libcore|String: Added printf-style formatting, utility methods

skyjake · Mar 20, 2016 · ada6b6c · ada6b6c
1 parent 9c83fd3
commit ada6b6c
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Showing 2 changed files with 75 additions and 0 deletions.
diff --git a/doomsday/sdk/libcore/include/de/data/string.h b/doomsday/sdk/libcore/include/de/data/string.h
@@ -284,6 +284,20 @@ class DENG2_PUBLIC String : public QString
      */
     dint toInt(bool *ok = 0, int base = 10, IntConversionFlags flags = AllowOnlyWhitespace) const;
 
+    /**
+     * Adds a prefix to each line in the text.
+     *
+     * @param prefix  Prefix text.
+     *
+     * @return Prefixed text.
+     */
+    String addLinePrefix(String const &prefix) const;
+
+    /**
+     * Prefixes double quotes and backslashes with a backslash.
+     */
+    String escaped() const;
+
 public:
     /**
      * Builds a String out of an array of bytes that contains a UTF-8 string.
@@ -321,6 +335,15 @@ class DENG2_PUBLIC String : public QString
      */
     static void skipSpace(String::const_iterator &i, String::const_iterator const &end);
 
+    /**
+     * Formats a string using standard printf() formatting. Uses UTF-8 encoding.
+     *
+     * @param format  Format string.
+     *
+     * @return Formatted output..
+     */
+    static String format(String format, ...);
+
     /**
      * Formats data according to formatting instructions. Outputs a
      * string containing the formatted data.

diff --git a/doomsday/sdk/libcore/src/data/string.cpp b/doomsday/sdk/libcore/src/data/string.cpp
@@ -23,6 +23,8 @@
 
 #include <QDir>
 #include <QTextStream>
+#include <cstdio>
+#include <cstdarg>
 
 using namespace de;
 
@@ -462,6 +464,38 @@ void String::skipSpace(String::const_iterator &i, String::const_iterator const &
     while(i != end && (*i).isSpace()) ++i;
 }
 
+String String::format(String format, ...)
+{
+    va_list args;
+    Block buffer;
+    int neededSize = 1024;
+
+    forever
+    {
+        buffer.resize(neededSize);
+
+        va_start(args, format);
+        int count = vsnprintf((char *) buffer.data(), buffer.size(), format.toUtf8(), args);
+        va_end(args);
+
+        if(count >= 0 && count < neededSize)
+        {
+            buffer.resize(count);
+            return fromUtf8(buffer);
+        }
+
+        if(count >= 0)
+        {
+            neededSize = count + 1;
+        }
+        else
+        {
+            neededSize *= 2; // Try bigger.
+        }
+    }
+    return fromUtf8(buffer);
+}
+
 // Seems like an ommission on the part of QChar...
 static inline bool isSign(QChar const &ch)
 {
@@ -489,6 +523,24 @@ dint String::toInt(bool *ok, int base, IntConversionFlags flags) const
     return token.QString::toInt(ok, base);
 }
 
+String String::addLinePrefix(String const &prefix) const
+{
+    String result;
+    for(auto const &str : QString::split(QChar('\n')))
+    {
+        if(!result.isEmpty()) result += "\n";
+        result += prefix + str;
+    }
+    return result;
+}
+
+String String::escaped() const
+{
+    String esc = *this;
+    esc.replace("\\", "\\\\").replace("\"", "\\\"");
+    return esc;
+}
+
 void String::advanceFormat(String::const_iterator &i, String::const_iterator const &end)
 {
     ++i;