unpack_lod.cpp

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// Q'N'D code.

// lod file format unpacker; it unpacks to the current directory!
//c clang++ -std=c++11 unpack_lod.cpp -o unpack_lod -lz

#define int int
static_assert(4 == sizeof(int), "define 32-bit int type");

#include <stdio.h>
#include <zlib.h>
#include <stdlib.h>

struct File
{
    FILE * f {};
    File(const char * n, const char * mode = "rb") : f {fopen (n, mode)} {}
    ~File() { if (f) fclose (f), f = 0; }
    operator bool() { return 0 != f; }
    bool Seek(long pos) { return *this ? 0 == fseek (f, pos, SEEK_SET) : false; }
    long Tell() { return *this ? ftell (f) : -1; }
    template <typename T> bool Read(T & v, unsigned int n = 1)
    {
        auto b = n * sizeof (T);
        return *this ? ! b ? false : b == fread (&v, 1, b, f) : false;
    }
    template <typename T> bool Write(T & v, unsigned int n = 1)
    {
        auto b = n * sizeof (T);
        return *this ? ! b ? false : b == fwrite (&v, 1, b, f) : false;
    }
};

struct ZipStream
{
    z_stream s {};
    int r {~Z_OK};
    ZipStream() { r = inflateInit (&s); }
    ~ZipStream() { inflateEnd (&s); }
    operator bool() { return Z_OK == r; }
    bool Inflate(Bytef * a, unsigned int & ac, Bytef * b, unsigned int & bc)
    {
        // printf ("p1 in:%d, out:%d\n", ac, bc);
        s.avail_in = ac;
        s.next_in = a;
        s.avail_out = bc;
        s.next_out = b;
        r = inflate (&s, Z_FINISH);
        if (Z_STREAM_END == r) r = ! s.avail_in && ! s.avail_out ? Z_OK : r;
        inflateReset (&s);
        // printf ("p2 in:%d, out:%d, r:%d\n", s.avail_in, s.avail_out, r);
        return *this;
    }
};

template <typename T> struct Buf
{
    T * p {};
    Buf(unsigned int n = 1) { p = n ? (T*)malloc (n*sizeof(T)) : 0; }
    ~Buf() { if (p) free (p), p = 0; }
    operator bool() { return 0 != p; }
    operator T*() { return p; }
};

int main(int c, char ** v)
{
    if (2 != c)
        return printf ("usage: unpack_lod lodfile\n");
    File f {v[1]};
    if (! f)
        return printf ("error: failed to open \"%s\"\n", v[1]);
    printf ("Working with: \"%s\"\n", v[1]);
    int cnt = 0;
    if (! f.Read (cnt))
        return printf ("error: failed to read signature\n");
    if (0x444f4c != cnt)
        return printf ("error: not a lod file\n");
    if (! f.Seek (8))
        return printf ("error: failed to seek 1st 8 bytes\n");
    if (! f.Read (cnt))
        return printf ("error: failed to read item count\n");
    if (cnt <= 0 || cnt > 8192)
        return printf ("error: invalid entry count\n");
    if (! f.Seek (92))
        return printf ("error: failed to read header\n");
    printf ("Working with: %d entries\n", cnt);
    unsigned char fn[16] {};
    unsigned int of {}, s1 {}, t {}, s2 {};
    ZipStream zs;
    for (int i = 0; i < cnt; i++) {
        if (! f.Read (fn[0], 16))
            return printf ("error: failed to read item name\n");
        if (! f.Read (of))
            return printf ("error: failed to read item ofs\n");
        if (! f.Read (s1))
            return printf ("error: failed to read item s1\n");
        if (! f.Read (t))
            return printf ("error: failed to read item type\n");
        if (! f.Read (s2))
            return printf ("error: failed to read item s2\n");
        printf ("name: %16s, ofs: %8d, s1: %8d, t: %4d, s2: %8d\n",
            fn, of, s1, t, s2);
#ifdef LIST_ONLY
        continue;
#endif
        // slow and simple
        auto sentinel = f.Tell ();
        if (! f.Seek (of))
            return printf ("error: failed to seek %d\n", of);
        Buf<unsigned char> d2 {s1};
        if (s2 > s1)
            return printf ("error: the impossible has happened: %d<%d\n",
                s1, s2);
        else if (s2 > 0) { // compressed
            Buf<unsigned char> d1 {s2};
            if (! f.Read (*d1, s2))
                return printf ("error: item read failed\n");
            if (! zs.Inflate (d1, s2, d2, s1))
                return printf ("error: failed to decompress item\n");
        }
        else if (! f.Read (*d2, s1))
            return printf ("error: item read failed\n");
        File f1 {(char *)fn, "wb+"};
        if (! f1.Write (*d2, s1))
            return printf ("error: failed to write \"%s\"\n", (char *)fn);
        if (! f.Seek (sentinel))
            return printf ("error: failed to seek after item write\n");
    }
    return 0;
}