Add read_kv for parsing strings with key/value pairs

This is a contribution by Ribose Inc (@riboseinc)

2 files changed, 111 insertions, 3 deletions

diff --git a/src/lib/utils/parsing.h b/src/lib/utils/parsing.h
index 9185cfaad..12cb3fa34 100644
--- a/src/lib/utils/parsing.h
+++ b/src/lib/utils/parsing.h
@@ -5,8 +5,8 @@
 * Botan is released under the Simplified BSD License (see license.txt)
 */
 
-#ifndef BOTAN_PARSER_H_
-#define BOTAN_PARSER_H_
+#ifndef BOTAN_PARSING_UTILS_H_
+#define BOTAN_PARSING_UTILS_H_
 
 #include <botan/types.h>
 #include <string>
@@ -40,6 +40,8 @@ BOTAN_PUBLIC_API(2,0) std::vector<std::string> split_on(
 * Split a string on a character predicate
 * @param str the input string
 * @param pred the predicate
+*
+* This function will likely be removed in a future release
 */
 BOTAN_PUBLIC_API(2,0) std::vector<std::string>
 split_on_pred(const std::string& str,
@@ -143,9 +145,30 @@ BOTAN_PUBLIC_API(2,0) std::string ipv4_to_string(uint32_t ip_addr);
 
 std::map<std::string, std::string> BOTAN_PUBLIC_API(2,0) read_cfg(std::istream& is);
 
+/**
+* Accepts key value pairs deliminated by commas:
+*
+* "" (returns empty map)
+* "K=V" (returns map {'K': 'V'})
+* "K1=V1,K2=V2"
+* "K1=V1,K2=V2,K3=V3"
+* "K1=V1,K2=V2,K3=a_value\,with\,commas_and_\=equals"
+*
+* Values may be empty, keys must be non-empty and unique. Duplicate
+* keys cause an exception.
+*
+* Within both key and value, comma and equals can be escaped with
+* backslash. Backslash can also be escaped.
+*/
+std::map<std::string, std::string> BOTAN_PUBLIC_API(2,8) read_kv(const std::string& kv);
+
 std::string BOTAN_PUBLIC_API(2,0) clean_ws(const std::string& s);
 
-bool BOTAN_PUBLIC_API(2,0) host_wildcard_match(const std::string& wildcard, const std::string& host);
+/**
+* Check if the given hostname is a match for the specified wildcard
+*/
+bool BOTAN_PUBLIC_API(2,0) host_wildcard_match(const std::string& wildcard,
+                                               const std::string& host);
 
 
 }
diff --git a/src/lib/utils/read_kv.cpp b/src/lib/utils/read_kv.cpp
new file mode 100644
index 000000000..cdc84c622
--- /dev/null
+++ b/src/lib/utils/read_kv.cpp
@@ -0,0 +1,85 @@
+/*
+* (C) 2018 Ribose Inc
+*
+* Botan is released under the Simplified BSD License (see license.txt)
+*/
+
+#include <botan/parsing.h>
+#include <botan/exceptn.h>
+
+namespace Botan {
+
+std::map<std::string, std::string> read_kv(const std::string& kv)
+   {
+   std::map<std::string, std::string> m;
+   if(kv == "")
+      return m;
+
+   std::vector<std::string> parts;
+
+   try
+      {
+      parts = split_on(kv, ',');
+      }
+   catch(std::exception&)
+      {
+      throw Invalid_Argument("Bad KV spec");
+      }
+
+   bool escaped = false;
+   bool reading_key = true;
+   std::string cur_key;
+   std::string cur_val;
+
+   for(char c : kv)
+      {
+      if(c == '\\' && !escaped)
+         {
+         escaped = true;
+         }
+      else if(c == ',' && !escaped)
+         {
+         if(cur_key.empty())
+            throw Invalid_Argument("Bad KV spec empty key");
+
+         if(m.find(cur_key) != m.end())
+            throw Invalid_Argument("Bad KV spec duplicated key");
+         m[cur_key] = cur_val;
+         cur_key = "";
+         cur_val = "";
+         reading_key = true;
+         }
+      else if(c == '=' && !escaped)
+         {
+         if(reading_key == false)
+            throw Invalid_Argument("Bad KV spec unexpected equals sign");
+         reading_key = false;
+         }
+      else
+         {
+         if(reading_key)
+            cur_key += c;
+         else
+            cur_val += c;
+
+         if(escaped)
+            escaped = false;
+         }
+      }
+
+   if(!cur_key.empty())
+      {
+      if(reading_key == false)
+         {
+         if(m.find(cur_key) != m.end())
+            throw Invalid_Argument("Bad KV spec duplicated key");
+         m[cur_key] = cur_val;
+         }
+      else
+         throw Invalid_Argument("Bad KV spec incomplete string");
+      }
+
+   return m;
+   }
+
+}