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/**********************************************************************
* Copyright (c) 2013, 2014 Pieter Wuille *
* Distributed under the MIT software license, see the accompanying *
* file COPYING or http://www.opensource.org/licenses/mit-license.php.*
**********************************************************************/
#ifndef SECP256K1_UTIL_H
#define SECP256K1_UTIL_H
#if defined HAVE_CONFIG_H
#include "libsecp256k1-config.h"
#endif
#include <stdlib.h>
#include <stdint.h>
#include <stdio.h>
#include <limits.h>
typedef struct {
void (*fn)(const char *text, void* data);
const void* data;
} secp256k1_callback;
static SECP256K1_INLINE void secp256k1_callback_call(const secp256k1_callback * const cb, const char * const text) {
cb->fn(text, (void*)cb->data);
}
#ifdef DETERMINISTIC
#define TEST_FAILURE(msg) do { \
fprintf(stderr, "%s\n", msg); \
abort(); \
} while(0);
#else
#define TEST_FAILURE(msg) do { \
fprintf(stderr, "%s:%d: %s\n", __FILE__, __LINE__, msg); \
abort(); \
} while(0)
#endif
#if SECP256K1_GNUC_PREREQ(3, 0)
#define EXPECT(x,c) __builtin_expect((x),(c))
#else
#define EXPECT(x,c) (x)
#endif
#ifdef DETERMINISTIC
#define CHECK(cond) do { \
if (EXPECT(!(cond), 0)) { \
TEST_FAILURE("test condition failed"); \
} \
} while(0)
#else
#define CHECK(cond) do { \
if (EXPECT(!(cond), 0)) { \
TEST_FAILURE("test condition failed: " #cond); \
} \
} while(0)
#endif
/* Like assert(), but when VERIFY is defined, and side-effect safe. */
#if defined(COVERAGE)
#define VERIFY_CHECK(check)
#define VERIFY_SETUP(stmt)
#elif defined(VERIFY)
#define VERIFY_CHECK CHECK
#define VERIFY_SETUP(stmt) do { stmt; } while(0)
#else
#define VERIFY_CHECK(cond) do { (void)(cond); } while(0)
#define VERIFY_SETUP(stmt)
#endif
/* Define `VG_UNDEF` and `VG_CHECK` when VALGRIND is defined */
#if !defined(VG_CHECK)
# if defined(VALGRIND)
# include <valgrind/memcheck.h>
# define VG_UNDEF(x,y) VALGRIND_MAKE_MEM_UNDEFINED((x),(y))
# define VG_CHECK(x,y) VALGRIND_CHECK_MEM_IS_DEFINED((x),(y))
# else
# define VG_UNDEF(x,y)
# define VG_CHECK(x,y)
# endif
#endif
/* Like `VG_CHECK` but on VERIFY only */
#if defined(VERIFY)
#define VG_CHECK_VERIFY(x,y) VG_CHECK((x), (y))
#else
#define VG_CHECK_VERIFY(x,y)
#endif
static SECP256K1_INLINE void *checked_malloc(const secp256k1_callback* cb, size_t size) {
void *ret = malloc(size);
if (ret == NULL) {
secp256k1_callback_call(cb, "Out of memory");
}
return ret;
}
static SECP256K1_INLINE void *checked_realloc(const secp256k1_callback* cb, void *ptr, size_t size) {
void *ret = realloc(ptr, size);
if (ret == NULL) {
secp256k1_callback_call(cb, "Out of memory");
}
return ret;
}
#if defined(__BIGGEST_ALIGNMENT__)
#define ALIGNMENT __BIGGEST_ALIGNMENT__
#else
/* Using 16 bytes alignment because common architectures never have alignment
* requirements above 8 for any of the types we care about. In addition we
* leave some room because currently we don't care about a few bytes. */
#define ALIGNMENT 16
#endif
#define ROUND_TO_ALIGN(size) (((size + ALIGNMENT - 1) / ALIGNMENT) * ALIGNMENT)
/* Assume there is a contiguous memory object with bounds [base, base + max_size)
* of which the memory range [base, *prealloc_ptr) is already allocated for usage,
* where *prealloc_ptr is an aligned pointer. In that setting, this functions
* reserves the subobject [*prealloc_ptr, *prealloc_ptr + alloc_size) of
* alloc_size bytes by increasing *prealloc_ptr accordingly, taking into account
* alignment requirements.
*
* The function returns an aligned pointer to the newly allocated subobject.
*
* This is useful for manual memory management: if we're simply given a block
* [base, base + max_size), the caller can use this function to allocate memory
* in this block and keep track of the current allocation state with *prealloc_ptr.
*
* It is VERIFY_CHECKed that there is enough space left in the memory object and
* *prealloc_ptr is aligned relative to base.
*/
static SECP256K1_INLINE void *manual_alloc(void** prealloc_ptr, size_t alloc_size, void* base, size_t max_size) {
size_t aligned_alloc_size = ROUND_TO_ALIGN(alloc_size);
void* ret;
VERIFY_CHECK(prealloc_ptr != NULL);
VERIFY_CHECK(*prealloc_ptr != NULL);
VERIFY_CHECK(base != NULL);
VERIFY_CHECK((unsigned char*)*prealloc_ptr >= (unsigned char*)base);
VERIFY_CHECK(((unsigned char*)*prealloc_ptr - (unsigned char*)base) % ALIGNMENT == 0);
VERIFY_CHECK((unsigned char*)*prealloc_ptr - (unsigned char*)base + aligned_alloc_size <= max_size);
ret = *prealloc_ptr;
*((unsigned char**)prealloc_ptr) += aligned_alloc_size;
return ret;
}
/* Macro for restrict, when available and not in a VERIFY build. */
#if defined(SECP256K1_BUILD) && defined(VERIFY)
# define SECP256K1_RESTRICT
#else
# if (!defined(__STDC_VERSION__) || (__STDC_VERSION__ < 199901L) )
# if SECP256K1_GNUC_PREREQ(3,0)
# define SECP256K1_RESTRICT __restrict__
# elif (defined(_MSC_VER) && _MSC_VER >= 1400)
# define SECP256K1_RESTRICT __restrict
# else
# define SECP256K1_RESTRICT
# endif
# else
# define SECP256K1_RESTRICT restrict
# endif
#endif
#if defined(_WIN32)
# define I64FORMAT "I64d"
# define I64uFORMAT "I64u"
#else
# define I64FORMAT "lld"
# define I64uFORMAT "llu"
#endif
#if defined(__GNUC__)
# define SECP256K1_GNUC_EXT __extension__
#else
# define SECP256K1_GNUC_EXT
#endif
/* If SECP256K1_{LITTLE,BIG}_ENDIAN is not explicitly provided, infer from various other system macros. */
#if !defined(SECP256K1_LITTLE_ENDIAN) && !defined(SECP256K1_BIG_ENDIAN)
/* Inspired by https://github.com/rofl0r/endianness.h/blob/9853923246b065a3b52d2c43835f3819a62c7199/endianness.h#L52L73 */
# if (defined(__BYTE_ORDER__) && defined(__ORDER_LITTLE_ENDIAN__) && __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__) || \
defined(_X86_) || defined(__x86_64__) || defined(__i386__) || \
defined(__i486__) || defined(__i586__) || defined(__i686__) || \
defined(__MIPSEL) || defined(_MIPSEL) || defined(MIPSEL) || \
defined(__ARMEL__) || defined(__AARCH64EL__) || \
(defined(__LITTLE_ENDIAN__) && __LITTLE_ENDIAN__ == 1) || \
(defined(_LITTLE_ENDIAN) && _LITTLE_ENDIAN == 1) || \
defined(_M_IX86) || defined(_M_AMD64) || defined(_M_ARM) /* MSVC */
# define SECP256K1_LITTLE_ENDIAN
# endif
# if (defined(__BYTE_ORDER__) && defined(__ORDER_BIG_ENDIAN__) && __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__) || \
defined(__MIPSEB) || defined(_MIPSEB) || defined(MIPSEB) || \
defined(__MICROBLAZEEB__) || defined(__ARMEB__) || defined(__AARCH64EB__) || \
(defined(__BIG_ENDIAN__) && __BIG_ENDIAN__ == 1) || \
(defined(_BIG_ENDIAN) && _BIG_ENDIAN == 1)
# define SECP256K1_BIG_ENDIAN
# endif
#endif
#if defined(SECP256K1_LITTLE_ENDIAN) == defined(SECP256K1_BIG_ENDIAN)
# error Please make sure that either SECP256K1_LITTLE_ENDIAN or SECP256K1_BIG_ENDIAN is set, see src/util.h.
#endif
/* Zero memory if flag == 1. Flag must be 0 or 1. Constant time. */
static SECP256K1_INLINE void memczero(void *s, size_t len, int flag) {
unsigned char *p = (unsigned char *)s;
/* Access flag with a volatile-qualified lvalue.
This prevents clang from figuring out (after inlining) that flag can
take only be 0 or 1, which leads to variable time code. */
volatile int vflag = flag;
unsigned char mask = -(unsigned char) vflag;
while (len) {
*p &= ~mask;
p++;
len--;
}
}
/** If flag is true, set *r equal to *a; otherwise leave it. Constant-time. Both *r and *a must be initialized and non-negative.*/
static SECP256K1_INLINE void secp256k1_int_cmov(int *r, const int *a, int flag) {
unsigned int mask0, mask1, r_masked, a_masked;
/* Access flag with a volatile-qualified lvalue.
This prevents clang from figuring out (after inlining) that flag can
take only be 0 or 1, which leads to variable time code. */
volatile int vflag = flag;
/* Casting a negative int to unsigned and back to int is implementation defined behavior */
VERIFY_CHECK(*r >= 0 && *a >= 0);
mask0 = (unsigned int)vflag + ~0u;
mask1 = ~mask0;
r_masked = ((unsigned int)*r & mask0);
a_masked = ((unsigned int)*a & mask1);
*r = (int)(r_masked | a_masked);
}
/* If USE_FORCE_WIDEMUL_{INT128,INT64} is set, use that wide multiplication implementation.
* Otherwise use the presence of __SIZEOF_INT128__ to decide.
*/
#if defined(USE_FORCE_WIDEMUL_INT128)
# define SECP256K1_WIDEMUL_INT128 1
#elif defined(USE_FORCE_WIDEMUL_INT64)
# define SECP256K1_WIDEMUL_INT64 1
#elif defined(__SIZEOF_INT128__)
# define SECP256K1_WIDEMUL_INT128 1
#else
# define SECP256K1_WIDEMUL_INT64 1
#endif
#if defined(SECP256K1_WIDEMUL_INT128)
SECP256K1_GNUC_EXT typedef unsigned __int128 uint128_t;
SECP256K1_GNUC_EXT typedef __int128 int128_t;
#endif
#endif /* SECP256K1_UTIL_H */
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