sprintf() and CPString +stringWithFormat

[cappuccino#34 state:resolved]

Foundation/CPString.j

@@ -116,7 +116,36 @@ var CPStringHashes      = new objj_dictionary();
 */
 - (id)initWithString:(CPString)aString
 {
-    return aString + "";
+    return String(aString);
+}
+
+/*
+    Initializes a string using C printf-style formatting. First argument should be a constant format string, like ' "float val = %f" ', remaining arguments should be the variables to print the values of, comma-separated.
+    @param format the format to be used, printf-style
+    @return the initialized <objj>CPString</objj>
+*/
+- (id)initWithFormat:(CPString)format, ...
+{
+    if (!format)
+        [CPException raise:CPInvalidArgumentException
+                    reason:"stringWithString: the format can't be 'nil'"];
+
+    self = sprintf.apply(this, Array.prototype.slice.call(arguments, 2));
+    return self;
+}
+
+/*
+    Creates a new string using C printf-style formatting. First argument should be a constant format string, like ' "float val = %f" ', remaining arguments should be the variables to print the values of, comma-separated.
+    @param format the format to be used, printf-style
+    @return the initialized <objj>CPString</objj>
+*/
++ (id)stringWithFormat:(CPString)format, ...
+{
+    if (!format)
+        [CPException raise:CPInvalidArgumentException
+                    reason:"stringWithString: the format can't be 'nil'"];
+
+    return sprintf.apply(this, Array.prototype.slice.call(arguments, 2));
 }
 
 /*
@@ -473,3 +502,177 @@ CPNumericSearch
 
 
 String.prototype.isa = CPString;
+
+
+// sprintf:
+
+var sprintfFormatRegex = new RegExp("([^%]+|%[\\+\\-\\ \\#0]*[0-9\\*]*(.[0-9\\*]+)?[hlL]?[cdieEfgGosuxXpn%])", "g");
+var sprintfTagRegex = new RegExp("(%)([\\+\\-\\ \\#0]*)([0-9\\*]*)((.[0-9\\*]+)?)([hlL]?)([cdieEfgGosuxXpn%])");
+
+/**
+  Creates a new string using C printf-style formatting. First argument should be a constant format string, like ' "float val = %f" ', remaining arguments should be the variables to print the values of, comma-separated.
+  @param format the format to be used, printf-style
+  @return the initialized <objj>CPString</objj>
+  */
+function sprintf(format)
+{
+    var format = arguments[0],
+        tokens = format.match(sprintfFormatRegex),
+        index = 0,
+        result = "",
+        arg = 1;
+
+    for (var i = 0; i < tokens.length; i++)
+    {
+        var t = tokens[i];
+        if (format.substring(index, index + t.length) != t)
+        {
+            return result;
+        }
+        index += t.length;
+
+        if (t.charAt(0) != "%")
+        {
+            result += t;
+        }
+        else
+        {
+            var subtokens = t.match(sprintfTagRegex);
+            if (subtokens.length != 8 || subtokens[0] != t)
+            {
+                return result;
+            }
+
+            var percentSign     = subtokens[1],
+                flags           = subtokens[2],
+                widthString     = subtokens[3],
+                precisionString = subtokens[4],
+                length          = subtokens[6],
+                specifier       = subtokens[7];
+
+            var width = null;
+            if (widthString == "*")
+                width = arguments[arg++];
+            else if (widthString != "")
+                width = Number(widthString);
+
+            var precision = null;
+            if (precisionString == ".*")
+                precision = arguments[arg++];
+            else if (precisionString != "")
+                precision = Number(precisionString.substring(1));
+
+            var leftJustify = (flags.indexOf("-") >= 0);
+            var padZeros    = (flags.indexOf("0") >= 0);
+
+            var subresult = "";
+
+            if (RegExp("[diufeExXo]").test(specifier))
+            {
+                var num = Number(arguments[arg++]);
+
+                var sign = "";
+                if (num < 0)
+                {
+                    sign = "-";
+                }
+                else
+                {
+                    if (flags.indexOf("+") >= 0)
+                        sign = "+";
+                    else if (flags.indexOf(" ") >= 0)
+                        sign = " ";
+                }
+
+                if (specifier == "d" || specifier == "i" || specifier == "u")
+                {
+                    var number = String(Math.abs(Math.floor(num)));
+
+                    subresult = sprintf_justify(sign, "", number, "", width, leftJustify, padZeros)
+                }
+
+                if (specifier == "f")
+                {
+                    var number = String((precision != null) ? Math.abs(num).toFixed(precision) : Math.abs(num));
+                    var suffix = (flags.indexOf("#") >= 0 && number.indexOf(".") < 0) ? "." : "";
+
+                    subresult = sprintf_justify(sign, "", number, suffix, width, leftJustify, padZeros);
+                }
+
+                if (specifier == "e" || specifier == "E")
+                {
+                    var number = String(Math.abs(num).toExponential(precision != null ? precision : 21));
+                    var suffix = (flags.indexOf("#") >= 0 && number.indexOf(".") < 0) ? "." : "";
+
+                    subresult = sprintf_justify(sign, "", number, suffix, width, leftJustify, padZeros);
+                }
+
+                if (specifier == "x" || specifier == "X")
+                {
+                    var number = String(Math.abs(num).toString(16));
+                    var prefix = (flags.indexOf("#") >= 0 && num != 0) ? "0x" : "";
+
+                    subresult = sprintf_justify(sign, prefix, number, "", width, leftJustify, padZeros);
+                }
+
+                if (specifier == "o")
+                {
+                    var number = String(Math.abs(num).toString(8));
+                    var prefix = (flags.indexOf("#") >= 0 && num != 0) ? "0" : "";
+
+                    subresult = sprintf_justify(sign, prefix, number, "", width, leftJustify, padZeros);
+                }
+
+                if (RegExp("[A-Z]").test(specifier))
+                    subresult = subresult.toUpperCase();
+                else
+                    subresult = subresult.toLowerCase();
+            }
+            else
+            {
+                var subresult = "";
+
+                if (specifier == "%")
+                    subresult = "%";
+                else if (specifier == "c")
+                    subresult = String(arguments[arg++]).charAt(0);
+                else if (specifier == "s")
+                    subresult = String(arguments[arg++]);
+                else if (specifier == "p" || specifier == "n")
+                {
+                    arg++;
+                    subresult = "";
+                }
+
+                subresult = sprintf_justify("", "", subresult, "", width, leftJustify, false);
+            }
+
+            result += subresult;
+        }
+    }
+    return result;
+}
+
+var sprintf_justify = function(sign, prefix, string, suffix, width, leftJustify, padZeros)
+{
+    var length = (sign.length + prefix.length + string.length + suffix.length);
+    if (leftJustify)
+    {
+        return sign + prefix + string + suffix + sprintf_pad(width - length, " ");
+    }
+    else
+    {
+        if (padZeros)
+            return sign + prefix + sprintf_pad(width - length, "0") + string + suffix;
+        else
+            return sprintf_pad(width - length, " ") + sign + prefix + string + suffix;
+    }
+}
+
+var sprintf_pad = function(n, ch)
+{
+    var result = "";
+    for (var i = 0; i < n; i++)
+        result += ch;
+    return result;
+}