un picolo cambio

[z.facultad/75.06/emufs.git] / emufs / idx.c

diff --git a/emufs/idx.c b/emufs/idx.c
index 52f3b59933ccf788b0f8e5f681b24df642b4d34f..ea971023895af951102674f475556be4b8b41e46 100644 (file)
--- a/emufs/idx.c
+++ b/emufs/idx.c
@@ -1,20 +1,76 @@
+/* vim: set noexpandtab tabstop=4 shiftwidth=4:
+ *----------------------------------------------------------------------------
+ *                                  emufs
+ *----------------------------------------------------------------------------
+ * This file is part of emufs.
+ *
+ * emufs is free software; you can redistribute it and/or modify it under the
+ * terms of the GNU General Public License as published by the Free Software
+ * Foundation; either version 2 of the License, or (at your option) any later
+ * version.
+ *
+ * emufs is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with emufs; if not, write to the Free Software Foundation, Inc., 59 Temple
+ * Place, Suite 330, Boston, MA  02111-1307  USA
+ *----------------------------------------------------------------------------
+ * Creado:  jue abr  8 18:10:35 ART 2004
+ * Autores: Nicolás Dimov <sagardua@uolsinectis.com.ar>
+ *----------------------------------------------------------------------------
+ *
+ * $Id$
+ *
+ */
+
+/** \file
+ *
+ * Manejo de archivos de índice de registros.
+ * 
+ * Implementación del manejo de archivos de índice de registros.
+ *
+ */
+
 #include "idx.h"
-#include "tipo3.h"
+#include <stdlib.h>
+#include <strings.h>
+
+FILE* emufs_idx_abrir(EMUFS* efs, const char* mode)
+{
+       FILE* f;
+       char* filename;
+
+       filename = (char*) malloc(sizeof(char) * (strlen(efs->nombre)
+                               + strlen(EMUFS_IDX_EXT) + 1));
+       if (filename == NULL) {
+               /* TODO Manejo de errores */
+               return NULL;
+       }
+       strcpy(filename, efs->nombre);
+       strcat(filename, EMUFS_IDX_EXT);
+       f = fopen(filename, mode);
+       free(filename);
+       return f;
+}
 
 int emufs_idx_buscar_mayor_id(EMUFS *emu)
 {
        int id, max = -1;
        FILE *f_idx;    
-       BLOCK_REG_T reg;
-       char name_f_idx[255];
+       EMUFS_IDX reg;
+       char name_f_idx[255]; /* TODO usar malloc para no limitar el tamaño de nombre de archivo */
 
        strcpy(name_f_idx,emu->nombre);
-       strcat(name_f_idx,".idx");
+       strcat(name_f_idx, EMUFS_IDX_EXT);
 
        if ( (f_idx = fopen(name_f_idx,"r")) == NULL) return -1; /*ERROR*/
+       id = -1;
        while ( !feof(f_idx) ){
                /* Me aseguro de leer la cantidad de bytes correcta */
-               if (fread(&reg,sizeof(BLOCK_REG_T),1,f_idx) != 1) continue;
+               if (fread(&reg,sizeof(EMUFS_IDX),1,f_idx) != 1) continue;
                if ( reg.id_reg >= max ) 
                        max = reg.id_reg;
        }
@@ -23,3 +79,46 @@ int emufs_idx_buscar_mayor_id(EMUFS *emu)
 
        return id;      
 }
+
+/*busca el registro ID en el archivo ".idx" y devuelve el nro de bloque en el que se encuentra*/
+int emufs_idx_buscar_registro(EMUFS *emu, int ID)
+{
+       FILE* f_idx;
+       EMUFS_IDX reg;
+       char name_f_idx[255];
+       strcpy(name_f_idx,emu->nombre);
+       strcat(name_f_idx, EMUFS_IDX_EXT);
+       
+       if ( (f_idx = fopen(name_f_idx,"r")) == NULL) return -1; /*ERROR*/
+       reg.id_reg = -1;
+       reg.block = -1;
+       while ( !feof(f_idx) ){
+               if (fread(&reg,sizeof(EMUFS_IDX),1,f_idx) != 1) continue;
+               if ( reg.id_reg == ID ){
+                       break;
+               }
+       }
+       
+       fclose(f_idx);
+       return reg.block;
+}
+
+/* agrega un registro al final del archivo */
+int emufs_idx_agregar(EMUFS *emu, int num_bloque, int ID_aux)
+{
+       FILE *f_idx;
+       EMUFS_IDX reg;
+       char name_f_idx[255];
+       
+       strcpy(name_f_idx,emu->nombre);
+       strcat(name_f_idx, EMUFS_IDX_EXT);
+
+       if ( (f_idx = fopen(name_f_idx,"a+"))==NULL ) return -1;
+               
+       reg.block = num_bloque;
+       reg.id_reg = ID_aux;
+       fwrite(&reg,sizeof(EMUFS_IDX),1,f_idx); 
+       fclose(f_idx);
+       return 0;
+}
+