[librsvg/rustification] RsvgLength: make ::parse() a constructor, not a standalone parse_length() function

[Federico Mena Quintero <federico src gnome org>]

commit 822459f29b74e4e154d721c80f6e16fe6f05e0f2
Author: Federico Mena Quintero <federico gnome org>
Date:   Tue Nov 15 18:38:10 2016 -0600

    RsvgLength: make ::parse() a constructor, not a standalone parse_length() function

 rust/src/length.rs |  168 ++++++++++++++++++++++++++--------------------------
 1 files changed, 85 insertions(+), 83 deletions(-)
---
diff --git a/rust/src/length.rs b/rust/src/length.rs
index adf291a..eeffb12 100644
--- a/rust/src/length.rs
+++ b/rust/src/length.rs
@@ -68,7 +68,7 @@ fn compute_named_size (name: &str) -> f64 {
 pub extern fn rsvg_length_parse (string: *const libc::c_char, dir: LengthDir) -> RsvgLength {
     let my_string = unsafe { &String::from_glib_none (string) };
 
-    parse_length (my_string, dir)
+    RsvgLength::parse (my_string, dir)
 }
 
 /* https://www.w3.org/TR/SVG/types.html#DataTypeLength
@@ -82,77 +82,79 @@ pub extern fn rsvg_length_parse (string: *const libc::c_char, dir: LengthDir) ->
  * when _rsvg_css_normalize_length() needs to know to what the
  * length refers.
  */
-pub fn parse_length (string: &str, dir: LengthDir) -> RsvgLength {
-    let unit: LengthUnit;
-
-    let (mut value, rest) = strtod (string);
-
-    match rest.as_ref () {
-        "%" => {
-            value *= 0.01; // normalize to [0, 1]
-            unit = LengthUnit::Percent;
-        },
-
-        "em" => {
-            unit = LengthUnit::FontEm;
-        },
-
-        "ex" => {
-            unit = LengthUnit::FontEx;
-        },
-
-        "pt" => {
-            value /= POINTS_PER_INCH;
-            unit = LengthUnit::Inch;
-        },
-
-        "in" => {
-            unit = LengthUnit::Inch;
-        },
-
-        "cm" => {
-            value /= CM_PER_INCH;
-            unit = LengthUnit::Inch;
-        },
-
-        "mm" => {
-            value /= MM_PER_INCH;
-            unit = LengthUnit::Inch;
-        },
-
-        "pc" => {
-            value /= PICA_PER_INCH;
-            unit = LengthUnit::Inch;
-        },
-
-        "larger" => {
-            unit = LengthUnit::RelativeLarger;
-        },
-
-        "smaller" => {
-            unit = LengthUnit::RelativeSmaller;
-        },
-
-        "xx-small" |
-        "x-small" |
-        "small" |
-        "medium" |
-        "large" |
-        "x-large" |
-        "xx-large" => {
-            value = compute_named_size (rest);
-            unit = LengthUnit::Inch;
-        },
-
-        _ => {
-            unit = LengthUnit::Default;
+impl RsvgLength {
+    pub fn parse (string: &str, dir: LengthDir) -> RsvgLength {
+        let unit: LengthUnit;
+
+        let (mut value, rest) = strtod (string);
+
+        match rest.as_ref () {
+            "%" => {
+                value *= 0.01; // normalize to [0, 1]
+                unit = LengthUnit::Percent;
+            },
+
+            "em" => {
+                unit = LengthUnit::FontEm;
+            },
+
+            "ex" => {
+                unit = LengthUnit::FontEx;
+            },
+
+            "pt" => {
+                value /= POINTS_PER_INCH;
+                unit = LengthUnit::Inch;
+            },
+
+            "in" => {
+                unit = LengthUnit::Inch;
+            },
+
+            "cm" => {
+                value /= CM_PER_INCH;
+                unit = LengthUnit::Inch;
+            },
+
+            "mm" => {
+                value /= MM_PER_INCH;
+                unit = LengthUnit::Inch;
+            },
+
+            "pc" => {
+                value /= PICA_PER_INCH;
+                unit = LengthUnit::Inch;
+            },
+
+            "larger" => {
+                unit = LengthUnit::RelativeLarger;
+            },
+
+            "smaller" => {
+                unit = LengthUnit::RelativeSmaller;
+            },
+
+            "xx-small" |
+            "x-small" |
+            "small" |
+            "medium" |
+            "large" |
+            "x-large" |
+            "xx-large" => {
+                value = compute_named_size (rest);
+                unit = LengthUnit::Inch;
+            },
+
+            _ => {
+                unit = LengthUnit::Default;
+            }
         }
-    }
 
-    RsvgLength {
-        length: value,
-        unit: unit,
-        dir: dir
+        RsvgLength {
+            length: value,
+            unit: unit,
+            dir: dir
+        }
     }
 }
 
@@ -175,13 +177,13 @@ mod tests {
 
     #[test]
     fn parses_default () {
-        assert_eq! (parse_length ("42", LengthDir::Horizontal),
+        assert_eq! (RsvgLength::parse ("42", LengthDir::Horizontal),
                     RsvgLength {
                         length: 42.0,
                         unit:   LengthUnit::Default,
                         dir:    LengthDir::Horizontal});
 
-        assert_eq! (parse_length ("-42px", LengthDir::Horizontal),
+        assert_eq! (RsvgLength::parse ("-42px", LengthDir::Horizontal),
                     RsvgLength {
                         length: -42.0,
                         unit:   LengthUnit::Default,
@@ -190,7 +192,7 @@ mod tests {
 
     #[test]
     fn parses_percent () {
-        assert_eq! (parse_length ("50.0%", LengthDir::Horizontal),
+        assert_eq! (RsvgLength::parse ("50.0%", LengthDir::Horizontal),
                     RsvgLength {
                         length: 0.5,
                         unit:   LengthUnit::Percent,
@@ -199,7 +201,7 @@ mod tests {
 
     #[test]
     fn parses_font_em () {
-        assert_eq! (parse_length ("22.5em", LengthDir::Vertical),
+        assert_eq! (RsvgLength::parse ("22.5em", LengthDir::Vertical),
                     RsvgLength {
                         length: 22.5,
                         unit:   LengthUnit::FontEm,
@@ -208,7 +210,7 @@ mod tests {
 
     #[test]
     fn parses_font_ex () {
-        assert_eq! (parse_length ("22.5ex", LengthDir::Vertical),
+        assert_eq! (RsvgLength::parse ("22.5ex", LengthDir::Vertical),
                     RsvgLength {
                         length: 22.5,
                         unit:   LengthUnit::FontEx,
@@ -217,31 +219,31 @@ mod tests {
 
     #[test]
     fn parses_physical_units () {
-        assert_eq! (parse_length ("72pt", LengthDir::Both),
+        assert_eq! (RsvgLength::parse ("72pt", LengthDir::Both),
                     RsvgLength {
                         length: 1.0,
                         unit:   LengthUnit::Inch,
                         dir:    LengthDir::Both });
 
-        assert_eq! (parse_length ("-22.5in", LengthDir::Both),
+        assert_eq! (RsvgLength::parse ("-22.5in", LengthDir::Both),
                     RsvgLength {
                         length: -22.5,
                         unit:   LengthUnit::Inch,
                         dir:    LengthDir::Both });
 
-        assert_eq! (parse_length ("-25.4cm", LengthDir::Both),
+        assert_eq! (RsvgLength::parse ("-25.4cm", LengthDir::Both),
                     RsvgLength {
                         length: -10.0,
                         unit:   LengthUnit::Inch,
                         dir:    LengthDir::Both });
 
-        assert_eq! (parse_length ("254mm", LengthDir::Both),
+        assert_eq! (RsvgLength::parse ("254mm", LengthDir::Both),
                     RsvgLength {
                         length: 10.0,
                         unit:   LengthUnit::Inch,
                         dir:    LengthDir::Both });
 
-        assert_eq! (parse_length ("60pc", LengthDir::Both),
+        assert_eq! (RsvgLength::parse ("60pc", LengthDir::Both),
                     RsvgLength {
                         length: 10.0,
                         unit:   LengthUnit::Inch,
@@ -250,7 +252,7 @@ mod tests {
 
     #[test]
     fn parses_relative_larger () {
-        assert_eq! (parse_length ("larger", LengthDir::Vertical),
+        assert_eq! (RsvgLength::parse ("larger", LengthDir::Vertical),
                     RsvgLength {
                         length: 0.0,
                         unit:   LengthUnit::RelativeLarger,
@@ -259,7 +261,7 @@ mod tests {
 
     #[test]
     fn parses_relative_smaller () {
-        assert_eq! (parse_length ("smaller", LengthDir::Vertical),
+        assert_eq! (RsvgLength::parse ("smaller", LengthDir::Vertical),
                     RsvgLength {
                         length: 0.0,
                         unit:   LengthUnit::RelativeSmaller,
@@ -282,7 +284,7 @@ mod tests {
         // enforce a particular sequence.
 
         for name in names {
-            let length = parse_length (name, LengthDir::Both);
+            let length = RsvgLength::parse (name, LengthDir::Both);
 
             assert_eq! (length.unit, LengthUnit::Inch);
             assert_eq! (length.dir, LengthDir::Both);