1 files changed, 76 insertions, 0 deletions
diff --git a/modules/brotli/dec/bit_reader.c b/modules/brotli/dec/bit_reader.c
new file mode 100644
index 0000000000..7f7b256a40
--- /dev/null
+++ b/modules/brotli/dec/bit_reader.c
@@ -0,0 +1,76 @@
+/* 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 */
+
+#include "./bit_reader.h"
+
+#include "../common/platform.h"
+#include <brotli/types.h>
+
+#if defined(__cplusplus) || defined(c_plusplus)
+extern "C" {
+#endif
+
+const uint32_t kBrotliBitMask[33] = {   0x00000000,
+    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
+};
+
+void BrotliInitBitReader(BrotliBitReader* const br) {
+  br->val_ = 0;
+  br->bit_pos_ = sizeof(br->val_) << 3;
+}
+
+BROTLI_BOOL BrotliWarmupBitReader(BrotliBitReader* const br) {
+  size_t aligned_read_mask = (sizeof(br->val_) >> 1) - 1;
+  /* Fixing alignment after unaligned BrotliFillWindow would result accumulator
+     overflow. If unalignment is caused by BrotliSafeReadBits, then there is
+     enough space in accumulator to fix alignment. */
+  if (!BROTLI_ALIGNED_READ) {
+    aligned_read_mask = 0;
+  }
+  if (BrotliGetAvailableBits(br) == 0) {
+    if (!BrotliPullByte(br)) {
+      return BROTLI_FALSE;
+    }
+  }
+
+  while ((((size_t)br->next_in) & aligned_read_mask) != 0) {
+    if (!BrotliPullByte(br)) {
+      /* If we consumed all the input, we don't care about the alignment. */
+      return BROTLI_TRUE;
+    }
+  }
+  return BROTLI_TRUE;
+}
+
+BROTLI_BOOL BrotliSafeReadBits32Slow(BrotliBitReader* const br,
+    uint32_t n_bits, uint32_t* val) {
+  uint32_t low_val;
+  uint32_t high_val;
+  BrotliBitReaderState memento;
+  BROTLI_DCHECK(n_bits <= 32);
+  BROTLI_DCHECK(n_bits > 24);
+  BrotliBitReaderSaveState(br, &memento);
+  if (!BrotliSafeReadBits(br, 16, &low_val) ||
+      !BrotliSafeReadBits(br, n_bits - 16, &high_val)) {
+    BrotliBitReaderRestoreState(br, &memento);
+    return BROTLI_FALSE;
+  }
+  *val = low_val | (high_val << 16);
+  return BROTLI_TRUE;
+}
+
+#if defined(__cplusplus) || defined(c_plusplus)
+}  /* extern "C" */
+#endif