src/joepack.cpp

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#include "model.h"
#include "joepack.h"

#define JPKVERSION "JPK01.00"

#define VERBOSE false

#define DPRINT(text) {if (VERBOSE) cout << text << endl;}

bool JOEPACK::LoadPack(string fn)
{
        ClosePack();
        
        f = fopen(fn.c_str(), "rb");
        
        if (f)
        {
                packpath = utility.GetPathFromFilename(fn);
                
                //load header
                string versionstr = JPKVERSION;
                char versioncstr[versionstr.length()+1];
                fread(versioncstr, 1, versionstr.length(), f);
                versioncstr[versionstr.length()] = '\0';
                string fversionstr = versioncstr;
                if (versioncstr != versionstr)
                {
                        //write out an error?
                        return false;
                }
                
                unsigned int numobjs = 0;
                fread(&numobjs, sizeof(unsigned int), 1, f);
                numobjs = ENDIAN_SWAP_32(numobjs);
                
                DPRINT(numobjs << " objects");
                
                unsigned int maxstrlen = 0;
                fread(&maxstrlen, sizeof(unsigned int), 1, f);
                maxstrlen = ENDIAN_SWAP_32(maxstrlen);
                
                DPRINT(maxstrlen << " max string length");
                
                char fnch[maxstrlen+1];
                
                //load FAT
                for (unsigned int i = 0; i < numobjs; i++)
                {
                        JOEPACK_FADATA fa;
                        fread(&(fa.offset), 1, sizeof(unsigned int), f);
                        fa.offset = ENDIAN_SWAP_32(fa.offset);
                        fread(&(fa.length), 1, sizeof(unsigned int), f);
                        fa.length = ENDIAN_SWAP_32(fa.length);
                        fread(fnch, 1, maxstrlen, f);
                        fnch[maxstrlen] = '\0';
                        string filename = fnch;
                        fat[filename] = fa;
                        
                        DPRINT(filename << ": offest " << fa.offset << " length " << fa.length);
                }
                
                return true;
        }
        else
        {
                //write an error?
                return false;
        }
}

void JOEPACK::ClosePack()
{
        Pack_fclose();
        fat.clear();
        if (f != NULL)
        {
                fclose(f);
                f = NULL;
        }
        packpath.clear();
}

void JOEPACK::Pack_fclose()
{
        curfa = NULL;
}

bool JOEPACK::Pack_fopen(string fn)
{
        if (fn.find(packpath, 0) < fn.length())
        {
                string newfn = fn.substr(packpath.length()+1);
                DPRINT(fn << " -> " << newfn);
                fn = newfn;
        }
        
        DPRINT("Opening " << fn << " by seeking to " << fat[fn].offset);
        
        if (fat[fn].offset == 0)
        {
                curfa = NULL;
                //write an error?
                return false;
        }
        else
        {
                curfa = &(fat[fn]);
                fseek(f, curfa->offset, SEEK_SET);
                return true;
        }
}

int JOEPACK::Pack_fread(void * buffer, unsigned int size, unsigned int count)
{
        if (curfa != NULL)
        {
                unsigned int abspos = ftell(f);
                assert(abspos >= curfa->offset);
                unsigned int relpos = abspos - curfa->offset;
                //DPRINT("relpos: " << relpos);
                assert(curfa->length >= relpos);
                unsigned int fileleft = curfa->length - relpos;
                unsigned int requestedread = size*count;
                
                if (requestedread > fileleft)
                {
                        //overflow
                        requestedread = fileleft;
                }
                
                DPRINT("JOEPACK fread: " << abspos << "," << relpos << "," << fileleft << "," << requestedread);
                
                return fread(buffer, 1, requestedread, f);
        }
        else
        {
                //write error?
                return 0;
        }
}

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