Restored the monotonic allocator

src/ArduinoJson/Memory/MemoryPool.hpp

@@ -9,7 +9,6 @@
 #include "../Strings/StringInMemoryPool.hpp"
 #include "Alignment.hpp"
 #include "MemoryPool.hpp"
-#include "SlotList.hpp"
 #include "StringSlot.hpp"
 #include "VariantSlot.hpp"
 
@@ -60,24 +59,11 @@ class MemoryPool {
   }
 
   size_t size() const {
-    return allocated_bytes() - _freeVariants.size() - _freeStrings.size();
+    return size_t(_left - _begin + _end - _right);
   }
 
   VariantSlot* allocVariant() {
-    VariantSlot* s = _freeVariants.pop();
-    if (s) return s;
-    return s ? s : allocRight<VariantSlot>();
-  }
-
-  void freeVariant(VariantSlot* slot) {
-    freeVariantSlot(slot);
-    compactRightSide();
-  }
-
-  void freeString(StringSlot* slot) {
-    freeStringSlot(slot);
-    compactLeftSide(slot->value, slot->size);
-    compactRightSide();
+    return allocRight<VariantSlot>();
   }
 
   StringSlot* allocFrozenString(size_t n) {
@@ -88,7 +74,6 @@ class MemoryPool {
     s->value = _left;
     s->size = n;
     _left += n;
-    _usedString.push(s);
     checkInvariants();
 
     return s;
@@ -100,7 +85,6 @@ class MemoryPool {
 
     s->value = _left;
     s->size = size_t(_right - _left);
-    _usedString.push(s);
     _left = _right;
 
     checkInvariants();
@@ -116,9 +100,6 @@ class MemoryPool {
   void clear() {
     _left = _begin;
     _right = _end;
-    _freeVariants.clear();
-    _freeStrings.clear();
-    _usedString.clear();
   }
 
   bool canAlloc(size_t bytes) const {
@@ -146,50 +127,10 @@ class MemoryPool {
   }
 
  private:
-  size_t allocated_bytes() const {
-    return size_t(_left - _begin + _end - _right);
-  }
-
   StringSlot* allocStringSlot() {
-    StringSlot* s = _freeStrings.pop();
-    if (s) return s;
     return allocRight<StringSlot>();
   }
 
-  void freeVariantSlot(VariantSlot* slot) {
-    _freeVariants.push(slot);
-  }
-
-  void freeStringSlot(StringSlot* slot) {
-    _usedString.remove(slot);
-    _freeStrings.push(slot);
-  }
-
-  void compactLeftSide(char* holeAddress, size_t holeSize) {
-    ARDUINOJSON_ASSERT(holeAddress >= _begin);
-    ARDUINOJSON_ASSERT(holeAddress + holeSize <= _left);
-    char* holeEnd = holeAddress + holeSize;
-    memmove(holeAddress,               // where the hole begun
-            holeEnd,                   // where the hole ended
-            size_t(_left - holeEnd));  // everything after the hole
-    _left -= holeSize;
-    _usedString.forEach(UpdateStringSlotAddress(holeAddress, holeSize));
-    checkInvariants();
-  }
-
-  void compactRightSide() {
-  loop:
-    if (_freeStrings.remove(_right)) {
-      _right += sizeof(StringSlot);
-      goto loop;
-    }
-    if (_freeVariants.remove(_right)) {
-      _right += sizeof(VariantSlot);
-      goto loop;
-    }
-    checkInvariants();
-  }
-
   void checkInvariants() {
     ARDUINOJSON_ASSERT(_begin <= _left);
     ARDUINOJSON_ASSERT(_left <= _right);
@@ -198,9 +139,6 @@ class MemoryPool {
   }
 
   char *_begin, *_left, *_right, *_end;
-  SlotList<VariantSlot> _freeVariants;
-  SlotList<StringSlot> _freeStrings;
-  SlotList<StringSlot> _usedString;
 };
 
 }  // namespace ARDUINOJSON_NAMESPACE

src/ArduinoJson/Memory/SlotList.hpp

@@ -1,67 +0,0 @@
-// ArduinoJson - arduinojson.org
-// Copyright Benoit Blanchon 2014-2018
-// MIT License
-
-#pragma once
-
-#include <stddef.h>  // for size_t
-
-namespace ARDUINOJSON_NAMESPACE {
-
-template <typename TSlot>
-class SlotList {
- public:
-  SlotList() : _head(0) {}
-
-  TSlot *pop() {
-    TSlot *slot = _head;
-    if (slot) _head = slot->next;
-    return slot;
-  }
-
-  void push(TSlot *slot) {
-    slot->next = _head;
-    _head = slot;
-  }
-
-  bool remove(const TSlot *slot) {
-    if (_head == slot) {
-      _head = slot->next;
-      return true;
-    }
-
-    for (TSlot *s = _head; s; s = s->next) {
-      if (s->next == slot) {
-        s->next = slot->next;
-        return true;
-      }
-    }
-
-    return false;
-  }
-
-  bool remove(const void *slot) {
-    return remove(reinterpret_cast<const TSlot *>(slot));
-  }
-
-  template <typename Functor>
-  void forEach(const Functor &f) {
-    for (TSlot *s = _head; s; s = s->next) {
-      f(s);
-    }
-  }
-
-  size_t size() const {
-    size_t sum = 0;
-    for (TSlot *s = _head; s; s = s->next) sum += sizeof(TSlot);
-    return sum;
-  }
-
-  void clear() {
-    _head = 0;
-  }
-
- private:
-  TSlot *_head;
-};
-}  // namespace ARDUINOJSON_NAMESPACE