zlib的应用
Posted baldermurphy
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主要分析应用的demo，有空再分析底层实现
官方demo位于zlib-1.2.11contribminizip
我自己的分析
/* miniunz.c Version 1.1, February 14h, 2010 sample part of the MiniZip project - ( http://www.winimage.com/zLibDll/minizip.html ) Copyright (C) 1998-2010 Gilles Vollant (minizip) ( http://www.winimage.com/zLibDll/minizip.html ) Modifications of Unzip for Zip64 Copyright (C) 2007-2008 Even Rouault Modifications for Zip64 support on both zip and unzip Copyright (C) 2009-2010 Mathias Svensson ( http://result42.com ) */ #if (!defined(_WIN32)) && (!defined(WIN32)) && (!defined(__APPLE__)) #ifndef __USE_FILE_OFFSET64 #define __USE_FILE_OFFSET64 #endif #ifndef __USE_LARGEFILE64 #define __USE_LARGEFILE64 #endif #ifndef _LARGEFILE64_SOURCE #define _LARGEFILE64_SOURCE #endif #ifndef _FILE_OFFSET_BIT #define _FILE_OFFSET_BIT 64 #endif #endif #ifdef __APPLE__ // In darwin and perhaps other BSD variants off_t is a 64 bit value, hence no need for specific 64 bit functions #define FOPEN_FUNC(filename, mode) fopen(filename, mode) #define FTELLO_FUNC(stream) ftello(stream) #define FSEEKO_FUNC(stream, offset, origin) fseeko(stream, offset, origin) #else #define FOPEN_FUNC(filename, mode) fopen64(filename, mode) #define FTELLO_FUNC(stream) ftello64(stream) #define FSEEKO_FUNC(stream, offset, origin) fseeko64(stream, offset, origin) #endif #include <stdio.h> #include <stdlib.h> #include <string.h> #include <time.h> #include <errno.h> #include <fcntl.h> #ifdef _WIN32 # include <direct.h> # include <io.h> #else # include <unistd.h> # include <utime.h> #endif #include "unzip.h" #define CASESENSITIVITY (0) #define WRITEBUFFERSIZE (8192) #define MAXFILENAME (256) #ifdef _WIN32 #define USEWIN32IOAPI #include "iowin32.h" #endif /* mini unzip, demo of unzip package usage : Usage : miniunz [-exvlo] file.zip [file_to_extract] [-d extractdir] list the file in the zipfile, and print the content of FILE_ID.ZIP or README.TXT if it exists */ /* change_file_date : change the date/time of a file filename : the filename of the file where date/time must be modified dosdate : the new date at the MSDos format (4 bytes) tmu_date : the SAME new date at the tm_unz format */ void change_file_date(filename,dosdate,tmu_date) const char *filename; uLong dosdate; tm_unz tmu_date; { #ifdef _WIN32 HANDLE hFile; FILETIME ftm,ftLocal,ftCreate,ftLastAcc,ftLastWrite; hFile = CreateFileA(filename,GENERIC_READ | GENERIC_WRITE, 0,NULL,OPEN_EXISTING,0,NULL); GetFileTime(hFile,&ftCreate,&ftLastAcc,&ftLastWrite); DosDateTimeToFileTime((WORD)(dosdate>>16),(WORD)dosdate,&ftLocal); LocalFileTimeToFileTime(&ftLocal,&ftm); SetFileTime(hFile,&ftm,&ftLastAcc,&ftm); CloseHandle(hFile); #else #ifdef unix || __APPLE__ struct utimbuf ut; struct tm newdate; newdate.tm_sec = tmu_date.tm_sec; newdate.tm_min=tmu_date.tm_min; newdate.tm_hour=tmu_date.tm_hour; newdate.tm_mday=tmu_date.tm_mday; newdate.tm_mon=tmu_date.tm_mon; if (tmu_date.tm_year > 1900) newdate.tm_year=tmu_date.tm_year - 1900; else newdate.tm_year=tmu_date.tm_year ; newdate.tm_isdst=-1; ut.actime=ut.modtime=mktime(&newdate); utime(filename,&ut); #endif #endif } /* mymkdir and change_file_date are not 100 % portable As I don‘t know well Unix, I wait feedback for the unix portion */ int mymkdir(dirname) const char* dirname; { int ret=0; #ifdef _WIN32 ret = _mkdir(dirname); #elif unix ret = mkdir (dirname,0775); #elif __APPLE__ ret = mkdir (dirname,0775); #endif return ret; } int makedir (newdir) char *newdir; { char *buffer ; char *p; int len = (int)strlen(newdir); if (len <= 0) return 0; buffer = (char*)malloc(len+1); if (buffer==NULL) { printf("Error allocating memory "); return UNZ_INTERNALERROR; } strcpy(buffer,newdir); if (buffer[len-1] == ‘/‘) { buffer[len-1] = ‘ ‘; } if (mymkdir(buffer) == 0) { free(buffer); return 1; } p = buffer+1; while (1) { char hold; while(*p && *p != ‘\‘ && *p != ‘/‘) p++; hold = *p; *p = 0; if ((mymkdir(buffer) == -1) && (errno == ENOENT)) { printf("couldn‘t create directory %s ",buffer); free(buffer); return 0; } if (hold == 0) break; *p++ = hold; } free(buffer); return 1; } void do_banner() { printf("MiniUnz 1.01b, demo of zLib + Unz package written by Gilles Vollant "); printf("more info at http://www.winimage.com/zLibDll/unzip.html "); } void do_help() { printf("Usage : miniunz [-e] [-x] [-v] [-l] [-o] [-p password] file.zip [file_to_extr.] [-d extractdir] " " -e Extract without pathname (junk paths) " " -x Extract with pathname " " -v list files " " -l list files " " -d directory to extract into " " -o overwrite files without prompting " " -p extract crypted file using password "); } void Display64BitsSize(ZPOS64_T n, int size_char) { /* to avoid compatibility problem , we do here the conversion */ char number[21]; int offset=19; int pos_string = 19; number[20]=0; for (;;) { number[offset]=(char)((n%10)+‘0‘); if (number[offset] != ‘0‘) pos_string=offset; n/=10; if (offset==0) break; offset--; } { int size_display_string = 19-pos_string; while (size_char > size_display_string) { size_char--; printf(" "); } } printf("%s",&number[pos_string]); } int do_list(uf) unzFile uf; { uLong i; unz_global_info64 gi; int err; err = unzGetGlobalInfo64(uf,&gi); if (err!=UNZ_OK) printf("error %d with zipfile in unzGetGlobalInfo ",err); printf(" Length Method Size Ratio Date Time CRC-32 Name "); printf(" ------ ------ ---- ----- ---- ---- ------ ---- "); for (i=0;i<gi.number_entry;i++) { char filename_inzip[256]; unz_file_info64 file_info; uLong ratio=0; const char *string_method; char charCrypt=‘ ‘; err = unzGetCurrentFileInfo64(uf,&file_info,filename_inzip,sizeof(filename_inzip),NULL,0,NULL,0); if (err!=UNZ_OK) { printf("error %d with zipfile in unzGetCurrentFileInfo ",err); break; } if (file_info.uncompressed_size>0) ratio = (uLong)((file_info.compressed_size*100)/file_info.uncompressed_size); /* display a ‘*‘ if the file is crypted */ if ((file_info.flag & 1) != 0) charCrypt=‘*‘; if (file_info.compression_method==0) string_method="Stored"; else if (file_info.compression_method==Z_DEFLATED) { uInt iLevel=(uInt)((file_info.flag & 0x6)/2); if (iLevel==0) string_method="Defl:N"; else if (iLevel==1) string_method="Defl:X"; else if ((iLevel==2) || (iLevel==3)) string_method="Defl:F"; /* 2:fast , 3 : extra fast*/ } else if (file_info.compression_method==Z_BZIP2ED) { string_method="BZip2 "; } else string_method="Unkn. "; Display64BitsSize(file_info.uncompressed_size,7); printf(" %6s%c",string_method,charCrypt); Display64BitsSize(file_info.compressed_size,7); printf(" %3lu%% %2.2lu-%2.2lu-%2.2lu %2.2lu:%2.2lu %8.8lx %s ", ratio, (uLong)file_info.tmu_date.tm_mon + 1, (uLong)file_info.tmu_date.tm_mday, (uLong)file_info.tmu_date.tm_year % 100, (uLong)file_info.tmu_date.tm_hour,(uLong)file_info.tmu_date.tm_min, (uLong)file_info.crc,filename_inzip); if ((i+1)<gi.number_entry) { err = unzGoToNextFile(uf); if (err!=UNZ_OK) { printf("error %d with zipfile in unzGoToNextFile ",err); break; } } } return 0; } /*** popt_extract_without_path : 解压的时候是否需要中间的路径 **/ int do_extract_currentfile(uf,popt_extract_without_path,popt_overwrite,password) unzFile uf; const int* popt_extract_without_path; int* popt_overwrite; const char* password; { char filename_inzip[256]; char* filename_withoutpath; char* p; int err=UNZ_OK; FILE *fout=NULL; void* buf; uInt size_buf; unz_file_info64 file_info; uLong ratio=0; err = unzGetCurrentFileInfo64(uf,&file_info,filename_inzip,sizeof(filename_inzip),NULL,0,NULL,0);//filename_inzip 得到uf内部的文件名 if (err!=UNZ_OK) { printf("error %d with zipfile in unzGetCurrentFileInfo ",err); return err; } size_buf = WRITEBUFFERSIZE; buf = (void*)malloc(size_buf); if (buf==NULL) { printf("Error allocating memory "); return UNZ_INTERNALERROR; } p = filename_withoutpath = filename_inzip; while ((*p) != ‘ ‘) { if (((*p)==‘/‘) || ((*p)==‘\‘)) filename_withoutpath = p+1;//得到最底层的文件名 p++; } if ((*filename_withoutpath)==‘ ‘)//如果底层文件名是一个目录，那么就创建目录 { if ((*popt_extract_without_path)==0) { printf("creating directory: %s ",filename_inzip); mymkdir(filename_inzip); } } else { const char* write_filename; int skip=0; if ((*popt_extract_without_path)==0) write_filename = filename_inzip;//包含中间路径 else write_filename = filename_withoutpath;//不包含中间路径 err = unzOpenCurrentFilePassword(uf,password);//打开当前内部文件 if (err!=UNZ_OK) { printf("error %d with zipfile in unzOpenCurrentFilePassword ",err); } if (((*popt_overwrite)==0) && (err==UNZ_OK))//设置为重写，并且打开成功 { char rep=0; FILE* ftestexist; ftestexist = FOPEN_FUNC(write_filename,"rb"); if (ftestexist!=NULL)//已经存在这个解压出的文件，会不停询问是否覆盖，直到得到确切答案 { fclose(ftestexist); do { char answer[128]; int ret; printf("The file %s exists. Overwrite ? [y]es, [n]o, [A]ll: ",write_filename); ret = scanf("%1s",answer); if (ret != 1) { exit(EXIT_FAILURE); } rep = answer[0] ; if ((rep>=‘a‘) && (rep<=‘z‘)) rep -= 0x20; } while ((rep!=‘Y‘) && (rep!=‘N‘) && (rep!=‘A‘)); } if (rep == ‘N‘) skip = 1; if (rep == ‘A‘) *popt_overwrite=1;//设置popt_overwrite为全部覆盖 } if ((skip==0) && (err==UNZ_OK))//覆盖 { fout=FOPEN_FUNC(write_filename,"wb"); /* some zipfile don‘t contain directory alone before file */ if ((fout==NULL) && ((*popt_extract_without_path)==0) && (filename_withoutpath!=(char*)filename_inzip)) { //FOPEN_FUNC(write_filename,"wb")本身是创建文件，可是如果没有现成的上级目录，创建不会成功，所以说明不存在对应的目录 //filename_inzip,filename_withoutpath,write_filename是同一个字符串的不同位置，所以可以任意操作其中一个 char c=*(filename_withoutpath-1); *(filename_withoutpath-1)=‘ ‘;//修改了最后一个路径符为结束符，就是一个路径 makedir(write_filename);//创建路径 *(filename_withoutpath-1)=c;//还原原来的路径 fout=FOPEN_FUNC(write_filename,"wb"); } if (fout==NULL) { printf("error opening %s ",write_filename); } } if (fout!=NULL) { printf(" extracting: %s ",write_filename); do { err = unzReadCurrentFile(uf,buf,size_buf);//8K的内存 if (err<0) { printf("error %d with zipfile in unzReadCurrentFile ",err); break; } if (err>0) if (fwrite(buf,err,1,fout)!=1) { printf("error in writing extracted file "); err=UNZ_ERRNO; break; } } while (err>0); if (fout) fclose(fout); if (err==0)//结束 change_file_date(write_filename,file_info.dosDate, file_info.tmu_date);//还原创建时间 } if (err==UNZ_OK) { err = unzCloseCurrentFile (uf); if (err!=UNZ_OK) { printf("error %d with zipfile in unzCloseCurrentFile ",err); } } else unzCloseCurrentFile(uf); /* don‘t lose the error */ } free(buf); return err; } /** 打开一个ZIP文件后， 需要先使用unzGetGlobalInfo64来取得该文件的一些信息，来了解这个压缩包里一共包含了多少个文件，等等。 目前我们用得着的就是这个文件数目。 然后开始遍历ZIP中的文件，初始时自动会定位在第一个文件，以后处理完一个后用unzGoToNextFile来跳到下一个文件。 对于每个内部文件，可用unzGetCurrentFileInfo64来查内部文件名。 这个文件名和刚才zipOpenNewFileInZip的第二个参数是一样的形式，所以有可能包含路径。 也有可能会以路径分隔符（/）结尾，表明这是个目录项（其实压缩操作的时候也可以针对目录写入这样的内部文件，上面没有做）。 所以接下来要根据情况创建（多级）目录。 unzGetCurrentFileInfo64的第三个参数是unz_file_info64结构，其中也有一项包含了dosDate信息，可以还原文件时间。 对于非目录的内部文件，用 unzOpenCurrentFile，打开，然后unzReadCurrentFile读取文件内容，写入到真实文件中。 unzReadCurrentFile返回 0 表示文件读取结束。 uf ：zip文件对象 opt_extract_without_path ：0或者1 opt_overwrite ：0或者1 password ：密码 **/ int do_extract(uf,opt_extract_without_path,opt_overwrite,password) unzFile uf; int opt_extract_without_path; int opt_overwrite; const char* password; { uLong i; unz_global_info64 gi; int err; FILE* fout=NULL; err = unzGetGlobalInfo64(uf,&gi);//获取解压信息 unz_global_info64 if (err!=UNZ_OK) printf("error %d with zipfile in unzGetGlobalInfo ",err); for (i=0;i<gi.number_entry;i++) { if (do_extract_currentfile(uf,&opt_extract_without_path, &opt_overwrite, password) != UNZ_OK)//对当前内部文件解压 break; if ((i+1)<gi.number_entry) { err = unzGoToNextFile(uf);//跳到下一个内部文件 if (err!=UNZ_OK) { printf("error %d with zipfile in unzGoToNextFile ",err); break; } } } return 0; } int do_extract_onefile(uf,filename,opt_extract_without_path,opt_overwrite,password) unzFile uf; const char* filename; int opt_extract_without_path; int opt_overwrite; const char* password; { int err = UNZ_OK; if (unzLocateFile(uf,filename,CASESENSITIVITY)!=UNZ_OK) { printf("file %s not found in the zipfile ",filename); return 2; } if (do_extract_currentfile(uf,&opt_extract_without_path, &opt_overwrite, password) == UNZ_OK) return 0; else return 1; } /** "Usage : miniunz [-e] [-x] [-v] [-l] [-o] [-p password] file.zip [file_to_extr.] [-d extractdir] " " -e Extract without pathname (junk paths) " " -x Extract with pathname " " -v list files " " -l list files " " -d directory to extract into " " -o overwrite files without prompting " " -p extract crypted file using password " ***/ int main(argc,argv) int argc; char *argv[]; { const char *zipfilename=NULL; const char *filename_to_extract=NULL; const char *password=NULL; char filename_try[MAXFILENAME+16] = ""; int i; int ret_value=0; int opt_do_list=0; int opt_do_extract=1; int opt_do_extract_withoutpath=0; int opt_overwrite=0; int opt_extractdir=0; const char *dirname=NULL; unzFile uf=NULL; do_banner(); if (argc==1) { do_help();//提示帮助 return 0; } else { for (i=1;i<argc;i++) { if ((*argv[i])==‘-‘) { const char *p=argv[i]+1; while ((*p)!=‘ ‘) { char c=*(p++);; if ((c==‘l‘) || (c==‘L‘)) opt_do_list = 1; if ((c==‘v‘) || (c==‘V‘)) opt_do_list = 1; if ((c==‘x‘) || (c==‘X‘)) opt_do_extract = 1; if ((c==‘e‘) || (c==‘E‘)) opt_do_extract = opt_do_extract_withoutpath = 1; if ((c==‘o‘) || (c==‘O‘)) opt_overwrite=1; if ((c==‘d‘) || (c==‘D‘)) { opt_extractdir=1; dirname=argv[i+1];//解压到dirname目录路径 } if (((c==‘p‘) || (c==‘P‘)) && (i+1<argc)) { password=argv[i+1];//密码为password i++; } } } else { if (zipfilename == NULL) zipfilename = argv[i];//zip的文件名zipfilename else if ((filename_to_extract==NULL) && (!opt_extractdir)) filename_to_extract = argv[i] ;//如果没有指定解压路径dirname，zip文件解压为指定的名称filename_to_extract } } } if (zipfilename!=NULL) { # ifdef USEWIN32IOAPI zlib_filefunc64_def ffunc; # endif strncpy(filename_try, zipfilename,MAXFILENAME-1);//拷贝filename_try，防止越界 /* strncpy doesnt append the trailing NULL, of the string is too long. */ filename_try[ MAXFILENAME ] = ‘ ‘; # ifdef USEWIN32IOAPI fill_win32_filefunc64A(&ffunc); uf = unzOpen2_64(zipfilename,&ffunc); # else uf = unzOpen64(zipfilename);//打开zip文件 # endif if (uf==NULL) { strcat(filename_try,".zip");//如果没有成功，尝试添加后缀名.zip # ifdef USEWIN32IOAPI uf = unzOpen2_64(filename_try,&ffunc); # else uf = unzOpen64(filename_try); # endif } } if (uf==NULL) { printf("Cannot open %s or %s.zip ",zipfilename,zipfilename); return 1; } printf("%s opened ",filename_try); if (opt_do_list==1) ret_value = do_list(uf);//查看里面的zip文件里面的目录结果 else if (opt_do_extract==1) { #ifdef _WIN32 if (opt_extractdir && _chdir(dirname))//如果指定了解压路径 #else if (opt_extractdir && chdir(dirname))//修改当前工作目录 #endif { printf("Error changing into %s, aborting ", dirname); exit(-1); } if (filename_to_extract == NULL) ret_value = do_extract(uf, opt_do_extract_withoutpath, opt_overwrite, password); else ret_value = do_extract_onefile(uf, filename_to_extract, opt_do_extract_withoutpath, opt_overwrite, password);//指定解压名称 } unzClose(uf); return ret_value; }
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