platform.h

/* Copyright 2016 Google Inc. All Rights Reserved.

   Distributed under MIT license.
   See file LICENSE for detail or copy at https://opensource.org/licenses/MIT
*/

/* Macros for compiler / platform specific features and build options.

   Build options are:
    * BROTLI_BUILD_32_BIT disables 64-bit optimizations
    * BROTLI_BUILD_64_BIT forces to use 64-bit optimizations
    * BROTLI_BUILD_BIG_ENDIAN forces to use big-endian optimizations
    * BROTLI_BUILD_ENDIAN_NEUTRAL disables endian-aware optimizations
    * BROTLI_BUILD_LITTLE_ENDIAN forces to use little-endian optimizations
    * BROTLI_BUILD_PORTABLE disables dangerous optimizations, like unaligned
      read and overlapping memcpy; this reduces decompression speed by 5%
    * BROTLI_BUILD_NO_RBIT disables "rbit" optimization for ARM CPUs
    * BROTLI_DEBUG dumps file name and line number when decoder detects stream
      or memory error
    * BROTLI_ENABLE_LOG enables asserts and dumps various state information
*/

#ifndef BROTLI_COMMON_PLATFORM_H_
#define BROTLI_COMMON_PLATFORM_H_

#include <string.h>  /* memcpy */
#include <stdlib.h>  /* malloc, free */

#include <brotli/port.h>
#include <brotli/types.h>

#if defined(OS_LINUX) || defined(OS_CYGWIN)
#include <endian.h>
#elif defined(OS_FREEBSD)
#include <machine/endian.h>
#elif defined(OS_MACOSX)
#include <machine/endian.h>
/* Let's try and follow the Linux convention */
#define BROTLI_X_BYTE_ORDER BYTE_ORDER
#define BROTLI_X_LITTLE_ENDIAN LITTLE_ENDIAN
#define BROTLI_X_BIG_ENDIAN BIG_ENDIAN
#endif

#if defined(BROTLI_ENABLE_LOG) || defined(BROTLI_DEBUG)
#include <assert.h>
#include <stdio.h>
#endif

/* The following macros were borrowed from https://github.com/nemequ/hedley
 * with permission of original author - Evan Nemerson <evan@nemerson.com> */

/* >>> >>> >>> hedley macros */

/* Define "BROTLI_PREDICT_TRUE" and "BROTLI_PREDICT_FALSE" macros for capable
   compilers.

To apply compiler hint, enclose the branching condition into macros, like this:

  if (BROTLI_PREDICT_TRUE(zero == 0)) {
    // main execution path
  } else {
    // compiler should place this code outside of main execution path
  }

OR:

  if (BROTLI_PREDICT_FALSE(something_rare_or_unexpected_happens)) {
    // compiler should place this code outside of main execution path
  }

*/
#if BROTLI_GNUC_HAS_BUILTIN(__builtin_expect, 3, 0, 0) || \
    BROTLI_INTEL_VERSION_CHECK(16, 0, 0) ||               \
    BROTLI_SUNPRO_VERSION_CHECK(5, 15, 0) ||              \
    BROTLI_ARM_VERSION_CHECK(4, 1, 0) ||                  \
    BROTLI_IBM_VERSION_CHECK(10, 1, 0) ||                 \
    BROTLI_TI_VERSION_CHECK(7, 3, 0) ||                   \
    BROTLI_TINYC_VERSION_CHECK(0, 9, 27)
#define BROTLI_PREDICT_TRUE(x) (__builtin_expect(!!(x), 1))
#define BROTLI_PREDICT_FALSE(x) (__builtin_expect(x, 0))
#else
#define BROTLI_PREDICT_FALSE(x) (x)
#define BROTLI_PREDICT_TRUE(x) (x)
#endif

#if defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) && \
    !defined(__cplusplus)
#define BROTLI_RESTRICT restrict
#elif BROTLI_GNUC_VERSION_CHECK(3, 1, 0) ||                         \
    BROTLI_MSVC_VERSION_CHECK(14, 0, 0) ||                          \
    BROTLI_INTEL_VERSION_CHECK(16, 0, 0) ||                         \
    BROTLI_ARM_VERSION_CHECK(4, 1, 0) ||                            \
    BROTLI_IBM_VERSION_CHECK(10, 1, 0) ||                           \
    BROTLI_PGI_VERSION_CHECK(17, 10, 0) ||                          \
    BROTLI_TI_VERSION_CHECK(8, 0, 0) ||                             \
    BROTLI_IAR_VERSION_CHECK(8, 0, 0) ||                            \
    (BROTLI_SUNPRO_VERSION_CHECK(5, 14, 0) && defined(__cplusplus))
#define BROTLI_RESTRICT __restrict
#elif BROTLI_SUNPRO_VERSION_CHECK(5, 3, 0) && !defined(__cplusplus)
#define BROTLI_RESTRICT _Restrict
#else
#define BROTLI_RESTRICT
#endif

#if (defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L)) || \
    (defined(__cplusplus) && (__cplusplus >= 199711L))
#define BROTLI_MAYBE_INLINE inline
#elif defined(__GNUC_STDC_INLINE__) || defined(__GNUC_GNU_INLINE__) || \
    BROTLI_ARM_VERSION_CHECK(6, 2, 0)
#define BROTLI_MAYBE_INLINE __inline__
#elif BROTLI_MSVC_VERSION_CHECK(12, 0, 0) || \
    BROTLI_ARM_VERSION_CHECK(4, 1, 0) || BROTLI_TI_VERSION_CHECK(8, 0, 0)
#define BROTLI_MAYBE_INLINE __inline
#else
#define BROTLI_MAYBE_INLINE
#endif

#if BROTLI_GNUC_HAS_ATTRIBUTE(always_inline, 4, 0, 0) ||                       \
    BROTLI_INTEL_VERSION_CHECK(16, 0, 0) ||                                    \
    BROTLI_SUNPRO_VERSION_CHECK(5, 11, 0) ||                                   \
    BROTLI_ARM_VERSION_CHECK(4, 1, 0) ||                                       \
    BROTLI_IBM_VERSION_CHECK(10, 1, 0) ||                                      \
    BROTLI_TI_VERSION_CHECK(8, 0, 0) ||                                        \
    (BROTLI_TI_VERSION_CHECK(7, 3, 0) && defined(__TI_GNU_ATTRIBUTE_SUPPORT__))
#define BROTLI_INLINE BROTLI_MAYBE_INLINE __attribute__((__always_inline__))
#elif BROTLI_MSVC_VERSION_CHECK(12, 0, 0)
#define BROTLI_INLINE BROTLI_MAYBE_INLINE __forceinline
#elif BROTLI_TI_VERSION_CHECK(7, 0, 0) && defined(__cplusplus)
#define BROTLI_INLINE BROTLI_MAYBE_INLINE _Pragma("FUNC_ALWAYS_INLINE;")
#elif BROTLI_IAR_VERSION_CHECK(8, 0, 0)
#define BROTLI_INLINE BROTLI_MAYBE_INLINE _Pragma("inline=forced")
#else
#define BROTLI_INLINE BROTLI_MAYBE_INLINE
#endif

#if BROTLI_GNUC_HAS_ATTRIBUTE(noinline, 4, 0, 0) ||                            \
    BROTLI_INTEL_VERSION_CHECK(16, 0, 0) ||                                    \
    BROTLI_SUNPRO_VERSION_CHECK(5, 11, 0) ||                                   \
    BROTLI_ARM_VERSION_CHECK(4, 1, 0) ||                                       \
    BROTLI_IBM_VERSION_CHECK(10, 1, 0) ||                                      \
    BROTLI_TI_VERSION_CHECK(8, 0, 0) ||                                        \
    (BROTLI_TI_VERSION_CHECK(7, 3, 0) && defined(__TI_GNU_ATTRIBUTE_SUPPORT__))
#define BROTLI_NOINLINE __attribute__((__noinline__))
#elif BROTLI_MSVC_VERSION_CHECK(13, 10, 0)
#define BROTLI_NOINLINE __declspec(noinline)
#elif BROTLI_PGI_VERSION_CHECK(10, 2, 0)
#define BROTLI_NOINLINE _Pragma("noinline")
#elif BROTLI_TI_VERSION_CHECK(6, 0, 0) && defined(__cplusplus)
#define BROTLI_NOINLINE _Pragma("FUNC_CANNOT_INLINE;")
#elif BROTLI_IAR_VERSION_CHECK(8, 0, 0)
#define BROTLI_NOINLINE _Pragma("inline=never")
#else
#define BROTLI_NOINLINE
#endif

/* BROTLI_INTERNAL could be defined to override visibility, e.g. for tests. */
#if !defined(BROTLI_INTERNAL)
#if defined(_WIN32) || defined(__CYGWIN__)
#define BROTLI_INTERNAL
#elif BROTLI_GNUC_VERSION_CHECK(3, 3, 0) ||                         \
    BROTLI_TI_VERSION_CHECK(8, 0, 0) ||                             \
    BROTLI_INTEL_VERSION_CHECK(16, 0, 0) ||                         \
    BROTLI_ARM_VERSION_CHECK(4, 1, 0) ||                            \
    BROTLI_IBM_VERSION_CHECK(13, 1, 0) ||                           \
    BROTLI_SUNPRO_VERSION_CHECK(5, 11, 0) ||                        \
    (BROTLI_TI_VERSION_CHECK(7, 3, 0) &&                            \
     defined(__TI_GNU_ATTRIBUTE_SUPPORT__) && defined(__TI_EABI__))
#define BROTLI_INTERNAL __attribute__ ((visibility ("hidden")))
#else
#define BROTLI_INTERNAL
#endif
#endif

/* <<< <<< <<< end of hedley macros. */

#if BROTLI_GNUC_HAS_ATTRIBUTE(unused, 2, 7, 0) || \
    BROTLI_INTEL_VERSION_CHECK(16, 0, 0)
#define BROTLI_UNUSED_FUNCTION static BROTLI_INLINE __attribute__ ((unused))
#else
#define BROTLI_UNUSED_FUNCTION static BROTLI_INLINE
#endif

#if BROTLI_GNUC_HAS_ATTRIBUTE(aligned, 2, 7, 0)
#define BROTLI_ALIGNED(N) __attribute__((aligned(N)))
#else
#define BROTLI_ALIGNED(N)
#endif

#if (defined(__ARM_ARCH) && (__ARM_ARCH == 7)) || \
    (defined(M_ARM) && (M_ARM == 7))
#define BROTLI_TARGET_ARMV7
#endif  /* ARMv7 */

#if (defined(__ARM_ARCH) && (__ARM_ARCH == 8)) || \
    defined(__aarch64__) || defined(__ARM64_ARCH_8__)
#define BROTLI_TARGET_ARMV8_ANY

#if defined(__ARM_32BIT_STATE)
#define BROTLI_TARGET_ARMV8_32
#elif defined(__ARM_64BIT_STATE)
#define BROTLI_TARGET_ARMV8_64
#endif

#endif  /* ARMv8 */

#if defined(__ARM_NEON__) || defined(__ARM_NEON)
#define BROTLI_TARGET_NEON
#endif

#if defined(__i386) || defined(_M_IX86)
#define BROTLI_TARGET_X86
#endif

#if defined(__x86_64__) || defined(_M_X64)
#define BROTLI_TARGET_X64
#endif

#if defined(__PPC64__)
#define BROTLI_TARGET_POWERPC64
#endif

#if defined(__riscv) && defined(__riscv_xlen) && __riscv_xlen == 64
#define BROTLI_TARGET_RISCV64
#endif

#if defined(BROTLI_BUILD_64_BIT)
#define BROTLI_64_BITS 1
#elif defined(BROTLI_BUILD_32_BIT)
#define BROTLI_64_BITS 0
#elif defined(BROTLI_TARGET_X64) || defined(BROTLI_TARGET_ARMV8_64) || \
    defined(BROTLI_TARGET_POWERPC64) || defined(BROTLI_TARGET_RISCV64)
#define BROTLI_64_BITS 1
#else
#define BROTLI_64_BITS 0
#endif

#if (BROTLI_64_BITS)
#define brotli_reg_t uint64_t
#else
#define brotli_reg_t uint32_t
#endif

#if defined(BROTLI_BUILD_BIG_ENDIAN)
#define BROTLI_BIG_ENDIAN 1
#elif defined(BROTLI_BUILD_LITTLE_ENDIAN)
#define BROTLI_LITTLE_ENDIAN 1
#elif defined(BROTLI_BUILD_ENDIAN_NEUTRAL)
/* Just break elif chain. */
#elif defined(__BYTE_ORDER__) && (__BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__)
#define BROTLI_LITTLE_ENDIAN 1
#elif defined(_WIN32) || defined(BROTLI_TARGET_X64)
/* Win32 & x64 can currently always be assumed to be little endian */
#define BROTLI_LITTLE_ENDIAN 1
#elif defined(__BYTE_ORDER__) && (__BYTE_ORDER__ == __ORDER_BIG_ENDIAN__)
#define BROTLI_BIG_ENDIAN 1
#elif defined(BROTLI_X_BYTE_ORDER)
#if BROTLI_X_BYTE_ORDER == BROTLI_X_LITTLE_ENDIAN
#define BROTLI_LITTLE_ENDIAN 1
#elif BROTLI_X_BYTE_ORDER == BROTLI_X_BIG_ENDIAN
#define BROTLI_BIG_ENDIAN 1
#endif
#endif  /* BROTLI_X_BYTE_ORDER */

#if !defined(BROTLI_LITTLE_ENDIAN)
#define BROTLI_LITTLE_ENDIAN 0
#endif

#if !defined(BROTLI_BIG_ENDIAN)
#define BROTLI_BIG_ENDIAN 0
#endif

#if defined(BROTLI_X_BYTE_ORDER)
#undef BROTLI_X_BYTE_ORDER
#undef BROTLI_X_LITTLE_ENDIAN
#undef BROTLI_X_BIG_ENDIAN
#endif

#if defined(BROTLI_BUILD_PORTABLE)
#define BROTLI_ALIGNED_READ (!!1)
#elif defined(BROTLI_TARGET_X86) || defined(BROTLI_TARGET_X64) || \
    defined(BROTLI_TARGET_ARMV7) || defined(BROTLI_TARGET_ARMV8_ANY) || \
    defined(BROTLI_TARGET_RISCV64)
/* Allow unaligned read only for white-listed CPUs. */
#define BROTLI_ALIGNED_READ (!!0)
#else
#define BROTLI_ALIGNED_READ (!!1)
#endif

#if BROTLI_ALIGNED_READ
/* Portable unaligned memory access: read / write values via memcpy. */
static BROTLI_INLINE uint16_t BrotliUnalignedRead16(const void* p) {
  uint16_t t;
  memcpy(&t, p, sizeof t);
  return t;
}
static BROTLI_INLINE uint32_t BrotliUnalignedRead32(const void* p) {
  uint32_t t;
  memcpy(&t, p, sizeof t);
  return t;
}
static BROTLI_INLINE uint64_t BrotliUnalignedRead64(const void* p) {
  uint64_t t;
  memcpy(&t, p, sizeof t);
  return t;
}
static BROTLI_INLINE void BrotliUnalignedWrite64(void* p, uint64_t v) {
  memcpy(p, &v, sizeof v);
}
#else  /* BROTLI_ALIGNED_READ */
/* Unaligned memory access is allowed: just cast pointer to requested type. */
#if defined(ADDRESS_SANITIZER) || defined(THREAD_SANITIZER) || \
    defined(MEMORY_SANITIZER)
/* Consider we have an unaligned load/store of 4 bytes from address 0x...05.
   AddressSanitizer will treat it as a 3-byte access to the range 05:07 and
   will miss a bug if 08 is the first unaddressable byte.
   ThreadSanitizer will also treat this as a 3-byte access to 05:07 and will
   miss a race between this access and some other accesses to 08.
   MemorySanitizer will correctly propagate the shadow on unaligned stores
   and correctly report bugs on unaligned loads, but it may not properly
   update and report the origin of the uninitialized memory.
   For all three tools, replacing an unaligned access with a tool-specific
   callback solves the problem. */
#if defined(__cplusplus)
extern "C" {
#endif  /* __cplusplus */
  uint16_t __sanitizer_unaligned_load16(const void* p);
  uint32_t __sanitizer_unaligned_load32(const void* p);
  uint64_t __sanitizer_unaligned_load64(const void* p);
  void __sanitizer_unaligned_store64(void* p, uint64_t v);
#if defined(__cplusplus)
}  /* extern "C" */
#endif  /* __cplusplus */
#define BrotliUnalignedRead16 __sanitizer_unaligned_load16
#define BrotliUnalignedRead32 __sanitizer_unaligned_load32
#define BrotliUnalignedRead64 __sanitizer_unaligned_load64
#define BrotliUnalignedWrite64 __sanitizer_unaligned_store64
#else
static BROTLI_INLINE uint16_t BrotliUnalignedRead16(const void* p) {
  return *(const uint16_t*)p;
}
static BROTLI_INLINE uint32_t BrotliUnalignedRead32(const void* p) {
  return *(const uint32_t*)p;
}
#if (BROTLI_64_BITS)
static BROTLI_INLINE uint64_t BrotliUnalignedRead64(const void* p) {
  return *(const uint64_t*)p;
}
static BROTLI_INLINE void BrotliUnalignedWrite64(void* p, uint64_t v) {
  *(uint64_t*)p = v;
}
#else  /* BROTLI_64_BITS */
/* Avoid emitting LDRD / STRD, which require properly aligned address. */
/* If __attribute__(aligned) is available, use that. Otherwise, memcpy. */

#if BROTLI_GNUC_HAS_ATTRIBUTE(aligned, 2, 7, 0)
typedef BROTLI_ALIGNED(1) uint64_t brotli_unaligned_uint64_t;

static BROTLI_INLINE uint64_t BrotliUnalignedRead64(const void* p) {
  return (uint64_t) ((brotli_unaligned_uint64_t*) p)[0];
}
static BROTLI_INLINE void BrotliUnalignedWrite64(void* p, uint64_t v) {
  brotli_unaligned_uint64_t* dwords = (brotli_unaligned_uint64_t*) p;
  dwords[0] = (brotli_unaligned_uint64_t) v;
}
#else /* BROTLI_GNUC_HAS_ATTRIBUTE(aligned, 2, 7, 0) */
static BROTLI_INLINE uint64_t BrotliUnalignedRead64(const void* p) {
  uint64_t v;
  memcpy(&v, p, sizeof(uint64_t));
  return v;
}

static BROTLI_INLINE void BrotliUnalignedWrite64(void* p, uint64_t v) {
  memcpy(p, &v, sizeof(uint64_t));
}
#endif  /* BROTLI_GNUC_HAS_ATTRIBUTE(aligned, 2, 7, 0) */
#endif  /* BROTLI_64_BITS */
#endif  /* ASAN / TSAN / MSAN */
#endif  /* BROTLI_ALIGNED_READ */

#if BROTLI_LITTLE_ENDIAN
/* Straight endianness. Just read / write values. */
#define BROTLI_UNALIGNED_LOAD16LE BrotliUnalignedRead16
#define BROTLI_UNALIGNED_LOAD32LE BrotliUnalignedRead32
#define BROTLI_UNALIGNED_LOAD64LE BrotliUnalignedRead64
#define BROTLI_UNALIGNED_STORE64LE BrotliUnalignedWrite64
#elif BROTLI_BIG_ENDIAN  /* BROTLI_LITTLE_ENDIAN */
/* Explain compiler to byte-swap values. */
#define BROTLI_BSWAP16_(V) ((uint16_t)( \
  (((V) & 0xFFU) << 8) | \
  (((V) >> 8) & 0xFFU)))
static BROTLI_INLINE uint16_t BROTLI_UNALIGNED_LOAD16LE(const void* p) {
  uint16_t value = BrotliUnalignedRead16(p);
  return BROTLI_BSWAP16_(value);
}
#define BROTLI_BSWAP32_(V) ( \
  (((V) & 0xFFU) << 24) | (((V) & 0xFF00U) << 8) | \
  (((V) >> 8) & 0xFF00U) | (((V) >> 24) & 0xFFU))
static BROTLI_INLINE uint32_t BROTLI_UNALIGNED_LOAD32LE(const void* p) {
  uint32_t value = BrotliUnalignedRead32(p);
  return BROTLI_BSWAP32_(value);
}
#define BROTLI_BSWAP64_(V) ( \
  (((V) & 0xFFU) << 56) | (((V) & 0xFF00U) << 40) | \
  (((V) & 0xFF0000U) << 24) | (((V) & 0xFF000000U) << 8) | \
  (((V) >> 8) & 0xFF000000U) | (((V) >> 24) & 0xFF0000U) | \
  (((V) >> 40) & 0xFF00U) | (((V) >> 56) & 0xFFU))
static BROTLI_INLINE uint64_t BROTLI_UNALIGNED_LOAD64LE(const void* p) {
  uint64_t value = BrotliUnalignedRead64(p);
  return BROTLI_BSWAP64_(value);
}
static BROTLI_INLINE void BROTLI_UNALIGNED_STORE64LE(void* p, uint64_t v) {
  uint64_t value = BROTLI_BSWAP64_(v);
  BrotliUnalignedWrite64(p, value);
}
#else  /* BROTLI_LITTLE_ENDIAN */
/* Read / store values byte-wise; hopefully compiler will understand. */
static BROTLI_INLINE uint16_t BROTLI_UNALIGNED_LOAD16LE(const void* p) {
  const uint8_t* in = (const uint8_t*)p;
  return (uint16_t)(in[0] | (in[1] << 8));
}
static BROTLI_INLINE uint32_t BROTLI_UNALIGNED_LOAD32LE(const void* p) {
  const uint8_t* in = (const uint8_t*)p;
  uint32_t value = (uint32_t)(in[0]);
  value |= (uint32_t)(in[1]) << 8;
  value |= (uint32_t)(in[2]) << 16;
  value |= (uint32_t)(in[3]) << 24;
  return value;
}
static BROTLI_INLINE uint64_t BROTLI_UNALIGNED_LOAD64LE(const void* p) {
  const uint8_t* in = (const uint8_t*)p;
  uint64_t value = (uint64_t)(in[0]);
  value |= (uint64_t)(in[1]) << 8;
  value |= (uint64_t)(in[2]) << 16;
  value |= (uint64_t)(in[3]) << 24;
  value |= (uint64_t)(in[4]) << 32;
  value |= (uint64_t)(in[5]) << 40;
  value |= (uint64_t)(in[6]) << 48;
  value |= (uint64_t)(in[7]) << 56;
  return value;
}
static BROTLI_INLINE void BROTLI_UNALIGNED_STORE64LE(void* p, uint64_t v) {
  uint8_t* out = (uint8_t*)p;
  out[0] = (uint8_t)v;
  out[1] = (uint8_t)(v >> 8);
  out[2] = (uint8_t)(v >> 16);
  out[3] = (uint8_t)(v >> 24);
  out[4] = (uint8_t)(v >> 32);
  out[5] = (uint8_t)(v >> 40);
  out[6] = (uint8_t)(v >> 48);
  out[7] = (uint8_t)(v >> 56);
}
#endif  /* BROTLI_LITTLE_ENDIAN */

/* BROTLI_IS_CONSTANT macros returns true for compile-time constants. */
#if BROTLI_GNUC_HAS_BUILTIN(__builtin_constant_p, 3, 0, 1) || \
    BROTLI_INTEL_VERSION_CHECK(16, 0, 0)
#define BROTLI_IS_CONSTANT(x) (!!__builtin_constant_p(x))
#else
#define BROTLI_IS_CONSTANT(x) (!!0)
#endif

#if defined(BROTLI_TARGET_ARMV7) || defined(BROTLI_TARGET_ARMV8_ANY)
#define BROTLI_HAS_UBFX (!!1)
#else
#define BROTLI_HAS_UBFX (!!0)
#endif

#if defined(BROTLI_ENABLE_LOG)
#define BROTLI_DCHECK(x) assert(x)
#define BROTLI_LOG(x) printf x
#else
#define BROTLI_DCHECK(x)
#define BROTLI_LOG(x)
#endif

#if defined(BROTLI_DEBUG) || defined(BROTLI_ENABLE_LOG)
static BROTLI_INLINE void BrotliDump(const char* f, int l, const char* fn) {
  fprintf(stderr, "%s:%d (%s)\n", f, l, fn);
  fflush(stderr);
}
#define BROTLI_DUMP() BrotliDump(__FILE__, __LINE__, __FUNCTION__)
#else
#define BROTLI_DUMP() (void)(0)
#endif

/* TODO: add appropriate icc/sunpro/arm/ibm/ti checks. */
#if (BROTLI_GNUC_VERSION_CHECK(3, 0, 0) || defined(__llvm__)) && \
    !defined(BROTLI_BUILD_NO_RBIT)
#if defined(BROTLI_TARGET_ARMV7) || defined(BROTLI_TARGET_ARMV8_ANY)
/* TODO: detect ARMv6T2 and enable this code for it. */
static BROTLI_INLINE brotli_reg_t BrotliRBit(brotli_reg_t input) {
  brotli_reg_t output;
  __asm__("rbit %0, %1\n" : "=r"(output) : "r"(input));
  return output;
}
#define BROTLI_RBIT(x) BrotliRBit(x)
#endif  /* armv7 / armv8 */
#endif  /* gcc || clang */
#if !defined(BROTLI_RBIT)
static BROTLI_INLINE void BrotliRBit(void) { /* Should break build if used. */ }
#endif  /* BROTLI_RBIT */

#define BROTLI_REPEAT(N, X) {     \
  if ((N & 1) != 0) {X;}          \
  if ((N & 2) != 0) {X; X;}       \
  if ((N & 4) != 0) {X; X; X; X;} \
}

#define BROTLI_UNUSED(X) (void)(X)

#define BROTLI_MIN_MAX(T)                                                      \
  static BROTLI_INLINE T brotli_min_ ## T (T a, T b) { return a < b ? a : b; } \
  static BROTLI_INLINE T brotli_max_ ## T (T a, T b) { return a > b ? a : b; }
BROTLI_MIN_MAX(double) BROTLI_MIN_MAX(float) BROTLI_MIN_MAX(int)
BROTLI_MIN_MAX(size_t) BROTLI_MIN_MAX(uint32_t) BROTLI_MIN_MAX(uint8_t)
#undef BROTLI_MIN_MAX
#define BROTLI_MIN(T, A, B) (brotli_min_ ## T((A), (B)))
#define BROTLI_MAX(T, A, B) (brotli_max_ ## T((A), (B)))

#define BROTLI_SWAP(T, A, I, J) { \
  T __brotli_swap_tmp = (A)[(I)]; \
  (A)[(I)] = (A)[(J)];            \
  (A)[(J)] = __brotli_swap_tmp;   \
}

/* Default brotli_alloc_func */
static void* BrotliDefaultAllocFunc(void* opaque, size_t size) {
  BROTLI_UNUSED(opaque);
  return malloc(size);
}

/* Default brotli_free_func */
static void BrotliDefaultFreeFunc(void* opaque, void* address) {
  BROTLI_UNUSED(opaque);
  free(address);
}

BROTLI_UNUSED_FUNCTION void BrotliSuppressUnusedFunctions(void) {
  BROTLI_UNUSED(&BrotliSuppressUnusedFunctions);
  BROTLI_UNUSED(&BrotliUnalignedRead16);
  BROTLI_UNUSED(&BrotliUnalignedRead32);
  BROTLI_UNUSED(&BrotliUnalignedRead64);
  BROTLI_UNUSED(&BrotliUnalignedWrite64);
  BROTLI_UNUSED(&BROTLI_UNALIGNED_LOAD16LE);
  BROTLI_UNUSED(&BROTLI_UNALIGNED_LOAD32LE);
  BROTLI_UNUSED(&BROTLI_UNALIGNED_LOAD64LE);
  BROTLI_UNUSED(&BROTLI_UNALIGNED_STORE64LE);
  BROTLI_UNUSED(&BrotliRBit);
  BROTLI_UNUSED(&brotli_min_double);
  BROTLI_UNUSED(&brotli_max_double);
  BROTLI_UNUSED(&brotli_min_float);
  BROTLI_UNUSED(&brotli_max_float);
  BROTLI_UNUSED(&brotli_min_int);
  BROTLI_UNUSED(&brotli_max_int);
  BROTLI_UNUSED(&brotli_min_size_t);
  BROTLI_UNUSED(&brotli_max_size_t);
  BROTLI_UNUSED(&brotli_min_uint32_t);
  BROTLI_UNUSED(&brotli_max_uint32_t);
  BROTLI_UNUSED(&brotli_min_uint8_t);
  BROTLI_UNUSED(&brotli_max_uint8_t);
  BROTLI_UNUSED(&BrotliDefaultAllocFunc);
  BROTLI_UNUSED(&BrotliDefaultFreeFunc);
#if defined(BROTLI_DEBUG) || defined(BROTLI_ENABLE_LOG)
  BROTLI_UNUSED(&BrotliDump);
#endif
}

#endif  /* BROTLI_COMMON_PLATFORM_H_ */