tar.cpp

00001 #include "mbed.h"
00002 #include "tar.h"
00003 
00004 FILE* fopenTar(char *tarfile, char *namefile) { 
00005     
00006     int i;
00007     char buf[32];
00008     char sizeStr[12];
00009     char *valExit = "error";
00010     int size, offset = 0;
00011     
00012     FILE *Tar = fopen(tarfile, "r");
00013     
00014     while(!feof(Tar)) {
00015         for(i=0; i <= strlen(namefile); i++) buf[i] = fgetc(Tar);
00016         
00017         if(!strcmp(buf, namefile)) {
00018             valExit = "";
00019             break;
00020         }
00021         
00022         fseek(Tar , 124+offset , SEEK_SET);
00023         for(i=0; i < 12; i++) sizeStr[i] = fgetc(Tar);
00024         //printf("size string: %s; octal: %d; dec.: %x\n", sizeStr, atoi(sizeStr), oct2dec(atoi(sizeStr)) );
00025         
00026         size = oct2dec(atoi(sizeStr));
00027         if(offset % 512 != 0) offset += (size/512 + 2)*512;
00028         else offset += (size/512 + 1)*512;
00029         
00030         fseek(Tar , offset , SEEK_SET);  
00031     }
00032     
00033     if(valExit == "error") {
00034         printf("file \"%s\" not find in tar\n", namefile); 
00035         return NULL;
00036     } else {
00037         fseek(Tar, offset+512 , SEEK_SET);
00038         return Tar;
00039     }
00040 }
00041 
00042 int oct2dec(int n) /* Function to convert octal to decimal */
00043 {
00044     int decimal=0, i=0, rem;
00045     while (n!=0)
00046     {
00047         rem = n%10;
00048         n/=10;
00049         decimal += rem*pow(8.0,i);
00050         ++i;
00051     }
00052     return decimal;
00053 }