diff --git a/library/DataDefs.cpp b/library/DataDefs.cpp
new file mode 100644
index 000000000..05988e419
--- /dev/null
+++ b/library/DataDefs.cpp
@@ -0,0 +1,393 @@
+/*
+https://github.com/peterix/dfhack
+Copyright (c) 2009-2011 Petr Mrázek (peterix@gmail.com)
+
+This software is provided 'as-is', without any express or implied
+warranty. In no event will the authors be held liable for any
+damages arising from the use of this software.
+
+Permission is granted to anyone to use this software for any
+purpose, including commercial applications, and to alter it and
+redistribute it freely, subject to the following restrictions:
+
+1. The origin of this software must not be misrepresented; you must
+not claim that you wrote the original software. If you use this
+software in a product, an acknowledgment in the product documentation
+would be appreciated but is not required.
+
+2. Altered source versions must be plainly marked as such, and
+must not be misrepresented as being the original software.
+
+3. This notice may not be removed or altered from any source
+distribution.
+*/
+
+#include "Internal.h"
+
+#include <string>
+#include <vector>
+#include <map>
+
+#include "MemAccess.h"
+#include "Core.h"
+#include "VersionInfo.h"
+#include "tinythread.h"
+// must be last due to MS stupidity
+#include "DataDefs.h"
+#include "DataIdentity.h"
+
+#include "MiscUtils.h"
+
+using namespace DFHack;
+
+
+void *type_identity::do_allocate_pod() {
+    void *p = malloc(size);
+    memset(p, 0, size);
+    return p;
+}
+
+void type_identity::do_copy_pod(void *tgt, const void *src) {
+    memmove(tgt, src, size);
+};
+
+bool type_identity::do_destroy_pod(void *obj) {
+    free(obj);
+    return true;
+}
+
+void *type_identity::allocate() {
+    if (can_allocate())
+        return do_allocate();
+    else
+        return NULL;
+}
+
+bool type_identity::copy(void *tgt, const void *src) {
+    if (can_allocate() && tgt && src)
+    {
+        do_copy(tgt, src);
+        return true;
+    }
+    else
+        return false;
+}
+
+bool type_identity::destroy(void *obj) {
+    if (can_allocate() && obj)
+        return do_destroy(obj);
+    else
+        return false;
+}
+
+void *enum_identity::do_allocate() {
+    void *p = malloc(byte_size());
+    memcpy(p, &first_item_value, std::min(byte_size(), sizeof(int64_t)));
+    return p;
+}
+
+/* The order of global object constructor calls is
+ * undefined between compilation units. Therefore,
+ * this list has to be plain data, so that it gets
+ * initialized by the loader in the initial mmap.
+ */
+compound_identity *compound_identity::list = NULL;
+std::vector<compound_identity*> compound_identity::top_scope;
+
+compound_identity::compound_identity(size_t size, TAllocateFn alloc,
+                                     compound_identity *scope_parent, const char *dfhack_name)
+    : constructed_identity(size, alloc), scope_parent(scope_parent), dfhack_name(dfhack_name)
+{
+    next = list; list = this;
+}
+
+void compound_identity::doInit(Core *)
+{
+    if (scope_parent)
+        scope_parent->scope_children.push_back(this);
+    else
+        top_scope.push_back(this);
+}
+
+std::string compound_identity::getFullName()
+{
+    if (scope_parent)
+        return scope_parent->getFullName() + "." + getName();
+    else
+        return getName();
+}
+
+static tthread::mutex *known_mutex = NULL;
+
+void compound_identity::Init(Core *core)
+{
+    if (!known_mutex)
+        known_mutex = new tthread::mutex();
+
+    // This cannot be done in the constructors, because
+    // they are called in an undefined order.
+    for (compound_identity *p = list; p; p = p->next)
+        p->doInit(core);
+}
+
+bitfield_identity::bitfield_identity(size_t size,
+                                     compound_identity *scope_parent, const char *dfhack_name,
+                                     int num_bits, const bitfield_item_info *bits)
+    : compound_identity(size, NULL, scope_parent, dfhack_name), bits(bits), num_bits(num_bits)
+{
+}
+
+enum_identity::enum_identity(size_t size,
+                             compound_identity *scope_parent, const char *dfhack_name,
+                             type_identity *base_type,
+                             int64_t first_item_value, int64_t last_item_value,
+                             const char *const *keys,
+                             const void *attrs, struct_identity *attr_type)
+    : compound_identity(size, NULL, scope_parent, dfhack_name),
+      first_item_value(first_item_value), last_item_value(last_item_value),
+      keys(keys), base_type(base_type), attrs(attrs), attr_type(attr_type)
+{
+}
+
+struct_identity::struct_identity(size_t size, TAllocateFn alloc,
+                                 compound_identity *scope_parent, const char *dfhack_name,
+                                 struct_identity *parent, const struct_field_info *fields)
+    : compound_identity(size, alloc, scope_parent, dfhack_name),
+      parent(parent), has_children(false), fields(fields)
+{
+}
+
+void struct_identity::doInit(Core *core)
+{
+    compound_identity::doInit(core);
+
+    if (parent) {
+        parent->children.push_back(this);
+        parent->has_children = true;
+    }
+}
+
+bool struct_identity::is_subclass(struct_identity *actual)
+{
+    if (!has_children && actual != this)
+        return false;
+
+    for (; actual; actual = actual->getParent())
+        if (actual == this) return true;
+
+    return false;
+}
+
+std::string pointer_identity::getFullName()
+{
+    return (target ? target->getFullName() : std::string("void")) + "*";
+}
+
+std::string container_identity::getFullName(type_identity *item)
+{
+    return "<" + (item ? item->getFullName() : std::string("void")) + ">";
+}
+
+std::string ptr_container_identity::getFullName(type_identity *item)
+{
+    return "<" + (item ? item->getFullName() : std::string("void")) + "*>";
+}
+
+std::string bit_container_identity::getFullName(type_identity *)
+{
+    return "<bool>";
+}
+
+std::string df::buffer_container_identity::getFullName(type_identity *item)
+{
+    return (item ? item->getFullName() : std::string("void")) +
+           (size > 0 ? stl_sprintf("[%d]", size) : std::string("[]"));
+}
+
+virtual_identity::virtual_identity(size_t size, TAllocateFn alloc,
+                                   const char *dfhack_name, const char *original_name,
+                                   virtual_identity *parent, const struct_field_info *fields)
+    : struct_identity(size, alloc, NULL, dfhack_name, parent, fields), original_name(original_name),
+      vtable_ptr(NULL)
+{
+}
+
+/* Vtable name to identity lookup. */
+static std::map<std::string, virtual_identity*> name_lookup;
+
+/* Vtable pointer to identity lookup. */
+std::map<void*, virtual_identity*> virtual_identity::known;
+
+void virtual_identity::doInit(Core *core)
+{
+    struct_identity::doInit(core);
+
+    auto vtname = getOriginalName();
+    name_lookup[vtname] = this;
+
+    vtable_ptr = core->vinfo->getVTable(vtname);
+    if (vtable_ptr)
+        known[vtable_ptr] = this;
+}
+
+virtual_identity *virtual_identity::get(virtual_ptr instance_ptr)
+{
+    if (!instance_ptr) return NULL;
+
+    // Actually, a reader/writer lock would be sufficient,
+    // since the table is only written once per class.
+    tthread::lock_guard<tthread::mutex> lock(*known_mutex);
+
+    void *vtable = get_vtable(instance_ptr);
+    std::map<void*, virtual_identity*>::iterator it = known.find(vtable);
+
+    if (it != known.end())
+        return it->second;
+
+    // If using a reader/writer lock, re-grab as write here, and recheck
+    Core &core = Core::getInstance();
+    std::string name = core.p->doReadClassName(vtable);
+
+    virtual_identity *actual = NULL;
+
+    auto name_it = name_lookup.find(name);
+    if (name_it != name_lookup.end()) {
+        virtual_identity *p = name_it->second;
+
+        if (p->vtable_ptr && p->vtable_ptr != vtable) {
+            std::cerr << "Conflicting vtable ptr for class '" << p->getName()
+                      << "': found 0x" << std::hex << unsigned(vtable)
+                      << ", previous 0x" << unsigned(p->vtable_ptr) << std::dec << std::endl;
+            abort();
+        } else if (!p->vtable_ptr) {
+            uint32_t pv = unsigned(vtable);
+            pv -= Core::getInstance().vinfo->getRebaseDelta();
+            std::cerr << "<vtable-address name='" << p->getOriginalName() << "' value='0x"
+                      << std::hex << pv << std::dec << "'/>" << std::endl;
+        }
+
+        known[vtable] = p;
+        p->vtable_ptr = vtable;
+        return p;
+    }
+
+    std::cerr << "UNKNOWN CLASS '" << name << "': vtable = 0x"
+              << std::hex << unsigned(vtable) << std::dec << std::endl;
+
+    known[vtable] = NULL;
+    return NULL;
+}
+
+void virtual_identity::adjust_vtable(virtual_ptr obj, virtual_identity *main)
+{
+    if (vtable_ptr) {
+        *(void**)obj = vtable_ptr;
+        return;
+    }
+
+    if (main && main != this && is_subclass(main))
+        return;
+
+    std::cerr << "Attempt to create class '" << getName() << "' without known vtable." << std::endl;
+    abort();
+}
+
+virtual_ptr virtual_identity::clone(virtual_ptr obj)
+{
+    virtual_identity *id = get(obj);
+    if (!id) return NULL;
+    virtual_ptr copy = id->instantiate();
+    if (!copy) return NULL;
+    id->do_copy(copy, obj);
+    return copy;
+}
+
+bool DFHack::findBitfieldField(unsigned *idx, const std::string &name,
+                               unsigned size, const bitfield_item_info *items)
+{
+    for (unsigned i = 0; i < size; i++) {
+        if (items[i].name && items[i].name == name)
+        {
+            *idx = i;
+            return true;
+        }
+    }
+
+    return false;
+}
+
+void DFHack::setBitfieldField(void *p, unsigned idx, unsigned size, int value)
+{
+    uint8_t *data = ((uint8_t*)p) + (idx/8);
+    unsigned shift = idx%8;
+    uint32_t mask = ((1<<size)-1) << shift;
+    uint32_t vmask = ((value << shift) & mask);
+
+#define ACCESS(type) *(type*)data = type((*(type*)data & ~mask) | vmask)
+
+    if (!(mask & ~0xFFU)) ACCESS(uint8_t);
+    else if (!(mask & ~0xFFFFU)) ACCESS(uint16_t);
+    else ACCESS(uint32_t);
+
+#undef ACCESS
+}
+
+int DFHack::getBitfieldField(const void *p, unsigned idx, unsigned size)
+{
+    const uint8_t *data = ((const uint8_t*)p) + (idx/8);
+    unsigned shift = idx%8;
+    uint32_t mask = ((1<<size)-1) << shift;
+
+#define ACCESS(type) return int((*(type*)data & mask) >> shift)
+
+    if (!(mask & ~0xFFU)) ACCESS(uint8_t);
+    else if (!(mask & ~0xFFFFU)) ACCESS(uint16_t);
+    else ACCESS(uint32_t);
+
+#undef ACCESS
+}
+
+void DFHack::bitfieldToString(std::vector<std::string> *pvec, const void *p,
+                              unsigned size, const bitfield_item_info *items)
+{
+    for (unsigned i = 0; i < size; i++) {
+        int value = getBitfieldField(p, i, std::min(1,items[i].size));
+
+        if (value) {
+            std::string name = format_key(items[i].name, i);
+
+            if (items[i].size > 1)
+                name += stl_sprintf("=%u", value);
+
+            pvec->push_back(name);
+        }
+
+        if (items[i].size > 1)
+            i += items[i].size-1;
+    }
+}
+
+int DFHack::findEnumItem(const std::string &name, int size, const char *const *items)
+{
+    for (int i = 0; i < size; i++) {
+        if (items[i] && items[i] == name)
+            return i;
+    }
+
+    return -1;
+}
+
+void DFHack::flagarrayToString(std::vector<std::string> *pvec, const void *p,
+                               int bytes, int base, int size, const char *const *items)
+{
+    for (unsigned i = 0; i < bytes*8; i++) {
+        int value = getBitfieldField(p, i, 1);
+
+        if (value)
+        {
+            int ridx = int(i) - base;
+            const char *name = (ridx >= 0 && ridx < size) ? items[ridx] : NULL;
+            pvec->push_back(format_key(name, i));
+        }
+    }
+}