2 * YAFFS: Yet Another Flash File System. A NAND-flash specific file system.
4 * Copyright (C) 2002-2010 Aleph One Ltd.
5 * for Toby Churchill Ltd and Brightstar Engineering
7 * Created by Charles Manning <charles@aleph1.co.uk>
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License version 2 as
11 * published by the Free Software Foundation.
15 * This simple implementation of a name-value store assumes a small number of values and fits
16 * into a small finite buffer.
18 * Each attribute is stored as a record:
19 * sizeof(int) bytes record size.
20 * strnlen+1 bytes name null terminated.
23 * total size stored in record size
25 * This code has not been tested with unicode yet.
29 #include "yaffs_nameval.h"
33 static int nval_find(const char *xb, int xb_size, const YCHAR *name,
39 memcpy(&size,xb,sizeof(int));
40 while(size > 0 && (size < xb_size) && (pos + size < xb_size)){
41 if(yaffs_strncmp((YCHAR *)(xb+pos+sizeof(int)),name,size) == 0){
47 if(pos < xb_size -sizeof(int))
48 memcpy(&size,xb + pos,sizeof(int));
57 static int nval_used(const char *xb, int xb_size)
62 memcpy(&size,xb + pos,sizeof(int));
63 while(size > 0 && (size < xb_size) && (pos + size < xb_size)){
65 if(pos < xb_size -sizeof(int))
66 memcpy(&size,xb + pos,sizeof(int));
73 int nval_del(char *xb, int xb_size, const YCHAR *name)
75 int pos = nval_find(xb, xb_size, name, NULL);
78 if(pos >= 0 && pos < xb_size){
79 /* Find size, shift rest over this record, then zero out the rest of buffer */
80 memcpy(&size,xb+pos,sizeof(int));
81 memcpy(xb + pos, xb + pos + size, xb_size - (pos + size));
82 memset(xb + (xb_size - size),0,size);
88 int nval_set(char *xb, int xb_size, const YCHAR *name, const char *buf, int bsize, int flags)
91 int namelen = yaffs_strnlen(name,xb_size);
97 pos = nval_find(xb,xb_size,name, &size_exist);
99 if(flags & XATTR_CREATE && pos >= 0)
101 if(flags & XATTR_REPLACE && pos < 0)
104 start = nval_used(xb,xb_size);
105 space = xb_size - start + size_exist;
107 reclen = (sizeof(int) + namelen + 1 + bsize);
113 nval_del(xb,xb_size,name);
114 start = nval_used(xb, xb_size);
119 memcpy(xb + pos,&reclen,sizeof(int));
121 yaffs_strncpy((YCHAR *)(xb + pos), name, reclen);
123 memcpy(xb + pos,buf,bsize);
127 int nval_get(const char *xb, int xb_size, const YCHAR *name, char *buf, int bsize)
129 int pos = nval_find(xb,xb_size,name,NULL);
132 if(pos >= 0 && pos< xb_size){
134 memcpy(&size,xb +pos,sizeof(int));
135 pos+=sizeof(int); /* advance past record length */
138 /* Advance over name string */
139 while(xb[pos] && size > 0 && pos < xb_size){
143 /*Advance over NUL */
148 memcpy(buf,xb + pos,size);
159 int nval_list(const char *xb, int xb_size, char *buf, int bsize)
167 memcpy(&size,xb + pos,sizeof(int));
168 while(size > sizeof(int) && size <= xb_size && (pos + size) < xb_size && !filled){
171 name_len = yaffs_strnlen((YCHAR *)(xb + pos), size);
172 if(ncopied + name_len + 1 < bsize){
173 memcpy(buf,xb+pos,name_len * sizeof(YCHAR));
177 if(sizeof(YCHAR) > 1){
181 ncopied += (name_len+1);
185 if(pos < xb_size -sizeof(int))
186 memcpy(&size,xb + pos,sizeof(int));
194 int nval_hasvalues(const char *xb, int xb_size)
196 return nval_used(xb, xb_size) > 0;