3 files changed, 100 insertions, 0 deletions

diff --git a/include/serd/env.h b/include/serd/env.h
index 2b2982f3..404c96b6 100644
--- a/include/serd/env.h
+++ b/include/serd/env.h
@@ -10,6 +10,8 @@
 #include "serd/status.h"
 #include "serd/string_view.h"
 
+#include <stdbool.h>
+
 SERD_BEGIN_DECLS
 
 /**
@@ -25,6 +27,14 @@ typedef struct SerdEnvImpl SerdEnv;
 SERD_API SerdEnv* SERD_ALLOCATED
 serd_env_new(SerdStringView base_uri);
 
+/// Copy an environment
+SERD_API SerdEnv* SERD_ALLOCATED
+serd_env_copy(const SerdEnv* SERD_NULLABLE env);
+
+/// Return true iff `a` is equal to `b`
+SERD_PURE_API bool
+serd_env_equals(const SerdEnv* SERD_NULLABLE a, const SerdEnv* SERD_NULLABLE b);
+
 /// Free `env`
 SERD_API void
 serd_env_free(SerdEnv* SERD_NULLABLE env);
diff --git a/src/env.c b/src/env.c
index a2096b70..c3f48e48 100644
--- a/src/env.c
+++ b/src/env.c
@@ -37,6 +37,31 @@ serd_env_new(const SerdStringView base_uri)
   return env;
 }
 
+SerdEnv*
+serd_env_copy(const SerdEnv* const env)
+{
+  if (!env) {
+    return NULL;
+  }
+
+  SerdEnv* copy = (SerdEnv*)calloc(1, sizeof(struct SerdEnvImpl));
+  if (copy) {
+    copy->n_prefixes = env->n_prefixes;
+    copy->prefixes = (SerdPrefix*)malloc(copy->n_prefixes * sizeof(SerdPrefix));
+    for (size_t i = 0; i < copy->n_prefixes; ++i) {
+      copy->prefixes[i].name = serd_node_copy(env->prefixes[i].name);
+      copy->prefixes[i].uri  = serd_node_copy(env->prefixes[i].uri);
+    }
+
+    const SerdNode* const base = serd_env_base_uri(env);
+    if (base) {
+      serd_env_set_base_uri(copy, serd_node_string_view(base));
+    }
+  }
+
+  return copy;
+}
+
 void
 serd_env_free(SerdEnv* const env)
 {
@@ -53,6 +78,28 @@ serd_env_free(SerdEnv* const env)
   free(env);
 }
 
+bool
+serd_env_equals(const SerdEnv* const a, const SerdEnv* const b)
+{
+  if (!a || !b) {
+    return !a == !b;
+  }
+
+  if (a->n_prefixes != b->n_prefixes ||
+      !serd_node_equals(a->base_uri_node, b->base_uri_node)) {
+    return false;
+  }
+
+  for (size_t i = 0; i < a->n_prefixes; ++i) {
+    if (!serd_node_equals(a->prefixes[i].name, b->prefixes[i].name) ||
+        !serd_node_equals(a->prefixes[i].uri, b->prefixes[i].uri)) {
+      return false;
+    }
+  }
+
+  return true;
+}
+
 SerdURIView
 serd_env_base_uri_view(const SerdEnv* const env)
 {
diff --git a/test/test_env.c b/test/test_env.c
index 4f947246..69b69061 100644
--- a/test/test_env.c
+++ b/test/test_env.c
@@ -13,6 +13,47 @@
 #include <assert.h>
 #include <string.h>
 
+static void
+test_copy(void)
+{
+  assert(!serd_env_copy(NULL));
+
+  SerdEnv* const env = serd_env_new(serd_string("http://example.org/base/"));
+
+  serd_env_set_prefix(
+    env, serd_string("eg"), serd_string("http://example.org/"));
+
+  SerdEnv* const env_copy = serd_env_copy(env);
+
+  assert(serd_env_equals(env, env_copy));
+
+  serd_env_set_prefix(
+    env_copy, serd_string("test"), serd_string("http://example.org/test"));
+
+  assert(!serd_env_equals(env, env_copy));
+
+  serd_env_set_prefix(
+    env, serd_string("test2"), serd_string("http://example.org/test2"));
+
+  assert(!serd_env_equals(env, env_copy));
+
+  serd_env_free(env_copy);
+  serd_env_free(env);
+}
+
+static void
+test_comparison(void)
+{
+  SerdEnv* const env = serd_env_new(serd_empty_string());
+
+  assert(!serd_env_equals(env, NULL));
+  assert(!serd_env_equals(NULL, env));
+  assert(serd_env_equals(NULL, NULL));
+  assert(serd_env_equals(env, env));
+
+  serd_env_free(env);
+}
+
 static SerdStatus
 count_prefixes(void* handle, const SerdEvent* event)
 {
@@ -118,6 +159,8 @@ test_env(void)
 int
 main(void)
 {
+  test_copy();
+  test_comparison();
   test_env();
   return 0;
 }