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/*

 * Copyright © 2010 Intel Corporation

 *

 * Permission is hereby granted, free of charge, to any person obtaining a

 * copy of this software and associated documentation files (the "Software"),

 * to deal in the Software without restriction, including without limitation

 * the rights to use, copy, modify, merge, publish, distribute, sublicense,

 * and/or sell copies of the Software, and to permit persons to whom the

 * Software is furnished to do so, subject to the following conditions:

 *

 * The above copyright notice and this permission notice (including the next

 * paragraph) shall be included in all copies or substantial portions of the

 * Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL

 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING

 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER

 * DEALINGS IN THE SOFTWARE.

 */

#include 

#include 

#include 

#include 

#include 

#include 

#include "ralloc.h"

#ifdef __GNUC__

#define likely(x)       __builtin_expect(!!(x),1)

#define unlikely(x)     __builtin_expect(!!(x),0)

#else

#define likely(x)       !!(x)

#define unlikely(x)     !!(x)

#endif

#define CANARY 0x5A1106

struct ralloc_header

{

   /* A canary value used to determine whether a pointer is ralloc'd. */

   unsigned canary;

   struct ralloc_header *parent;

   /* The first child (head of a linked list) */

   struct ralloc_header *child;

   /* Linked list of siblings */

   struct ralloc_header *prev;

   struct ralloc_header *next;

   void (*destructor)(void *);

};

typedef struct ralloc_header ralloc_header;

static void unlink_block(ralloc_header *info);

static void unsafe_free(ralloc_header *info);

static ralloc_header *

get_header(const void *ptr)

{

   ralloc_header *info = (ralloc_header *) (((char *) ptr) -

					    sizeof(ralloc_header));

   assert(info->canary == CANARY);

   return info;

}

#define PTR_FROM_HEADER(info) (((char *) info) + sizeof(ralloc_header))

static void

add_child(ralloc_header *parent, ralloc_header *info)

{

   if (parent != NULL) {

      info->parent = parent;

      info->next = parent->child;

      parent->child = info;

      if (info->next != NULL)

	 info->next->prev = info;

   }

}

void *

ralloc_context(const void *ctx)

{

   return ralloc_size(ctx, 0);

}

void *

ralloc_size(const void *ctx, size_t size)

{

   void *block = calloc(1, size + sizeof(ralloc_header));

   ralloc_header *info = (ralloc_header *) block;

   ralloc_header *parent = ctx != NULL ? get_header(ctx) : NULL;

   add_child(parent, info);

   info->canary = CANARY;

   return PTR_FROM_HEADER(info);

}

void *

rzalloc_size(const void *ctx, size_t size)

{

   void *ptr = ralloc_size(ctx, size);

   if (likely(ptr != NULL))

      memset(ptr, 0, size);

   return ptr;

}

/* helper function - assumes ptr != NULL */

static void *

resize(void *ptr, size_t size)

{

   ralloc_header *child, *old, *info;

   old = get_header(ptr);

   info = realloc(old, size + sizeof(ralloc_header));

   if (info == NULL)

      return NULL;

   /* Update parent and sibling's links to the reallocated node. */

   if (info != old && info->parent != NULL) {

      if (info->parent->child == old)

	 info->parent->child = info;

      if (info->prev != NULL)

	 info->prev->next = info;

      if (info->next != NULL)

	 info->next->prev = info;

   }

   /* Update child->parent links for all children */

   for (child = info->child; child != NULL; child = child->next)

      child->parent = info;

   return PTR_FROM_HEADER(info);

}

void *

reralloc_size(const void *ctx, void *ptr, size_t size)

{

   if (unlikely(ptr == NULL))

      return ralloc_size(ctx, size);

   assert(ralloc_parent(ptr) == ctx);

   return resize(ptr, size);

}

void *

ralloc_array_size(const void *ctx, size_t size, unsigned count)

{

   if (count > SIZE_MAX/size)

      return NULL;

   return ralloc_size(ctx, size * count);

}

void *

rzalloc_array_size(const void *ctx, size_t size, unsigned count)

{

   if (count > SIZE_MAX/size)

      return NULL;

   return rzalloc_size(ctx, size * count);

}

void *

reralloc_array_size(const void *ctx, void *ptr, size_t size, unsigned count)

{

   if (count > SIZE_MAX/size)

      return NULL;

   return reralloc_size(ctx, ptr, size * count);

}

void

ralloc_free(void *ptr)

{

   ralloc_header *info;

   if (ptr == NULL)

      return;

   info = get_header(ptr);

   unlink_block(info);

   unsafe_free(info);

}

static void

unlink_block(ralloc_header *info)

{

   /* Unlink from parent & siblings */

   if (info->parent != NULL) {

      if (info->parent->child == info)

	 info->parent->child = info->next;

      if (info->prev != NULL)

	 info->prev->next = info->next;

      if (info->next != NULL)

	 info->next->prev = info->prev;

   }

   info->parent = NULL;

   info->prev = NULL;

   info->next = NULL;

}

static void

unsafe_free(ralloc_header *info)

{

   /* Recursively free any children...don't waste time unlinking them. */

   ralloc_header *temp;

   while (info->child != NULL) {

      temp = info->child;

      info->child = temp->next;

      unsafe_free(temp);

   }

   /* Free the block itself.  Call the destructor first, if any. */

   if (info->destructor != NULL)

      info->destructor(PTR_FROM_HEADER(info));

   free(info);

}

void

ralloc_steal(const void *new_ctx, void *ptr)

{

   ralloc_header *info, *parent;

   if (unlikely(ptr == NULL))

      return;

   info = get_header(ptr);

   parent = get_header(new_ctx);

   unlink_block(info);

   add_child(parent, info);

}

void *

ralloc_parent(const void *ptr)

{

   ralloc_header *info;

   if (unlikely(ptr == NULL))

      return NULL;

   info = get_header(ptr);

   return PTR_FROM_HEADER(info->parent);

}

static void *autofree_context = NULL;

static void

autofree(void)

{

   ralloc_free(autofree_context);

}

void *

ralloc_autofree_context(void)

{

   if (unlikely(autofree_context == NULL)) {

      autofree_context = ralloc_context(NULL);

      atexit(autofree);

   }

   return autofree_context;

}

void

ralloc_set_destructor(const void *ptr, void(*destructor)(void *))

{

   ralloc_header *info = get_header(ptr);

   info->destructor = destructor;

}

char *

ralloc_strdup(const void *ctx, const char *str)

{

   size_t n;

   char *ptr;

   if (unlikely(str == NULL))

      return NULL;

   n = strlen(str);

   ptr = ralloc_array(ctx, char, n + 1);

   memcpy(ptr, str, n);

   ptr[n] = '\0';

   return ptr;

}

char *

ralloc_strndup(const void *ctx, const char *str, size_t max)

{

   size_t n;

   char *ptr;

   if (unlikely(str == NULL))

      return NULL;

   n = strlen(str);

   if (n > max)

      n = max;

   ptr = ralloc_array(ctx, char, n + 1);

   memcpy(ptr, str, n);

   ptr[n] = '\0';

   return ptr;

}

/* helper routine for strcat/strncat - n is the exact amount to copy */

static bool

cat(char **dest, const char *str, size_t n)

{

   char *both;

   size_t existing_length;

   assert(dest != NULL && *dest != NULL);

   existing_length = strlen(*dest);

   both = resize(*dest, existing_length + n + 1);

   if (unlikely(both == NULL))

      return false;

   memcpy(both + existing_length, str, n);

   both[existing_length + n] = '\0';

   *dest = both;

   return true;

}

bool

ralloc_strcat(char **dest, const char *str)

{

   return cat(dest, str, strlen(str));

}

bool

ralloc_strncat(char **dest, const char *str, size_t n)

{

   /* Clamp n to the string length */

   size_t str_length = strlen(str);

   if (str_length < n)

      n = str_length;

   return cat(dest, str, n);

}

char *

ralloc_asprintf(const void *ctx, const char *fmt, ...)

{

   char *ptr;

   va_list args;

   va_start(args, fmt);

   ptr = ralloc_vasprintf(ctx, fmt, args);

   va_end(args);

   return ptr;

}

/* Return the length of the string that would be generated by a printf-style

 * format and argument list, not including the \0 byte.

 */

static size_t

printf_length(const char *fmt, va_list untouched_args)

{

   int size;

   char junk;

   /* Make a copy of the va_list so the original caller can still use it */

   va_list args;

   va_copy(args, untouched_args);

   size = vsnprintf(&junk, 1, fmt, args);

   assert(size >= 0);

   va_end(args);

   return size;

}

char *

ralloc_vasprintf(const void *ctx, const char *fmt, va_list args)

{

   size_t size = printf_length(fmt, args) + 1;

   char *ptr = ralloc_size(ctx, size);

   if (ptr != NULL)

      vsnprintf(ptr, size, fmt, args);

   return ptr;

}

bool

ralloc_asprintf_append(char **str, const char *fmt, ...)

{

   bool success;

   va_list args;

   va_start(args, fmt);

   success = ralloc_vasprintf_append(str, fmt, args);

   va_end(args);

   return success;

}

bool

ralloc_vasprintf_append(char **str, const char *fmt, va_list args)

{

   size_t existing_length, new_length;

   char *ptr;

   assert(str != NULL);

   if (unlikely(*str == NULL)) {

      // Assuming a NULL context is probably bad, but it's expected behavior.

      *str = ralloc_vasprintf(NULL, fmt, args);

      return true;

   }

   existing_length = strlen(*str);

   new_length = printf_length(fmt, args);

   ptr = resize(*str, existing_length + new_length + 1);

   if (unlikely(ptr == NULL))

      return false;

   vsnprintf(ptr + existing_length, new_length + 1, fmt, args);

   *str = ptr;

   return true;

}