chromium/third_party/boringssl/src/include/openssl/stack.h

/* Copyright (C) 1995-1998 Eric Young ([email protected])
 * All rights reserved.
 *
 * This package is an SSL implementation written
 * by Eric Young ([email protected]).
 * 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 ([email protected]).
 *
 * 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 ([email protected])"
 *    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 ([email protected])"
 *
 * 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>

#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
// type is named like |STACK_OF(FOO)| and is accessed with functions named
// like |sk_FOO_*|. Note the stack will typically contain /pointers/ to |FOO|.
//
// The |DECLARE_STACK_OF| macro makes |STACK_OF(FOO)| available, and
// |DEFINE_STACK_OF| makes the corresponding functions available.


// Defining stacks.

// STACK_OF expands to the stack type for |type|.
#define STACK_OF(type) …

// DECLARE_STACK_OF declares the |STACK_OF(type)| type. It does not make the
// corresponding |sk_type_*| functions available. This macro should be used in
// files which only need the type.
#define DECLARE_STACK_OF(type) …

// DEFINE_NAMED_STACK_OF defines |STACK_OF(name)| to be a stack whose elements
// are |type| *. This macro makes the |sk_name_*| functions available.
//
// It is not necessary to use |DECLARE_STACK_OF| in files which use this macro.
#define DEFINE_NAMED_STACK_OF(name, type) …

// DEFINE_STACK_OF defines |STACK_OF(type)| to be a stack whose elements are
// |type| *. This macro makes the |sk_type_*| functions available.
//
// It is not necessary to use |DECLARE_STACK_OF| in files which use this macro.
#define DEFINE_STACK_OF(type) …

// DEFINE_CONST_STACK_OF defines |STACK_OF(type)| to be a stack whose elements
// are const |type| *. This macro makes the |sk_type_*| functions available.
//
// It is not necessary to use |DECLARE_STACK_OF| in files which use this macro.
#define DEFINE_CONST_STACK_OF(type) …


// Using stacks.
//
// After the |DEFINE_STACK_OF| macro is used, the following functions are
// available.

#if 0  // Sample

// sk_SAMPLE_free_func is a callback to free an element in a stack.
typedef void (*sk_SAMPLE_free_func)(SAMPLE *);

// sk_SAMPLE_copy_func is a callback to copy an element in a stack. It should
// return the copy or NULL on error.
typedef SAMPLE *(*sk_SAMPLE_copy_func)(const SAMPLE *);

// sk_SAMPLE_cmp_func is a callback to compare |*a| to |*b|. It should return 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 is the |qsort|/|bsearch| comparison
// function applied to an array of |SAMPLE*|.
typedef int (*sk_SAMPLE_cmp_func)(const SAMPLE *const *a,
                                  const SAMPLE *const *b);

// sk_SAMPLE_new creates a new, empty stack with the given comparison function,
// which may be NULL. It returns the new stack or NULL on allocation failure.
STACK_OF(SAMPLE) *sk_SAMPLE_new(sk_SAMPLE_cmp_func comp);

// sk_SAMPLE_new_null creates a new, empty stack. It returns the new stack or
// NULL on allocation failure.
STACK_OF(SAMPLE) *sk_SAMPLE_new_null(void);

// sk_SAMPLE_num returns the number of elements in |sk|. It is safe to cast this
// value to |int|. |sk| is guaranteed to have at most |INT_MAX| elements. If
// |sk| is NULL, it is treated as the empty list and this function returns zero.
size_t sk_SAMPLE_num(const STACK_OF(SAMPLE) *sk);

// sk_SAMPLE_zero resets |sk| to the empty state but does nothing to free the
// individual elements themselves.
void sk_SAMPLE_zero(STACK_OF(SAMPLE) *sk);

// sk_SAMPLE_value returns the |i|th pointer in |sk|, or NULL if |i| is out of
// range. If |sk| is NULL, it is treated as an empty list and the function
// returns NULL.
SAMPLE *sk_SAMPLE_value(const STACK_OF(SAMPLE) *sk, size_t i);

// sk_SAMPLE_set sets the |i|th pointer in |sk| to |p| and returns |p|. If |i|
// is out of range, it returns NULL.
SAMPLE *sk_SAMPLE_set(STACK_OF(SAMPLE) *sk, size_t i, SAMPLE *p);

// sk_SAMPLE_free frees |sk|, but does nothing to free the individual elements.
// Use |sk_SAMPLE_pop_free| to also free the elements.
void sk_SAMPLE_free(STACK_OF(SAMPLE) *sk);

// sk_SAMPLE_pop_free calls |free_func| on each element in |sk| and then
// frees the stack itself.
void sk_SAMPLE_pop_free(STACK_OF(SAMPLE) *sk, sk_SAMPLE_free_func free_func);

// sk_SAMPLE_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.
size_t sk_SAMPLE_insert(STACK_OF(SAMPLE) *sk, SAMPLE *p, size_t where);

// sk_SAMPLE_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.
SAMPLE *sk_SAMPLE_delete(STACK_OF(SAMPLE) *sk, size_t where);

// sk_SAMPLE_delete_ptr removes, at most, one instance of |p| from |sk| based on
// pointer equality. If an instance of |p| is found then |p| is returned,
// otherwise it returns NULL.
SAMPLE *sk_SAMPLE_delete_ptr(STACK_OF(SAMPLE) *sk, const SAMPLE *p);

// sk_SAMPLE_delete_if_func is the callback function for |sk_SAMPLE_delete_if|.
// It should return one to remove |p| and zero to keep it.
typedef int (*sk_SAMPLE_delete_if_func)(SAMPLE *p, void *data);

// sk_SAMPLE_delete_if calls |func| with each element of |sk| and removes the
// entries where |func| returned one. This function does not free or return
// removed pointers so, if |sk| owns its contents, |func| should release the
// pointers prior to returning one.
void sk_SAMPLE_delete_if(STACK_OF(SAMPLE) *sk, sk_SAMPLE_delete_if_func func,
                         void *data);

// sk_SAMPLE_find find the first value in |sk| equal to |p|. |sk|'s comparison
// function determines equality, or pointer equality if |sk| has no comparison
// function.
//
// If the stack is sorted (see |sk_SAMPLE_sort|), this function uses a binary
// search. Otherwise it performs a linear search. If it finds a matching
// element, it writes the index to |*out_index| (if |out_index| is not NULL) and
// returns one. Otherwise, it returns zero. If |sk| is NULL, it is treated as
// the empty list and the function returns zero.
//
// Note this differs from OpenSSL. The type signature is slightly different, and
// OpenSSL's version will implicitly sort |sk| if it has a comparison function
// defined.
int sk_SAMPLE_find(const STACK_OF(SAMPLE) *sk, size_t *out_index,
                   const SAMPLE *p);

// sk_SAMPLE_shift removes and returns the first element in |sk|, or NULL if
// |sk| is empty.
SAMPLE *sk_SAMPLE_shift(STACK_OF(SAMPLE) *sk);

// sk_SAMPLE_push appends |p| to |sk| and returns the length of the new stack,
// or 0 on allocation failure.
size_t sk_SAMPLE_push(STACK_OF(SAMPLE) *sk, SAMPLE *p);

// sk_SAMPLE_pop removes and returns the last element of |sk|, or NULL if |sk|
// is empty.
SAMPLE *sk_SAMPLE_pop(STACK_OF(SAMPLE) *sk);

// sk_SAMPLE_dup performs a shallow copy of a stack and returns the new stack,
// or NULL on error. Use |sk_SAMPLE_deep_copy| to also copy the elements.
STACK_OF(SAMPLE) *sk_SAMPLE_dup(const STACK_OF(SAMPLE) *sk);

// sk_SAMPLE_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.
void sk_SAMPLE_sort(STACK_OF(SAMPLE) *sk);

// sk_SAMPLE_is_sorted returns one if |sk| is known to be sorted and zero
// otherwise.
int sk_SAMPLE_is_sorted(const STACK_OF(SAMPLE) *sk);

// sk_SAMPLE_set_cmp_func sets the comparison function to be used by |sk| and
// returns the previous one.
sk_SAMPLE_cmp_func sk_SAMPLE_set_cmp_func(STACK_OF(SAMPLE) *sk,
                                          sk_SAMPLE_cmp_func comp);

// sk_SAMPLE_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, it calls
// |free_func| to free any copies already made and returns NULL.
STACK_OF(SAMPLE) *sk_SAMPLE_deep_copy(const STACK_OF(SAMPLE) *sk,
                                      sk_SAMPLE_copy_func copy_func,
                                      sk_SAMPLE_free_func free_func);

#endif  // Sample


// Private functions.
//
// The |sk_*| functions generated above are implemented internally using the
// type-erased functions below. Callers should use the typed wrappers instead.
// When using the type-erased functions, callers are responsible for ensuring
// the underlying types are correct. Casting pointers to the wrong types will
// result in memory errors.

// OPENSSL_sk_free_func is a function that frees an element in a stack. Note its
// actual type is void (*)(T *) for some T. Low-level |sk_*| functions will be
// passed a type-specific wrapper to call it correctly.
OPENSSL_sk_free_func;

// OPENSSL_sk_copy_func is a function that copies an element in a stack. Note
// its actual type is T *(*)(const T *) for some T. Low-level |sk_*| functions
// will be passed a type-specific wrapper to call it correctly.
OPENSSL_sk_copy_func;

// OPENSSL_sk_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.
//
// Note its actual type is |int (*)(const T *const *a, const T *const *b)|.
// Low-level |sk_*| functions will be passed a type-specific wrapper to call it
// correctly.
OPENSSL_sk_cmp_func;

// OPENSSL_sk_delete_if_func is the generic version of
// |sk_SAMPLE_delete_if_func|.
OPENSSL_sk_delete_if_func;

// The following function types call the above type-erased signatures with the
// true types.
OPENSSL_sk_call_free_func;
OPENSSL_sk_call_copy_func;
OPENSSL_sk_call_cmp_func;
OPENSSL_sk_call_delete_if_func;

// An OPENSSL_STACK contains an array of pointers. It is not designed to be used
// directly, rather the wrapper macros should be used.
OPENSSL_STACK;

// The following are raw stack functions. They implement the corresponding typed
// |sk_SAMPLE_*| functions generated by |DEFINE_STACK_OF|. Callers shouldn't be
// using them. Rather, callers should use the typed functions.
OPENSSL_EXPORT OPENSSL_STACK *OPENSSL_sk_new(OPENSSL_sk_cmp_func comp);
OPENSSL_EXPORT OPENSSL_STACK *OPENSSL_sk_new_null(void);
OPENSSL_EXPORT size_t OPENSSL_sk_num(const OPENSSL_STACK *sk);
OPENSSL_EXPORT void OPENSSL_sk_zero(OPENSSL_STACK *sk);
OPENSSL_EXPORT void *OPENSSL_sk_value(const OPENSSL_STACK *sk, size_t i);
OPENSSL_EXPORT void *OPENSSL_sk_set(OPENSSL_STACK *sk, size_t i, void *p);
OPENSSL_EXPORT void OPENSSL_sk_free(OPENSSL_STACK *sk);
OPENSSL_EXPORT void OPENSSL_sk_pop_free_ex(
    OPENSSL_STACK *sk, OPENSSL_sk_call_free_func call_free_func,
    OPENSSL_sk_free_func free_func);
OPENSSL_EXPORT size_t OPENSSL_sk_insert(OPENSSL_STACK *sk, void *p,
                                        size_t where);
OPENSSL_EXPORT void *OPENSSL_sk_delete(OPENSSL_STACK *sk, size_t where);
OPENSSL_EXPORT void *OPENSSL_sk_delete_ptr(OPENSSL_STACK *sk, const void *p);
OPENSSL_EXPORT void OPENSSL_sk_delete_if(
    OPENSSL_STACK *sk, OPENSSL_sk_call_delete_if_func call_func,
    OPENSSL_sk_delete_if_func func, void *data);
OPENSSL_EXPORT int OPENSSL_sk_find(const OPENSSL_STACK *sk, size_t *out_index,
                                   const void *p,
                                   OPENSSL_sk_call_cmp_func call_cmp_func);
OPENSSL_EXPORT void *OPENSSL_sk_shift(OPENSSL_STACK *sk);
OPENSSL_EXPORT size_t OPENSSL_sk_push(OPENSSL_STACK *sk, void *p);
OPENSSL_EXPORT void *OPENSSL_sk_pop(OPENSSL_STACK *sk);
OPENSSL_EXPORT OPENSSL_STACK *OPENSSL_sk_dup(const OPENSSL_STACK *sk);
OPENSSL_EXPORT void OPENSSL_sk_sort(OPENSSL_STACK *sk,
                                    OPENSSL_sk_call_cmp_func call_cmp_func);
OPENSSL_EXPORT int OPENSSL_sk_is_sorted(const OPENSSL_STACK *sk);
OPENSSL_EXPORT OPENSSL_sk_cmp_func
OPENSSL_sk_set_cmp_func(OPENSSL_STACK *sk, OPENSSL_sk_cmp_func comp);
OPENSSL_EXPORT OPENSSL_STACK *OPENSSL_sk_deep_copy(
    const OPENSSL_STACK *sk, OPENSSL_sk_call_copy_func call_copy_func,
    OPENSSL_sk_copy_func copy_func, OPENSSL_sk_call_free_func call_free_func,
    OPENSSL_sk_free_func free_func);


// Deprecated private functions (hidden).
//
// TODO(crbug.com/boringssl/499): Migrate callers to the typed wrappers, or at
// least the new names and remove the old ones.
//
// TODO(b/290792019, b/290785937): Ideally these would at least be inline
// functions, so we do not squat the symbols.

_STACK;

// The following functions call the corresponding |OPENSSL_sk_*| function.
OPENSSL_EXPORT OPENSSL_DEPRECATED OPENSSL_STACK *sk_new_null(void);
OPENSSL_EXPORT OPENSSL_DEPRECATED size_t sk_num(const OPENSSL_STACK *sk);
OPENSSL_EXPORT OPENSSL_DEPRECATED void *sk_value(const OPENSSL_STACK *sk,
                                                 size_t i);
OPENSSL_EXPORT OPENSSL_DEPRECATED void sk_free(OPENSSL_STACK *sk);
OPENSSL_EXPORT OPENSSL_DEPRECATED size_t sk_push(OPENSSL_STACK *sk, void *p);
OPENSSL_EXPORT OPENSSL_DEPRECATED void *sk_pop(OPENSSL_STACK *sk);

// sk_pop_free_ex calls |OPENSSL_sk_pop_free_ex|.
//
// TODO(b/291994116): Remove this.
OPENSSL_EXPORT OPENSSL_DEPRECATED void sk_pop_free_ex(
    OPENSSL_STACK *sk, OPENSSL_sk_call_free_func call_free_func,
    OPENSSL_sk_free_func free_func);

// sk_pop_free behaves like |OPENSSL_sk_pop_free_ex| but performs an invalid
// function pointer cast. It exists because some existing callers called
// |sk_pop_free| directly.
//
// TODO(davidben): Migrate callers to bssl::UniquePtr and remove this.
OPENSSL_EXPORT OPENSSL_DEPRECATED void sk_pop_free(
    OPENSSL_STACK *sk, OPENSSL_sk_free_func free_func);


#if !defined(BORINGSSL_NO_CXX)
extern "C++" {
BSSL_NAMESPACE_BEGIN
namespace internal {
template <typename T>
struct StackTraits { … };
}
BSSL_NAMESPACE_END
}

#define BORINGSSL_DEFINE_STACK_TRAITS(name, type, is_const) …

#else
#define BORINGSSL_DEFINE_STACK_TRAITS …
#endif

#define BORINGSSL_DEFINE_STACK_OF_IMPL(name, ptrtype, constptrtype) …


// Built-in stacks.

OPENSSL_STRING;

DEFINE_STACK_OF(void)
DEFINE_NAMED_STACK_OF(OPENSSL_STRING, char)


#if defined(__cplusplus)
}  // extern C
#endif

#if !defined(BORINGSSL_NO_CXX)
extern "C++" {

#include <type_traits>

BSSL_NAMESPACE_BEGIN

namespace internal {

// Stacks defined with |DEFINE_CONST_STACK_OF| are freed with |sk_free|.
DeleterImpl<Stack, std::enable_if_t<StackTraits<Stack>::kIsConst>>;

// Stacks defined with |DEFINE_STACK_OF| are freed with |sk_pop_free| and the
// corresponding type's deleter.
DeleterImpl<Stack, std::enable_if_t<!StackTraits<Stack>::kIsConst>>;

template <typename Stack>
class StackIteratorImpl { … };

StackIterator;

}  // namespace internal

// PushToStack pushes |elem| to |sk|. It returns true on success and false on
// allocation failure.
template <typename Stack>
inline std::enable_if_t<!internal::StackTraits<Stack>::kIsConst, bool>
PushToStack(Stack *sk,
            UniquePtr<typename internal::StackTraits<Stack>::Type> elem) { … }

BSSL_NAMESPACE_END

// Define begin() and end() for stack types so C++ range for loops work.
template <typename Stack>
inline bssl::internal::StackIterator<Stack> begin(const Stack *sk) { … }

template <typename Stack>
inline bssl::internal::StackIterator<Stack> end(const Stack *sk) { … }

}  // extern C++
#endif

#endif  // OPENSSL_HEADER_STACK_H