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
27 #include "yaffs_nameval.h"
31 static int nval_find(const char *xb, int xb_size, const char *name,
37 memcpy(&size,xb,sizeof(int));
38 while(size > 0 && (size < xb_size) && (pos + size < xb_size)){
39 if(strncmp(xb+pos+sizeof(int),name,size) == 0){
45 if(pos < xb_size -sizeof(int))
46 memcpy(&size,xb + pos,sizeof(int));
55 static int nval_used(const char *xb, int xb_size)
60 memcpy(&size,xb + pos,sizeof(int));
61 while(size > 0 && (size < xb_size) && (pos + size < xb_size)){
63 if(pos < xb_size -sizeof(int))
64 memcpy(&size,xb + pos,sizeof(int));
71 int nval_del(char *xb, int xb_size, const char *name)
73 int pos = nval_find(xb, xb_size, name, NULL);
76 if(pos >= 0 && pos < xb_size){
77 /* Find size, shift rest over this record, then zero out the rest of buffer */
78 memcpy(&size,xb+pos,sizeof(int));
79 memcpy(xb + pos, xb + pos + size, xb_size - (pos + size));
80 memset(xb + (xb_size - size),0,size);
86 int nval_set(char *xb, int xb_size, const char *name, const char *buf, int bsize, int flags)
89 int namelen = strnlen(name,xb_size);
95 pos = nval_find(xb,xb_size,name, &size_exist);
97 if(flags & NVAL_CREATE && pos >= 0)
99 if(flags & NVAL_REPLACE && pos < 0)
102 start = nval_used(xb,xb_size);
103 space = xb_size - start + size_exist;
105 reclen = (sizeof(int) + namelen + 1 + bsize);
111 nval_del(xb,xb_size,name);
112 start = nval_used(xb, xb_size);
117 memcpy(xb + pos,&reclen,sizeof(int));
119 strncpy(xb + pos, name, reclen);
121 memcpy(xb + pos,buf,bsize);
125 int nval_get(const char *xb, int xb_size, const char *name, char *buf, int bsize)
127 int pos = nval_find(xb,xb_size,name,NULL);
130 if(pos >= 0 && pos< xb_size){
132 memcpy(&size,xb +pos,sizeof(int));
133 pos+=sizeof(int); /* advance past record length */
136 /* Advance over name string */
137 while(xb[pos] && size > 0 && pos < xb_size){
141 /*Advance over NUL */
146 memcpy(buf,xb + pos,size);
154 int nval_list(const char *xb, int xb_size, char *buf, int bsize)
162 memcpy(&size,xb + pos,sizeof(int));
163 while(size > sizeof(int) && size <= xb_size && (pos + size) < xb_size && !filled){
166 name_len = strnlen(xb + pos, size);
167 if(ncopied + name_len + 1 < bsize){
168 memcpy(buf,xb+pos,name_len);
172 ncopied += (name_len+1);
176 if(pos < xb_size -sizeof(int))
177 memcpy(&size,xb + pos,sizeof(int));
184 int nval_load(char *xb, int xb_size, const char *src, int src_size)
190 if(tx_size > src_size)
193 memcpy(xb,src,tx_size);
194 used = nval_used(xb, xb_size);
197 memset(xb+ used, 0, xb_size - used);
201 int nval_save(const char *xb, int xb_size, char *dest, int dest_size)
206 if(tx_size > dest_size)
209 memcpy(dest,xb,tx_size);