From: Guilherme Maciel Ferreira <guilherme.maciel.ferreira@gmail.com>
Date: Sun, 19 Feb 2012 18:19:55 +0000 (-0200)
Subject: Implemented encode and decode methods for just 1 bit.
X-Git-Tag: v1.3~11^2~6
X-Git-Url: http://developer.intra2net.com/git/?a=commitdiff_plain;h=ad545958f408012956bcac4cf466c94bec014bcc;p=pingcheck

Implemented encode and decode methods for just 1 bit.
- In order to hide statements like "Payload[13] | bit ? 0x08 : 0x0" and "Payload[13] & 0x04".
---

diff --git a/src/host/messagepayload.cpp b/src/host/messagepayload.cpp
index ab738bc..77aa56e 100644
--- a/src/host/messagepayload.cpp
+++ b/src/host/messagepayload.cpp
@@ -196,6 +196,64 @@ void MessagePayload::append(
 }
 
 /**
+ * @brief Retrieve 1 bit from the payload buffer.
+ *
+ * @param byte_index The index of the byte.
+ * @param bit_index The index of bit within the byte. The indexes are as follow:
+ * [0|1|2|3|4|5|6|7], with the index zero being the left most bit within the byte.
+ *
+ * @return The bit value stored at @a bit_index.
+ */
+bool MessagePayload::decode1(
+        const int byte_index,
+        const int bit_index
+) const
+{
+    const int max_bit_index = 7;
+    BOOST_ASSERT( ( 0 <= byte_index ) && ( byte_index < static_cast<int>(PayloadSizeInBytes) ) );
+    BOOST_ASSERT( ( 0 <= bit_index ) && ( bit_index <= max_bit_index ) );
+
+    int shift_amount = max_bit_index - bit_index;
+    uint8_t bit_mask = static_cast<uint8_t>( 0x01U << shift_amount );
+    bool value = static_cast<bool>( Payload[ byte_index ] & bit_mask );
+
+    return value;
+}
+
+/**
+ * @brief Store 1 bit in the payload buffer.
+ *
+ * @param byte_index The index of the byte.
+ * @param bit_index The index of bit within the byte.
+ * @param value The bit value to store at @a bit_index.
+ *
+ * @return void
+ */
+void MessagePayload::encode1(
+        const int byte_index,
+        const int bit_index,
+        const bool value
+)
+{
+    const int max_bit_index = 7;
+    BOOST_ASSERT( ( 0 <= byte_index ) && ( byte_index < static_cast<int>(PayloadSizeInBytes) ) );
+    BOOST_ASSERT( ( 0 <= bit_index ) && ( bit_index <= max_bit_index ) );
+
+    int shift_amount = max_bit_index - bit_index;
+    uint8_t bit_mask = static_cast<uint8_t>( 0x01U << shift_amount );
+
+    if ( value )
+    {
+        Payload[ byte_index ] = Payload[ byte_index ] | bit_mask;
+    }
+    else
+    {
+        bit_mask = static_cast<uint8_t>( ~bit_mask );
+        Payload[ byte_index ] = Payload[ byte_index ] & bit_mask;
+    }
+}
+
+/**
  * @brief Retrieve 16 bits from the payload buffer.
  *
  * @param left_byte_index The index of the left byte.
diff --git a/src/host/messagepayload.h b/src/host/messagepayload.h
index 7425bf7..0766874 100644
--- a/src/host/messagepayload.h
+++ b/src/host/messagepayload.h
@@ -43,6 +43,16 @@ public:
             const std::size_t extra_payload_size_in_bytes
     );
 
+    bool decode1(
+            const int byte_index,
+            const int bit_index
+    ) const;
+    void encode1(
+            const int byte_index,
+            const int bit_index,
+            const bool value
+    );
+
     uint16_t decode16(
             const int left_byte_index,
             const int right_byte_index
diff --git a/test/test_messagepayload.cpp b/test/test_messagepayload.cpp
index fb05edf..37d9bbf 100644
--- a/test/test_messagepayload.cpp
+++ b/test/test_messagepayload.cpp
@@ -175,6 +175,57 @@ BOOST_AUTO_TEST_CASE( append )
     BOOST_CHECK_EQUAL( mp_original[19], 0xB9 );
 }
 
+BOOST_AUTO_TEST_CASE( decode1 )
+{
+    MessagePayload mp = create_message_payload( 2 );
+    mp[0] = 0xAA;
+    mp[1] = 0xAA;
+
+    BOOST_CHECK_EQUAL( mp.decode1( 0, 0 ), true );
+    BOOST_CHECK_EQUAL( mp.decode1( 0, 1 ), false );
+    BOOST_CHECK_EQUAL( mp.decode1( 0, 2 ), true );
+    BOOST_CHECK_EQUAL( mp.decode1( 0, 3 ), false );
+    BOOST_CHECK_EQUAL( mp.decode1( 0, 4 ), true );
+    BOOST_CHECK_EQUAL( mp.decode1( 0, 5 ), false );
+    BOOST_CHECK_EQUAL( mp.decode1( 0, 6 ), true );
+    BOOST_CHECK_EQUAL( mp.decode1( 0, 7 ), false );
+    BOOST_CHECK_EQUAL( mp.decode1( 1, 0 ), true );
+    BOOST_CHECK_EQUAL( mp.decode1( 1, 1 ), false );
+    BOOST_CHECK_EQUAL( mp.decode1( 1, 2 ), true );
+    BOOST_CHECK_EQUAL( mp.decode1( 1, 3 ), false );
+    BOOST_CHECK_EQUAL( mp.decode1( 1, 4 ), true );
+    BOOST_CHECK_EQUAL( mp.decode1( 1, 5 ), false );
+    BOOST_CHECK_EQUAL( mp.decode1( 1, 6 ), true );
+    BOOST_CHECK_EQUAL( mp.decode1( 1, 7 ), false );
+}
+
+BOOST_AUTO_TEST_CASE( encode1 )
+{
+    MessagePayload mp = create_message_payload( 2 );
+    mp[0] = 0x00;
+    mp[1] = 0xFF;
+
+    mp.encode1( 0, 0, true );
+    mp.encode1( 0, 1, false );
+    mp.encode1( 0, 2, true );
+    mp.encode1( 0, 3, false );
+    mp.encode1( 0, 4, true );
+    mp.encode1( 0, 5, false );
+    mp.encode1( 0, 6, true );
+    mp.encode1( 0, 7, false );
+    mp.encode1( 1, 0, true );
+    mp.encode1( 1, 1, false );
+    mp.encode1( 1, 2, true );
+    mp.encode1( 1, 3, false );
+    mp.encode1( 1, 4, true );
+    mp.encode1( 1, 5, false );
+    mp.encode1( 1, 6, true );
+    mp.encode1( 1, 7, false );
+
+    BOOST_CHECK_EQUAL( mp[0], 0xAA );
+    BOOST_CHECK_EQUAL( mp[1], 0xAA );
+}
+
 BOOST_AUTO_TEST_CASE( decode16 )
 {
     MessagePayload mp = create_message_payload( 10 );