1 files changed, 265 insertions, 0 deletions
diff --git a/botan/src/alloc/mem_pool/mem_pool.cpp b/botan/src/alloc/mem_pool/mem_pool.cpp
new file mode 100644
index 0000000..a6ebef3
--- /dev/null
+++ b/botan/src/alloc/mem_pool/mem_pool.cpp
@@ -0,0 +1,265 @@
+/*
+* Pooling Allocator
+* (C) 1999-2008 Jack Lloyd
+*     2005 Matthew Gregan
+*     2005-2006 Matt Johnston
+*
+* Distributed under the terms of the Botan license
+*/
+
+#include <botan/mem_pool.h>
+#include <botan/util.h>
+#include <botan/mem_ops.h>
+#include <algorithm>
+#include <exception>
+
+namespace Botan {
+
+namespace {
+
+/*
+* Memory Allocation Exception
+*/
+struct Memory_Exhaustion : public std::bad_alloc
+   {
+   const char* what() const throw()
+      { return "Ran out of memory, allocation failed"; }
+   };
+
+}
+
+/*
+* Memory_Block Constructor
+*/
+Pooling_Allocator::Memory_Block::Memory_Block(void* buf)
+   {
+   buffer = static_cast<byte*>(buf);
+   bitmap = 0;
+   buffer_end = buffer + (BLOCK_SIZE * BITMAP_SIZE);
+   }
+
+/*
+* See if ptr is contained by this block
+*/
+bool Pooling_Allocator::Memory_Block::contains(void* ptr,
+                                               u32bit length) const throw()
+   {
+   return ((buffer <= ptr) &&
+           (buffer_end >= static_cast<byte*>(ptr) + length * BLOCK_SIZE));
+   }
+
+/*
+* Allocate some memory, if possible
+*/
+byte* Pooling_Allocator::Memory_Block::alloc(u32bit n) throw()
+   {
+   if(n == 0 || n > BITMAP_SIZE)
+      return 0;
+
+   if(n == BITMAP_SIZE)
+      {
+      if(bitmap)
+         return 0;
+      else
+         {
+         bitmap = ~bitmap;
+         return buffer;
+         }
+      }
+
+   bitmap_type mask = (static_cast<bitmap_type>(1) << n) - 1;
+   u32bit offset = 0;
+
+   while(bitmap & mask)
+      {
+      mask <<= 1;
+      ++offset;
+
+      if((bitmap & mask) == 0)
+         break;
+      if(mask >> 63)
+         break;
+      }
+
+   if(bitmap & mask)
+      return 0;
+
+   bitmap |= mask;
+   return buffer + offset * BLOCK_SIZE;
+   }
+
+/*
+* Mark this memory as free, if we own it
+*/
+void Pooling_Allocator::Memory_Block::free(void* ptr, u32bit blocks) throw()
+   {
+   clear_mem(static_cast<byte*>(ptr), blocks * BLOCK_SIZE);
+
+   const u32bit offset = (static_cast<byte*>(ptr) - buffer) / BLOCK_SIZE;
+
+   if(offset == 0 && blocks == BITMAP_SIZE)
+      bitmap = ~bitmap;
+   else
+      {
+      for(u32bit j = 0; j != blocks; ++j)
+         bitmap &= ~(static_cast<bitmap_type>(1) << (j+offset));
+      }
+   }
+
+/*
+* Pooling_Allocator Constructor
+*/
+Pooling_Allocator::Pooling_Allocator(Mutex* m) : mutex(m)
+   {
+   last_used = blocks.begin();
+   }
+
+/*
+* Pooling_Allocator Destructor
+*/
+Pooling_Allocator::~Pooling_Allocator()
+   {
+   delete mutex;
+   if(blocks.size())
+      throw Invalid_State("Pooling_Allocator: Never released memory");
+   }
+
+/*
+* Free all remaining memory
+*/
+void Pooling_Allocator::destroy()
+   {
+   Mutex_Holder lock(mutex);
+
+   blocks.clear();
+
+   for(u32bit j = 0; j != allocated.size(); ++j)
+      dealloc_block(allocated[j].first, allocated[j].second);
+   allocated.clear();
+   }
+
+/*
+* Allocation
+*/
+void* Pooling_Allocator::allocate(u32bit n)
+   {
+   const u32bit BITMAP_SIZE = Memory_Block::bitmap_size();
+   const u32bit BLOCK_SIZE = Memory_Block::block_size();
+
+   Mutex_Holder lock(mutex);
+
+   if(n <= BITMAP_SIZE * BLOCK_SIZE)
+      {
+      const u32bit block_no = round_up(n, BLOCK_SIZE) / BLOCK_SIZE;
+
+      byte* mem = allocate_blocks(block_no);
+      if(mem)
+         return mem;
+
+      get_more_core(BOTAN_MEM_POOL_CHUNK_SIZE);
+
+      mem = allocate_blocks(block_no);
+      if(mem)
+         return mem;
+
+      throw Memory_Exhaustion();
+      }
+
+   void* new_buf = alloc_block(n);
+   if(new_buf)
+      return new_buf;
+
+   throw Memory_Exhaustion();
+   }
+
+/*
+* Deallocation
+*/
+void Pooling_Allocator::deallocate(void* ptr, u32bit n)
+   {
+   const u32bit BITMAP_SIZE = Memory_Block::bitmap_size();
+   const u32bit BLOCK_SIZE = Memory_Block::block_size();
+
+   if(ptr == 0 || n == 0)
+      return;
+
+   Mutex_Holder lock(mutex);
+
+   if(n > BITMAP_SIZE * BLOCK_SIZE)
+      dealloc_block(ptr, n);
+   else
+      {
+      const u32bit block_no = round_up(n, BLOCK_SIZE) / BLOCK_SIZE;
+
+      std::vector<Memory_Block>::iterator i =
+         std::lower_bound(blocks.begin(), blocks.end(), Memory_Block(ptr));
+
+      if(i == blocks.end() || !i->contains(ptr, block_no))
+         throw Invalid_State("Pointer released to the wrong allocator");
+
+      i->free(ptr, block_no);
+      }
+   }
+
+/*
+* Try to get some memory from an existing block
+*/
+byte* Pooling_Allocator::allocate_blocks(u32bit n)
+   {
+   if(blocks.empty())
+      return 0;
+
+   std::vector<Memory_Block>::iterator i = last_used;
+
+   do
+      {
+      byte* mem = i->alloc(n);
+      if(mem)
+         {
+         last_used = i;
+         return mem;
+         }
+
+      ++i;
+      if(i == blocks.end())
+         i = blocks.begin();
+      }
+   while(i != last_used);
+
+   return 0;
+   }
+
+/*
+* Allocate more memory for the pool
+*/
+void Pooling_Allocator::get_more_core(u32bit in_bytes)
+   {
+   const u32bit BITMAP_SIZE = Memory_Block::bitmap_size();
+   const u32bit BLOCK_SIZE = Memory_Block::block_size();
+
+   const u32bit TOTAL_BLOCK_SIZE = BLOCK_SIZE * BITMAP_SIZE;
+
+   // upper bound on allocation is 1 MiB
+   in_bytes = std::min<u32bit>(in_bytes, 1024 * 1024);
+
+   const u32bit in_blocks = round_up(in_bytes, BLOCK_SIZE) / TOTAL_BLOCK_SIZE;
+   const u32bit to_allocate = in_blocks * TOTAL_BLOCK_SIZE;
+
+   void* ptr = alloc_block(to_allocate);
+   if(ptr == 0)
+      throw Memory_Exhaustion();
+
+   allocated.push_back(std::make_pair(ptr, to_allocate));
+
+   for(u32bit j = 0; j != in_blocks; ++j)
+      {
+      byte* byte_ptr = static_cast<byte*>(ptr);
+      blocks.push_back(Memory_Block(byte_ptr + j * TOTAL_BLOCK_SIZE));
+      }
+
+   std::sort(blocks.begin(), blocks.end());
+   last_used = std::lower_bound(blocks.begin(), blocks.end(),
+                                Memory_Block(ptr));
+   }
+
+}