Easylzma是一个实现了LZMA压缩和解压缩算法的C语言库。
LZMA，（Lempel-Ziv-Markovchai-Algorithm的縮寫），是2001年以來得到發展的一個數據壓縮演算法，它用於7-Zip歸檔工具中的7z格式。它使用類似於LZ77的字典編碼機制，在一般的情況下壓縮率比bzip2為高，用於壓縮的字典檔大小可達4GB。
示例代码：
/* *aexampleofbasicLZMAcompressiotoadfrommemorybuffers *usigtheeasylzmalibrary. */ #iclude"easylzma/compress.h" #iclude<strig.h>#iclude<assert.h> structdataStream{ costusigedchar*iData; size_tiLe; usigedchar*outData; size_toutLe;};/*aiputcallbackthatwillbepassedtoelzma_compress_ru(), *itreadsfromamemorybuffer*/staticitiputCallback(void*ctx,void*buf,size_t*size){ size_trd=0; structdataStream*ds=(structdataStream*)ctx; assert(ds!=NULL); rd=(ds->iLe<*size)?ds->iLe:*size; if(rd>0){ memcpy(buf,(void*)ds->iData,rd); ds->iData+=rd; ds->iLe-=rd; } *size=rd; retur0;}/*aouputcallbackthatwillbepassedtoelzma_compress_ru(), *itreallocsadwritestoamemorybuffer*/staticsize_toutputCallback(void*ctx,costvoid*buf,size_tsize){ structdataStream*ds=(structdataStream*)ctx; assert(ds!=NULL); if(size>0){ ds->outData=realloc(ds->outData,ds->outLe+size); memcpy((void*)(ds->outData+ds->outLe),buf,size); ds->outLe+=size; } retursize;}/*afuctiothatwillcompressdatausiga1mbdictioaryada *clietspecifiedecodigformat(oeofELZMA_lziporELZMA_lzma)*/itsimpleCompress(elzma_file_formatformat,costusigedchar*iData, size_tiLe,usigedchar**outData, size_t*outLe){ itrc; elzma_compress_hadlehad; /*allocatecompressiohadle*/ had=elzma_compress_alloc(); assert(had!=NULL); /*cofigurethecompressioruwithmostlydefaultparameters */ rc=elzma_compress_cofig(had,ELZMA_LC_DEFAULT, ELZMA_LP_DEFAULT,ELZMA_PB_DEFAULT, 5,(1<<20)/*1mb*/, format,iLe); /*failifwecould'tallocate*/ if(rc!=ELZMA_E_OK){ elzma_compress_free(&had); returrc; } /*owruthecompressio*/ { /*setupthecotextstructurethatwillbepassedto *streamcallbacks*/ structdataStreamds; ds.iData=iData; ds.iLe=iLe; ds.outData=NULL; ds.outLe=0; /*ruthestreamigcompressio*/ rc=elzma_compress_ru(had,iputCallback,(void*)&ds, outputCallback,(void*)&ds); if(rc!=ELZMA_E_OK){ if(ds.outData!=NULL)free(ds.outData); elzma_compress_free(&had); returrc; } *outData=ds.outData; *outLe=ds.outLe; } returrc;}
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