.c中;
LZMA(AndroidStudio)是一个支持runtime C++的安卓工程,顶层接口封装在LZMALib.c中,build一下对应的.so库会装进apk包中,解压apk可以得到里面的LZMA so库(apk路径:..\app\build\outputs\apk\debug)。
7zSDK(VS)是LZMA官方完整的SDK和源码工程,编译LZMA动态库的工程是其中的LZMALib工程,路径为:..\C\Util\LzmaLib,顶层接口封装在LZMALib.c中。
封装接口预览
最顶层封装了两个接口,用于压缩和解压,压缩参数默认封在了接口内,如果要更改需要在相应的封装工程中修改并编译出新库:
// 自定义接口
MY_STDAPI DefaultLzmaCompress(const unsigned char *src,const size_t srcLen,unsigned char *dest,size_t *destLen);
MY_STDAPI DefaultLzmaUncompress(const unsigned char *src,size_t *srcLen,size_t *destLen);
//MY_STDAPI LZMAAdd(int x); // 测试用
/* LzmaLib.c -- LZMA library wrapper #include "Alloc.h" #include "LzmaDec.h" #include "LzmaEnc.h" #include "LzmaLib.h" unsigned char outProps[LZMA_PROPS_SIZE]; size_t outPropsSize = LZMA_PROPS_SIZE; MY_STDAPI LzmaCompress(unsigned char *dest,size_t *destLen,const unsigned char *src,size_t srcLen,unsigned char *outProps,size_t *outPropsSize,int level,/* 0 <= level <= 9,default = 5 */
unsigned dictSize,/* use (1 << N) or (3 << N). 4 KB < dictSize <= 128 MB */
int lc,/* 0 <= lc <= 8,default = 3 */
int lp,/* 0 <= lp <= 4,default = 0 */
int pb,/* 0 <= pb <= 4,default = 2 */
int fb,/* 5 <= fb <= 273,default = 32 */
int numThreads /* 1 or 2,default = 2 */
)
{
CLzmaEncProps props;
LzmaEncProps_Init(&props);
props.level = level;
props.dictSize = dictSize;
props.lc = lc;
props.lp = lp;
props.pb = pb;
props.fb = fb;
props.numThreads = numThreads;
return LzmaEncode(dest,destLen,src,srcLen,&props,outProps,outPropsSize,0,NULL,&g_Alloc,&g_Alloc);
}
MY_STDAPI LzmaUncompress(unsigned char *dest,const unsigned char *src,const unsigned char *props,size_t propsSize)
{
ELzmaStatus status;
return LzmaDecode(dest,props,(unsigned)propsSize,LZMA_FINISH_ANY,&status,&g_Alloc);
}
// 自定义接口
MY_STDAPI DefaultLzmaCompress(const unsigned char *src,size_t *destLen)
{
int level = 5;
unsigned dictSize = 1 << 23;
int lc = 3;
int lp = 0;
int pb = 2;
int fb = 128;
int numThreads = 1;
return LzmaCompress(dest,&outPropsSize,level,dictSize,lc,lp,pb,fb,numThreads);
}
MY_STDAPI DefaultLzmaUncompress(const unsigned char *src,size_t *destLen)
{
return LzmaUncompress(dest,outPropsSize);
}
MY_STDAPI LZMAAdd(int x)
{
return x + 1;
}
使用方法示例
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using System.Runtime.InteropServices;
using UnityEngine.UI;
public class Compress : MonoBehavIoUr {
public Text text = null;
[DllImport("LZMA")]
public static extern int LZMAAdd(int x);
[DllImport("LZMA")]
public static extern int DefaultLzmaCompress(byte[] src,int srcLen,byte[] dest,ref int destLen);
[DllImport("LZMA")]
public static extern int DefaultLzmaUncompress(byte[] src,ref int srcLen,ref int destLen);
// Use this for initialization
void Start () {
// 压缩
string input = "122333444455555666666777777788888888999999999";
byte[] src = System.Text.Encoding.Default.GetBytes(input);
byte[] dest = new byte[src.Length];
int srcLen = src.Length;
int destLen = dest.Length;
int compressRes = DefaultLzmaCompress(src,dest,ref destLen); // 压缩成功compressRes会返回0,destLen的值会变成压缩后的数据长度
// 解压
byte[] unsrc = new byte[destLen];
for (int i = 0; i < destLen; i++) {
unsrc[i] = dest[i]; // 将压缩后得到的dest数据复制到解压的src数据缓冲中
}
srcLen = destLen;
destLen = src.Length;
byte[] undest = new byte[destLen];
int uncompressRes = DefaultLzmaUncompress(unsrc,ref srcLen,undest,ref destLen);
string output = System.Text.Encoding.Default.GetString(undest); // 解压成功output应该和input值相同
}
// Update is called once per frame
void Update () {
}
}