/*********************************************************/

/*  ptycon: a pty-console bridge                         */

/*  Copyright (C) 2016--2017  SysDeer Technologies, LLC  */

/*  Released under GPLv2 and GPLv3; see COPYING.PTYCON.  */

/*********************************************************/

#include <stddef.h>

#include <ntapi/ntapi.h>

#include "ptycon_memfn_impl.h"

#include "ptycon_driver_impl.h"

void * ptyc_calloc(size_t n, size_t size)

{

	struct ptyc_memory_block block;

	if (!n || (size > (size_t)(-1) / n))

		return 0;

	size *= n;

	size += 0xf;

	size &= ~(size_t)0xf;

	block.addr = 0;

	block.size = size + sizeof(block);

	if (ntapi->zw_allocate_virtual_memory(

			NT_CURRENT_PROCESS_HANDLE,

			&block.addr,

			0,

			&block.size,

			NT_MEM_COMMIT,

			NT_PAGE_READWRITE))

		return 0;

	block.used  = size;

	block.avail = block.size - block.used;

	return (char *)block.addr + offsetof(struct ptyc_memory_block,buffer);

}

void * ptyc_balloc(

	struct ptyc_memory_block * cache,

	struct ptyc_memory_block * block,

	size_t n, size_t size)

{

	char * baddr;

	void * addr = 0;

	if (!n || (size > (size_t)(-1) / n))

		return 0;

	if (!cache || !cache->addr)

		addr = ptyc_calloc(n,size);

	size *= n;

	size += 0xf;

	size &= ~(size_t)0xf;

	if (size < block->avail)

		addr = ptyc_calloc(n,size);

	/* newly allocated block? */

	if (addr) {

		baddr  = addr;

		baddr -= offsetof(struct ptyc_memory_block,buffer);

		ntapi->tt_aligned_block_memcpy(

			(uintptr_t *)block,

			(uintptr_t *)baddr,

			sizeof(*block));

		return addr;

	}

	/* cache */

	addr = &block->buffer[block->used / sizeof(size_t)];

	block->used  += size;

	block->avail -= size;

	return addr;

}

void ptyc_free(void * addr)

{

	struct ptyc_memory_block block;

	block.addr = addr;

	block.size = 0;

	ntapi->zw_free_virtual_memory(

		NT_CURRENT_PROCESS_HANDLE,

		&block.addr,

		&block.size,

		NT_MEM_RELEASE);

}