TITANIC: Implement CDialogueFile read

2 files changed, 45 insertions, 6 deletions

diff --git a/engines/titanic/true_talk/dialogue_file.cpp b/engines/titanic/true_talk/dialogue_file.cpp
index b52bf2a885..1d1d789188 100644
--- a/engines/titanic/true_talk/dialogue_file.cpp
+++ b/engines/titanic/true_talk/dialogue_file.cpp
@@ -55,7 +55,7 @@ void CDialogueFile::clear() {
 
 DialogueFileCacheEntry *CDialogueFile::addToCache(int index) {
 	if (_entries.size() == 0 || index < 0 || index >= (int)_entries.size()
-			|| !_entries[index]._v1)
+			|| _cache.empty())
 		return nullptr;
 
 	// Scan cache for a free slot
@@ -70,7 +70,7 @@ DialogueFileCacheEntry *CDialogueFile::addToCache(int index) {
 
 	cacheEntry._active = true;
 	cacheEntry._offset = entry._offset;
-	cacheEntry.v3 = 0;
+	cacheEntry._bytesRead = 0;
 	cacheEntry._entryPtr = &entry;
 
 	// Figure out the size of the entry
@@ -80,7 +80,22 @@ DialogueFileCacheEntry *CDialogueFile::addToCache(int index) {
 		cacheEntry._size = _entries[index + 1]._offset - entry._offset;
 	}
 
+	// Return a pointer to the loaded entry
 	return &cacheEntry;
 }
 
+bool CDialogueFile::read(DialogueFileCacheEntry *cacheEntry, byte *buffer, size_t bytesToRead) {
+	// Sanity checks that a valid record is passed, and the size can be read
+	if (!cacheEntry || !cacheEntry->_active || !bytesToRead
+		|| (cacheEntry->_bytesRead + bytesToRead) > cacheEntry->_size)
+		return false;
+
+	// Move to the correct position in the file
+	_file.seek(cacheEntry->_offset + cacheEntry->_bytesRead);
+	bool result = _file.read(buffer, bytesToRead) == bytesToRead;
+	cacheEntry->_bytesRead += bytesToRead;
+
+	return result;
+}
+
 } // End of namespace Titanic
diff --git a/engines/titanic/true_talk/dialogue_file.h b/engines/titanic/true_talk/dialogue_file.h
index 8d40045686..5db91d9c4c 100644
--- a/engines/titanic/true_talk/dialogue_file.h
+++ b/engines/titanic/true_talk/dialogue_file.h
@@ -37,11 +37,16 @@ struct DialogueFileIndexEntry {
 
 struct DialogueFileCacheEntry {
 	bool _active;
-	uint _offset, v3, _size;
+	uint _offset, _bytesRead, _size;
 	DialogueFileIndexEntry *_entryPtr;
 
-	DialogueFileCacheEntry() : _active(false), _offset(0), _size(0),
-		v3(0), _entryPtr(nullptr) {}
+	DialogueFileCacheEntry() : _active(false), _offset(0),
+		_bytesRead(0), _size(0), _entryPtr(nullptr) {}
+
+	/**
+	 * Return the size of a cache entry
+	 */
+	int size() const { return _active ? _size : 0; }
 };
 
 class CDialogueFile {
@@ -49,6 +54,11 @@ private:
 	Common::File _file;
 	Common::Array<DialogueFileIndexEntry> _entries;
 	Common::Array<DialogueFileCacheEntry> _cache;
+private:
+	/**
+	 * Add a dialogue file entry to the active cache
+	 */
+	DialogueFileCacheEntry *addToCache(int index);
 public:
 	CDialogueFile(const CString &filename, uint count);
 	~CDialogueFile();
@@ -61,7 +71,21 @@ public:
 	/**
 	 * Add a dialogue file entry to the active cache
 	 */
-	DialogueFileCacheEntry *addToCache(int index);
+	DialogueFileCacheEntry *addToCacheDouble(int index) {
+		return addToCache(index * 2);
+	}
+
+	/**
+	 * Add a dialogue file entry to the active cache
+	 */
+	DialogueFileCacheEntry *addToCacheDouble1(int index) {
+		return addToCache(index * 2 + 1);
+	}
+
+	/**
+	 * Read data for a resource
+	 */
+	bool read(DialogueFileCacheEntry *cacheEntry, byte *buffer, size_t bytesToRead);
 };
 
 } // End of namespace Titanic