1 files changed, 59 insertions, 2 deletions

diff --git a/src/cc4group.c b/src/cc4group.c
index b00cc45..f257d6b 100644
--- a/src/cc4group.c
+++ b/src/cc4group.c
@@ -98,6 +98,9 @@ struct CC4Group_t {
 
 		char* lastFormattedMessage;
 	} error;
+
+	size_t referenceCounter;
+	CC4Group* parent;
 };
 
 static bool cc4group_applyMemoryManagementStart(CC4Group_MemoryManagement const management, const uint8_t** data, size_t size)
@@ -951,6 +954,9 @@ static void cc4group_init(CC4Group* const this)
 {
 	assert(this);
 
+	this->referenceCounter = 1;
+	this->parent = NULL;
+
 	this->uncompressedData = NULL;
 	this->uncompressedSize = 0;
 
@@ -1144,6 +1150,16 @@ static bool cc4group_openExisting(CC4Group* const this, const char* const path)
 	return cc4group_uncompressGroupFromFile(this, path);
 }
 
+static void cc4group_unreference(CC4Group* const this)
+{
+	assert(this);
+
+	if(--this->referenceCounter == 0)
+	{
+		cc4group_delete(this);
+	}
+}
+
 static void cc4group_delete(CC4Group* const this)
 {
 	assert(this);
@@ -1578,6 +1594,12 @@ static bool cc4group_saveIt(CC4Group* const this, const char* const path, bool c
 	assert(this);
 	assert(path);
 
+	if(this->parent != NULL)
+	{
+		SET_MESSAGE_ERROR("Saving is currently not implemented for groups opened with openAsChild");
+		return false;
+	}
+
 	bool success = false;
 	int file = open(path, O_WRONLY | O_BINARY | O_CREAT | (overwrite ? O_TRUNC : O_EXCL), 0644);
 
@@ -2047,6 +2069,38 @@ static bool cc4group_setExecutable(CC4Group* const this, bool const executable,
 	return true;
 }
 
+static CC4Group* cc4group_openAsChild(CC4Group* const this, const char* const path)
+{
+	assert(this);
+
+	const C4GroupEntryData* entry = cc4group_getDirectoryByPath(this, path, false);
+
+	if(entry == NULL)
+	{
+		return NULL;
+	}
+
+	CC4Group* child = cc4group_new();
+	if(child == NULL)
+	{
+		SET_ERRNO_ERROR("malloc: allocating the child group object");
+		return NULL;
+	}
+
+	memcpy(&child->root.core, &entry->core, sizeof(child->root.core));
+	child->root.data = entry->data;
+	child->root.core.Directory = 1;
+	child->root.core.FileName[0] = '\0';
+	child->root.children = entry->children;
+	child->parent = this;
+
+	++this->referenceCounter;
+
+	CleanUpJobListAppend(child->cleanupJobs, (CC4Group_CleanupJob){.func = (CC4Group_CleanupFunc)cc4group_unreference, .data = this});
+
+	return child;
+}
+
 CC4Group_API cc4group = {
 	.MemoryManagement = {
 		.Take = Take,
@@ -2065,7 +2119,7 @@ CC4Group_API cc4group = {
 
 
 	.new = cc4group_new,
-	.delete = cc4group_delete,
+	.delete = cc4group_unreference,
 
 
 	.create = cc4group_create,
@@ -2107,5 +2161,8 @@ CC4Group_API cc4group = {
 	.getErrorMessage = cc4group_getErrorMessage,
 	.getErrorCode = cc4group_getErrorCode,
 	.getErrorMethod = cc4group_getErrorMethod,
-	.getErrorCauser = cc4group_getErrorCauser
+	.getErrorCauser = cc4group_getErrorCauser,
+
+
+	.openAsChild = cc4group_openAsChild
 };