Z_StringPool: Growing pool for immutable strings in zone memory

src/qcommon/common.cpp

@@ -1135,6 +1135,13 @@ int Z_Size(void *pvAddress)
 	return pMemory->iSize;
 }
 
+memtag_t Z_Tag(void *pvAddress)
+{
+	zoneHeader_t *pMemory = ((zoneHeader_t *)pvAddress) - 1;
+
+	return pMemory->eTag;
+}
+
 
 // Frees a block of memory...
 //
@@ -1368,6 +1375,62 @@ const char *CopyString( const char *in, memtag_t eTag ) {
 	return out;
 }
 
+/*
+========================
+StringPool
+
+Growing pool for allocating immutable C strings in Zone Memory
+that avoids too many allocations and fragmentation
+========================
+*/
+
+typedef struct stringPool_s {
+	unsigned int		size;
+	unsigned int		tail;
+	struct stringPool_s	*next;
+	char				buffer[0];
+} stringPool_t;
+
+stringPool_t *Z_StringPoolNew(unsigned int size, memtag_t eTag) {
+	unsigned int size_ = PAD(size, 16);
+	stringPool_t *chunk = (stringPool_t *)Z_Malloc(offsetof(stringPool_t, buffer) + size_, eTag, qfalse);
+
+	chunk->size = size_;
+	chunk->tail = 0;
+	chunk->next = NULL;
+
+	return chunk;
+}
+
+void Z_StringPoolFree(stringPool_t * pool) {
+	stringPool_t *chunk = pool;
+
+	while (chunk) {
+		stringPool_t *nextChunk = chunk->next;
+		Z_Free(chunk);
+		chunk = nextChunk;
+	}
+}
+
+const char *Z_StringPoolAdd(stringPool_t * pool, const char * string) {
+	stringPool_t *chunk = pool;
+	unsigned int len = strlen(string) + 1;
+
+	while (chunk->size < chunk->tail + len) {
+		if (!chunk->next) {
+			unsigned int size = 2 * MAX(len, chunk->size);
+			memtag_t eTag = Z_Tag(chunk);
+			chunk->next = Z_StringPoolNew(size, eTag);
+		}
+
+		chunk = chunk->next;
+	}
+
+	memcpy(chunk->buffer + chunk->tail, string, len);
+	chunk->tail += len;
+
+	return chunk->buffer + chunk->tail - len;
+}
 
 /*
 ==============================================================================

src/qcommon/files.cpp

@@ -195,13 +195,6 @@ typedef struct fileInPack_s {
 	struct	fileInPack_s*	next;		// next file in the hash
 } fileInPack_t;
 
-typedef struct stringBuffer_s {
-	unsigned int			size;
-	unsigned int			tail;
-	struct stringBuffer_s	*next;
-	char					buffer[0];
-} stringBuffer_t;
-
 enum {
 	PACKGVC_UNKNOWN = 0,
 	PACKGVC_1_02 = 1,
@@ -222,7 +215,7 @@ typedef struct {
 	int				hashSize;					// hash table size (power of 2)
 	fileInPack_t*	*hashTable;					// hash table
 	fileInPack_t*	buildBuffer;				// buffer with the filenames etc.
-	stringBuffer_t*	namesBuffer;				// buffer with filenames
+	stringPool_t*	namesBuffer;			// buffer with filenames
 	int				gvc;						// game-version compatibility
 	qboolean		isJKA;						// jka assets
 } pack_t;
@@ -333,45 +326,6 @@ static inline qboolean FS_CheckHandle(const char *fname, fileHandle_t f, module_
 
 #define FS_CHECKHANDLE(f, module, retval) if (!FS_CheckHandle(__FUNCTION__, f, module)) return retval;
 
-static stringBuffer_t *FS_NewStringBuffer(unsigned int size) {
-	unsigned int size_ = PAD(size, 16);
-	stringBuffer_t *buffer = (stringBuffer_t *)Z_Malloc(offsetof(stringBuffer_t, buffer) + size_, TAG_FILESYS, qfalse);
-
-	buffer->size = size_;
-	buffer->tail = 0;
-	buffer->next = NULL;
-
-	return buffer;
-}
-
-static void FS_FreeStringBuffer(stringBuffer_t * buffer) {
-	stringBuffer_t *chunk = buffer;
-
-	while (chunk) {
-		stringBuffer_t *nextChunk = chunk->next;
-		Z_Free(chunk);
-		chunk = nextChunk;
-	}
-}
-
-static const char *FS_AppendStringBuffer(stringBuffer_t * buffer, const char * string) {
-	stringBuffer_t *chunk = buffer;
-	unsigned int len = strlen(string) + 1;
-
-	while (chunk->size < chunk->tail + len) {
-		if (!chunk->next) {
-			chunk->next = FS_NewStringBuffer(2 * MAX(len, chunk->size));
-		}
-
-		chunk = chunk->next;
-	}
-
-	memcpy(chunk->buffer + chunk->tail, string, len);
-	chunk->tail += len;
-
-	return chunk->buffer + chunk->tail - len;
-}
-
 /*
 ==============
 FS_Initialized
@@ -2007,7 +1961,7 @@ of a zip file.
 static pack_t *FS_LoadZipFile( char *zipfile, const char *basename, qboolean assetsJKA )
 {
 	fileInPack_t	*buildBuffer;
-	stringBuffer_t	*namesBuffer;
+	stringPool_t	*namesBuffer;
 	pack_t			*pack;
 	unzFile			uf;
 	int				err;
@@ -2031,7 +1985,7 @@ static pack_t *FS_LoadZipFile( char *zipfile, const char *basename, qboolean ass
 	fs_packFiles += gi.number_entry;
 
 	buildBuffer = (struct fileInPack_s *)Z_Malloc((int)((gi.number_entry * sizeof(fileInPack_t))), TAG_FILESYS, qtrue);
-	namesBuffer = FS_NewStringBuffer(gi.number_entry * 16);
+	namesBuffer = Z_StringPoolNew(gi.number_entry * 16, TAG_FILESYS);
 	fs_headerLongs = (int *)Z_Malloc( gi.number_entry * sizeof(int), TAG_FILESYS, qtrue );
 
 	// get the hash table size from the number of files in the zip
@@ -2083,7 +2037,7 @@ static pack_t *FS_LoadZipFile( char *zipfile, const char *basename, qboolean ass
 		}
 		Q_strlwr( filename_inzip );
 		hash = FS_HashFileName(filename_inzip, pack->hashSize);
-		buildBuffer[i].name = FS_AppendStringBuffer(namesBuffer, filename_inzip);
+		buildBuffer[i].name = Z_StringPoolAdd(namesBuffer, filename_inzip);
 		// store the file position in the zip
 		buildBuffer[i].pos = unzGetOffset(uf);
 		buildBuffer[i].len = file_info.uncompressed_size;
@@ -3182,7 +3136,7 @@ static void FS_AddGameDirectory( const char *path, const char *dir, qboolean ass
 			if (!found) {
 				// server has no interest in the file
 				unzClose(pak->handle);
-				FS_FreeStringBuffer(pak->namesBuffer);
+				Z_StringPoolFree(pak->namesBuffer);
 				Z_Free(pak->buildBuffer);
 				Z_Free(pak);
 				continue;
@@ -3440,7 +3394,7 @@ void FS_Shutdown( qboolean closemfp, qboolean keepModuleFiles ) {
 
 		if ( p->pack ) {
 			unzClose(p->pack->handle);
-			FS_FreeStringBuffer( p->pack->namesBuffer );
+			Z_StringPoolFree( p->pack->namesBuffer );
 			Z_Free( p->pack->buildBuffer );
 			Z_Free( p->pack );
 		}

src/qcommon/qcommon.h

@@ -777,6 +777,13 @@ MISC
 
 const char	*CopyString( const char *in );
 const char	*CopyString( const char *in, memtag_t eTag );
+
+struct stringPool_s;
+typedef struct stringPool_s stringPool_t;
+stringPool_t	*Z_StringPoolNew(unsigned int size, memtag_t eTag);
+void			Z_StringPoolFree(stringPool_t * pool);
+const char		*Z_StringPoolAdd(stringPool_t * pool, const char * string);
+
 void		Info_Print( const char *s );
 
 void		Com_BeginRedirect (char *buffer, size_t buffersize, void (*flush)(char *), qboolean silent);