From bc02cdde7024c528cb3ccb05b88329850a3ba512 Mon Sep 17 00:00:00 2001
From: Paul Duncan <pabs@pablotron.org>
Date: Thu, 3 Feb 2022 01:00:45 -0500
Subject: internal/cpe: add binding and tests

---
 internal/cpe/binding.go | 118 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 118 insertions(+)
 create mode 100644 internal/cpe/binding.go

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

diff --git a/internal/cpe/binding.go b/internal/cpe/binding.go
new file mode 100644
index 0000000..8c51d7d
--- /dev/null
+++ b/internal/cpe/binding.go
@@ -0,0 +1,118 @@
+package cpe
+
+import (
+  "encoding/json"
+  "errors"
+  "fmt"
+  "strings"
+)
+
+// Common Platform Enumeration binding.
+type Binding struct {
+  Part      Part      // Part attribute (NISTIR7695 5.3.3.1).
+  Vendor    AvString  // Vendor attribute (NISTIR7695 5.3.3.2).
+  Product   AvString  // Product attribute (NISTIR7695 5.3.3.3).
+  Version   AvString  // Version attribute (NISTIR7695 5.3.3.4).
+  Update    AvString  // Update attribute (NISTIR7695 5.3.3.5).
+  Edition   AvString  // Edition attribute (NISTIR7695 5.3.3.6).
+  SwEdition AvString  // Software edition attribute (NISTIR7695 5.3.3.7).
+  TargetSw  AvString  // Target software attribute (NISTIR7695 5.3.3.8).
+  TargetHw  AvString  // Target hardware attribute (NISTIR7695 5.3.3.9).
+  Lang      AvString  // Language attribute (NISTIR7695 5.3.3.10).
+  Other     AvString  // Other attribute (NISTIR7695 5.3.3.11).
+}
+
+// cpe 2.3 formatted string prefix
+var cpe23Prefix = "cpe:2.3:"
+
+// missing prefix error
+var missingPrefix = errors.New("missing CPE 2.3 prefix")
+
+// Create CPE 2.3 binding from formatted string.
+func NewBinding(s string) (Binding, error) {
+  // check prefix
+  if s[0:len(cpe23Prefix)] != cpe23Prefix {
+    return Binding{}, missingPrefix
+  }
+
+  // tokenize string, check for error
+  toks, err := tokenize([]byte(s[len(cpe23Prefix):]))
+  if err != nil {
+    return Binding{}, err
+  }
+
+  // check token count
+  if len(toks) != 11 {
+    err = fmt.Errorf("invalid attribute count: %d != 11", len(toks))
+    return Binding{}, err
+  }
+
+  // create part
+  part, err := newPart(toks[0])
+  if err != nil {
+    return Binding{}, err
+  }
+
+  // parse tokens into strings
+  strs := make([]AvString, len(toks) - 1)
+  for i, t := range(toks[1:]) {
+    if strs[i], err = newAvString(t); err != nil {
+      return Binding{}, err
+    }
+  }
+
+  // build and return result
+  return Binding {
+    Part: part,
+    Vendor: strs[0],
+    Product: strs[1],
+    Version: strs[2],
+    Update: strs[3],
+    Edition: strs[4],
+    Lang: strs[5],
+    SwEdition: strs[6],
+    TargetSw: strs[7],
+    TargetHw: strs[8],
+    Other: strs[9],
+  }, nil
+}
+
+func (v Binding) String() string {
+  return cpe23Prefix + strings.Join([]string {
+    v.Part.String(),
+    v.Vendor.String(),
+    v.Product.String(),
+    v.Version.String(),
+    v.Update.String(),
+    v.Edition.String(),
+    v.Lang.String(),
+    v.SwEdition.String(),
+    v.TargetSw.String(),
+    v.TargetHw.String(),
+    v.Other.String(),
+  }, ":")
+}
+
+// Unmarshal CPE formatted string from JSON string.
+func (me *Binding) UnmarshalJSON(b []byte) error {
+  // decode json string
+  var s string
+  if err := json.Unmarshal(b, &s); err != nil {
+    return err
+  }
+
+  // create binding
+  binding, err := NewBinding(s)
+  if err != nil {
+    return err
+  }
+
+  // save result, return success
+  *me = binding
+  return nil
+}
+
+// Marshal CPE formatted string as JSON string.
+func (v Binding) MarshalJSON() ([]byte, error) {
+  return json.Marshal(v.String())
+}
-- 
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