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Moved String.Format() to native #261

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Merged
josesimoes merged 1 commit into from
Dec 6, 2025
Merged

Moved String.Format() to native #261

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206 changes: 4 additions & 202 deletions nanoFramework.CoreLibrary/System/String.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -718,212 +718,14 @@ public static string IsInterned(string str)
#if NANOCLR_REFLECTION

#nullable enable
public static string Format(string format, params object?[] args)
[MethodImpl(MethodImplOptions.InternalCall)]
public static extern string Format(string format, params object?[] args);
#nullable restore

#else
public static string Format(string format, params object[] args)
[MethodImpl(MethodImplOptions.InternalCall)]
public static extern string Format(string format, params object[] args);
#endif
{
var index = 0;
var alignment = 0;
var chr = '\0';
var len = format.Length;
var fmt = Empty;
var token = Empty;
var output = Empty;

if (format is null)
{
throw new ArgumentNullException("format can't be null");
}

for (var i = 0; i < len; i++)
{
token = Empty;
chr = format[i];

if (chr == '{')
{
if (i + 1 == len)
{
throw new ArgumentException("Format error: no closed brace, column " + i);
}

if (format[i + 1] == '{')
{
output += chr;
i++;
continue;
}
else
{
alignment = 0;
fmt = Empty;

for (i++; i < len; i++)
{
chr = format[i];

if (chr >= '0' && chr <= '9')
{
token += chr;
}
else if (chr == ',' || chr == ':' || chr == '}')
{
break;
}
else
{
throw new ArgumentException("Format error: wrong symbol at {}, column " + i);
}
}

if (token.Length > 0)
{
index = int.Parse(token);
}
else
{
throw new ArgumentException("Format error: empty {}, column " + i);
}

if (chr == ',')
{
if (format[i + 1] == '-')
{
token = "-";
i++;
}
else
{
token = Empty;
}

for (i++; i < len; i++)
{
chr = format[i];

if (chr >= '0' && chr <= '9')
{
token += chr;
}
else if (chr == ':' || chr == '}')
{
break;
}
else
{
throw new ArgumentException("Format error: wrong symbol at alignment, column " + i);
}
}

if (token.Length > 0)
{
alignment = int.Parse(token);
}
else
{
throw new ArgumentException("Format error: empty alignment, column " + i);
}
}

if (chr == ':')
{
token = Empty;
for (i++; i < len; i++)
{
chr = format[i];

if (chr == '}')
{
break;
}
else
{
token += chr;
}
}

if (token.Length > 0)
{
fmt = token;
}
else
{
throw new ArgumentException("Format error: empty format after ':', column " + i);
}
}
}

if (chr != '}')
{
throw new ArgumentException("Format error: no closed brace, column " + i);
}

if (fmt.Length > 0)
{
#if NANOCLR_REFLECTION

if (args[index] is null)
{
token = "";
}
else
{
var method = args[index].GetType().GetMethod("ToString", new Type[] { typeof(string) });
token = (method is null)
? args[index].ToString()
: method.Invoke(args[index], new object[] { token }).ToString();
}
#else
throw new NotImplementedException();
#endif // NANOCLR_REFLECTION

}
else
{
token = args[index] == null ? "" : args[index].ToString();
}

if (alignment > 0)
{
output += token.PadLeft(alignment);
}
else if (alignment < 0)
{
output += token.PadRight(MathInternal.Abs(alignment));
}
else
{
output += token;
}
}
else if (chr == '}')
{
if (i + 1 == len)
{
throw new ArgumentException("Format error: no closed brace, column " + i);
}

if (format[i + 1] == '}')
{
output += chr;
i++;
}
else
{
throw new ArgumentException("Format error: no closed brace, column " + i);
}
}
else
{
output += chr;
}
}

return output;
}

/// <summary>
/// Returns a new string that right-aligns the characters in this instance by padding them on the left with a specified Unicode character, for a specified total length.
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