|  | /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) | 
|  | * All rights reserved. | 
|  | * | 
|  | * This package is an SSL implementation written | 
|  | * by Eric Young (eay@cryptsoft.com). | 
|  | * The implementation was written so as to conform with Netscapes SSL. | 
|  | * | 
|  | * This library is free for commercial and non-commercial use as long as | 
|  | * the following conditions are aheared to.  The following conditions | 
|  | * apply to all code found in this distribution, be it the RC4, RSA, | 
|  | * lhash, DES, etc., code; not just the SSL code.  The SSL documentation | 
|  | * included with this distribution is covered by the same copyright terms | 
|  | * except that the holder is Tim Hudson (tjh@cryptsoft.com). | 
|  | * | 
|  | * Copyright remains Eric Young's, and as such any Copyright notices in | 
|  | * the code are not to be removed. | 
|  | * If this package is used in a product, Eric Young should be given attribution | 
|  | * as the author of the parts of the library used. | 
|  | * This can be in the form of a textual message at program startup or | 
|  | * in documentation (online or textual) provided with the package. | 
|  | * | 
|  | * Redistribution and use in source and binary forms, with or without | 
|  | * modification, are permitted provided that the following conditions | 
|  | * are met: | 
|  | * 1. Redistributions of source code must retain the copyright | 
|  | *    notice, this list of conditions and the following disclaimer. | 
|  | * 2. Redistributions in binary form must reproduce the above copyright | 
|  | *    notice, this list of conditions and the following disclaimer in the | 
|  | *    documentation and/or other materials provided with the distribution. | 
|  | * 3. All advertising materials mentioning features or use of this software | 
|  | *    must display the following acknowledgement: | 
|  | *    "This product includes cryptographic software written by | 
|  | *     Eric Young (eay@cryptsoft.com)" | 
|  | *    The word 'cryptographic' can be left out if the rouines from the library | 
|  | *    being used are not cryptographic related :-). | 
|  | * 4. If you include any Windows specific code (or a derivative thereof) from | 
|  | *    the apps directory (application code) you must include an acknowledgement: | 
|  | *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)" | 
|  | * | 
|  | * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND | 
|  | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | 
|  | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | 
|  | * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE | 
|  | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL | 
|  | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS | 
|  | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | 
|  | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | 
|  | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY | 
|  | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF | 
|  | * SUCH DAMAGE. | 
|  | * | 
|  | * The licence and distribution terms for any publically available version or | 
|  | * derivative of this code cannot be changed.  i.e. this code cannot simply be | 
|  | * copied and put under another distribution licence | 
|  | * [including the GNU Public Licence.] */ | 
|  |  | 
|  | #ifndef OPENSSL_HEADER_STACK_H | 
|  | #define OPENSSL_HEADER_STACK_H | 
|  |  | 
|  | #include <openssl/base.h> | 
|  |  | 
|  | #include <openssl/type_check.h> | 
|  |  | 
|  | #if defined(__cplusplus) | 
|  | extern "C" { | 
|  | #endif | 
|  |  | 
|  |  | 
|  | // A stack, in OpenSSL, is an array of pointers. They are the most commonly | 
|  | // used collection object. | 
|  | // | 
|  | // This file defines macros for type safe use of the stack functions. A stack | 
|  | // of a specific type of object has type |STACK_OF(type)|. This can be defined | 
|  | // (once) with |DEFINE_STACK_OF(type)| and declared where needed with | 
|  | // |DECLARE_STACK_OF(type)|. For example: | 
|  | // | 
|  | //   typedef struct foo_st { | 
|  | //     int bar; | 
|  | //   } FOO; | 
|  | // | 
|  | //   DEFINE_STACK_OF(FOO); | 
|  | // | 
|  | // Although note that the stack will contain /pointers/ to |FOO|. | 
|  | // | 
|  | // A macro will be defined for each of the sk_* functions below. For | 
|  | // STACK_OF(FOO), the macros would be sk_FOO_new, sk_FOO_pop etc. | 
|  |  | 
|  |  | 
|  | // stack_cmp_func is a comparison function that returns a value < 0, 0 or > 0 | 
|  | // if |*a| is less than, equal to or greater than |*b|, respectively.  Note the | 
|  | // extra indirection - the function is given a pointer to a pointer to the | 
|  | // element. This differs from the usual qsort/bsearch comparison function. | 
|  | typedef int (*stack_cmp_func)(const void **a, const void **b); | 
|  |  | 
|  | // stack_st contains an array of pointers. It is not designed to be used | 
|  | // directly, rather the wrapper macros should be used. | 
|  | typedef struct stack_st { | 
|  | // num contains the number of valid pointers in |data|. | 
|  | size_t num; | 
|  | void **data; | 
|  | // sorted is non-zero if the values pointed to by |data| are in ascending | 
|  | // order, based on |comp|. | 
|  | int sorted; | 
|  | // num_alloc contains the number of pointers allocated in the buffer pointed | 
|  | // to by |data|, which may be larger than |num|. | 
|  | size_t num_alloc; | 
|  | // comp is an optional comparison function. | 
|  | stack_cmp_func comp; | 
|  | } _STACK; | 
|  |  | 
|  |  | 
|  | #define STACK_OF(type) struct stack_st_##type | 
|  |  | 
|  | #define DECLARE_STACK_OF(type) STACK_OF(type); | 
|  |  | 
|  | // These are the raw stack functions, you shouldn't be using them. Rather you | 
|  | // should be using the type stack macros implemented above. | 
|  |  | 
|  | // sk_new creates a new, empty stack with the given comparison function, which | 
|  | // may be zero. It returns the new stack or NULL on allocation failure. | 
|  | OPENSSL_EXPORT _STACK *sk_new(stack_cmp_func comp); | 
|  |  | 
|  | // sk_new_null creates a new, empty stack. It returns the new stack or NULL on | 
|  | // allocation failure. | 
|  | OPENSSL_EXPORT _STACK *sk_new_null(void); | 
|  |  | 
|  | // sk_num returns the number of elements in |s|. | 
|  | OPENSSL_EXPORT size_t sk_num(const _STACK *sk); | 
|  |  | 
|  | // sk_zero resets |sk| to the empty state but does nothing to free the | 
|  | // individual elements themselves. | 
|  | OPENSSL_EXPORT void sk_zero(_STACK *sk); | 
|  |  | 
|  | // sk_value returns the |i|th pointer in |sk|, or NULL if |i| is out of | 
|  | // range. | 
|  | OPENSSL_EXPORT void *sk_value(const _STACK *sk, size_t i); | 
|  |  | 
|  | // sk_set sets the |i|th pointer in |sk| to |p| and returns |p|. If |i| is out | 
|  | // of range, it returns NULL. | 
|  | OPENSSL_EXPORT void *sk_set(_STACK *sk, size_t i, void *p); | 
|  |  | 
|  | // sk_free frees the given stack and array of pointers, but does nothing to | 
|  | // free the individual elements. Also see |sk_pop_free|. | 
|  | OPENSSL_EXPORT void sk_free(_STACK *sk); | 
|  |  | 
|  | // sk_pop_free calls |free_func| on each element in the stack and then frees | 
|  | // the stack itself. | 
|  | OPENSSL_EXPORT void sk_pop_free(_STACK *sk, void (*free_func)(void *)); | 
|  |  | 
|  | // sk_insert inserts |p| into the stack at index |where|, moving existing | 
|  | // elements if needed. It returns the length of the new stack, or zero on | 
|  | // error. | 
|  | OPENSSL_EXPORT size_t sk_insert(_STACK *sk, void *p, size_t where); | 
|  |  | 
|  | // sk_delete removes the pointer at index |where|, moving other elements down | 
|  | // if needed. It returns the removed pointer, or NULL if |where| is out of | 
|  | // range. | 
|  | OPENSSL_EXPORT void *sk_delete(_STACK *sk, size_t where); | 
|  |  | 
|  | // sk_delete_ptr removes, at most, one instance of |p| from the stack based on | 
|  | // pointer equality. If an instance of |p| is found then |p| is returned, | 
|  | // otherwise it returns NULL. | 
|  | OPENSSL_EXPORT void *sk_delete_ptr(_STACK *sk, void *p); | 
|  |  | 
|  | // sk_find returns the first value in the stack equal to |p|. If a comparison | 
|  | // function has been set on the stack, equality is defined by it, otherwise | 
|  | // pointer equality is used. If the stack is sorted, then a binary search is | 
|  | // used, otherwise a linear search is performed. If a matching element is found, | 
|  | // its index is written to | 
|  | // |*out_index| (if |out_index| is not NULL) and one is returned. Otherwise zero | 
|  | // is returned. | 
|  | // | 
|  | // Note this differs from OpenSSL. The type signature is slightly different, and | 
|  | // OpenSSL's sk_find will implicitly sort |sk| if it has a comparison function | 
|  | // defined. | 
|  | OPENSSL_EXPORT int sk_find(const _STACK *sk, size_t *out_index, void *p); | 
|  |  | 
|  | // sk_shift removes and returns the first element in the stack, or returns NULL | 
|  | // if the stack is empty. | 
|  | OPENSSL_EXPORT void *sk_shift(_STACK *sk); | 
|  |  | 
|  | // sk_push appends |p| to the stack and returns the length of the new stack, or | 
|  | // 0 on allocation failure. | 
|  | OPENSSL_EXPORT size_t sk_push(_STACK *sk, void *p); | 
|  |  | 
|  | // sk_pop returns and removes the last element on the stack, or NULL if the | 
|  | // stack is empty. | 
|  | OPENSSL_EXPORT void *sk_pop(_STACK *sk); | 
|  |  | 
|  | // sk_dup performs a shallow copy of a stack and returns the new stack, or NULL | 
|  | // on error. | 
|  | OPENSSL_EXPORT _STACK *sk_dup(const _STACK *sk); | 
|  |  | 
|  | // sk_sort sorts the elements of |sk| into ascending order based on the | 
|  | // comparison function. The stack maintains a |sorted| flag and sorting an | 
|  | // already sorted stack is a no-op. | 
|  | OPENSSL_EXPORT void sk_sort(_STACK *sk); | 
|  |  | 
|  | // sk_is_sorted returns one if |sk| is known to be sorted and zero | 
|  | // otherwise. | 
|  | OPENSSL_EXPORT int sk_is_sorted(const _STACK *sk); | 
|  |  | 
|  | // sk_set_cmp_func sets the comparison function to be used by |sk| and returns | 
|  | // the previous one. | 
|  | OPENSSL_EXPORT stack_cmp_func sk_set_cmp_func(_STACK *sk, stack_cmp_func comp); | 
|  |  | 
|  | // sk_deep_copy performs a copy of |sk| and of each of the non-NULL elements in | 
|  | // |sk| by using |copy_func|. If an error occurs, |free_func| is used to free | 
|  | // any copies already made and NULL is returned. | 
|  | OPENSSL_EXPORT _STACK *sk_deep_copy(const _STACK *sk, | 
|  | void *(*copy_func)(void *), | 
|  | void (*free_func)(void *)); | 
|  |  | 
|  |  | 
|  | // Defining stack types. | 
|  | // | 
|  | // This set of macros is used to emit the typed functions that act on a | 
|  | // |STACK_OF(T)|. | 
|  |  | 
|  | #if !defined(BORINGSSL_NO_CXX) | 
|  | extern "C++" { | 
|  | namespace bssl { | 
|  | namespace internal { | 
|  | template <typename T> | 
|  | struct StackTraits {}; | 
|  | } | 
|  | } | 
|  | } | 
|  |  | 
|  | #define BORINGSSL_DEFINE_STACK_TRAITS(name, type, is_const) \ | 
|  | extern "C++" {                                            \ | 
|  | namespace bssl {                                          \ | 
|  | namespace internal {                                      \ | 
|  | template <>                                               \ | 
|  | struct StackTraits<STACK_OF(name)> {                      \ | 
|  | static constexpr bool kIsStack = true;                  \ | 
|  | using Type = type;                                      \ | 
|  | static constexpr bool kIsConst = is_const;              \ | 
|  | };                                                        \ | 
|  | }                                                         \ | 
|  | }                                                         \ | 
|  | } | 
|  |  | 
|  | #else | 
|  | #define BORINGSSL_DEFINE_STACK_TRAITS(name, type, is_const) | 
|  | #endif | 
|  |  | 
|  | // Stack functions must be tagged unused to support file-local stack types. | 
|  | // Clang's -Wunused-function only allows unused static inline functions if they | 
|  | // are defined in a header. | 
|  |  | 
|  | #define BORINGSSL_DEFINE_STACK_OF_IMPL(name, ptrtype, constptrtype)            \ | 
|  | DECLARE_STACK_OF(name)                                                       \ | 
|  | \ | 
|  | typedef int (*stack_##name##_cmp_func)(constptrtype *a, constptrtype *b);    \ | 
|  | \ | 
|  | static inline OPENSSL_UNUSED STACK_OF(name) *                                \ | 
|  | sk_##name##_new(stack_##name##_cmp_func comp) {                          \ | 
|  | return (STACK_OF(name) *)sk_new((stack_cmp_func)comp);                     \ | 
|  | }                                                                            \ | 
|  | \ | 
|  | static inline OPENSSL_UNUSED STACK_OF(name) *sk_##name##_new_null(void) {    \ | 
|  | return (STACK_OF(name) *)sk_new_null();                                    \ | 
|  | }                                                                            \ | 
|  | \ | 
|  | static inline OPENSSL_UNUSED size_t sk_##name##_num(                         \ | 
|  | const STACK_OF(name) *sk) {                                              \ | 
|  | return sk_num((const _STACK *)sk);                                         \ | 
|  | }                                                                            \ | 
|  | \ | 
|  | static inline OPENSSL_UNUSED void sk_##name##_zero(STACK_OF(name) *sk) {     \ | 
|  | sk_zero((_STACK *)sk);                                                     \ | 
|  | }                                                                            \ | 
|  | \ | 
|  | static inline OPENSSL_UNUSED ptrtype sk_##name##_value(                      \ | 
|  | const STACK_OF(name) *sk, size_t i) {                                    \ | 
|  | return (ptrtype)sk_value((const _STACK *)sk, i);                           \ | 
|  | }                                                                            \ | 
|  | \ | 
|  | static inline OPENSSL_UNUSED ptrtype sk_##name##_set(STACK_OF(name) *sk,     \ | 
|  | size_t i, ptrtype p) {  \ | 
|  | return (ptrtype)sk_set((_STACK *)sk, i, (void *)p);                        \ | 
|  | }                                                                            \ | 
|  | \ | 
|  | static inline OPENSSL_UNUSED void sk_##name##_free(STACK_OF(name) *sk) {     \ | 
|  | sk_free((_STACK *)sk);                                                     \ | 
|  | }                                                                            \ | 
|  | \ | 
|  | static inline OPENSSL_UNUSED void sk_##name##_pop_free(                      \ | 
|  | STACK_OF(name) *sk, void (*free_func)(ptrtype p)) {                      \ | 
|  | sk_pop_free((_STACK *)sk, (void (*)(void *))free_func);                    \ | 
|  | }                                                                            \ | 
|  | \ | 
|  | static inline OPENSSL_UNUSED size_t sk_##name##_insert(                      \ | 
|  | STACK_OF(name) *sk, ptrtype p, size_t where) {                           \ | 
|  | return sk_insert((_STACK *)sk, (void *)p, where);                          \ | 
|  | }                                                                            \ | 
|  | \ | 
|  | static inline OPENSSL_UNUSED ptrtype sk_##name##_delete(STACK_OF(name) *sk,  \ | 
|  | size_t where) {      \ | 
|  | return (ptrtype)sk_delete((_STACK *)sk, where);                            \ | 
|  | }                                                                            \ | 
|  | \ | 
|  | static inline OPENSSL_UNUSED ptrtype sk_##name##_delete_ptr(                 \ | 
|  | STACK_OF(name) *sk, ptrtype p) {                                         \ | 
|  | return (ptrtype)sk_delete_ptr((_STACK *)sk, (void *)p);                    \ | 
|  | }                                                                            \ | 
|  | \ | 
|  | static inline OPENSSL_UNUSED int sk_##name##_find(                           \ | 
|  | const STACK_OF(name) *sk, size_t *out_index, ptrtype p) {                \ | 
|  | return sk_find((const _STACK *)sk, out_index, (void *)p);                  \ | 
|  | }                                                                            \ | 
|  | \ | 
|  | static inline OPENSSL_UNUSED ptrtype sk_##name##_shift(STACK_OF(name) *sk) { \ | 
|  | return (ptrtype)sk_shift((_STACK *)sk);                                    \ | 
|  | }                                                                            \ | 
|  | \ | 
|  | static inline OPENSSL_UNUSED size_t sk_##name##_push(STACK_OF(name) *sk,     \ | 
|  | ptrtype p) {            \ | 
|  | return sk_push((_STACK *)sk, (void *)p);                                   \ | 
|  | }                                                                            \ | 
|  | \ | 
|  | static inline OPENSSL_UNUSED ptrtype sk_##name##_pop(STACK_OF(name) *sk) {   \ | 
|  | return (ptrtype)sk_pop((_STACK *)sk);                                      \ | 
|  | }                                                                            \ | 
|  | \ | 
|  | static inline OPENSSL_UNUSED STACK_OF(name) *                                \ | 
|  | sk_##name##_dup(const STACK_OF(name) *sk) {                              \ | 
|  | return (STACK_OF(name) *)sk_dup((const _STACK *)sk);                       \ | 
|  | }                                                                            \ | 
|  | \ | 
|  | static inline OPENSSL_UNUSED void sk_##name##_sort(STACK_OF(name) *sk) {     \ | 
|  | sk_sort((_STACK *)sk);                                                     \ | 
|  | }                                                                            \ | 
|  | \ | 
|  | static inline OPENSSL_UNUSED int sk_##name##_is_sorted(                      \ | 
|  | const STACK_OF(name) *sk) {                                              \ | 
|  | return sk_is_sorted((const _STACK *)sk);                                   \ | 
|  | }                                                                            \ | 
|  | \ | 
|  | static inline OPENSSL_UNUSED stack_##name##_cmp_func                         \ | 
|  | sk_##name##_set_cmp_func(STACK_OF(name) *sk,                             \ | 
|  | stack_##name##_cmp_func comp) {                 \ | 
|  | return (stack_##name##_cmp_func)sk_set_cmp_func((_STACK *)sk,              \ | 
|  | (stack_cmp_func)comp);     \ | 
|  | }                                                                            \ | 
|  | \ | 
|  | static inline OPENSSL_UNUSED STACK_OF(name) *                                \ | 
|  | sk_##name##_deep_copy(const STACK_OF(name) *sk,                          \ | 
|  | ptrtype(*copy_func)(ptrtype),                      \ | 
|  | void (*free_func)(ptrtype)) {                      \ | 
|  | return (STACK_OF(name) *)sk_deep_copy((const _STACK *)sk,                  \ | 
|  | (void *(*)(void *))copy_func,        \ | 
|  | (void (*)(void *))free_func);        \ | 
|  | } | 
|  |  | 
|  | // DEFINE_NAMED_STACK_OF defines |STACK_OF(name)| to be a stack whose elements | 
|  | // are |type| *. | 
|  | #define DEFINE_NAMED_STACK_OF(name, type)                    \ | 
|  | BORINGSSL_DEFINE_STACK_OF_IMPL(name, type *, const type *) \ | 
|  | BORINGSSL_DEFINE_STACK_TRAITS(name, type, false) | 
|  |  | 
|  | // DEFINE_STACK_OF defines |STACK_OF(type)| to be a stack whose elements are | 
|  | // |type| *. | 
|  | #define DEFINE_STACK_OF(type) DEFINE_NAMED_STACK_OF(type, type) | 
|  |  | 
|  | // DEFINE_CONST_STACK_OF defines |STACK_OF(type)| to be a stack whose elements | 
|  | // are const |type| *. | 
|  | #define DEFINE_CONST_STACK_OF(type)                                \ | 
|  | BORINGSSL_DEFINE_STACK_OF_IMPL(type, const type *, const type *) \ | 
|  | BORINGSSL_DEFINE_STACK_TRAITS(type, const type, true) | 
|  |  | 
|  | // DEFINE_SPECIAL_STACK_OF defines |STACK_OF(type)| to be a stack whose elements | 
|  | // are |type|, where |type| must be a typedef for a pointer. | 
|  | #define DEFINE_SPECIAL_STACK_OF(type)                          \ | 
|  | OPENSSL_COMPILE_ASSERT(sizeof(type) == sizeof(void *),       \ | 
|  | special_stack_of_non_pointer_##type); \ | 
|  | BORINGSSL_DEFINE_STACK_OF_IMPL(type, type, const type) | 
|  |  | 
|  |  | 
|  | typedef char *OPENSSL_STRING; | 
|  |  | 
|  | DEFINE_STACK_OF(void) | 
|  | DEFINE_SPECIAL_STACK_OF(OPENSSL_STRING) | 
|  |  | 
|  |  | 
|  | #if defined(__cplusplus) | 
|  | }  // extern C | 
|  | #endif | 
|  |  | 
|  | #if !defined(BORINGSSL_NO_CXX) | 
|  | extern "C++" { | 
|  |  | 
|  | #include <type_traits> | 
|  |  | 
|  | namespace bssl { | 
|  |  | 
|  | namespace internal { | 
|  |  | 
|  | // Stacks defined with |DEFINE_CONST_STACK_OF| are freed with |sk_free|. | 
|  | template <typename Stack> | 
|  | struct DeleterImpl< | 
|  | Stack, typename std::enable_if<StackTraits<Stack>::kIsConst>::type> { | 
|  | static void Free(Stack *sk) { sk_free(reinterpret_cast<_STACK *>(sk)); } | 
|  | }; | 
|  |  | 
|  | // Stacks defined with |DEFINE_STACK_OF| are freed with |sk_pop_free| and the | 
|  | // corresponding type's deleter. | 
|  | template <typename Stack> | 
|  | struct DeleterImpl< | 
|  | Stack, typename std::enable_if<!StackTraits<Stack>::kIsConst>::type> { | 
|  | static void Free(Stack *sk) { | 
|  | sk_pop_free( | 
|  | reinterpret_cast<_STACK *>(sk), | 
|  | reinterpret_cast<void (*)(void *)>( | 
|  | DeleterImpl<typename StackTraits<Stack>::Type>::Free)); | 
|  | } | 
|  | }; | 
|  |  | 
|  | template <typename Stack> | 
|  | class StackIteratorImpl { | 
|  | public: | 
|  | using Type = typename StackTraits<Stack>::Type; | 
|  | // Iterators must be default-constructable. | 
|  | StackIteratorImpl() : sk_(nullptr), idx_(0) {} | 
|  | StackIteratorImpl(const Stack *sk, size_t idx) : sk_(sk), idx_(idx) {} | 
|  |  | 
|  | bool operator==(StackIteratorImpl other) const { | 
|  | return sk_ == other.sk_ && idx_ == other.idx_; | 
|  | } | 
|  | bool operator!=(StackIteratorImpl other) const { | 
|  | return !(*this == other); | 
|  | } | 
|  |  | 
|  | Type *operator*() const { | 
|  | return reinterpret_cast<Type *>( | 
|  | sk_value(reinterpret_cast<const _STACK *>(sk_), idx_)); | 
|  | } | 
|  |  | 
|  | StackIteratorImpl &operator++(/* prefix */) { | 
|  | idx_++; | 
|  | return *this; | 
|  | } | 
|  |  | 
|  | StackIteratorImpl operator++(int /* postfix */) { | 
|  | StackIteratorImpl copy(*this); | 
|  | ++(*this); | 
|  | return copy; | 
|  | } | 
|  |  | 
|  | private: | 
|  | const Stack *sk_; | 
|  | size_t idx_; | 
|  | }; | 
|  |  | 
|  | template <typename Stack> | 
|  | using StackIterator = typename std::enable_if<StackTraits<Stack>::kIsStack, | 
|  | StackIteratorImpl<Stack>>::type; | 
|  |  | 
|  | }  // namespace internal | 
|  |  | 
|  | // PushToStack pushes |elem| to |sk|. It returns true on success and false on | 
|  | // allocation failure. | 
|  | template <typename Stack> | 
|  | static inline | 
|  | typename std::enable_if<!internal::StackTraits<Stack>::kIsConst, bool>::type | 
|  | PushToStack(Stack *sk, | 
|  | UniquePtr<typename internal::StackTraits<Stack>::Type> elem) { | 
|  | if (!sk_push(reinterpret_cast<_STACK *>(sk), elem.get())) { | 
|  | return false; | 
|  | } | 
|  | // sk_push takes ownership on success. | 
|  | elem.release(); | 
|  | return true; | 
|  | } | 
|  |  | 
|  | }  // namespace bssl | 
|  |  | 
|  | // Define begin() and end() for stack types so C++ range for loops work. | 
|  | template <typename Stack> | 
|  | static inline bssl::internal::StackIterator<Stack> begin(const Stack *sk) { | 
|  | return bssl::internal::StackIterator<Stack>(sk, 0); | 
|  | } | 
|  |  | 
|  | template <typename Stack> | 
|  | static inline bssl::internal::StackIterator<Stack> end(const Stack *sk) { | 
|  | return bssl::internal::StackIterator<Stack>( | 
|  | sk, sk_num(reinterpret_cast<const _STACK *>(sk))); | 
|  | } | 
|  |  | 
|  | }  // extern C++ | 
|  | #endif | 
|  |  | 
|  | #endif  // OPENSSL_HEADER_STACK_H |