Simplify DAB label handling

The DabLabel object only save the label in the unpadded form,
and handle padding with spaces at the time of usage.

3 files changed, 30 insertions, 17 deletions

diff --git a/src/DabMux.cpp b/src/DabMux.cpp
index ecbedc4..d83dbce 100644
--- a/src/DabMux.cpp
+++ b/src/DabMux.cpp
@@ -1661,7 +1661,7 @@ int main(int argc, char *argv[])
                 fig1_0->EId = htons(ensemble->id);
                 index = index + 4;
 
-                memcpy(&etiFrame[index], ensemble->label.text(), 16);
+                ensemble->label.writeLabel(&etiFrame[index]);
                 index = index + 16;
 
                 etiFrame[index++] = ensemble->label.flag() >> 8;
@@ -1892,7 +1892,7 @@ int main(int argc, char *argv[])
                     index += 6;
                     figSize += 6;
                 }
-                memcpy(&etiFrame[index], (*service)->label.text(), 16);
+                (*service)->label.writeLabel(&etiFrame[index]);
                 index += 16;
                 figSize += 16;
                 etiFrame[index++] = (*service)->label.flag() >> 8;
@@ -1943,7 +1943,7 @@ int main(int argc, char *argv[])
                         index += 7;
                         figSize += 7;
                     }
-                    memcpy(&etiFrame[index], (*component)->label.text(), 16);
+                    (*component)->label.writeLabel(&etiFrame[index]);
                     index += 16;
                     figSize += 16;
 
diff --git a/src/MuxElements.cpp b/src/MuxElements.cpp
index 65045db..a452220 100644
--- a/src/MuxElements.cpp
+++ b/src/MuxElements.cpp
@@ -24,6 +24,7 @@
 */
 
 #include <vector>
+#include <algorithm>
 
 #include "MuxElements.h"
 #include <boost/algorithm/string.hpp>
@@ -46,12 +47,9 @@ using namespace std;
 int DabLabel::setLabel(const std::string& label)
 {
     size_t len = label.length();
-    if (len > sizeof(m_text))
+    if (len > DABLABEL_LENGTH)
         return -3;
 
-    memcpy(m_text, label.c_str(), len);
-    memset(m_text + len, 0x20, sizeof(m_text) - len);
-
     m_flag = 0xFF00; // truncate the label to the eight first characters
 
     m_label = label;
@@ -73,7 +71,6 @@ int DabLabel::setLabel(const std::string& label, const std::string& short_label)
         return flag;
 
     // short label is valid.
-    memcpy(m_text, newlabel.m_text, sizeof(m_text));
     m_flag = flag & 0xFFFF;
     m_label = newlabel.m_label;
 
@@ -105,8 +102,8 @@ int DabLabel::setShortLabel(const std::string& slabel)
     /* Iterate over the label and set the bits in the flag
      * according to the characters in the slabel
      */
-    for (int i = 0; i < 32; ++i) {
-        if (*slab == m_text[i]) {
+    for (size_t i = 0; i < m_label.size(); ++i) {
+        if (*slab == m_label[i]) {
             flag |= 0x8000 >> i;
             if (*(++slab) == 0) {
                 break;
@@ -118,7 +115,7 @@ int DabLabel::setShortLabel(const std::string& slabel)
      * we went through the whole label, the short label
      * cannot be represented
      */
-    if (*slab != 0) {
+    if (*slab != '\0') {
         return -1;
     }
 
@@ -139,15 +136,22 @@ int DabLabel::setShortLabel(const std::string& slabel)
 const string DabLabel::short_label() const
 {
     stringstream shortlabel;
-    for (int i = 0; i < 32; ++i) {
+    for (size_t i = 0; i < m_label.size(); ++i) {
         if (m_flag & 0x8000 >> i) {
-            shortlabel << m_text[i];
+            shortlabel << m_label[i];
         }
     }
 
     return shortlabel.str();
 }
 
+void DabLabel::writeLabel(uint8_t* buf) const
+{
+    memset(buf, ' ', DABLABEL_LENGTH);
+    if (m_label.size() <= DABLABEL_LENGTH) {
+        std::copy(m_label.begin(), m_label.end(), (char*)buf);
+    }
+}
 
 vector<dabSubchannel*>::iterator getSubchannel(
         vector<dabSubchannel*>& subchannels, int id)
diff --git a/src/MuxElements.h b/src/MuxElements.h
index 22112db..a116427 100644
--- a/src/MuxElements.h
+++ b/src/MuxElements.h
@@ -51,6 +51,7 @@ struct dabOutput {
     DabOutput* output;
 };
 
+#define DABLABEL_LENGTH 16
 
 class DabLabel
 {
@@ -71,18 +72,26 @@ class DabLabel
          */
         int setLabel(const std::string& label);
 
-        const char* text() const { return m_text; }
+        /* Write the label to the 16-byte buffer given in buf
+         * In the DAB standard, the label is 16 bytes long, and is
+         * padded using spaces.
+         */
+        void writeLabel(uint8_t* buf) const;
+
         uint16_t flag() const { return m_flag; }
         const std::string long_label() const { return m_label; }
         const std::string short_label() const;
 
     private:
-        // In the DAB standard, the label is 16 bytes long.
-        // We use spaces for padding at the end if needed.
-        char m_text[16];
+        /* The flag field selects which label characters make
+         * up the short label
+         */
         uint16_t m_flag;
+
+        /* The m_label is not padded in any way */
         std::string m_label;
 
+        /* Checks and calculates the flag */
         int setShortLabel(const std::string& slabel);
 };