From: Andre Noll <maan@systemlinux.org>
Date: Sun, 18 Oct 2009 20:21:55 +0000 (+0200)
Subject: Simplify get_bits1().
X-Git-Tag: v0.4.1~58
X-Git-Url: http://git.tuebingen.mpg.de/?a=commitdiff_plain;ds=sidebyside;h=4163d3460d5dc61264636ebeb7b3fe8052b93568;p=paraslash.git

Simplify get_bits1().
---

diff --git a/bitstream.h b/bitstream.h
index cc56a83c..d13ef4c2 100644
--- a/bitstream.h
+++ b/bitstream.h
@@ -56,16 +56,12 @@ static inline unsigned int get_bits(struct getbit_context *gbc, int n)
 	return ret;
 }
 
+/* This is rather hot, we can do better than get_bits(gbc, 1). */
 static inline unsigned int get_bits1(struct getbit_context *gbc)
 {
-	int idx = gbc->index;
-	uint8_t result = gbc->buffer[idx >> 3];
-
-	result <<= (idx & 0x07);
-	result >>= 8 - 1;
-	idx++;
-	gbc->index = idx;
-	return result;
+	int idx = gbc->index++;
+	uint8_t tmp = gbc->buffer[idx >> 3], mask = (1 << (7 - (idx & 7)));
+	return !!(tmp & mask);
 }
 
 /**