mirror of
https://github.com/ruby/ruby.git
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286 lines
8.9 KiB
C++
286 lines
8.9 KiB
C++
#ifndef RBIMPL_MEMORY_H /*-*-C++-*-vi:se ft=cpp:*/
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#define RBIMPL_MEMORY_H
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/**
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* @file
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* @author Ruby developers <ruby-core@ruby-lang.org>
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* @copyright This file is a part of the programming language Ruby.
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* Permission is hereby granted, to either redistribute and/or
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* modify this file, provided that the conditions mentioned in the
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* file COPYING are met. Consult the file for details.
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* @warning Symbols prefixed with either `RBIMPL` or `rbimpl` are
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* implementation details. Don't take them as canon. They could
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* rapidly appear then vanish. The name (path) of this header file
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* is also an implementation detail. Do not expect it to persist
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* at the place it is now. Developers are free to move it anywhere
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* anytime at will.
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* @note To ruby-core: remember that this header can be possibly
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* recursively included from extension libraries written in C++.
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* Do not expect for instance `__VA_ARGS__` is always available.
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* We assume C99 for ruby itself but we don't assume languages of
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* extension libraries. They could be written in C++98.
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* @brief Memory management stuff.
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*/
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#include "ruby/internal/config.h"
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#ifdef STDC_HEADERS
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# include <stddef.h>
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#endif
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#ifdef HAVE_STRING_H
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# include <string.h>
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#endif
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#ifdef HAVE_STDINT_H
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# include <stdint.h>
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#endif
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#ifdef HAVE_ALLOCA_H
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# include <alloca.h>
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#endif
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#if defined(_MSC_VER) && defined(_WIN64)
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# include <intrin.h>
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# pragma intrinsic(_umul128)
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#endif
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#include "ruby/internal/attr/alloc_size.h"
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#include "ruby/internal/attr/const.h"
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#include "ruby/internal/attr/constexpr.h"
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#include "ruby/internal/attr/noalias.h"
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#include "ruby/internal/attr/nonnull.h"
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#include "ruby/internal/attr/noreturn.h"
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#include "ruby/internal/attr/restrict.h"
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#include "ruby/internal/attr/returns_nonnull.h"
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#include "ruby/internal/cast.h"
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#include "ruby/internal/dllexport.h"
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#include "ruby/internal/has/builtin.h"
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#include "ruby/internal/stdalign.h"
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#include "ruby/internal/stdbool.h"
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#include "ruby/internal/xmalloc.h"
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#include "ruby/backward/2/limits.h"
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#include "ruby/backward/2/long_long.h"
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#include "ruby/backward/2/assume.h"
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#include "ruby/defines.h"
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/* Make alloca work the best possible way. */
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#if defined(alloca)
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# /* Take that. */
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#elif RBIMPL_HAS_BUILTIN(__builtin_alloca)
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# define alloca __builtin_alloca
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#elif defined(_AIX)
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# pragma alloca
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#elif defined(__cplusplus)
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extern "C" void *alloca(size_t);
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#else
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extern void *alloca();
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#endif
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#if defined(HAVE_INT128_T) && SIZEOF_SIZE_T <= 8
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# define DSIZE_T uint128_t
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#elif SIZEOF_SIZE_T * 2 <= SIZEOF_LONG_LONG
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# define DSIZE_T unsigned LONG_LONG
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#endif
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#ifdef C_ALLOCA
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# define RUBY_ALLOCV_LIMIT 0
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#else
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# define RUBY_ALLOCV_LIMIT 1024
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#endif
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#ifdef __GNUC__
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#define RB_GC_GUARD(v) \
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(*__extension__ ({ \
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volatile VALUE *rb_gc_guarded_ptr = &(v); \
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__asm__("" : : "m"(rb_gc_guarded_ptr)); \
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rb_gc_guarded_ptr; \
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}))
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#elif defined _MSC_VER
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#define RB_GC_GUARD(v) (*rb_gc_guarded_ptr(&(v)))
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#else
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#define HAVE_RB_GC_GUARDED_PTR_VAL 1
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#define RB_GC_GUARD(v) (*rb_gc_guarded_ptr_val(&(v),(v)))
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#endif
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/* Casts needed because void* is NOT compaible with others in C++. */
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#define RB_ALLOC_N(type,n) RBIMPL_CAST((type *)ruby_xmalloc2((n), sizeof(type)))
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#define RB_ALLOC(type) RBIMPL_CAST((type *)ruby_xmalloc(sizeof(type)))
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#define RB_ZALLOC_N(type,n) RBIMPL_CAST((type *)ruby_xcalloc((n), sizeof(type)))
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#define RB_ZALLOC(type) (RB_ZALLOC_N(type, 1))
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#define RB_REALLOC_N(var,type,n) \
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((var) = RBIMPL_CAST((type *)ruby_xrealloc2((void *)(var), (n), sizeof(type))))
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/* I don't know why but __builtin_alloca_with_align's second argument
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takes bits rather than bytes. */
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#if RBIMPL_HAS_BUILTIN(__builtin_alloca_with_align)
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# define ALLOCA_N(type, n) \
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RBIMPL_CAST((type *) \
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__builtin_alloca_with_align( \
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rbimpl_size_mul_or_raise(sizeof(type), (n)), \
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RUBY_ALIGNOF(type) * CHAR_BIT))
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#else
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# define ALLOCA_N(type,n) \
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RBIMPL_CAST((type *)alloca(rbimpl_size_mul_or_raise(sizeof(type), (n))))
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#endif
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/* allocates _n_ bytes temporary buffer and stores VALUE including it
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* in _v_. _n_ may be evaluated twice. */
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#define RB_ALLOCV(v, n) \
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((n) < RUBY_ALLOCV_LIMIT ? \
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((v) = 0, alloca(n)) : \
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rb_alloc_tmp_buffer(&(v), (n)))
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#define RB_ALLOCV_N(type, v, n) \
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RBIMPL_CAST((type *) \
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(((size_t)(n) < RUBY_ALLOCV_LIMIT / sizeof(type)) ? \
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((v) = 0, alloca((n) * sizeof(type))) : \
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rb_alloc_tmp_buffer2(&(v), (n), sizeof(type))))
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#define RB_ALLOCV_END(v) rb_free_tmp_buffer(&(v))
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#define MEMZERO(p,type,n) memset((p), 0, rbimpl_size_mul_or_raise(sizeof(type), (n)))
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#define MEMCPY(p1,p2,type,n) memcpy((p1), (p2), rbimpl_size_mul_or_raise(sizeof(type), (n)))
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#define MEMMOVE(p1,p2,type,n) memmove((p1), (p2), rbimpl_size_mul_or_raise(sizeof(type), (n)))
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#define MEMCMP(p1,p2,type,n) memcmp((p1), (p2), rbimpl_size_mul_or_raise(sizeof(type), (n)))
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#define ALLOC_N RB_ALLOC_N
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#define ALLOC RB_ALLOC
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#define ZALLOC_N RB_ZALLOC_N
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#define ZALLOC RB_ZALLOC
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#define REALLOC_N RB_REALLOC_N
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#define ALLOCV RB_ALLOCV
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#define ALLOCV_N RB_ALLOCV_N
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#define ALLOCV_END RB_ALLOCV_END
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/* Expecting this struct to be eliminated by function inlinings */
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struct rbimpl_size_mul_overflow_tag {
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bool left;
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size_t right;
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};
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RBIMPL_SYMBOL_EXPORT_BEGIN()
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RBIMPL_ATTR_RESTRICT()
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RBIMPL_ATTR_RETURNS_NONNULL()
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RBIMPL_ATTR_ALLOC_SIZE((2))
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void *rb_alloc_tmp_buffer(volatile VALUE *store, long len);
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RBIMPL_ATTR_RESTRICT()
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RBIMPL_ATTR_RETURNS_NONNULL()
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RBIMPL_ATTR_ALLOC_SIZE((2,3))
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void *rb_alloc_tmp_buffer_with_count(volatile VALUE *store, size_t len,size_t count);
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void rb_free_tmp_buffer(volatile VALUE *store);
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RBIMPL_ATTR_NORETURN()
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void ruby_malloc_size_overflow(size_t, size_t);
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#ifdef HAVE_RB_GC_GUARDED_PTR_VAL
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volatile VALUE *rb_gc_guarded_ptr_val(volatile VALUE *ptr, VALUE val);
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#endif
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RBIMPL_SYMBOL_EXPORT_END()
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#ifdef _MSC_VER
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# pragma optimize("", off)
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static inline volatile VALUE *
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rb_gc_guarded_ptr(volatile VALUE *ptr)
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{
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return ptr;
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}
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# pragma optimize("", on)
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#endif
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/* Does anyone use it? Just here for backwards compatibility. */
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static inline int
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rb_mul_size_overflow(size_t a, size_t b, size_t max, size_t *c)
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{
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#ifdef DSIZE_T
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RB_GNUC_EXTENSION DSIZE_T da, db, c2;
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da = a;
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db = b;
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c2 = da * db;
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if (c2 > max) return 1;
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*c = RBIMPL_CAST((size_t)c2);
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#else
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if (b != 0 && a > max / b) return 1;
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*c = a * b;
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#endif
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return 0;
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}
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#if RBIMPL_COMPILER_SINCE(GCC, 7, 0, 0)
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RBIMPL_ATTR_CONSTEXPR(CXX14) /* https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70507 */
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#elif RBIMPL_COMPILER_SINCE(Clang, 7, 0, 0)
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RBIMPL_ATTR_CONSTEXPR(CXX14) /* https://bugs.llvm.org/show_bug.cgi?id=37633 */
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#endif
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RBIMPL_ATTR_CONST()
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static inline struct rbimpl_size_mul_overflow_tag
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rbimpl_size_mul_overflow(size_t x, size_t y)
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{
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struct rbimpl_size_mul_overflow_tag ret = { false, 0, };
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#if RBIMPL_HAS_BUILTIN(__builtin_mul_overflow)
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ret.left = __builtin_mul_overflow(x, y, &ret.right);
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#elif defined(DSIZE_T)
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RB_GNUC_EXTENSION DSIZE_T dx = x;
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RB_GNUC_EXTENSION DSIZE_T dy = y;
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RB_GNUC_EXTENSION DSIZE_T dz = dx * dy;
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ret.left = dz > SIZE_MAX;
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ret.right = RBIMPL_CAST((size_t)dz);
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#elif defined(_MSC_VER) && defined(_WIN64)
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unsigned __int64 dp = 0;
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unsigned __int64 dz = _umul128(x, y, &dp);
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ret.left = RBIMPL_CAST((bool)dp);
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ret.right = RBIMPL_CAST((size_t)dz);
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#else
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/* https://wiki.sei.cmu.edu/confluence/display/c/INT30-C.+Ensure+that+unsigned+integer+operations+do+not+wrap */
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ret.left = (y != 0) && (x > SIZE_MAX / y);
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ret.right = x * y;
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#endif
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return ret;
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}
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static inline size_t
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rbimpl_size_mul_or_raise(size_t x, size_t y)
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{
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struct rbimpl_size_mul_overflow_tag size =
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rbimpl_size_mul_overflow(x, y);
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if (RB_LIKELY(! size.left)) {
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return size.right;
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}
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else {
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ruby_malloc_size_overflow(x, y);
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RBIMPL_UNREACHABLE_RETURN(0);
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}
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}
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static inline void *
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rb_alloc_tmp_buffer2(volatile VALUE *store, long count, size_t elsize)
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{
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return rb_alloc_tmp_buffer_with_count(
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store, rbimpl_size_mul_or_raise(count, elsize), count);
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}
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RBIMPL_ATTR_NOALIAS()
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RBIMPL_ATTR_NONNULL((1))
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RBIMPL_ATTR_RETURNS_NONNULL()
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/* At least since 2004, glibc's <string.h> annotates memcpy to be
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* __attribute__((__nonnull__(1, 2))). However it is safe to pass NULL to the
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* source pointer, if n is 0. Let's wrap memcpy. */
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static inline void *
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ruby_nonempty_memcpy(void *dest, const void *src, size_t n)
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{
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if (n) {
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return memcpy(dest, src, n);
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}
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else {
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return dest;
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}
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}
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#undef memcpy
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#define memcpy ruby_nonempty_memcpy
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#endif /* RBIMPL_MEMORY_H */
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