src/hb-blob.cc - third_party/harfbuzz - Git at Google

 /*
  * Copyright © 2009  Red Hat, Inc.
  *
  *  This is part of HarfBuzz, a text shaping library.
  *
  * Permission is hereby granted, without written agreement and without
  * license or royalty fees, to use, copy, modify, and distribute this
  * software and its documentation for any purpose, provided that the
  * above copyright notice and the following two paragraphs appear in
  * all copies of this software.
  *
  * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
  * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
  * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
  * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
  * DAMAGE.
  *
  * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
  * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
  * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
  * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
  * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
  *
  * Red Hat Author(s): Behdad Esfahbod
  */

 /* http://www.oracle.com/technetwork/articles/servers-storage-dev/standardheaderfiles-453865.html */
 #ifndef _POSIX_C_SOURCE
 #define _POSIX_C_SOURCE 199309L
 #endif

 #include "hb-private.hh"

 #include "hb-object-private.hh"

 #ifdef HAVE_SYS_MMAN_H
 #ifdef HAVE_UNISTD_H
 #include <unistd.h>
 #endif /* HAVE_UNISTD_H */
 #include <sys/mman.h>
 #endif /* HAVE_SYS_MMAN_H */

 #include <stdio.h>
 #include <errno.h>


 #ifndef HB_DEBUG_BLOB
 #define HB_DEBUG_BLOB (HB_DEBUG+0)
 #endif


 struct hb_blob_t {
   hb_object_header_t header;
   ASSERT_POD ();

   bool immutable;

   const char *data;
   unsigned int length;
   hb_memory_mode_t mode;

   void *user_data;
   hb_destroy_func_t destroy;
 };


 static bool _try_writable (hb_blob_t *blob);

 static void
 _hb_blob_destroy_user_data (hb_blob_t *blob)
 {
   if (blob->destroy) {
     blob->destroy (blob->user_data);
     blob->user_data = nullptr;
     blob->destroy = nullptr;
   }
 }

 /**
  * hb_blob_create: (skip)
  * @data: Pointer to blob data.
  * @length: Length of @data in bytes.
  * @mode: Memory mode for @data.
  * @user_data: Data parameter to pass to @destroy.
  * @destroy: Callback to call when @data is not needed anymore.
  *
  * Creates a new "blob" object wrapping @data.  The @mode parameter is used
  * to negotiate ownership and lifecycle of @data.
  *
  * Return value: New blob, or the empty blob if something failed or if @length is
  * zero.  Destroy with hb_blob_destroy().
  *
  * Since: 0.9.2
  **/
 hb_blob_t *
 hb_blob_create (const char        *data,
 		unsigned int       length,
 		hb_memory_mode_t   mode,
 		void              *user_data,
 		hb_destroy_func_t  destroy)
 {
   hb_blob_t *blob;

   if (!length ||
       length >= 1u << 31 ||
       !(blob = hb_object_create<hb_blob_t> ())) {
     if (destroy)
       destroy (user_data);
     return hb_blob_get_empty ();
   }

   blob->data = data;
   blob->length = length;
   blob->mode = mode;

   blob->user_data = user_data;
   blob->destroy = destroy;

   if (blob->mode == HB_MEMORY_MODE_DUPLICATE) {
     blob->mode = HB_MEMORY_MODE_READONLY;
     if (!_try_writable (blob)) {
       hb_blob_destroy (blob);
       return hb_blob_get_empty ();
     }
   }

   return blob;
 }

 static void
 _hb_blob_destroy (void *data)
 {
   hb_blob_destroy ((hb_blob_t *) data);
 }

 /**
  * hb_blob_create_sub_blob:
  * @parent: Parent blob.
  * @offset: Start offset of sub-blob within @parent, in bytes.
  * @length: Length of sub-blob.
  *
  * Returns a blob that represents a range of bytes in @parent.  The new
  * blob is always created with %HB_MEMORY_MODE_READONLY, meaning that it
  * will never modify data in the parent blob.  The parent data is not
  * expected to be modified, and will result in undefined behavior if it
  * is.
  *
  * Makes @parent immutable.
  *
  * Return value: New blob, or the empty blob if something failed or if
  * @length is zero or @offset is beyond the end of @parent's data.  Destroy
  * with hb_blob_destroy().
  *
  * Since: 0.9.2
  **/
 hb_blob_t *
 hb_blob_create_sub_blob (hb_blob_t    *parent,
 			 unsigned int  offset,
 			 unsigned int  length)
 {
   hb_blob_t *blob;

   if (!length || offset >= parent->length)
     return hb_blob_get_empty ();

   hb_blob_make_immutable (parent);

   blob = hb_blob_create (parent->data + offset,
 			 MIN (length, parent->length - offset),
 			 HB_MEMORY_MODE_READONLY,
 			 hb_blob_reference (parent),
 			 _hb_blob_destroy);

   return blob;
 }

 /**
  * hb_blob_get_empty:
  *
  * Returns the singleton empty blob.
  *
  * See TODO:link object types for more information.
  *
  * Return value: (transfer full): the empty blob.
  *
  * Since: 0.9.2
  **/
 hb_blob_t *
 hb_blob_get_empty (void)
 {
   static const hb_blob_t _hb_blob_nil = {
     HB_OBJECT_HEADER_STATIC,

     true, /* immutable */

     nullptr, /* data */
     0, /* length */
     HB_MEMORY_MODE_READONLY, /* mode */

     nullptr, /* user_data */
     nullptr  /* destroy */
   };

   return const_cast<hb_blob_t *> (&_hb_blob_nil);
 }

 /**
  * hb_blob_reference: (skip)
  * @blob: a blob.
  *
  * Increases the reference count on @blob.
  *
  * See TODO:link object types for more information.
  *
  * Return value: @blob.
  *
  * Since: 0.9.2
  **/
 hb_blob_t *
 hb_blob_reference (hb_blob_t *blob)
 {
   return hb_object_reference (blob);
 }

 /**
  * hb_blob_destroy: (skip)
  * @blob: a blob.
  *
  * Descreases the reference count on @blob, and if it reaches zero, destroys
  * @blob, freeing all memory, possibly calling the destroy-callback the blob
  * was created for if it has not been called already.
  *
  * See TODO:link object types for more information.
  *
  * Since: 0.9.2
  **/
 void
 hb_blob_destroy (hb_blob_t *blob)
 {
   if (!hb_object_destroy (blob)) return;

   _hb_blob_destroy_user_data (blob);

   free (blob);
 }

 /**
  * hb_blob_set_user_data: (skip)
  * @blob: a blob.
  * @key: key for data to set.
  * @data: data to set.
  * @destroy: callback to call when @data is not needed anymore.
  * @replace: whether to replace an existing data with the same key.
  *
  * Return value:
  *
  * Since: 0.9.2
  **/
 hb_bool_t
 hb_blob_set_user_data (hb_blob_t          *blob,
 		       hb_user_data_key_t *key,
 		       void *              data,
 		       hb_destroy_func_t   destroy,
 		       hb_bool_t           replace)
 {
   return hb_object_set_user_data (blob, key, data, destroy, replace);
 }

 /**
  * hb_blob_get_user_data: (skip)
  * @blob: a blob.
  * @key: key for data to get.
  *
  *
  *
  * Return value: (transfer none):
  *
  * Since: 0.9.2
  **/
 void *
 hb_blob_get_user_data (hb_blob_t          *blob,
 		       hb_user_data_key_t *key)
 {
   return hb_object_get_user_data (blob, key);
 }


 /**
  * hb_blob_make_immutable:
  * @blob: a blob.
  *
  *
  *
  * Since: 0.9.2
  **/
 void
 hb_blob_make_immutable (hb_blob_t *blob)
 {
   if (hb_object_is_inert (blob))
     return;

   blob->immutable = true;
 }

 /**
  * hb_blob_is_immutable:
  * @blob: a blob.
  *
  *
  *
  * Return value: TODO
  *
  * Since: 0.9.2
  **/
 hb_bool_t
 hb_blob_is_immutable (hb_blob_t *blob)
 {
   return blob->immutable;
 }


 /**
  * hb_blob_get_length:
  * @blob: a blob.
  *
  *
  *
  * Return value: the length of blob data in bytes.
  *
  * Since: 0.9.2
  **/
 unsigned int
 hb_blob_get_length (hb_blob_t *blob)
 {
   return blob->length;
 }

 /**
  * hb_blob_get_data:
  * @blob: a blob.
  * @length: (out):
  *
  *
  *
  * Returns: (transfer none) (array length=length):
  *
  * Since: 0.9.2
  **/
 const char *
 hb_blob_get_data (hb_blob_t *blob, unsigned int *length)
 {
   if (length)
     *length = blob->length;

   return blob->data;
 }

 /**
  * hb_blob_get_data_writable:
  * @blob: a blob.
  * @length: (out): output length of the writable data.
  *
  * Tries to make blob data writable (possibly copying it) and
  * return pointer to data.
  *
  * Fails if blob has been made immutable, or if memory allocation
  * fails.
  *
  * Returns: (transfer none) (array length=length): Writable blob data,
  * or %NULL if failed.
  *
  * Since: 0.9.2
  **/
 char *
 hb_blob_get_data_writable (hb_blob_t *blob, unsigned int *length)
 {
   if (!_try_writable (blob)) {
     if (length)
       *length = 0;

     return nullptr;
   }

   if (length)
     *length = blob->length;

   return const_cast<char *> (blob->data);
 }


 static hb_bool_t
 _try_make_writable_inplace_unix (hb_blob_t *blob)
 {
 #if defined(HAVE_SYS_MMAN_H) && defined(HAVE_MPROTECT)
   uintptr_t pagesize = -1, mask, length;
   const char *addr;

 #if defined(HAVE_SYSCONF) && defined(_SC_PAGE_SIZE)
   pagesize = (uintptr_t) sysconf (_SC_PAGE_SIZE);
 #elif defined(HAVE_SYSCONF) && defined(_SC_PAGESIZE)
   pagesize = (uintptr_t) sysconf (_SC_PAGESIZE);
 #elif defined(HAVE_GETPAGESIZE)
   pagesize = (uintptr_t) getpagesize ();
 #endif

   if ((uintptr_t) -1L == pagesize) {
     DEBUG_MSG_FUNC (BLOB, blob, "failed to get pagesize: %s", strerror (errno));
     return false;
   }
   DEBUG_MSG_FUNC (BLOB, blob, "pagesize is %lu", (unsigned long) pagesize);

   mask = ~(pagesize-1);
   addr = (const char *) (((uintptr_t) blob->data) & mask);
   length = (const char *) (((uintptr_t) blob->data + blob->length + pagesize-1) & mask)  - addr;
   DEBUG_MSG_FUNC (BLOB, blob,
 		  "calling mprotect on [%p..%p] (%lu bytes)",
 		  addr, addr+length, (unsigned long) length);
   if (-1 == mprotect ((void *) addr, length, PROT_READ | PROT_WRITE)) {
     DEBUG_MSG_FUNC (BLOB, blob, "mprotect failed: %s", strerror (errno));
     return false;
   }

   blob->mode = HB_MEMORY_MODE_WRITABLE;

   DEBUG_MSG_FUNC (BLOB, blob,
 		  "successfully made [%p..%p] (%lu bytes) writable\n",
 		  addr, addr+length, (unsigned long) length);
   return true;
 #else
   return false;
 #endif
 }

 static bool
 _try_writable_inplace (hb_blob_t *blob)
 {
   DEBUG_MSG_FUNC (BLOB, blob, "making writable inplace\n");

   if (_try_make_writable_inplace_unix (blob))
     return true;

   DEBUG_MSG_FUNC (BLOB, blob, "making writable -> FAILED\n");

   /* Failed to make writable inplace, mark that */
   blob->mode = HB_MEMORY_MODE_READONLY;
   return false;
 }

 static bool
 _try_writable (hb_blob_t *blob)
 {
   if (blob->immutable)
     return false;

   if (blob->mode == HB_MEMORY_MODE_WRITABLE)
     return true;

   if (blob->mode == HB_MEMORY_MODE_READONLY_MAY_MAKE_WRITABLE && _try_writable_inplace (blob))
     return true;

   if (blob->mode == HB_MEMORY_MODE_WRITABLE)
     return true;


   DEBUG_MSG_FUNC (BLOB, blob, "current data is -> %p\n", blob->data);

   char *new_data;

   new_data = (char *) malloc (blob->length);
   if (unlikely (!new_data))
     return false;

   DEBUG_MSG_FUNC (BLOB, blob, "dupped successfully -> %p\n", blob->data);

   memcpy (new_data, blob->data, blob->length);
   _hb_blob_destroy_user_data (blob);
   blob->mode = HB_MEMORY_MODE_WRITABLE;
   blob->data = new_data;
   blob->user_data = new_data;
   blob->destroy = free;

   return true;
 }
	/*
	* Copyright © 2009 Red Hat, Inc.
	*
	* This is part of HarfBuzz, a text shaping library.
	*
	* Permission is hereby granted, without written agreement and without
	* license or royalty fees, to use, copy, modify, and distribute this
	* software and its documentation for any purpose, provided that the
	* above copyright notice and the following two paragraphs appear in
	* all copies of this software.
	*
	* IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
	* DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
	* ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
	* IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
	* DAMAGE.
	*
	* THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
	* BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
	* FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
	* ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
	* PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
	*
	* Red Hat Author(s): Behdad Esfahbod
	*/

	/* http://www.oracle.com/technetwork/articles/servers-storage-dev/standardheaderfiles-453865.html */
	#ifndef _POSIX_C_SOURCE
	#define _POSIX_C_SOURCE 199309L
	#endif

	#include "hb-private.hh"

	#include "hb-object-private.hh"

	#ifdef HAVE_SYS_MMAN_H
	#ifdef HAVE_UNISTD_H
	#include <unistd.h>
	#endif /* HAVE_UNISTD_H */
	#include <sys/mman.h>
	#endif /* HAVE_SYS_MMAN_H */

	#include <stdio.h>
	#include <errno.h>



	#ifndef HB_DEBUG_BLOB
	#define HB_DEBUG_BLOB (HB_DEBUG+0)
	#endif


	struct hb_blob_t {
	hb_object_header_t header;
	ASSERT_POD ();

	bool immutable;

	const char *data;
	unsigned int length;
	hb_memory_mode_t mode;

	void *user_data;
	hb_destroy_func_t destroy;
	};


	static bool _try_writable (hb_blob_t *blob);

	static void
	_hb_blob_destroy_user_data (hb_blob_t *blob)
	{
	if (blob->destroy) {
	blob->destroy (blob->user_data);
	blob->user_data = nullptr;
	blob->destroy = nullptr;
	}
	}

	/**
	* hb_blob_create: (skip)
	* @data: Pointer to blob data.
	* @length: Length of @data in bytes.
	* @mode: Memory mode for @data.
	* @user_data: Data parameter to pass to @destroy.
	* @destroy: Callback to call when @data is not needed anymore.
	*
	* Creates a new "blob" object wrapping @data. The @mode parameter is used
	* to negotiate ownership and lifecycle of @data.
	*
	* Return value: New blob, or the empty blob if something failed or if @length is
	* zero. Destroy with hb_blob_destroy().
	*
	* Since: 0.9.2
	**/
	hb_blob_t *
	hb_blob_create (const char *data,
	unsigned int length,
	hb_memory_mode_t mode,
	void *user_data,
	hb_destroy_func_t destroy)
	{
	hb_blob_t *blob;

	if (!length \|\|
	length >= 1u << 31 \|\|
	!(blob = hb_object_create<hb_blob_t> ())) {
	if (destroy)
	destroy (user_data);
	return hb_blob_get_empty ();
	}

	blob->data = data;
	blob->length = length;
	blob->mode = mode;

	blob->user_data = user_data;
	blob->destroy = destroy;

	if (blob->mode == HB_MEMORY_MODE_DUPLICATE) {
	blob->mode = HB_MEMORY_MODE_READONLY;
	if (!_try_writable (blob)) {
	hb_blob_destroy (blob);
	return hb_blob_get_empty ();
	}
	}

	return blob;
	}

	static void
	_hb_blob_destroy (void *data)
	{
	hb_blob_destroy ((hb_blob_t *) data);
	}

	/**
	* hb_blob_create_sub_blob:
	* @parent: Parent blob.
	* @offset: Start offset of sub-blob within @parent, in bytes.
	* @length: Length of sub-blob.
	*
	* Returns a blob that represents a range of bytes in @parent. The new
	* blob is always created with %HB_MEMORY_MODE_READONLY, meaning that it
	* will never modify data in the parent blob. The parent data is not
	* expected to be modified, and will result in undefined behavior if it
	* is.
	*
	* Makes @parent immutable.
	*
	* Return value: New blob, or the empty blob if something failed or if
	* @length is zero or @offset is beyond the end of @parent's data. Destroy
	* with hb_blob_destroy().
	*
	* Since: 0.9.2
	**/
	hb_blob_t *
	hb_blob_create_sub_blob (hb_blob_t *parent,
	unsigned int offset,
	unsigned int length)
	{
	hb_blob_t *blob;

	if (!length \|\| offset >= parent->length)
	return hb_blob_get_empty ();

	hb_blob_make_immutable (parent);

	blob = hb_blob_create (parent->data + offset,
	MIN (length, parent->length - offset),
	HB_MEMORY_MODE_READONLY,
	hb_blob_reference (parent),
	_hb_blob_destroy);

	return blob;
	}

	/**
	* hb_blob_get_empty:
	*
	* Returns the singleton empty blob.
	*
	* See TODO:link object types for more information.
	*
	* Return value: (transfer full): the empty blob.
	*
	* Since: 0.9.2
	**/
	hb_blob_t *
	hb_blob_get_empty (void)
	{
	static const hb_blob_t _hb_blob_nil = {
	HB_OBJECT_HEADER_STATIC,

	true, /* immutable */

	nullptr, /* data */
	0, /* length */
	HB_MEMORY_MODE_READONLY, /* mode */

	nullptr, /* user_data */
	nullptr /* destroy */
	};

	return const_cast<hb_blob_t *> (&_hb_blob_nil);
	}

	/**
	* hb_blob_reference: (skip)
	* @blob: a blob.
	*
	* Increases the reference count on @blob.
	*
	* See TODO:link object types for more information.
	*
	* Return value: @blob.
	*
	* Since: 0.9.2
	**/
	hb_blob_t *
	hb_blob_reference (hb_blob_t *blob)
	{
	return hb_object_reference (blob);
	}

	/**
	* hb_blob_destroy: (skip)
	* @blob: a blob.
	*
	* Descreases the reference count on @blob, and if it reaches zero, destroys
	* @blob, freeing all memory, possibly calling the destroy-callback the blob
	* was created for if it has not been called already.
	*
	* See TODO:link object types for more information.
	*
	* Since: 0.9.2
	**/
	void
	hb_blob_destroy (hb_blob_t *blob)
	{
	if (!hb_object_destroy (blob)) return;

	_hb_blob_destroy_user_data (blob);

	free (blob);
	}

	/**
	* hb_blob_set_user_data: (skip)
	* @blob: a blob.
	* @key: key for data to set.
	* @data: data to set.
	* @destroy: callback to call when @data is not needed anymore.
	* @replace: whether to replace an existing data with the same key.
	*
	* Return value:
	*
	* Since: 0.9.2
	**/
	hb_bool_t
	hb_blob_set_user_data (hb_blob_t *blob,
	hb_user_data_key_t *key,
	void * data,
	hb_destroy_func_t destroy,
	hb_bool_t replace)
	{
	return hb_object_set_user_data (blob, key, data, destroy, replace);
	}

	/**
	* hb_blob_get_user_data: (skip)
	* @blob: a blob.
	* @key: key for data to get.
	*
	*
	*
	* Return value: (transfer none):
	*
	* Since: 0.9.2
	**/
	void *
	hb_blob_get_user_data (hb_blob_t *blob,
	hb_user_data_key_t *key)
	{
	return hb_object_get_user_data (blob, key);
	}


	/**
	* hb_blob_make_immutable:
	* @blob: a blob.
	*
	*
	*
	* Since: 0.9.2
	**/
	void
	hb_blob_make_immutable (hb_blob_t *blob)
	{
	if (hb_object_is_inert (blob))
	return;

	blob->immutable = true;
	}

	/**
	* hb_blob_is_immutable:
	* @blob: a blob.
	*
	*
	*
	* Return value: TODO
	*
	* Since: 0.9.2
	**/
	hb_bool_t
	hb_blob_is_immutable (hb_blob_t *blob)
	{
	return blob->immutable;
	}


	/**
	* hb_blob_get_length:
	* @blob: a blob.
	*
	*
	*
	* Return value: the length of blob data in bytes.
	*
	* Since: 0.9.2
	**/
	unsigned int
	hb_blob_get_length (hb_blob_t *blob)
	{
	return blob->length;
	}

	/**
	* hb_blob_get_data:
	* @blob: a blob.
	* @length: (out):
	*
	*
	*
	* Returns: (transfer none) (array length=length):
	*
	* Since: 0.9.2
	**/
	const char *
	hb_blob_get_data (hb_blob_t blob, unsigned int length)
	{
	if (length)
	*length = blob->length;

	return blob->data;
	}

	/**
	* hb_blob_get_data_writable:
	* @blob: a blob.
	* @length: (out): output length of the writable data.
	*
	* Tries to make blob data writable (possibly copying it) and
	* return pointer to data.
	*
	* Fails if blob has been made immutable, or if memory allocation
	* fails.
	*
	* Returns: (transfer none) (array length=length): Writable blob data,
	* or %NULL if failed.
	*
	* Since: 0.9.2
	**/
	char *
	hb_blob_get_data_writable (hb_blob_t blob, unsigned int length)
	{
	if (!_try_writable (blob)) {
	if (length)
	*length = 0;

	return nullptr;
	}

	if (length)
	*length = blob->length;

	return const_cast<char *> (blob->data);
	}


	static hb_bool_t
	_try_make_writable_inplace_unix (hb_blob_t *blob)
	{
	#if defined(HAVE_SYS_MMAN_H) && defined(HAVE_MPROTECT)
	uintptr_t pagesize = -1, mask, length;
	const char *addr;

	#if defined(HAVE_SYSCONF) && defined(_SC_PAGE_SIZE)
	pagesize = (uintptr_t) sysconf (_SC_PAGE_SIZE);
	#elif defined(HAVE_SYSCONF) && defined(_SC_PAGESIZE)
	pagesize = (uintptr_t) sysconf (_SC_PAGESIZE);
	#elif defined(HAVE_GETPAGESIZE)
	pagesize = (uintptr_t) getpagesize ();
	#endif

	if ((uintptr_t) -1L == pagesize) {
	DEBUG_MSG_FUNC (BLOB, blob, "failed to get pagesize: %s", strerror (errno));
	return false;
	}
	DEBUG_MSG_FUNC (BLOB, blob, "pagesize is %lu", (unsigned long) pagesize);

	mask = ~(pagesize-1);
	addr = (const char *) (((uintptr_t) blob->data) & mask);
	length = (const char *) (((uintptr_t) blob->data + blob->length + pagesize-1) & mask) - addr;
	DEBUG_MSG_FUNC (BLOB, blob,
	"calling mprotect on [%p..%p] (%lu bytes)",
	addr, addr+length, (unsigned long) length);
	if (-1 == mprotect ((void *) addr, length, PROT_READ \| PROT_WRITE)) {
	DEBUG_MSG_FUNC (BLOB, blob, "mprotect failed: %s", strerror (errno));
	return false;
	}

	blob->mode = HB_MEMORY_MODE_WRITABLE;

	DEBUG_MSG_FUNC (BLOB, blob,
	"successfully made [%p..%p] (%lu bytes) writable\n",
	addr, addr+length, (unsigned long) length);
	return true;
	#else
	return false;
	#endif
	}

	static bool
	_try_writable_inplace (hb_blob_t *blob)
	{
	DEBUG_MSG_FUNC (BLOB, blob, "making writable inplace\n");

	if (_try_make_writable_inplace_unix (blob))
	return true;

	DEBUG_MSG_FUNC (BLOB, blob, "making writable -> FAILED\n");

	/* Failed to make writable inplace, mark that */
	blob->mode = HB_MEMORY_MODE_READONLY;
	return false;
	}

	static bool
	_try_writable (hb_blob_t *blob)
	{
	if (blob->immutable)
	return false;

	if (blob->mode == HB_MEMORY_MODE_WRITABLE)
	return true;

	if (blob->mode == HB_MEMORY_MODE_READONLY_MAY_MAKE_WRITABLE && _try_writable_inplace (blob))
	return true;

	if (blob->mode == HB_MEMORY_MODE_WRITABLE)
	return true;


	DEBUG_MSG_FUNC (BLOB, blob, "current data is -> %p\n", blob->data);

	char *new_data;

	new_data = (char *) malloc (blob->length);
	if (unlikely (!new_data))
	return false;

	DEBUG_MSG_FUNC (BLOB, blob, "dupped successfully -> %p\n", blob->data);

	memcpy (new_data, blob->data, blob->length);
	_hb_blob_destroy_user_data (blob);
	blob->mode = HB_MEMORY_MODE_WRITABLE;
	blob->data = new_data;
	blob->user_data = new_data;
	blob->destroy = free;

	return true;
	}