大文件二进制模式下搜索匹配怎么写呢?
4G大小二进制文件,搜索一个起始字符串,搜索一个终止字符串,若条件匹配,也就是说找到一个起始和终止字符串,则复制这段内容生成一个文件,然后重新应用这个算法,直到文件结尾。
这个该怎么写呢?搜索算法到是写了,不过在遍历上出了问题,目前代码如下
while (!feof(inFile))
{
val = fgetc(inFile);
++uCurrentPos;
}
目前是这样遍历文件的,但是会有一个问题,就是遍历的字节数与文件体积不对应,文件是4G,而目前这个只能读出0x70f也就是1807个字节,这是怎么回事呢?我该如何正确实现这个功能?
[解决办法]
_lseeki64
仅供参考
#include <sys\stat.h>#include <io.h>#include <fcntl.h>#include <share.h>#include <stdlib.h>#include <stdio.h>#include <conio.h>#include <string.h>#define MAX_CLU_BYTES 65536FILE *fo;int fh;__int64 offs,offs1;__int64 rvi64;int rv,wrv;unsigned char buf[MAX_CLU_BYTES];char ofn[_MAX_PATH];char offstr[80];void strcpybutcomma(char *t,char *s) { char c; while (1) { c = *s++; if (','!=c) *t++ = c; if (0==c) break; }}void main(int argc,char **argv) { if (argc<3) { printf("Copy File Tail.\n"); printf("Usage:\n"); printf(" cft filename.ext offset_begin[-offset_end]\n"); printf("Copy filename.ext offset_begin[-offset_end] to offset_begin[-offset_end]-filename.ext\n"); printf("Note: Byte at offset_end is NOT included.\n"); printf("Example:\n"); printf(" cft abc.rar 12345\n"); printf("Copy abc.rar offset 12345-end to 12345-abc.rar\n"); printf(" cft abc.rar 123-12345\n"); printf("Copy abc.rar offset 123-12345 to 123-12345-abc.rar\n"); printf(" cft abc.rar 0xAB-0xCD\n"); printf("Copy abc.rar offset 0xAB-0xCD to 0xAB-0xCD-abc.rar\n"); return; } strcpybutcomma(offstr,argv[2]); rv=sscanf(offstr,"%I64i-%I64i",&offs,&offs1); if (rv==0) { printf("offset %s is not number\n",argv[2]); return; } fh=_sopen(argv[1],_O_BINARY|_O_RDONLY|_O_RANDOM,_SH_DENYWR); if (fh==-1) { printf("_sopen %s errno=%d\n",argv[1],errno); return; } if (rv==1) { offs1=_filelengthi64(fh); if (offs1==-1i64) { printf("%I64=_filelengthi64 errno=%d\n",offs1,errno); _close(fh); return; } } else {//rv==2 if (offs1<offs) { printf("%s offset_begin>offset_end error\n",argv[2]); _close(fh); return; } } rvi64=_lseeki64(fh,offs,SEEK_SET); if (rvi64!=offs) { printf("%I64u=_lseeki64 %I64u errno=%d\n",rvi64,offs,errno); _close(fh); return; } sprintf(ofn,"%s-",offstr); strcat(ofn,argv[1]); fo=fopen(ofn,"wb"); if (fo==NULL) { _close(fh); printf("fopen %s error\n",ofn); return; } cprintf("\n%I64u\r",offs); while (1) { rv=_read(fh,buf,(unsigned int)__min(offs1-offs,MAX_CLU_BYTES)); if (rv==0) break;// if (rv<0) { fclose(fo); _close(fh); printf("_read %s offset %I64u error\n",argv[1],offs); return; } wrv=fwrite(buf,1,rv,fo); if (wrv!=rv) { fclose(fo); _close(fh); printf("fwrite %s error\n",ofn); return; } else { offs+=rv; cprintf("%I64u\r",offs); if (offs>=offs1) break;// } } fclose(fo); _close(fh); printf("Copy %s offset %s to %s OK.\n",argv[1],argv[2],ofn);}