Function decode_delta_d

libavcodec/iff.c:1275–1332

}

static void decode_delta_d(uint8_t *dst,
                           const uint8_t *buf, const uint8_t *buf_end,
                           int w, int flag, int bpp, int dst_size)
{
    int planepitch = FFALIGN(w, 16) >> 3;
    int pitch = planepitch * bpp;
    int planepitch_byte = (w + 7) / 8;
    unsigned entries, ofssrc;
    GetByteContext gb, ptrs;
    PutByteContext pb;
    int k;

    if (buf_end - buf <= 4 * bpp)
        return;

    bytestream2_init_writer(&pb, dst, dst_size);
    bytestream2_init(&ptrs, buf, bpp * 4);

    for (k = 0; k < bpp; k++) {
        ofssrc = bytestream2_get_be32(&ptrs);

        if (!ofssrc)
            continue;

        if (ofssrc >= buf_end - buf)
            continue;

        bytestream2_init(&gb, buf + ofssrc, buf_end - (buf + ofssrc));

        entries = bytestream2_get_be32(&gb);
        if (entries * 8LL > bytestream2_get_bytes_left(&gb))
            return;

        while (entries && bytestream2_get_bytes_left(&gb) >= 8) {
            int32_t opcode  = bytestream2_get_be32(&gb);
            unsigned offset = bytestream2_get_be32(&gb);

            bytestream2_seek_p(&pb, (offset / planepitch_byte) * pitch + (offset % planepitch_byte) + k * planepitch, SEEK_SET);
            if (opcode >= 0) {
                uint32_t x = bytestream2_get_be32(&gb);
                if (opcode && 4 + (opcode - 1LL) * pitch > bytestream2_get_bytes_left_p(&pb))
                    continue;
                while (opcode && bytestream2_get_bytes_left_p(&pb) > 0) {
                    bytestream2_put_be32(&pb, x);
                    bytestream2_skip_p(&pb, pitch - 4);
                    opcode--;
                }
            } else {
                while (opcode && bytestream2_get_bytes_left(&gb) > 0) {
                    bytestream2_put_be32(&pb, bytestream2_get_be32(&gb));
                    bytestream2_skip_p(&pb, pitch - 4);
                    opcode++;
                }
            }
            entries--;
        }
    }
}