1 files changed, 71 insertions, 0 deletions
diff --git a/third_party/dav1d/src/getbits.h b/third_party/dav1d/src/getbits.h
new file mode 100644
index 0000000000..67925943cd
--- /dev/null
+++ b/third_party/dav1d/src/getbits.h
@@ -0,0 +1,71 @@
+/*
+ * Copyright © 2018, VideoLAN and dav1d authors
+ * Copyright © 2018, Two Orioles, LLC
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
+ * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef DAV1D_SRC_GETBITS_H
+#define DAV1D_SRC_GETBITS_H
+
+#include <stddef.h>
+#include <stdint.h>
+
+typedef struct GetBits {
+    uint64_t state;
+    int bits_left, error;
+    const uint8_t *ptr, *ptr_start, *ptr_end;
+} GetBits;
+
+void dav1d_init_get_bits(GetBits *c, const uint8_t *data, size_t sz);
+unsigned dav1d_get_bit(GetBits *c);
+unsigned dav1d_get_bits(GetBits *c, int n);
+int dav1d_get_sbits(GetBits *c, int n);
+unsigned dav1d_get_uleb128(GetBits *c);
+
+// Output in range 0..max-1
+unsigned dav1d_get_uniform(GetBits *c, unsigned max);
+unsigned dav1d_get_vlc(GetBits *c);
+int dav1d_get_bits_subexp(GetBits *c, int ref, unsigned n);
+
+// Discard bits from the buffer until we're next byte-aligned.
+static inline void dav1d_bytealign_get_bits(GetBits *c) {
+    // bits_left is never more than 7, because it is only incremented
+    // by refill(), called by dav1d_get_bits and that never reads more
+    // than 7 bits more than it needs.
+    //
+    // If this wasn't true, we would need to work out how many bits to
+    // discard (bits_left % 8), subtract that from bits_left and then
+    // shift state right by that amount.
+    assert(c->bits_left <= 7);
+
+    c->bits_left = 0;
+    c->state = 0;
+}
+
+// Return the current bit position relative to the start of the buffer.
+static inline unsigned dav1d_get_bits_pos(const GetBits *c) {
+    return (unsigned) (c->ptr - c->ptr_start) * 8 - c->bits_left;
+}
+
+#endif /* DAV1D_SRC_GETBITS_H */