unpack_vid.cpp

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// Q'N'D code.

//c clang++ -std=c++11 -fsanitize=address,undefined,integer -fvisibility=hidden -I. -Ios -Ios/posix -Iutils -Istream -O0 -g -DH3R_DEBUG -fno-exceptions -fno-threadsafe-statics main.a unpack_vid.cpp -o unpack_vid

#include "h3r_os_error.h"
H3R_ERR_DEFINE_UNHANDLED
H3R_ERR_DEFINE_HANDLER(Memory,H3R_ERR_HANDLER_UNHANDLED)

#include "h3r_filestream.h"

H3R_NAMESPACE
namespace OS {

class FileErrReplace final : public Error
{
    public: bool Handled(Error * e = nullptr) override
    {
        FileError * fe = (FileError *)e;
        if (FileError::Op::Replace == fe->Op)
            return fe->Replace = true;
        return false;
    }
};

} // namespace OS
NAMESPACE_H3R
static H3R_NS::OS::FileErrReplace my_file_err;
H3R_ERR_DEFINE_HANDLER(File,my_file_err)

int main(int argc, char ** argv)
{
    if (2 != argc)
        return printf ("usage: unpack_vid vidfile\n");

    H3R_NS::OS::FileStream s {argv[1], H3R_NS::OS::FileStream::Mode::ReadOnly};

    int cnt;
    s.Read (&cnt, 4);
    H3R_ENSURE(cnt > 0 && cnt < 1024, "that's way too many videos")

    H3R_NS::Array<int> ofs {cnt};
    H3R_NS::Array<H3R_NS::String> name {cnt};
    for (int i = 0; i < cnt; i++) {
        char fname[40] {};
        s.Read (fname, 40);
        fname[39] = '\0';
        name[i] = fname;
        s.Read (&ofs[i], 4);
        printf ("Entry #%2d: name: \"%s\", offset: %8d" EOL,
            i, name[i].AsZStr (), ofs[i]);
    }
#ifdef LIST_ONLY
    return 0;
#endif

    const size_t BUF_SIZE {1<<16};
    H3R_NS::Array<H3R_NS::byte> buf {BUF_SIZE};
    for (int i = 0; i < cnt; i++) {
        s.Seek (ofs[i] - s.Tell ());
        off_t size = (i < (cnt-1) ? ofs[i + 1] : s.Size ()) - ofs[i];
        H3R_ENSURE(size > 0, "vid size can't be <= 0")

        H3R_NS::OS::FileStream n {name[i],
            H3R_NS::OS::FileStream::Mode::WriteOnly};
        printf ("Entry #%2d: name: \"%s\", offset: %8d, size: %8lu" EOL,
            i, name[i].AsZStr (), ofs[i], size);
        while (size > 0) { // block (buffered) RW
            size_t read = size < BUF_SIZE ? size : BUF_SIZE;
            s.Read ((H3R_NS::byte *)buf, read);
            n.Write ((H3R_NS::byte *)buf, read);
            size -= read;
        }
    }

    return 0;
} // main()