From ed95388324f10ebad71fd3a8e3691400ba6ff7f8 Mon Sep 17 00:00:00 2001
From: Moritz Bunkus <moritz@bunkus.org>
Date: Mon, 11 Aug 2003 21:17:13 +0000
Subject: [PATCH] Changed the return value of the bit cursor get_bit*
 functions. They now return true if the operation was successfull to be more
 consistent with the rest of this code.

---
 src/aac_common.cpp | 12 ++++++------
 src/common.h       | 16 ++++++++++------
 src/dts_common.cpp |  2 +-
 3 files changed, 17 insertions(+), 13 deletions(-)

diff --git a/src/aac_common.cpp b/src/aac_common.cpp
index f612a61c0..12bc9ed95 100644
--- a/src/aac_common.cpp
+++ b/src/aac_common.cpp
@@ -45,7 +45,7 @@ int parse_aac_adif_header(unsigned char *buf, int size,
   bc.get_bit(b);                // copyright_id_present
   if (b) {
     for (i = 0; i < 3; i++)
-      eob = bc.get_bits(24, bits); // copyright_id
+      eob = !bc.get_bits(24, bits); // copyright_id
   }
   bc.get_bit(b);                // original_copy
   bc.get_bit(b);                // home
@@ -74,7 +74,7 @@ int parse_aac_adif_header(unsigned char *buf, int size,
     bc.get_bit(b);              // matrix_mixdown_idx_present
     if (b) {
       bc.get_bits(2, bits);     // matrix_mixdown_idx
-      eob = bc.get_bits(1, bits); // pseudo_surround_enable
+      eob = !bc.get_bits(1, bits); // pseudo_surround_enable
     }
     channels = nfront_c_e + nside_c_e + nback_c_e;
     for (k = 0; k < (nfront_c_e + nside_c_e + nback_c_e); k++) {
@@ -91,9 +91,9 @@ int parse_aac_adif_header(unsigned char *buf, int size,
       bc.get_bits(4, bits);     // valid_cc_e_tag_select
     }
     bc.byte_align();
-    eob = bc.get_bits(8, bits);
+    eob = !bc.get_bits(8, bits);
     for (k = 0; k < comment_field_bytes; k++)
-      eob = bc.get_bits(8, bits);
+      eob = !bc.get_bits(8, bits);
   }
 
   if (eob)
@@ -139,9 +139,9 @@ static int is_adts_header(unsigned char *buf, int size, int bpos,
   bc.get_bit(b);                // copyright_id_start
   bc.get_bits(13, frame_length);
   bc.get_bits(11, bits);        // adts_buffer_fullness
-  eob = bc.get_bits(2, bits);   // no_raw_blocks_in_frame
+  eob = !bc.get_bits(2, bits);   // no_raw_blocks_in_frame
   if (!protection_absent)
-    eob = bc.get_bits(16, bits);
+    eob = !bc.get_bits(16, bits);
 
   if (eob)
     return 0;
diff --git a/src/common.h b/src/common.h
index 2ff0bb0a1..3dbff2ecd 100644
--- a/src/common.h
+++ b/src/common.h
@@ -143,13 +143,13 @@ public:
   }
 
   bool get_bits(unsigned int n, unsigned long &r) {
-    // returns true if less bits are available than asked for
+    // returns false if less bits are available than asked for
     r = 0;
 
     while (n > 0) {
       if (byte_position >= end_of_data) {
         out_of_data = true;
-        return true;
+        return false;
       }
 
       unsigned int b = 8; // number of bits to extract from the current byte
@@ -172,7 +172,7 @@ public:
       n -= b;
     }
 
-    return false;
+    return true;
   }
 
   bool get_bits(unsigned int n, int &r) {
@@ -198,12 +198,12 @@ public:
 
   bool byte_align() {
     if (out_of_data)
-      return true;
-    if (bits_valid == 8)
       return false;
+    if (bits_valid == 8)
+      return true;
     bits_valid = 0;
     byte_position += 1;
-    return false;
+    return true;
   }
 
   bool set_bit_position(unsigned int pos) {
@@ -219,6 +219,10 @@ public:
   int get_bit_position() {
     return byte_position - start_of_data + 8 - bits_valid;
   }
+
+  bool skip_bits(unsigned int num) {
+    return set_bit_position(get_bit_position() + num);
+  }
 };
 
 class byte_cursor_c {
diff --git a/src/dts_common.cpp b/src/dts_common.cpp
index 246ab3fd6..73b1a48ce 100644
--- a/src/dts_common.cpp
+++ b/src/dts_common.cpp
@@ -241,7 +241,7 @@ int find_dts_header(const unsigned char *buf, unsigned int size,
 
   bc.get_bit(dts_header->surround_sum_difference);
 
-  bool out_of_data = bc.get_bits(4, t);
+  bool out_of_data = !bc.get_bits(4, t);
   if (dts_header->encoder_software_revision == 7) {
     dts_header->dialog_normalization_gain = -((int)t);
   } else if (dts_header->encoder_software_revision == 6) {