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src/util/ralloc.h

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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.
+ */
+
+/**
+ * \file ralloc.h
+ *
+ * ralloc: a recursive memory allocator
+ *
+ * The ralloc memory allocator creates a hierarchy of allocated
+ * objects. Every allocation is in reference to some parent, and
+ * every allocated object can in turn be used as the parent of a
+ * subsequent allocation. This allows for extremely convenient
+ * discarding of an entire tree/sub-tree of allocations by calling
+ * ralloc_free on any particular object to free it and all of its
+ * children.
+ *
+ * The conceptual working of ralloc was directly inspired by Andrew
+ * Tridgell's talloc, but ralloc is an independent implementation
+ * released under the MIT license and tuned for Mesa.
+ *
+ * talloc is more sophisticated than ralloc in that it includes reference
+ * counting and useful debugging features.  However, it is released under
+ * a non-permissive open source license.
+ */
+
+#ifndef RALLOC_H
+#define RALLOC_H
+
+#include <stddef.h>
+#include <stdarg.h>
+#include <stdbool.h>
+
+#include "macros.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * \def ralloc(ctx, type)
+ * Allocate a new object chained off of the given context.
+ *
+ * This is equivalent to:
+ * \code
+ * ((type *) ralloc_size(ctx, sizeof(type))
+ * \endcode
+ */
+#define ralloc(ctx, type)  ((type *) ralloc_size(ctx, sizeof(type)))
+
+/**
+ * \def rzalloc(ctx, type)
+ * Allocate a new object out of the given context and initialize it to zero.
+ *
+ * This is equivalent to:
+ * \code
+ * ((type *) rzalloc_size(ctx, sizeof(type))
+ * \endcode
+ */
+#define rzalloc(ctx, type) ((type *) rzalloc_size(ctx, sizeof(type)))
+
+/**
+ * Allocate a new ralloc context.
+ *
+ * While any ralloc'd pointer can be used as a context, sometimes it is useful
+ * to simply allocate a context with no associated memory.
+ *
+ * It is equivalent to:
+ * \code
+ * ((type *) ralloc_size(ctx, 0)
+ * \endcode
+ */
+void *ralloc_context(const void *ctx);
+
+/**
+ * Allocate memory chained off of the given context.
+ *
+ * This is the core allocation routine which is used by all others.  It
+ * simply allocates storage for \p size bytes and returns the pointer,
+ * similar to \c malloc.
+ */
+void *ralloc_size(const void *ctx, size_t size) MALLOCLIKE;
+
+/**
+ * Allocate zero-initialized memory chained off of the given context.
+ *
+ * This is similar to \c calloc with a size of 1.
+ */
+void *rzalloc_size(const void *ctx, size_t size) MALLOCLIKE;
+
+/**
+ * Resize a piece of ralloc-managed memory, preserving data.
+ *
+ * Similar to \c realloc.  Unlike C89, passing 0 for \p size does not free the
+ * memory.  Instead, it resizes it to a 0-byte ralloc context, just like
+ * calling ralloc_size(ctx, 0).  This is different from talloc.
+ *
+ * \param ctx  The context to use for new allocation.  If \p ptr != NULL,
+ *             it must be the same as ralloc_parent(\p ptr).
+ * \param ptr  Pointer to the memory to be resized.  May be NULL.
+ * \param size The amount of memory to allocate, in bytes.
+ */
+void *reralloc_size(const void *ctx, void *ptr, size_t size);
+
+/**
+ * Resize a ralloc-managed array, preserving data and initializing any newly
+ * allocated data to zero.
+ *
+ * Similar to \c realloc.  Unlike C89, passing 0 for \p size does not free the
+ * memory.  Instead, it resizes it to a 0-byte ralloc context, just like
+ * calling ralloc_size(ctx, 0).  This is different from talloc.
+ *
+ * \param ctx        The context to use for new allocation.  If \p ptr != NULL,
+ *                   it must be the same as ralloc_parent(\p ptr).
+ * \param ptr        Pointer to the memory to be resized.  May be NULL.
+ * \param old_size   The amount of memory in the previous allocation, in bytes.
+ * \param new_size   The amount of memory to allocate, in bytes.
+ */
+void *rerzalloc_size(const void *ctx, void *ptr,
+                     size_t old_size, size_t new_size);
+
+/// \defgroup array Array Allocators @{
+
+/**
+ * \def ralloc_array(ctx, type, count)
+ * Allocate an array of objects chained off the given context.
+ *
+ * Similar to \c calloc, but does not initialize the memory to zero.
+ *
+ * More than a convenience function, this also checks for integer overflow when
+ * multiplying \c sizeof(type) and \p count.  This is necessary for security.
+ *
+ * This is equivalent to:
+ * \code
+ * ((type *) ralloc_array_size(ctx, sizeof(type), count)
+ * \endcode
+ */
+#define ralloc_array(ctx, type, count) \
+   ((type *) ralloc_array_size(ctx, sizeof(type), count))
+
+/**
+ * \def rzalloc_array(ctx, type, count)
+ * Allocate a zero-initialized array chained off the given context.
+ *
+ * Similar to \c calloc.
+ *
+ * More than a convenience function, this also checks for integer overflow when
+ * multiplying \c sizeof(type) and \p count.  This is necessary for security.
+ *
+ * This is equivalent to:
+ * \code
+ * ((type *) rzalloc_array_size(ctx, sizeof(type), count)
+ * \endcode
+ */
+#define rzalloc_array(ctx, type, count) \
+   ((type *) rzalloc_array_size(ctx, sizeof(type), count))
+
+/**
+ * \def reralloc(ctx, ptr, type, count)
+ * Resize a ralloc-managed array, preserving data.
+ *
+ * Similar to \c realloc.  Unlike C89, passing 0 for \p size does not free the
+ * memory.  Instead, it resizes it to a 0-byte ralloc context, just like
+ * calling ralloc_size(ctx, 0).  This is different from talloc.
+ *
+ * More than a convenience function, this also checks for integer overflow when
+ * multiplying \c sizeof(type) and \p count.  This is necessary for security.
+ *
+ * \param ctx   The context to use for new allocation.  If \p ptr != NULL,
+ *              it must be the same as ralloc_parent(\p ptr).
+ * \param ptr   Pointer to the array to be resized.  May be NULL.
+ * \param type  The element type.
+ * \param count The number of elements to allocate.
+ */
+#define reralloc(ctx, ptr, type, count) \
+   ((type *) reralloc_array_size(ctx, ptr, sizeof(type), count))
+
+/**
+ * \def rerzalloc(ctx, ptr, type, count)
+ * Resize a ralloc-managed array, preserving data and initializing any newly
+ * allocated data to zero.
+ *
+ * Similar to \c realloc.  Unlike C89, passing 0 for \p size does not free the
+ * memory.  Instead, it resizes it to a 0-byte ralloc context, just like
+ * calling ralloc_size(ctx, 0).  This is different from talloc.
+ *
+ * More than a convenience function, this also checks for integer overflow when
+ * multiplying \c sizeof(type) and \p count.  This is necessary for security.
+ *
+ * \param ctx        The context to use for new allocation.  If \p ptr != NULL,
+ *                   it must be the same as ralloc_parent(\p ptr).
+ * \param ptr        Pointer to the array to be resized.  May be NULL.
+ * \param type       The element type.
+ * \param old_count  The number of elements in the previous allocation.
+ * \param new_count  The number of elements to allocate.
+ */
+#define rerzalloc(ctx, ptr, type, old_count, new_count) \
+   ((type *) rerzalloc_array_size(ctx, ptr, sizeof(type), old_count, new_count))
+
+/**
+ * Allocate memory for an array chained off the given context.
+ *
+ * Similar to \c calloc, but does not initialize the memory to zero.
+ *
+ * More than a convenience function, this also checks for integer overflow when
+ * multiplying \p size and \p count.  This is necessary for security.
+ */
+void *ralloc_array_size(const void *ctx, size_t size, unsigned count) MALLOCLIKE;
+
+/**
+ * Allocate a zero-initialized array chained off the given context.
+ *
+ * Similar to \c calloc.
+ *
+ * More than a convenience function, this also checks for integer overflow when
+ * multiplying \p size and \p count.  This is necessary for security.
+ */
+void *rzalloc_array_size(const void *ctx, size_t size, unsigned count) MALLOCLIKE;
+
+/**
+ * Resize a ralloc-managed array, preserving data.
+ *
+ * Similar to \c realloc.  Unlike C89, passing 0 for \p size does not free the
+ * memory.  Instead, it resizes it to a 0-byte ralloc context, just like
+ * calling ralloc_size(ctx, 0).  This is different from talloc.
+ *
+ * More than a convenience function, this also checks for integer overflow when
+ * multiplying \c sizeof(type) and \p count.  This is necessary for security.
+ *
+ * \param ctx   The context to use for new allocation.  If \p ptr != NULL,
+ *              it must be the same as ralloc_parent(\p ptr).
+ * \param ptr   Pointer to the array to be resized.  May be NULL.
+ * \param size  The size of an individual element.
+ * \param count The number of elements to allocate.
+ *
+ * \return True unless allocation failed.
+ */
+void *reralloc_array_size(const void *ctx, void *ptr, size_t size,
+			  unsigned count);
+
+/**
+ * Resize a ralloc-managed array, preserving data and initializing any newly
+ * allocated data to zero.
+ *
+ * Similar to \c realloc.  Unlike C89, passing 0 for \p size does not free the
+ * memory.  Instead, it resizes it to a 0-byte ralloc context, just like
+ * calling ralloc_size(ctx, 0).  This is different from talloc.
+ *
+ * More than a convenience function, this also checks for integer overflow when
+ * multiplying \c sizeof(type) and \p count.  This is necessary for security.
+ *
+ * \param ctx        The context to use for new allocation.  If \p ptr != NULL,
+ *                   it must be the same as ralloc_parent(\p ptr).
+ * \param ptr        Pointer to the array to be resized.  May be NULL.
+ * \param size       The size of an individual element.
+ * \param old_count  The number of elements in the previous allocation.
+ * \param new_count  The number of elements to allocate.
+ *
+ * \return True unless allocation failed.
+ */
+void *rerzalloc_array_size(const void *ctx, void *ptr, size_t size,
+			   unsigned old_count, unsigned new_count);
+/// @}
+
+/**
+ * Free a piece of ralloc-managed memory.
+ *
+ * This will also free the memory of any children allocated this context.
+ */
+void ralloc_free(void *ptr);
+
+/**
+ * "Steal" memory from one context, changing it to another.
+ *
+ * This changes \p ptr's context to \p new_ctx.  This is quite useful if
+ * memory is allocated out of a temporary context.
+ */
+void ralloc_steal(const void *new_ctx, void *ptr);
+
+/**
+ * Reparent all children from one context to another.
+ *
+ * This effectively calls ralloc_steal(new_ctx, child) for all children of \p old_ctx.
+ */
+void ralloc_adopt(const void *new_ctx, void *old_ctx);
+
+/**
+ * Return the given pointer's ralloc context.
+ */
+void *ralloc_parent(const void *ptr);
+
+/**
+ * Set a callback to occur just before an object is freed.
+ */
+void ralloc_set_destructor(const void *ptr, void(*destructor)(void *));
+
+/**
+ * Duplicate memory, allocating the memory from the given context.
+ */
+void *ralloc_memdup(const void *ctx, const void *mem, size_t n) MALLOCLIKE;
+
+/// \defgroup array String Functions @{
+/**
+ * Duplicate a string, allocating the memory from the given context.
+ */
+char *ralloc_strdup(const void *ctx, const char *str) MALLOCLIKE;
+
+/**
+ * Duplicate a string, allocating the memory from the given context.
+ *
+ * Like \c strndup, at most \p n characters are copied.  If \p str is longer
+ * than \p n characters, \p n are copied, and a termining \c '\0' byte is added.
+ */
+char *ralloc_strndup(const void *ctx, const char *str, size_t n) MALLOCLIKE;
+
+/**
+ * Concatenate two strings, allocating the necessary space.
+ *
+ * This appends \p str to \p *dest, similar to \c strcat, using ralloc_resize
+ * to expand \p *dest to the appropriate size.  \p dest will be updated to the
+ * new pointer unless allocation fails.
+ *
+ * The result will always be null-terminated.
+ *
+ * \return True unless allocation failed.
+ */
+bool ralloc_strcat(char **dest, const char *str);
+
+/**
+ * Concatenate two strings, allocating the necessary space.
+ *
+ * This appends at most \p n bytes of \p str to \p *dest, using ralloc_resize
+ * to expand \p *dest to the appropriate size.  \p dest will be updated to the
+ * new pointer unless allocation fails.
+ *
+ * The result will always be null-terminated; \p str does not need to be null
+ * terminated if it is longer than \p n.
+ *
+ * \return True unless allocation failed.
+ */
+bool ralloc_strncat(char **dest, const char *str, size_t n);
+
+/**
+ * Concatenate two strings, allocating the necessary space.
+ *
+ * This appends \p n bytes of \p str to \p *dest, using ralloc_resize
+ * to expand \p *dest to the appropriate size.  \p dest will be updated to the
+ * new pointer unless allocation fails.
+ *
+ * The result will always be null-terminated.
+ *
+ * This function differs from ralloc_strcat() and ralloc_strncat() in that it
+ * does not do any strlen() calls which can become costly on large strings.
+ *
+ * \return True unless allocation failed.
+ */
+bool
+ralloc_str_append(char **dest, const char *str,
+                  size_t existing_length, size_t str_size);
+
+/**
+ * Print to a string.
+ *
+ * This is analogous to \c sprintf, but allocates enough space (using \p ctx
+ * as the context) for the resulting string.
+ *
+ * \return The newly allocated string.
+ */
+char *ralloc_asprintf (const void *ctx, const char *fmt, ...) PRINTFLIKE(2, 3) MALLOCLIKE;
+
+/**
+ * Print to a string, given a va_list.
+ *
+ * This is analogous to \c vsprintf, but allocates enough space (using \p ctx
+ * as the context) for the resulting string.
+ *
+ * \return The newly allocated string.
+ */
+char *ralloc_vasprintf(const void *ctx, const char *fmt, va_list args) MALLOCLIKE;
+
+/**
+ * Rewrite the tail of an existing string, starting at a given index.
+ *
+ * Overwrites the contents of *str starting at \p start with newly formatted
+ * text, including a new null-terminator.  Allocates more memory as necessary.
+ *
+ * This can be used to append formatted text when the length of the existing
+ * string is already known, saving a strlen() call.
+ *
+ * \sa ralloc_asprintf_append
+ *
+ * \param str   The string to be updated.
+ * \param start The index to start appending new data at.
+ * \param fmt   A printf-style formatting string
+ *
+ * \p str will be updated to the new pointer unless allocation fails.
+ * \p start will be increased by the length of the newly formatted text.
+ *
+ * \return True unless allocation failed.
+ */
+bool ralloc_asprintf_rewrite_tail(char **str, size_t *start,
+				  const char *fmt, ...)
+				  PRINTFLIKE(3, 4);
+
+/**
+ * Rewrite the tail of an existing string, starting at a given index.
+ *
+ * Overwrites the contents of *str starting at \p start with newly formatted
+ * text, including a new null-terminator.  Allocates more memory as necessary.
+ *
+ * This can be used to append formatted text when the length of the existing
+ * string is already known, saving a strlen() call.
+ *
+ * \sa ralloc_vasprintf_append
+ *
+ * \param str   The string to be updated.
+ * \param start The index to start appending new data at.
+ * \param fmt   A printf-style formatting string
+ * \param args  A va_list containing the data to be formatted
+ *
+ * \p str will be updated to the new pointer unless allocation fails.
+ * \p start will be increased by the length of the newly formatted text.
+ *
+ * \return True unless allocation failed.
+ */
+bool ralloc_vasprintf_rewrite_tail(char **str, size_t *start, const char *fmt,
+				   va_list args);
+
+/**
+ * Append formatted text to the supplied string.
+ *
+ * This is equivalent to
+ * \code
+ * ralloc_asprintf_rewrite_tail(str, strlen(*str), fmt, ...)
+ * \endcode
+ *
+ * \sa ralloc_asprintf
+ * \sa ralloc_asprintf_rewrite_tail
+ * \sa ralloc_strcat
+ *
+ * \p str will be updated to the new pointer unless allocation fails.
+ *
+ * \return True unless allocation failed.
+ */
+bool ralloc_asprintf_append (char **str, const char *fmt, ...)
+			     PRINTFLIKE(2, 3);
+
+/**
+ * Append formatted text to the supplied string, given a va_list.
+ *
+ * This is equivalent to
+ * \code
+ * ralloc_vasprintf_rewrite_tail(str, strlen(*str), fmt, args)
+ * \endcode
+ *
+ * \sa ralloc_vasprintf
+ * \sa ralloc_vasprintf_rewrite_tail
+ * \sa ralloc_strcat
+ *
+ * \p str will be updated to the new pointer unless allocation fails.
+ *
+ * \return True unless allocation failed.
+ */
+bool ralloc_vasprintf_append(char **str, const char *fmt, va_list args);
+/// @}
+
+/**
+ * Estimate the memory usage in bytes of a ralloc context, recursively including
+ * all of its child counts. This is only available in debug builds as release
+ * builds do not track size information. It is providing as a aid for debugging
+ * memory bloat.
+ */
+#ifndef NDEBUG
+size_t ralloc_total_size(const void *ptr);
+#endif
+
+typedef struct gc_ctx gc_ctx;
+
+/**
+ * Allocate a new garbage collection context. The children of the
+ * context are not necessarily ralloc'd pointers and cannot be stolen to a ralloc context. Instead,
+ * The user should use the mark-and-sweep interface below to free any unused children. Under the
+ * hood, this restriction lets us manage allocations ourselves, using a freelist. This means that
+ * GC contexts should be used for scenarios where there are many allocations and frees, most of
+ * which use only a few different sizes.
+ */
+gc_ctx *gc_context(const void *parent);
+
+#define gc_alloc(ctx, type, count) gc_alloc_size(ctx, sizeof(type) * (count), alignof(type))
+#define gc_zalloc(ctx, type, count) gc_zalloc_size(ctx, sizeof(type) * (count), alignof(type))
+
+#define gc_alloc_zla(ctx, type, type2, count) \
+   gc_alloc_size(ctx, sizeof(type) + sizeof(type2) * (count), MAX2(alignof(type), alignof(type2)))
+#define gc_zalloc_zla(ctx, type, type2, count) \
+   gc_zalloc_size(ctx, sizeof(type) + sizeof(type2) * (count), MAX2(alignof(type), alignof(type2)))
+
+void *gc_alloc_size(gc_ctx *ctx, size_t size, size_t alignment) MALLOCLIKE;
+void *gc_zalloc_size(gc_ctx *ctx, size_t size, size_t alignment) MALLOCLIKE;
+void gc_free(void *ptr);
+gc_ctx *gc_get_context(void *ptr);
+
+void gc_sweep_start(gc_ctx *ctx);
+void gc_mark_live(gc_ctx *ctx, const void *mem);
+void gc_sweep_end(gc_ctx *ctx);
+
+/**
+ * Declare C++ new and delete operators which use ralloc.
+ *
+ * Placing this macro in the body of a class makes it possible to do:
+ *
+ * TYPE *var = new(mem_ctx) TYPE(...);
+ * delete var;
+ *
+ * which is more idiomatic in C++ than calling ralloc.
+ */
+#define DECLARE_RALLOC_CXX_OPERATORS_TEMPLATE(TYPE, ALLOC_FUNC)          \
+private:                                                                 \
+   static void _ralloc_destructor(void *p)                               \
+   {                                                                     \
+      reinterpret_cast<TYPE *>(p)->TYPE::~TYPE();                        \
+   }                                                                     \
+public:                                                                  \
+   static void* operator new(size_t size, void *mem_ctx)                 \
+   {                                                                     \
+      void *p = ALLOC_FUNC(mem_ctx, size);                               \
+      assert(p != NULL);                                                 \
+      if (!HAS_TRIVIAL_DESTRUCTOR(TYPE))                                 \
+         ralloc_set_destructor(p, _ralloc_destructor);                   \
+      return p;                                                          \
+   }                                                                     \
+                                                                         \
+   static void operator delete(void *p)                                  \
+   {                                                                     \
+      /* The object's destructor is guaranteed to have already been      \
+       * called by the delete operator at this point -- Make sure it's   \
+       * not called again.                                               \
+       */                                                                \
+      if (!HAS_TRIVIAL_DESTRUCTOR(TYPE))                                 \
+         ralloc_set_destructor(p, NULL);                                 \
+      ralloc_free(p);                                                    \
+   }
+
+#define DECLARE_RALLOC_CXX_OPERATORS(type) \
+   DECLARE_RALLOC_CXX_OPERATORS_TEMPLATE(type, ralloc_size)
+
+#define DECLARE_RZALLOC_CXX_OPERATORS(type) \
+   DECLARE_RALLOC_CXX_OPERATORS_TEMPLATE(type, rzalloc_size)
+
+
+#define DECLARE_LINEAR_ALLOC_CXX_OPERATORS_TEMPLATE(TYPE, ALLOC_FUNC, new_cmd, new_array_cmd, ATTRIBUTE) \
+public:                                                                  \
+   ATTRIBUTE                                                             \
+   static void* operator new(size_t size, linear_ctx *ctx)               \
+   {                                                                     \
+      void *p = ALLOC_FUNC(ctx, size);                                   \
+      assert(p != NULL);                                                 \
+      new_cmd                                                            \
+      return p;                                                          \
+   }                                                                     \
+   ATTRIBUTE                                                             \
+   static void* operator new[](size_t size, linear_ctx *ctx)             \
+   {                                                                     \
+      void *p = ALLOC_FUNC(ctx, size);                                   \
+      assert(p != NULL);                                                 \
+      new_array_cmd                                                      \
+      return p;                                                          \
+   }
+
+#define DECLARE_LINEAR_ALLOC_CXX_OPERATORS(type, new_cmd, new_array_cmd) \
+   DECLARE_LINEAR_ALLOC_CXX_OPERATORS_TEMPLATE(type, linear_alloc_child, \
+                                               new_cmd, new_array_cmd,)
+
+#define DECLARE_LINEAR_ZALLOC_CXX_OPERATORS(type, new_cmd, new_array_cmd) \
+   DECLARE_LINEAR_ALLOC_CXX_OPERATORS_TEMPLATE(type, linear_zalloc_child, \
+                                               new_cmd, new_array_cmd,)
+
+#define DECLARE_LINEAR_ZALLOC_CXX_OPERATORS_NO_SANITIZE(type, new_cmd, new_array_cmd, FLAG) \
+   DECLARE_LINEAR_ALLOC_CXX_OPERATORS_TEMPLATE(type, linear_zalloc_child, \
+                                               new_cmd, new_array_cmd,    \
+                                               ATTRIBUTE_NO_SANITIZE_##FLAG)
+
+typedef struct linear_ctx linear_ctx;
+
+/**
+ * Do a fast allocation from the linear context, also known as the child node
+ * from the allocator's point of view. It can't be freed directly. You have
+ * to free the linear context or the ralloc parent.
+ *
+ * \param ctx      linear context of the allocator
+ * \param size     size to allocate (max 32 bits)
+ */
+void *linear_alloc_child(linear_ctx *ctx, unsigned size);
+
+typedef struct {
+   unsigned min_buffer_size;
+} linear_opts;
+
+/**
+ * Allocate a linear context that will internally hold linear buffers.
+ * Use it for all child node allocations.
+ *
+ * \param ralloc_ctx  ralloc context, must not be NULL
+ */
+linear_ctx *linear_context(void *ralloc_ctx);
+
+linear_ctx *linear_context_with_opts(void *ralloc_ctx, const linear_opts *opts);
+
+/**
+ * Same as linear_alloc_child, but also clears memory.
+ */
+void *linear_zalloc_child(linear_ctx *ctx, unsigned size) MALLOCLIKE;
+
+/**
+ * Free a linear context. This will free all child nodes too.
+ * Alternatively, freeing the ralloc parent will also free
+ * the linear context.
+ */
+void linear_free_context(linear_ctx *ctx);
+
+/**
+ * Same as ralloc_steal, but steals the entire linear context.
+ */
+void ralloc_steal_linear_context(void *new_ralloc_ctx, linear_ctx *ctx);
+
+/**
+ * Return the ralloc parent of the linear context.
+ */
+void *ralloc_parent_of_linear_context(linear_ctx *ctx);
+
+/**
+ * Do a fast allocation of an array from the linear context and initialize it to zero.
+ *
+ * Similar to \c calloc, but does not initialize the memory to zero.
+ *
+ * More than a convenience function, this also checks for integer overflow when
+ * multiplying \p size and \p count.  This is necessary for security.
+ */
+void *linear_alloc_child_array(linear_ctx *ctx, size_t size, unsigned count) MALLOCLIKE;
+
+/**
+ * Do a fast allocation of an array from the linear context.
+ *
+ * Similar to \c calloc.
+ *
+ * More than a convenience function, this also checks for integer overflow when
+ * multiplying \p size and \p count.  This is necessary for security.
+ */
+void *linear_zalloc_child_array(linear_ctx *ctx, size_t size, unsigned count) MALLOCLIKE;
+
+/* The functions below have the same semantics as their ralloc counterparts,
+ * except that they always allocate a linear child node.
+ */
+char *linear_strdup(linear_ctx *ctx, const char *str) MALLOCLIKE;
+char *linear_asprintf(linear_ctx *ctx, const char *fmt, ...) PRINTFLIKE(2, 3) MALLOCLIKE;
+char *linear_vasprintf(linear_ctx *ctx, const char *fmt, va_list args) MALLOCLIKE;
+void *linear_memdup(linear_ctx *ctx, const void *mem, size_t n) MALLOCLIKE;
+bool linear_asprintf_append(linear_ctx *ctx, char **str, const char *fmt, ...) PRINTFLIKE(3, 4);
+bool linear_vasprintf_append(linear_ctx *ctx, char **str, const char *fmt,
+                             va_list args);
+bool linear_asprintf_rewrite_tail(linear_ctx *ctx, char **str, size_t *start,
+                                  const char *fmt, ...) PRINTFLIKE(4, 5);
+bool linear_vasprintf_rewrite_tail(linear_ctx *ctx, char **str, size_t *start,
+                                   const char *fmt, va_list args);
+bool linear_strcat(linear_ctx *ctx, char **dest, const char *str);
+
+/**
+ * \def linear_alloc(ctx, type)
+ * Do a fast allocation from the linear context.
+ *
+ * This is equivalent to:
+ * \code
+ * ((type *) linear_alloc_child(ctx, sizeof(type))
+ * \endcode
+ */
+#define linear_alloc(ctx, type)  ((type *) linear_alloc_child(ctx, sizeof(type)))
+
+/**
+ * \def linear_zalloc(ctx, type)
+ * Do a fast allocation from the linear context and initialize it to zero.
+ *
+ * This is equivalent to:
+ * \code
+ * ((type *) linear_zalloc_child(ctx, sizeof(type))
+ * \endcode
+ */
+#define linear_zalloc(ctx, type) ((type *) linear_zalloc_child(ctx, sizeof(type)))
+
+/**
+ * \def linear_alloc_array(ctx, type, count)
+ * Do a fast allocation of an array from the linear context.
+ *
+ * Similar to \c calloc, but does not initialize the memory to zero.
+ *
+ * More than a convenience function, this also checks for integer overflow when
+ * multiplying \c sizeof(type) and \p count.  This is necessary for security.
+ *
+ * This is equivalent to:
+ * \code
+ * ((type *) linear_alloc_child_array(ctx, sizeof(type), count)
+ * \endcode
+ */
+#define linear_alloc_array(ctx, type, count) \
+   ((type *) linear_alloc_child_array(ctx, sizeof(type), count))
+
+/**
+ * \def linear_zalloc_array(ctx, type, count)
+ * Do a fast allocation of an array from the linear context and initialize it to zero
+ *
+ * Similar to \c calloc.
+ *
+ * More than a convenience function, this also checks for integer overflow when
+ * multiplying \c sizeof(type) and \p count.  This is necessary for security.
+ *
+ * This is equivalent to:
+ * \code
+ * ((type *) linear_zalloc_child_array(ctx, sizeof(type), count)
+ * \endcode
+ */
+#define linear_zalloc_array(ctx, type, count) \
+   ((type *) linear_zalloc_child_array(ctx, sizeof(type), count))
+
+enum {
+   RALLOC_PRINT_INFO_SUMMARY_ONLY = 1 << 0,
+};
+
+void ralloc_print_info(FILE *f, const void *p, unsigned flags);
+
+#ifdef __cplusplus
+} /* end of extern "C" */
+#endif
+
+#endif