Add create and create_or_throw factories for Compression_Algorithm and Decompression_Algorithm.

2 files changed, 71 insertions, 0 deletions

diff --git a/src/lib/compression/compression.cpp b/src/lib/compression/compression.cpp
index ded6b3b08..361bf7dd3 100644
--- a/src/lib/compression/compression.cpp
+++ b/src/lib/compression/compression.cpp
@@ -7,6 +7,7 @@
 
 #include <botan/compression.h>
 #include <botan/mem_ops.h>
+#include <botan/exceptn.h>
 #include <cstdlib>
 
 #if defined(BOTAN_HAS_ZLIB)
@@ -48,6 +49,25 @@ Compression_Algorithm* make_compressor(const std::string& name)
    return nullptr;
    }
 
+//static
+std::unique_ptr<Compression_Algorithm>
+Compression_Algorithm::create(const std::string& algo)
+   {
+   std::unique_ptr<Compression_Algorithm> compressor(make_compressor(algo));
+   return compressor;
+   }
+
+//static
+std::unique_ptr<Compression_Algorithm>
+Compression_Algorithm::create_or_throw(const std::string& algo)
+   {
+   if(auto compressor = Compression_Algorithm::create(algo))
+      {
+      return compressor;
+      }
+   throw Lookup_Error("Compression", algo, "");
+   }
+
 Decompression_Algorithm* make_decompressor(const std::string& name)
    {
 #if defined(BOTAN_HAS_ZLIB)
@@ -73,5 +93,24 @@ Decompression_Algorithm* make_decompressor(const std::string& name)
    return nullptr;
    }
 
+//static
+std::unique_ptr<Decompression_Algorithm>
+Decompression_Algorithm::create(const std::string& algo)
+   {
+   std::unique_ptr<Decompression_Algorithm> decompressor(make_decompressor(algo));
+   return decompressor;
+   }
+
+//static
+std::unique_ptr<Decompression_Algorithm>
+Decompression_Algorithm::create_or_throw(const std::string& algo)
+   {
+   if(auto decompressor = Decompression_Algorithm::create(algo))
+      {
+      return decompressor;
+      }
+   throw Lookup_Error("Decompression", algo, "");
+   }
 
 }
+
diff --git a/src/lib/compression/compression.h b/src/lib/compression/compression.h
index 2ebde3f2f..403b335e1 100644
--- a/src/lib/compression/compression.h
+++ b/src/lib/compression/compression.h
@@ -20,6 +20,22 @@ class BOTAN_PUBLIC_API(2,0) Compression_Algorithm
    {
    public:
       /**
+      * Create an instance based on a name, or return null if the
+      * algo/provider combination cannot be found. If provider is
+      * empty then best available is chosen.
+      */
+      static std::unique_ptr<Compression_Algorithm>
+         create(const std::string& algo_spec);
+
+      /**
+      * Create an instance based on a name
+      * @param algo_spec algorithm name
+      * Throws Lookup_Error if not not found.
+      */
+      static std::unique_ptr<Compression_Algorithm>
+         create_or_throw(const std::string& algo_spec);
+
+      /**
       * Begin compressing. Most compression algorithms offer a tunable
       * time/compression tradeoff parameter generally represented by
       * an integer in the range of 1 to 9.
@@ -66,6 +82,22 @@ class BOTAN_PUBLIC_API(2,0) Decompression_Algorithm
    {
    public:
       /**
+      * Create an instance based on a name, or return null if the
+      * algo/provider combination cannot be found. If provider is
+      * empty then best available is chosen.
+      */
+      static std::unique_ptr<Decompression_Algorithm>
+         create(const std::string& algo_spec);
+
+      /**
+      * Create an instance based on a name
+      * @param algo_spec algorithm name
+      * Throws Lookup_Error if not not found.
+      */
+      static std::unique_ptr<Decompression_Algorithm>
+         create_or_throw(const std::string& algo_spec);
+
+      /**
       * Begin decompressing.
       * Decompression does not support levels, as compression does.
       */