feat: Removed dependency on Foundation

Sources/Histogram/Histogram.swift

@@ -10,7 +10,12 @@
 
 // swiftlint:disable file_length type_body_length line_length identifier_name
 
-import Foundation
+#if canImport(Darwin)
+import Darwin
+#elseif canImport(Glibc)
+import Glibc
+#endif
+
 import Numerics
 
 /**
@@ -1369,4 +1374,30 @@ extension Histogram: TextOutputStreamable {
  }
 }
 
+private extension String {
+ // Replacement for Foundation formatting routine.
+ // Loosly Based on example code found on
+ // https://developer.apple.com/documentation/swift/using-imported-c-functions-in-swift
+ // but using vsnprintf instead of vasprintf due to the latter being unavailabie in Glibc.
+ //
+ init(format: String, _ arguments: any CVarArg...) {
+ guard let value: String = withVaList(arguments, { va_list in
+ let bufferSize = 1_024
+ var buffer = [Int8](repeating: 0, count: bufferSize)
+ let valid = buffer.withUnsafeMutableBytes { ptr in
+ // vsnprintf guarantees not to write more than bufferSize - 1 characters plus a final null byte.
+ // Negative value indicates some failure; positive values indicate a valid null-terminated
+ // string.
+ 0..<bufferSize ~= format.withCString {
+ Int(vsnprintf(ptr.baseAddress, bufferSize, $0, va_list))
+ }
+ }
+ return valid ? String(validatingUTF8: buffer) : ""
+ }) else {
+ fatalError("Invalid String format for given arguments")
+ }
+ self = value
+ }
+}
+
 // swiftlint:enable file_length type_body_length line_length identifier_name