From 5db2e66f30d671f334486ad3dfbb178f4fef6817 Mon Sep 17 00:00:00 2001
From: Paul Duncan <pabs@pablotron.org>
Date: Wed, 2 Feb 2022 22:38:49 -0500
Subject: internal/cpe: add avstring and tests

---
 internal/cpe/avstring.go | 54 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 54 insertions(+)
 create mode 100644 internal/cpe/avstring.go

(limited to 'internal/cpe/avstring.go')

diff --git a/internal/cpe/avstring.go b/internal/cpe/avstring.go
new file mode 100644
index 0000000..46e16cf
--- /dev/null
+++ b/internal/cpe/avstring.go
@@ -0,0 +1,54 @@
+package cpe
+
+//go:generate stringer -linecomment -type=AvStringType
+
+import (
+  "fmt"
+)
+
+// type of avstring.
+type AvStringType byte
+
+const (
+  AnyString AvStringType = iota // any
+  NaString // na
+  ValString // val
+)
+
+// String value (NISTIR 7695, CPE 2.3 spec, Figure 6-3)
+type AvString struct {
+  Type AvStringType // value type
+  Val  string // value
+}
+
+// token type to avstring type map
+var avTypes = map[tokenType]AvStringType {
+  anyToken: AnyString,
+  naToken: NaString,
+  valToken: ValString,
+}
+
+// create new AvString from token.
+func newAvString(t token) (AvString, error) {
+  if at, ok := avTypes[t.Type]; ok {
+    return AvString { at, t.Val }, nil
+  } else {
+    err := fmt.Errorf("invalid token type: 0x%02x", byte(t.Type))
+    return AvString { 0, "" }, err
+  }
+}
+
+// Serialize as string.
+func (s AvString) String() string {
+  switch s.Type {
+  case AnyString:
+    return "*"
+  case NaString:
+    return "-"
+  case ValString:
+    return s.Val
+  default:
+    // not sure what to return here
+    return ""
+  }
+}
-- 
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