sourcemod/sourcepawn/compiler/memory-buffer.h
2014-08-23 13:26:03 -07:00

104 lines
2.5 KiB
C++

// vim: set sts=2 ts=8 sw=2 tw=99 et:
//
// Copyright (C) 2012-2014 AlliedModders LLC, David Anderson
//
// This file is part of SourcePawn.
//
// SourcePawn is free software: you can redistribute it and/or modify it under
// the terms of the GNU General Public License as published by the Free
// Software Foundation, either version 3 of the License, or (at your option)
// any later version.
//
// SourcePawn is distributed in the hope that it will be useful, but WITHOUT ANY
// WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
// FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License along with
// SourcePawn. If not, see http://www.gnu.org/licenses/.
#ifndef _include_sp_memory_buffer_h_
#define _include_sp_memory_buffer_h_
#include <stdio.h>
#include <am-utility.h>
#include "smx-builder.h"
// Interface for SmxBuilder to blit bytes.
class ISmxBuffer
{
public:
virtual bool write(const void *bytes, size_t len) = 0;
virtual size_t pos() const = 0;
};
// An in-memory buffer for SmxBuilder.
class MemoryBuffer : public ISmxBuffer
{
static const size_t kDefaultSize = 4096;
public:
MemoryBuffer() {
buffer_ = (uint8_t *)calloc(kDefaultSize, 1);
pos_ = buffer_;
end_ = buffer_ + kDefaultSize;
}
~MemoryBuffer() {
free(buffer_);
}
bool write(const void *bytes, size_t len) KE_OVERRIDE {
if (pos_ + len > end_)
grow(len);
memcpy(pos_, bytes, len);
pos_ += len;
return true;
}
size_t pos() const KE_OVERRIDE {
return pos_ - buffer_;
}
uint8_t *bytes() const {
return buffer_;
}
size_t size() const {
return pos();
}
void rewind(size_t newpos) {
assert(newpos < pos());
pos_ = buffer_ + newpos;
}
private:
void grow(size_t len) {
if (!ke::IsUintPtrAddSafe(pos(), len)) {
fprintf(stderr, "Allocation overflow!\n");
abort();
}
size_t new_maxsize = end_ - buffer_;
while (pos() + len > new_maxsize) {
if (!ke::IsUintPtrMultiplySafe(new_maxsize, 2)) {
fprintf(stderr, "Allocation overflow!\n");
abort();
}
new_maxsize *= 2;
}
uint8_t *newbuffer = (uint8_t *)realloc(buffer_, new_maxsize);
if (!newbuffer) {
fprintf(stderr, "Out of memory!\n");
abort();
}
pos_ = newbuffer + (pos_ - buffer_);
end_ = newbuffer + new_maxsize;
buffer_ = newbuffer;
}
private:
uint8_t *buffer_;
uint8_t *pos_;
uint8_t *end_;
};
#endif // _include_sp_memory_buffer_h_