Update brotli to v1.0.0-snapshot.

third_party/brotli/dec/bit_reader.h

 /* Copyright 2013 Google Inc. All Rights Reserved.
 
    Distributed under MIT license.
    See file LICENSE for detail or copy at https://opensource.org/licenses/MIT
 */
 
 /* Bit reading helpers */
 
 #ifndef BROTLI_DEC_BIT_READER_H_
 #define BROTLI_DEC_BIT_READER_H_
 
 #include <string.h>  /* memcpy */
 
+#include <brotli/types.h>
 #include "./port.h"
-#include "./types.h"
 
 #if defined(__cplusplus) || defined(c_plusplus)
 extern "C" {
 #endif
 
-#if (BROTLI_64_BITS)
-#define BROTLI_SHORT_FILL_BIT_WINDOW_READ 4
-typedef uint64_t reg_t;
-#else
-#define BROTLI_SHORT_FILL_BIT_WINDOW_READ 2
-typedef uint32_t reg_t;
-#endif
+#define BROTLI_SHORT_FILL_BIT_WINDOW_READ (sizeof(reg_t) >> 1)
 
 static const uint32_t kBitMask[33] = { 0x0000,
     0x00000001, 0x00000003, 0x00000007, 0x0000000F,
     0x0000001F, 0x0000003F, 0x0000007F, 0x000000FF,
     0x000001FF, 0x000003FF, 0x000007FF, 0x00000FFF,
     0x00001FFF, 0x00003FFF, 0x00007FFF, 0x0000FFFF,
     0x0001FFFF, 0x0003FFFF, 0x0007FFFF, 0x000FFFFF,
     0x001FFFFF, 0x003FFFFF, 0x007FFFFF, 0x00FFFFFF,
     0x01FFFFFF, 0x03FFFFFF, 0x07FFFFFF, 0x0FFFFFFF,
     0x1FFFFFFF, 0x3FFFFFFF, 0x7FFFFFFF, 0xFFFFFFFF
@@ skipping 16 matching lines @@
   size_t avail_in;
 } BrotliBitReader;
 
 typedef struct {
   reg_t val_;
   uint32_t bit_pos_;
   const uint8_t* next_in;
   size_t avail_in;
 } BrotliBitReaderState;
 
-/* Initializes the bitreader fields. */
+/* Initializes the BrotliBitReader fields. */
 BROTLI_INTERNAL void BrotliInitBitReader(BrotliBitReader* const br);
 
 /* Ensures that accumulator is not empty. May consume one byte of input.
    Returns 0 if data is required but there is no input available.
    For BROTLI_ALIGNED_READ this function also prepares bit reader for aligned
    reading. */
-BROTLI_INTERNAL int BrotliWarmupBitReader(BrotliBitReader* const br);
+BROTLI_INTERNAL BROTLI_BOOL BrotliWarmupBitReader(BrotliBitReader* const br);
 
 static BROTLI_INLINE void BrotliBitReaderSaveState(
     BrotliBitReader* const from, BrotliBitReaderState* to) {
   to->val_ = from->val_;
   to->bit_pos_ = from->bit_pos_;
   to->next_in = from->next_in;
   to->avail_in = from->avail_in;
 }
 
 static BROTLI_INLINE void BrotliBitReaderRestoreState(
     BrotliBitReader* const to, BrotliBitReaderState* from) {
   to->val_ = from->val_;
   to->bit_pos_ = from->bit_pos_;
   to->next_in = from->next_in;
   to->avail_in = from->avail_in;
 }
 
 static BROTLI_INLINE uint32_t BrotliGetAvailableBits(
     const BrotliBitReader* br) {
   return (BROTLI_64_BITS ? 64 : 32) - br->bit_pos_;
 }
 
 /* Returns amount of unread bytes the bit reader still has buffered from the
    BrotliInput, including whole bytes in br->val_. */
 static BROTLI_INLINE size_t BrotliGetRemainingBytes(BrotliBitReader* br) {
   return br->avail_in + (BrotliGetAvailableBits(br) >> 3);
 }
 
-/* Checks if there is at least num bytes left in the input ringbuffer (excluding
-   the bits remaining in br->val_). */
-static BROTLI_INLINE int BrotliCheckInputAmount(
+/* Checks if there is at least |num| bytes left in the input ring-buffer
+   (excluding the bits remaining in br->val_). */
+static BROTLI_INLINE BROTLI_BOOL BrotliCheckInputAmount(
     BrotliBitReader* const br, size_t num) {
-  return br->avail_in >= num;
+  return TO_BROTLI_BOOL(br->avail_in >= num);
 }
 
 static BROTLI_INLINE uint16_t BrotliLoad16LE(const uint8_t* in) {
   if (BROTLI_LITTLE_ENDIAN) {
     return *((const uint16_t*)in);
   } else if (BROTLI_BIG_ENDIAN) {
     uint16_t value = *((const uint16_t*)in);
     return (uint16_t)(((value & 0xFFU) << 8) | ((value & 0xFF00U) >> 8));
   } else {
     return (uint16_t)(in[0] | (in[1] << 8));
@@ skipping 41 matching lines @@
     value |= (uint64_t)(*(in++)) << 48;
     value |= (uint64_t)(*(in++)) << 56;
     return value;
   }
 }
 #endif
 
 /* Guarantees that there are at least n_bits + 1 bits in accumulator.
    Precondition: accumulator contains at least 1 bit.
    n_bits should be in the range [1..24] for regular build. For portable
-   non-64-bit little endian build only 16 bits are safe to request. */
+   non-64-bit little-endian build only 16 bits are safe to request. */
 static BROTLI_INLINE void BrotliFillBitWindow(
     BrotliBitReader* const br, uint32_t n_bits) {
 #if (BROTLI_64_BITS)
   if (!BROTLI_ALIGNED_READ && IS_CONSTANT(n_bits) && (n_bits <= 8)) {
     if (br->bit_pos_ >= 56) {
       br->val_ >>= 56;
       br->bit_pos_ ^= 56;  /* here same as -= 56 because of the if condition */
       br->val_ |= BrotliLoad64LE(br->next_in) << 8;
       br->avail_in -= 7;
       br->next_in += 7;
@@ skipping 29 matching lines @@
       br->val_ >>= 16;
       br->bit_pos_ ^= 16;  /* here same as -= 16 because of the if condition */
       br->val_ |= ((uint32_t)BrotliLoad16LE(br->next_in)) << 16;
       br->avail_in -= BROTLI_SHORT_FILL_BIT_WINDOW_READ;
       br->next_in += BROTLI_SHORT_FILL_BIT_WINDOW_READ;
     }
   }
 #endif
 }
 
-/* Mosltly like BrotliFillBitWindow, but guarantees only 16 bits and reads no
+/* Mostly like BrotliFillBitWindow, but guarantees only 16 bits and reads no
    more than BROTLI_SHORT_FILL_BIT_WINDOW_READ bytes of input. */
 static BROTLI_INLINE void BrotliFillBitWindow16(BrotliBitReader* const br) {
   BrotliFillBitWindow(br, 17);
 }
 
 /* Pulls one byte of input to accumulator. */
-static BROTLI_INLINE int BrotliPullByte(BrotliBitReader* const br) {
+static BROTLI_INLINE BROTLI_BOOL BrotliPullByte(BrotliBitReader* const br) {
   if (br->avail_in == 0) {
-    return 0;
+    return BROTLI_FALSE;
   }
   br->val_ >>= 8;
 #if (BROTLI_64_BITS)
   br->val_ |= ((uint64_t)*br->next_in) << 56;
 #else
   br->val_ |= ((uint32_t)*br->next_in) << 24;
 #endif
   br->bit_pos_ -= 8;
   --br->avail_in;
   ++br->next_in;
-  return 1;
+  return BROTLI_TRUE;
 }
 
 /* Returns currently available bits.
-   The number of valid bits could be calclulated by BrotliGetAvailableBits. */
+   The number of valid bits could be calculated by BrotliGetAvailableBits. */
 static BROTLI_INLINE reg_t BrotliGetBitsUnmasked(BrotliBitReader* const br) {
   return br->val_ >> br->bit_pos_;
 }
 
 /* Like BrotliGetBits, but does not mask the result.
    The result contains at least 16 valid bits. */
 static BROTLI_INLINE uint32_t BrotliGet16BitsUnmasked(
     BrotliBitReader* const br) {
   BrotliFillBitWindow(br, 16);
   return (uint32_t)BrotliGetBitsUnmasked(br);
 }
 
-/* Returns the specified number of bits from br without advancing bit pos. */
+/* Returns the specified number of bits from |br| without advancing bit pos. */
 static BROTLI_INLINE uint32_t BrotliGetBits(
     BrotliBitReader* const br, uint32_t n_bits) {
   BrotliFillBitWindow(br, n_bits);
   return (uint32_t)BrotliGetBitsUnmasked(br) & BitMask(n_bits);
 }
 
 /* Tries to peek the specified amount of bits. Returns 0, if there is not
    enough input. */
-static BROTLI_INLINE int BrotliSafeGetBits(
+static BROTLI_INLINE BROTLI_BOOL BrotliSafeGetBits(
     BrotliBitReader* const br, uint32_t n_bits, uint32_t* val) {
   while (BrotliGetAvailableBits(br) < n_bits) {
     if (!BrotliPullByte(br)) {
-      return 0;
+      return BROTLI_FALSE;
     }
   }
   *val = (uint32_t)BrotliGetBitsUnmasked(br) & BitMask(n_bits);
-  return 1;
+  return BROTLI_TRUE;
 }
 
 /* Advances the bit pos by n_bits. */
 static BROTLI_INLINE void BrotliDropBits(
     BrotliBitReader* const br, uint32_t n_bits) {
   br->bit_pos_ += n_bits;
 }
 
 static BROTLI_INLINE void BrotliBitReaderUnload(BrotliBitReader* br) {
   uint32_t unused_bytes = BrotliGetAvailableBits(br) >> 3;
   uint32_t unused_bits = unused_bytes << 3;
   br->avail_in += unused_bytes;
   br->next_in -= unused_bytes;
   if (unused_bits == sizeof(br->val_) << 3) {
     br->val_ = 0;
   } else {
     br->val_ <<= unused_bits;
   }
   br->bit_pos_ += unused_bits;
 }
 
-/* Reads the specified number of bits from br and advances the bit pos.
+/* Reads the specified number of bits from |br| and advances the bit pos.
    Precondition: accumulator MUST contain at least n_bits. */
 static BROTLI_INLINE void BrotliTakeBits(
   BrotliBitReader* const br, uint32_t n_bits, uint32_t* val) {
   *val = (uint32_t)BrotliGetBitsUnmasked(br) & BitMask(n_bits);
   BROTLI_LOG(("[BrotliReadBits]  %d %d %d val: %6x\n",
       (int)br->avail_in, (int)br->bit_pos_, n_bits, (int)*val));
   BrotliDropBits(br, n_bits);
 }
 
-/* Reads the specified number of bits from br and advances the bit pos.
+/* Reads the specified number of bits from |br| and advances the bit pos.
    Assumes that there is enough input to perform BrotliFillBitWindow. */
 static BROTLI_INLINE uint32_t BrotliReadBits(
     BrotliBitReader* const br, uint32_t n_bits) {
   if (BROTLI_64_BITS || (n_bits <= 16)) {
     uint32_t val;
     BrotliFillBitWindow(br, n_bits);
     BrotliTakeBits(br, n_bits, &val);
     return val;
   } else {
     uint32_t low_val;
     uint32_t high_val;
     BrotliFillBitWindow(br, 16);
     BrotliTakeBits(br, 16, &low_val);
     BrotliFillBitWindow(br, 8);
     BrotliTakeBits(br, n_bits - 16, &high_val);
     return low_val | (high_val << 16);
   }
 }
 
 /* Tries to read the specified amount of bits. Returns 0, if there is not
    enough input. n_bits MUST be positive. */
-static BROTLI_INLINE int BrotliSafeReadBits(
+static BROTLI_INLINE BROTLI_BOOL BrotliSafeReadBits(
     BrotliBitReader* const br, uint32_t n_bits, uint32_t* val) {
   while (BrotliGetAvailableBits(br) < n_bits) {
     if (!BrotliPullByte(br)) {
-      return 0;
+      return BROTLI_FALSE;
     }
   }
   BrotliTakeBits(br, n_bits, val);
-  return 1;
+  return BROTLI_TRUE;
 }
 
 /* Advances the bit reader position to the next byte boundary and verifies
    that any skipped bits are set to zero. */
-static BROTLI_INLINE int BrotliJumpToByteBoundary(BrotliBitReader* br) {
+static BROTLI_INLINE BROTLI_BOOL BrotliJumpToByteBoundary(BrotliBitReader* br) {
   uint32_t pad_bits_count = BrotliGetAvailableBits(br) & 0x7;
   uint32_t pad_bits = 0;
   if (pad_bits_count != 0) {
     BrotliTakeBits(br, pad_bits_count, &pad_bits);
   }
-  return pad_bits == 0;
-}
-
-/* Peeks a byte at specified offset.
-   Precondition: bit reader is parked to a byte boundary.
-   Returns -1 if operation is not feasible. */
-static BROTLI_INLINE int BrotliPeekByte(BrotliBitReader* br, size_t offset) {
-  uint32_t available_bits = BrotliGetAvailableBits(br);
-  size_t bytes_left = available_bits >> 3;
-  BROTLI_DCHECK((available_bits & 7) == 0);
-  if (offset < bytes_left) {
-    return (BrotliGetBitsUnmasked(br) >> (unsigned)(offset << 3)) & 0xFF;
-  }
-  offset -= bytes_left;
-  if (offset < br->avail_in) {
-    return br->next_in[offset];
-  }
-  return -1;
+  return TO_BROTLI_BOOL(pad_bits == 0);
 }
 
 /* Copies remaining input bytes stored in the bit reader to the output. Value
    num may not be larger than BrotliGetRemainingBytes. The bit reader must be
    warmed up again after this. */
 static BROTLI_INLINE void BrotliCopyBytes(uint8_t* dest,
                                           BrotliBitReader* br, size_t num) {
   while (BrotliGetAvailableBits(br) >= 8 && num > 0) {
     *dest = (uint8_t)BrotliGetBitsUnmasked(br);
     BrotliDropBits(br, 8);
     ++dest;
     --num;
   }
   memcpy(dest, br->next_in, num);
   br->avail_in -= num;
   br->next_in += num;
 }
 
 #if defined(__cplusplus) || defined(c_plusplus)
 }  /* extern "C" */
 #endif
 
 #endif  /* BROTLI_DEC_BIT_READER_H_ */