diff --git a/luprex/core/cpp/animqueue.cpp b/luprex/core/cpp/animqueue.cpp
index b1f57cae..51890dcf 100644
--- a/luprex/core/cpp/animqueue.cpp
+++ b/luprex/core/cpp/animqueue.cpp
@@ -6,15 +6,21 @@ AnimStep::AnimStep() {}
 AnimStep::~AnimStep() {}
 
 AnimQueue::AnimQueue() {
+    id_ = 0;
     size_limit_ = 10; // Default size limit.
+    clear_steps();
+}
+
+void AnimQueue::clear_steps() {
+    steps_.clear();
     steps_.emplace_back();
     AnimStep &init = steps_.back();
     init.id_ = 0;
+    init.bits_ = AnimStep::HAS_EVERYTHING;
     init.facing_ = 0;
     init.xyz_ = util::XYZ(0,0,0);
     init.graphic_ = "nothing";
     init.plane_ = "nowhere";
-    init.bits_ = AnimStep::HAS_EVERYTHING;
 }
 
 void AnimQueue::set_size_limit(int n) {
@@ -163,6 +169,94 @@ void AnimQueue::set_plane(const std::string &p) {
     last.plane_ = p;
 }
 
+bool AnimQueue::valid() {
+    // Animqueue must have at least one step.
+    if (steps_.empty()) {
+        return false;
+    }
+    // First action should be blank.
+    if (steps_[0].action_ != "") {
+        return false;
+    }
+    // First step should have all bits.
+    if (steps_[0].bits_ != AnimStep::HAS_EVERYTHING) {
+        return false;
+    }
+    // Any unset bit should correspond to a value copied from the previous step.
+    for (size_t i = 1; i < steps_.size(); i++) {
+        const AnimStep &prev = steps_[i - 1];
+        const AnimStep &curr = steps_[i];
+        if (!curr.has_facing() && (curr.facing_ != prev.facing_)) {
+            return false;
+        }
+        if (!curr.has_xyz() && (curr.xyz_ != prev.xyz_)) {
+            return false;
+        }
+        if (!curr.has_graphic() && (curr.graphic_ != prev.graphic_)) {
+            return false;
+        }
+        if (!curr.has_plane() && (curr.plane_ != prev.plane_)) {
+            return false;
+        }
+    }
+    return true;
+}
+
+void AnimQueue::serialize(StreamBuffer *sb) {
+    assert(valid()); // can't serialize an invalid animqueue.
+    sb->write_int64(id_);
+    sb->write_int32(size_limit_);
+    sb->write_size(steps_.size());
+    for (const AnimStep &step : steps_) {
+        sb->write_int64(step.id_);
+        sb->write_int16(step.bits_);
+        sb->write_string(step.action_);
+        if (step.has_facing()) {
+            sb->write_float(step.facing_);
+        }
+        if (step.has_xyz()) {
+            sb->write_float(step.xyz_.x);
+            sb->write_float(step.xyz_.y);
+            sb->write_float(step.xyz_.z);
+        }
+        if (step.has_graphic()) {
+            sb->write_string(step.graphic_);
+        }
+        if (step.has_plane()) {
+            sb->write_string(step.plane_);
+        }
+    }
+}
+
+void AnimQueue::deserialize(StreamBuffer *sb) {
+    id_ = sb->read_int64();
+    size_limit_ = sb->read_int32();
+    size_t nsteps = sb->read_size();
+    steps_.clear();
+    steps_.resize(nsteps);
+    for (size_t i = 0; i < nsteps; i++) {
+        AnimStep &step = steps_[i];
+        if (i > 0) step = steps_[i - 1];
+        step.id_ = sb->read_int64();
+        step.bits_ = sb->read_int16();
+        step.action_ = sb->read_string();
+        if (step.has_facing()) {
+            step.facing_ = sb->read_float();
+        }
+        if (step.has_xyz()) {
+            step.xyz_.x = sb->read_float();
+            step.xyz_.y = sb->read_float();
+            step.xyz_.z = sb->read_float();
+        }
+        if (step.has_graphic()) {
+            step.graphic_ = sb->read_string();
+        }
+        if (step.has_plane()) {
+            step.plane_ = sb->read_string();
+        }
+    }
+}
+
 const std::string &AnimQueue::get_graphic() const {
     const AnimStep &last = steps_.back();
     return last.graphic_;
@@ -181,8 +275,11 @@ const util::XYZ &AnimQueue::get_xyz() const {
 LuaDefine(unittests_animqueue, "c") {
     // Check initial state.
     AnimQueue aq;
+    StreamBuffer sb;
+    AnimQueue aqds;
     aq.set_size_limit(3);
     
+    LuaAssert(L, aq.valid());
     LuaAssert(L, aq.size() == 1);
     const AnimStep *st = &aq.nth(0);
     LuaAssert(L, st->id() == 0);
@@ -195,6 +292,7 @@ LuaDefine(unittests_animqueue, "c") {
 
     // Add a step.
     aq.add(12345, "walk");
+    LuaAssert(L, aq.valid());
     LuaAssert(L, aq.size() == 2);
     st = &aq.nth(1);
     LuaAssert(L, st->id() == 12345);
@@ -218,6 +316,7 @@ LuaDefine(unittests_animqueue, "c") {
     aq.set_graphic("something");
     LuaAssert(L, st->graphic() == "something");
     LuaAssert(L, st->bits() == (AnimStep::HAS_FACING | AnimStep::HAS_XYZ | AnimStep::HAS_PLANE | AnimStep::HAS_GRAPHIC));
+    LuaAssert(L, aq.valid());
     
     // Exceed the length limit, dropping first element.
     aq.add(12346, "walk");
@@ -228,5 +327,56 @@ LuaDefine(unittests_animqueue, "c") {
     LuaAssert(L, aq.nth(0).bits() == AnimStep::HAS_EVERYTHING);
     LuaAssert(L, aq.nth(1).id() == 12346);
     LuaAssert(L, aq.nth(2).id() == 12347);
+    LuaAssert(L, aq.valid());
+
+    // Test serialization and deserialization.
+    aq.set_id(123);
+    aq.set_size_limit(5);
+    aq.clear_steps();
+    aq.add(12345, "walk");
+    aq.set_xyz(util::XYZ(3,4,5));
+    aq.add(12346, "setgraphic");
+    aq.set_graphic("banana");
+    aq.add(12347, "setfacing");
+    aq.set_facing(301.0);
+    aq.serialize(&sb);
+    aqds.deserialize(&sb);
+
+    LuaAssert(L, aqds.get_id() == 123);
+    LuaAssert(L, aqds.size_limit() == 5);
+    LuaAssert(L, aqds.size() == 4);
+
+    LuaAssert(L, aqds.nth(0).id() == 0);
+    LuaAssert(L, aqds.nth(0).bits() == AnimStep::HAS_EVERYTHING);
+    LuaAssert(L, aqds.nth(0).action() == "");
+    LuaAssert(L, aqds.nth(0).facing() == 0.0);
+    LuaAssert(L, aqds.nth(0).xyz() == util::XYZ(0,0,0));
+    LuaAssert(L, aqds.nth(0).graphic() == "nothing");
+    LuaAssert(L, aqds.nth(0).plane() == "nowhere");
+    
+    LuaAssert(L, aqds.nth(1).id() == 12345);
+    LuaAssert(L, aqds.nth(1).bits() == AnimStep::HAS_XYZ);
+    LuaAssert(L, aqds.nth(1).action() == "walk");
+    LuaAssert(L, aqds.nth(1).facing() == 0.0);
+    LuaAssert(L, aqds.nth(1).xyz() == util::XYZ(3,4,5));
+    LuaAssert(L, aqds.nth(1).graphic() == "nothing");
+    LuaAssert(L, aqds.nth(1).plane() == "nowhere");
+
+    LuaAssert(L, aqds.nth(2).id() == 12346);
+    LuaAssert(L, aqds.nth(2).bits() == AnimStep::HAS_GRAPHIC);
+    LuaAssert(L, aqds.nth(2).action() == "setgraphic");
+    LuaAssert(L, aqds.nth(2).facing() == 0.0);
+    LuaAssert(L, aqds.nth(2).xyz() == util::XYZ(3,4,5));
+    LuaAssert(L, aqds.nth(2).graphic() == "banana");
+    LuaAssert(L, aqds.nth(2).plane() == "nowhere");
+
+    LuaAssert(L, aqds.nth(3).id() == 12347);
+    LuaAssert(L, aqds.nth(3).bits() == AnimStep::HAS_FACING);
+    LuaAssert(L, aqds.nth(3).action() == "setfacing");
+    LuaAssert(L, aqds.nth(3).facing() == 301.0);
+    LuaAssert(L, aqds.nth(3).xyz() == util::XYZ(3,4,5));
+    LuaAssert(L, aqds.nth(3).graphic() == "banana");
+    LuaAssert(L, aqds.nth(3).plane() == "nowhere");
+
     return 0;
 }
diff --git a/luprex/core/cpp/animqueue.hpp b/luprex/core/cpp/animqueue.hpp
index c2c559dc..bf6a7049 100644
--- a/luprex/core/cpp/animqueue.hpp
+++ b/luprex/core/cpp/animqueue.hpp
@@ -29,6 +29,7 @@
 #include <deque>
 #include <cassert>
 #include <unordered_map>
+#include "streambuffer.hpp"
 #include "util.hpp"
 
 
@@ -45,8 +46,8 @@ public:
 
 private:
     int64_t id_;
+    int16_t bits_;
     std::string action_;
-    int bits_;
 
     float facing_;
     util::XYZ xyz_;
@@ -58,8 +59,8 @@ public:
     ~AnimStep();
 
     int64_t id() const { return id_; }
-    const std::string &action() const { return action_; }
     int bits() const { return bits_; }
+    const std::string &action() const { return action_; }
 
     double facing() const { return facing_; }
     util::XYZ xyz() const { return xyz_; }
@@ -75,15 +76,21 @@ public:
 class AnimQueue {
 private:
     int64_t id_;
-    int size_limit_;
+    int32_t size_limit_;
     std::deque<AnimStep> steps_;
+
 public:    
     AnimQueue();
+    
     int64_t get_id() const { return id_; }
     void set_id(int64_t id) { id_ = id; }
     const AnimStep &nth(int n) const { return steps_[n]; }
-    int size() const { return steps_.size(); }
+    size_t size() const { return steps_.size(); }
+    int32_t size_limit() const { return size_limit_; }
 
+    // Clear the steps.  Doesn't affect size_limit or id.
+    void clear_steps();
+    
     // Mutators to create new steps from C++
     //
     void add(int64_t id, const std::string &action);
@@ -92,6 +99,10 @@ public:
     void set_graphic(const std::string &g);
     void set_plane(const std::string &p);
 
+    // Serialize or deserialize to a StreamBuffer
+    void serialize(StreamBuffer *sb);
+    void deserialize(StreamBuffer *sb);
+
     // Mutator to create new steps from lua.
     //
     // Lua stack must contain a table, which may contain:
@@ -113,8 +124,11 @@ public:
     const std::string &get_plane() const;
     const util::XYZ &get_xyz() const;
 
-    // Functions for unit testing.
-    void set_size_limit(int n);
+    // (For testing): change the size limit.
+    void set_size_limit(int32_t n);
+
+    // (For testing): make sure the invariants are preserved.
+    bool valid();
 };
 
 #endif // ANIMQUEUE_HPP
diff --git a/luprex/core/cpp/idalloc.cpp b/luprex/core/cpp/idalloc.cpp
index 39fca25e..314f3284 100644
--- a/luprex/core/cpp/idalloc.cpp
+++ b/luprex/core/cpp/idalloc.cpp
@@ -84,24 +84,24 @@ int64_t IdGlobalPool::alloc_id_for_thread(lua_State *L) {
 }
 
 void IdGlobalPool::serialize(StreamBuffer *sb) {
-    sb->write_int64(salvaged_.size());
+    sb->write_int64(next_batch_);
+    sb->write_int64(next_id_);
+    sb->write_int32(queue_fill_);
+    sb->write_size(salvaged_.size());
     for (int64_t batch : salvaged_) {
         sb->write_int64(batch);
     }
-    sb->write_int64(next_batch_);
-    sb->write_int64(next_id_);
-    sb->write_int64(queue_fill_);
 }
 
 void IdGlobalPool::deserialize(StreamBuffer *sb) {
-    int64_t salvaged_size = sb->read_int64();
-    salvaged_.resize(salvaged_size);
-    for (int i=0; i < salvaged_size; i++) {
-        salvaged_[i] = sb->read_int64();
-    }
     next_batch_ = sb->read_int64();
     next_id_ = sb->read_int64();
-    queue_fill_ = sb->read_int64();
+    queue_fill_ = sb->read_int32();
+    size_t salvaged_size = sb->read_size();
+    salvaged_.resize(salvaged_size);
+    for (int i=0; i < int(salvaged_size); i++) {
+        salvaged_[i] = sb->read_int64();
+    }
 }
 
 IdPlayerPool::IdPlayerPool(IdGlobalPool *gp) {
@@ -155,16 +155,16 @@ void IdPlayerPool::prepare_thread(lua_State *L) {
 }
 
 void IdPlayerPool::serialize(StreamBuffer *sb) {
-    sb->write_int64(ranges_.size());
+    sb->write_size(ranges_.size());
     for (int64_t batch : ranges_) {
         sb->write_int64(batch);
     }
 }
 
 void IdPlayerPool::deserialize(StreamBuffer *sb) {
-    int64_t ranges_size = sb->read_int64();
+    size_t ranges_size = sb->read_size();
     ranges_.resize(ranges_size);
-    for (int i=0; i < ranges_size; i++) {
+    for (int i=0; i < int(ranges_size); i++) {
         ranges_[i] = sb->read_int64();
     }
 }
@@ -172,6 +172,9 @@ void IdPlayerPool::deserialize(StreamBuffer *sb) {
 LuaDefine(unittests_idalloc, "c") {
     IdGlobalPool gp;
     IdPlayerPool pp(&gp);
+    IdGlobalPool gpds;
+    IdPlayerPool ppds(&gpds);
+    StreamBuffer sb;
 
     // Synchronous pools produce IDs starting at 0x001E000000000000
     gp.init_synch(3);
@@ -277,5 +280,35 @@ LuaDefine(unittests_idalloc, "c") {
     LuaAssert(L, gp.alloc_id_for_thread(L) == 0x0010000000000000);
     LuaAssert(L, lua_getnextid(L) == 0);
     
+    // Serialize and deserialize a global pool.
+    gp.init_master(3);
+    gpds.init_master(10);
+    LuaAssert(L, gp.get_one() == 0x0010000000000000);
+    LuaAssert(L, gp.get_batch() == nthbatch(0));
+    gp.salvage(nthbatch(182));
+    gp.salvage(nthbatch(183));
+    gp.serialize(&sb);
+    gpds.deserialize(&sb);
+    LuaAssert(L, gpds.queue_fill() == 3);
+    LuaAssert(L, gpds.get_one() == 0x0010000000000001);
+    LuaAssert(L, gpds.get_batch() == nthbatch(183));
+    LuaAssert(L, gpds.get_batch() == nthbatch(182));
+    LuaAssert(L, gpds.get_batch() == nthbatch(1));
+
+    // Serialize and deserialize a player pool.
+    gp.init_master(3);
+    gpds.init_synch(5);
+    LuaAssert(L, gp.get_batch() == nthbatch(0));
+    pp.purge();
+    pp.refill();
+    LuaAssert(L, pp.size() == 3);
+    ppds.purge();
+    pp.serialize(&sb);
+    ppds.deserialize(&sb);
+    LuaAssert(L, ppds.size() == 3);
+    LuaAssert(L, ppds.get_batch() == nthbatch(1));
+    LuaAssert(L, ppds.get_batch() == nthbatch(2));
+    LuaAssert(L, ppds.get_batch() == nthbatch(3));
+
     return 0;
 }
diff --git a/luprex/core/cpp/idalloc.hpp b/luprex/core/cpp/idalloc.hpp
index 55225d27..30b95c85 100644
--- a/luprex/core/cpp/idalloc.hpp
+++ b/luprex/core/cpp/idalloc.hpp
@@ -76,7 +76,7 @@ private:
     std::vector<int64_t> salvaged_;
     int64_t next_batch_;
     int64_t next_id_;
-    int queue_fill_;
+    int32_t queue_fill_;
     friend int unittests_idalloc(lua_State *L);
 
 public:
@@ -120,10 +120,8 @@ public:
     // batch if possible.  If not, fetches one ID from the global pool.
     int64_t alloc_id_for_thread(lua_State *L);
 
-    // Serialize to a streambuffer.
+    // Serialize to or deserialize from a streambuffer.
     void serialize(StreamBuffer *sb);
-
-    // Deserialize from a streambuffer.
     void deserialize(StreamBuffer *sb);
 };
 
@@ -163,10 +161,9 @@ public:
     // Return the size of the queue.
     int size() { return ranges_.size(); }
 
-    // Serialize to a streambuffer.
+    // Serialize to or deserialize from a streambuffer.
+    // Caution: the pointer to the global pool is not serialized or deserialized.
     void serialize(StreamBuffer *sb);
-
-    // Deserialize from a streambuffer.
     void deserialize(StreamBuffer *sb);
 };
 
diff --git a/luprex/core/cpp/streambuffer.cpp b/luprex/core/cpp/streambuffer.cpp
index 677aac64..eb69cbad 100644
--- a/luprex/core/cpp/streambuffer.cpp
+++ b/luprex/core/cpp/streambuffer.cpp
@@ -139,6 +139,18 @@ void StreamBuffer::write_int64(int64_t v) {
     write_cursor_ += 8;
 }
 
+void StreamBuffer::write_float(float f) {
+    make_space(4);
+    memcpy(write_cursor_, &f, 4);
+    write_cursor_ += 4;
+}
+
+void StreamBuffer::write_double(double d) {
+    make_space(8);
+    memcpy(write_cursor_, &d, 8);
+    write_cursor_ += 8;
+}
+
 void StreamBuffer::write_bytes(const char *s, int64_t len) {
     make_space(len);
     memcpy(write_cursor_, s, len);
@@ -212,6 +224,34 @@ int64_t StreamBuffer::read_int64() {
     return v;
 }
 
+float StreamBuffer::read_float() {
+    check_available(4);
+    float f;
+    memcpy(&f, read_cursor_, 4);
+    read_cursor_ += 4;
+    return f;
+}
+
+double StreamBuffer::read_double() {
+    check_available(8);
+    double d;
+    memcpy(&d, read_cursor_, 8);
+    read_cursor_ += 8;
+    return d;
+}
+
+size_t StreamBuffer::read_size() {
+    return read_size_limit(0xFFFFFFF);
+}
+
+size_t StreamBuffer::read_size_limit(size_t limit) {
+    int64_t value = read_int64();
+    if ((value < 0)||(value > int64_t(limit))) {
+        throw StreamCorruption();
+    }
+    return size_t(value);
+}
+
 const char *StreamBuffer::read_bytes(int64_t bytes) {
     check_available(bytes);
     char *data = read_cursor_;
@@ -219,7 +259,11 @@ const char *StreamBuffer::read_bytes(int64_t bytes) {
     return data;
 }
 
-std::string StreamBuffer::read_string(int64_t max_allowed) {
+std::string StreamBuffer::read_string() {
+    return read_string_limit(0xFFFFFFF);
+}
+
+std::string StreamBuffer::read_string_limit(int64_t max_allowed) {
     int64_t len = read_uint8();
     if (len == 255) {
         len = read_int64();
@@ -388,9 +432,9 @@ LuaDefine(unittests_streambuffer, "c") {
     sb11.write_string("");
     sb11.write_string("de");
     assert(sb11.layout_is(0, 8, 3));
-    assert(sb11.read_string(1000) == "abc");
-    assert(sb11.read_string(1000) == "");
-    assert(sb11.read_string(1000) == "de");
+    assert(sb11.read_string() == "abc");
+    assert(sb11.read_string() == "");
+    assert(sb11.read_string() == "de");
 
     return 0;
 }
diff --git a/luprex/core/cpp/streambuffer.hpp b/luprex/core/cpp/streambuffer.hpp
index 616a50f5..f24a2173 100644
--- a/luprex/core/cpp/streambuffer.hpp
+++ b/luprex/core/cpp/streambuffer.hpp
@@ -308,18 +308,22 @@ public:
     char *alloc_space(int64_t bytes);
     void wrote_space(int64_t bytes);
 
-    // Write values into the buffer.
+    // Write numbers into the buffer.
     void write_int8(int8_t v);
     void write_int16(int16_t v);
     void write_int32(int32_t v);
     void write_int64(int64_t v);
+    void write_float(float f);
+    void write_double(double d);
     void write_uint8(uint8_t v) { write_int8(v); }
     void write_uint16(uint16_t v) { write_int16(v); }
     void write_uint32(uint32_t v) { write_int32(v); }
     void write_uint64(uint64_t v) { write_int64(v); }
-    
-    void write_bytes(const char *bytes, int64_t len);
+    void write_size(size_t sz) { write_int64(sz); }
+
+    // Write strings or blocks of bytes into the buffer.
     void write_string(const std::string &s);
+    void write_bytes(const char *bytes, int64_t len);
     void write_ztbytes(const char *bytes);
 
     // Overwrite values previously written to the buffer.
@@ -332,19 +336,26 @@ public:
     void overwrite_uint32(int64_t write_count_after, uint32_t v) { overwrite_int32(write_count_after, v); }
     void overwrite_uint64(int64_t write_count_after, uint64_t v) { overwrite_int64(write_count_after, v); }
 
-    // Read integers from the buffer.  May throw StreamEof.
+    // Read numbers from the buffer.  May throw StreamEof.
     int8_t  read_int8();
     int16_t read_int16();
     int32_t read_int32();
     int64_t read_int64();
+    float read_float();
+    double read_double();
     uint8_t  read_uint8() { return read_int8(); }
     uint16_t read_uint16() { return read_int16(); }
     uint32_t read_uint32() { return read_int32(); }
     uint64_t read_uint64() { return read_int64(); }
 
-    // Read a string of no more than the specified length. May throw StreamEof
-    // or StreamCorruption.
-    std::string read_string(int64_t max_allowed);
+    // May throw StreamEof or StreamCorruption.
+    size_t read_size();
+    size_t read_size_limit(size_t limit);
+
+    // Read a string of no more than the specified length.
+    // May throw StreamEof or StreamCorruption.
+    std::string read_string();
+    std::string read_string_limit(int64_t max_allowed);
 
     // Read a block of bytes.  May throw StreamEof.
     const char *read_bytes(int64_t bytes);
diff --git a/luprex/core/cpp/util.hpp b/luprex/core/cpp/util.hpp
index 347dc02e..5867024a 100644
--- a/luprex/core/cpp/util.hpp
+++ b/luprex/core/cpp/util.hpp
@@ -52,7 +52,8 @@ struct XYZ {
     float x, y, z;
     XYZ() { x=0; y=0; z=0; }
     XYZ(float ix, float iy, float iz) { x=ix; y=iy; z=iz; }
-    bool operator ==(const XYZ &o) { return x==o.x && y == o.y && z==o.z; }
+    bool operator ==(const XYZ &o) const { return x==o.x && y == o.y && z==o.z; }
+    bool operator !=(const XYZ &o) const { return x!=o.x || y != o.y || z!=o.z; }
 };
 std::ostream & operator << (std::ostream &out, const XYZ &xyz);