/* * 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 #ifdef __cplusplus extern "C" { #endif #include <stddef.h> #include <stdarg.h> #include <stdbool.h> #include "macros.h" /** * \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); /// \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)) /** * 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); /// @} /** * 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); /** * Return the given pointer's ralloc context. */ void *ralloc_parent(const void *ptr); /** * Return a context whose memory will be automatically freed at program exit. * * The first call to this function creates a context and registers a handler * to free it using \c atexit. This may cause trouble if used in a library * loaded with \c dlopen. */ void *ralloc_autofree_context(void); /** * Set a callback to occur just before an object is freed. */ void ralloc_set_destructor(const void *ptr, void(*destructor)(void *)); /// \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); /** * 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); /// @} #ifdef __cplusplus } /* end of extern "C" */ #endif /** * 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(TYPE) \ private: \ static void _ralloc_destructor(void *p) \ { \ reinterpret_cast<TYPE *>(p)->~TYPE(); \ } \ public: \ static void* operator new(size_t size, void *mem_ctx) \ { \ void *p = ralloc_size(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); \ } #endif