c 语言 获取文件类型
利用C 或者是windows 的API实现度文件的类型进行判定，如aha.txt 可以判别为文本文档。。。
[解决办法]
不得而知。一切皆为文件。windows下是否判断后缀名就可以了？
[解决办法]
根据文件扩展名，查询注册表HKEY_CLASSES_ROOT
[解决办法]
文件头中有类型信息
[解决办法]
仅供参考
#include <stdio.h>
struct EH {
char e[32];
char h[32];
} eh[29]={
{"Windows Bitmap (bmp)" , "424D"},
{"JPEG (jpg)" , "FFD8FF"},
{"MPEG (mpg)" , "000001B3"},
{"MPEG (mpg)" , "000001BA"},
{"Outlook (pst)" , "2142444E"},
{"Real Media (rm)" , "2E524D46"},
{"Real Audio (ram)" , "2E7261FD"},
{"Adobe Photoshop (psd)" , "38425053"},
{"CAD (dwg)" , "41433130"},
{"AVI (avi)" , "41564920"},
{"GIF (gif)" , "47494638"},
{"TIFF (tif)" , "49492A00"},
{"MIDI (mid)" , "4D546864"},
{"ZIP Archive (zip)" , "504B0304"},
{"RAR Archive (rar)" , "52617221"},
{"Wave (wav)" , "57415645"},
{"Quicktime (mov)" , "6D6F6F76"},
{"PNG (png)" , "89504E47"},
{"Quicken (qdf)" , "AC9EBD8F"},
{"MS Word/Excel (xls.or.doc)" , "D0CF11E0"},
{"Windows Password (pwl)" , "E3828596"},
{"WordPerfect (wpd)" , "FF575043"},
{"XML (xml)" , "3C3F786D6C"},
{"HTML (html)" , "68746D6C3E"},
{"Rich Text Format (rtf)" , "7B5C727466"},
{"Adobe Acrobat (pdf)" , "255044462D312E"},
{"Windows Media (asf)" , "3026B2758E66CF11"},
{"Outlook Express (dbx)" , "CFAD12FEC5FD746F"},
{"MS Access (mdb)" , "5374616E64617264204A"},
};
FILE *f;
static char s[32];
int i,j,c;
int main(int argc,char **argv) {
if (argc<2
[解决办法]
argc>2) {
fprintf(stderr,"GuessFileExt according to head bytes.\nUsage: %s filename\n",argv[0]);
return 1;
}
f=fopen(argv[1],"rb");
if (NULL==f) {
fprintf(stderr,"Can not open file %s\n",argv[1]);
return 2;
}
for (i=0;i<14;i++) {
c=fgetc(f);
if (c==EOF) break;//
sprintf(s+i*2,"%2X",(unsigned char)c);
for (j=0;j<29;j++) {
if (0==strcmp(s,eh[j].h)) {
printf("%s\n",eh[j].e);
fclose(f);
return 0;
}
}
}
printf("Unknown\n");
fclose(f);
return 3;
}
