From aa9d3360ba6f27bd985df78e9247d3e756141bee Mon Sep 17 00:00:00 2001
From: Andrey Smirnov <Smirnov.Andrey@gmail.com>
Date: Wed, 11 Mar 2015 00:46:39 +0300
Subject: [PATCH] Canonical case-folding for Debian stanzas. #193

---
 deb/format.go      | 28 +++++++++++++++++++++++++++-
 deb/format_test.go | 12 ++++++++++++
 2 files changed, 39 insertions(+), 1 deletion(-)

diff --git a/deb/format.go b/deb/format.go
index 5663a564..ccc6327d 100644
--- a/deb/format.go
+++ b/deb/format.go
@@ -5,6 +5,7 @@ import (
 	"errors"
 	"io"
 	"strings"
+	"unicode"
 )
 
 // Stanza or paragraph of Debian control file
@@ -157,6 +158,31 @@ func init() {
 	multilineFields["MD5Sum"] = true
 }
 
+func canonicalCase(field string) string {
+	upper := strings.ToUpper(field)
+	if upper == "SHA1" || upper == "SHA256" {
+		return upper
+	}
+	if upper == "MD5SUM" {
+		return "MD5Sum"
+	}
+
+	startOfWord := true
+
+	return strings.Map(func(r rune) rune {
+		if startOfWord {
+			startOfWord = false
+			return unicode.ToUpper(r)
+		}
+
+		if r == '-' {
+			startOfWord = true
+		}
+
+		return unicode.ToLower(r)
+	}, field)
+}
+
 // ControlFileReader implements reading of control files stanza by stanza
 type ControlFileReader struct {
 	scanner *bufio.Scanner
@@ -195,7 +221,7 @@ func (c *ControlFileReader) ReadStanza() (Stanza, error) {
 			if len(parts) != 2 {
 				return nil, ErrMalformedStanza
 			}
-			lastField = parts[0]
+			lastField = canonicalCase(parts[0])
 			_, lastFieldMultiline = multilineFields[lastField]
 			if lastFieldMultiline {
 				stanza[lastField] = parts[1]
diff --git a/deb/format_test.go b/deb/format_test.go
index 41046def..d7f43acc 100644
--- a/deb/format_test.go
+++ b/deb/format_test.go
@@ -123,6 +123,18 @@ func (s *ControlFileSuite) TestReadWriteStanza(c *C) {
 	c.Assert(strings.HasPrefix(str, "Package: "), Equals, true)
 }
 
+func (s *ControlFileSuite) TestCanonicalCase(c *C) {
+	c.Check(canonicalCase("Package"), Equals, "Package")
+	c.Check(canonicalCase("package"), Equals, "Package")
+	c.Check(canonicalCase("pAckaGe"), Equals, "Package")
+	c.Check(canonicalCase("MD5Sum"), Equals, "MD5Sum")
+	c.Check(canonicalCase("SHA1"), Equals, "SHA1")
+	c.Check(canonicalCase("SHA256"), Equals, "SHA256")
+	c.Check(canonicalCase("Package-List"), Equals, "Package-List")
+	c.Check(canonicalCase("package-list"), Equals, "Package-List")
+	c.Check(canonicalCase("packaGe-lIst"), Equals, "Package-List")
+}
+
 func (s *ControlFileSuite) BenchmarkReadStanza(c *C) {
 	for i := 0; i < c.N; i++ {
 		reader := bytes.NewBufferString(controlFile)