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Diffstat (limited to 'src/util/ralloc.h')
| -rw-r--r-- | src/util/ralloc.h | 444 |
1 files changed, 444 insertions, 0 deletions
diff --git a/src/util/ralloc.h b/src/util/ralloc.h new file mode 100644 index 00000000000..1fe53573f0d --- /dev/null +++ b/src/util/ralloc.h @@ -0,0 +1,444 @@ +/* + * 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 "main/compiler.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); + +/** + * 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); + +/** + * 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); + +/** + * 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); + +/** + * 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); + +/** + * 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); + +/** + * 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); + +/** + * 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); + +/** + * 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 |