| // Copyright 2019 The Fuchsia Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #include "util.h" |
| |
| #include <assert.h> |
| #include <stdlib.h> |
| |
| // |
| // |
| // |
| |
| #if defined(_MSC_VER) && !defined(__clang__) |
| |
| #include <intrin.h> |
| |
| #endif |
| |
| // |
| // |
| // |
| |
| bool |
| is_pow2_u32(uint32_t n) |
| { |
| return n && !(n & (n - 1)); |
| } |
| |
| // |
| // |
| // |
| |
| uint32_t |
| pow2_ru_u32(uint32_t n) |
| { |
| assert(n <= 0x80000000U); |
| |
| n--; |
| n |= n >> 1; |
| n |= n >> 2; |
| n |= n >> 4; |
| n |= n >> 8; |
| n |= n >> 16; |
| n++; |
| |
| return n; |
| } |
| |
| // |
| // |
| // |
| |
| uint32_t |
| pow2_rd_u32(uint32_t n) |
| { |
| assert(n > 0); |
| |
| return 1u << msb_idx_u32(n); |
| } |
| |
| // |
| // ASSUMES NON-ZERO |
| // |
| |
| uint32_t |
| msb_idx_u32(uint32_t n) |
| { |
| assert(n > 0); |
| #if defined(_MSC_VER) && !defined(__clang__) |
| |
| uint32_t index; |
| |
| _BitScanReverse((unsigned long *)&index, n); |
| |
| return index; |
| |
| #elif defined(__GNUC__) |
| |
| return __builtin_clz(n) ^ 31; |
| |
| #else |
| |
| #error "No msb_index()" |
| |
| #endif |
| } |
| |
| // |
| // Invokes malloc()/calloc() and asserts if NULL. |
| // |
| void * |
| malloc_assert(size_t size) |
| { |
| void * p = malloc(size); |
| |
| assert(p != NULL); |
| |
| return p; |
| } |
| |
| void * |
| calloc_assert(size_t num, size_t size) |
| { |
| void * p = calloc(num, size); |
| |
| assert(p != NULL); |
| |
| return p; |
| } |
| |
| // |
| // |
| // |