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)
36 memcpy(&size,xb,sizeof(int));
37 while(size > 0 && (size < xb_size) && (pos + size < xb_size)){
38 if(strncmp(xb+pos+sizeof(int),name,size) == 0)
41 if(pos < xb_size -sizeof(int))
42 memcpy(&size,xb + pos,sizeof(int));
49 static int nval_used(const char *xb, int xb_size)
54 memcpy(&size,xb + pos,sizeof(int));
55 while(size > 0 && (size < xb_size) && (pos + size < xb_size)){
57 if(pos < xb_size -sizeof(int))
58 memcpy(&size,xb + pos,sizeof(int));
65 int nval_del(char *xb, int xb_size, const char *name)
67 int pos = nval_find(xb, xb_size, name);
70 if(pos >= 0 && pos < xb_size){
71 /* Find size, shift rest over this record, then zero out the rest of buffer */
72 memcpy(&size,xb+pos,sizeof(int));
73 memcpy(xb + pos, xb + pos + size, xb_size - (pos + size));
74 memset(xb + (xb_size - size),0,size);
80 int nval_set(char *xb, int xb_size, const char *name, const char *buf, int bsize, int flags)
82 int pos = nval_find(xb,xb_size,name);
83 int namelen = strnlen(name,xb_size);
86 if(flags & NVAL_CREATE && pos >= 0)
88 if(flags & NVAL_REPLACE && pos < 0)
91 nval_del(xb,xb_size,name);
93 pos = nval_used(xb, xb_size);
95 if(pos < xb_size && bsize < xb_size && namelen < xb_size){
96 reclen = (sizeof(int) + namelen + 1 + bsize);
97 if( pos + reclen < xb_size){
98 memcpy(xb + pos,&reclen,sizeof(int));
100 strncpy(xb + pos, name, reclen);
102 memcpy(xb + pos,buf,bsize);
110 int nval_get(const char *xb, int xb_size, const char *name, char *buf, int bsize)
112 int pos = nval_find(xb,xb_size,name);
115 if(pos >= 0 && pos< xb_size){
117 memcpy(&size,xb +pos,sizeof(int));
118 pos+=sizeof(int); /* advance past record length */
121 /* Advance over name string */
122 while(xb[pos] && size > 0 && pos < xb_size){
126 /*Advance over NUL */
131 memcpy(buf,xb + pos,size);
139 int nval_list(const char *xb, int xb_size, char *buf, int bsize)
147 memcpy(&size,xb + pos,sizeof(int));
148 while(size > sizeof(int) && size <= xb_size && (pos + size) < xb_size && !filled){
151 name_len = strnlen(xb + pos, size);
152 if(ncopied + name_len + 1 < bsize){
153 memcpy(buf,xb+pos,name_len);
157 ncopied += (name_len+1);
161 if(pos < xb_size -sizeof(int))
162 memcpy(&size,xb + pos,sizeof(int));
169 int nval_load(char *xb, int xb_size, const char *src, int src_size)
175 if(tx_size > src_size)
178 memcpy(xb,src,tx_size);
179 used = nval_used(xb, xb_size);
182 memset(xb+ used, 0, xb_size - used);
186 int nval_save(const char *xb, int xb_size, char *dest, int dest_size)
191 if(tx_size > dest_size)
194 memcpy(dest,xb,tx_size);