X-Git-Url: http://www.aleph1.co.uk/gitweb/?p=yaffs2.git;a=blobdiff_plain;f=yaffs_nameval.c;fp=yaffs_nameval.c;h=88ee25bfd6c87d8c0ea4324abcdc529955bae7f8;hp=0000000000000000000000000000000000000000;hb=4a96d43bb566f00596a31a41c535cabbf52d4f20;hpb=523109e39ed14c0153c7947ad7a8f31a0917df93;ds=sidebyside

diff --git a/yaffs_nameval.c b/yaffs_nameval.c
new file mode 100644
index 0000000..88ee25b
--- /dev/null
+++ b/yaffs_nameval.c
@@ -0,0 +1,196 @@
+/*
+ * YAFFS: Yet Another Flash File System. A NAND-flash specific file system.
+ *
+ * Copyright (C) 2002-2010 Aleph One Ltd.
+ *   for Toby Churchill Ltd and Brightstar Engineering
+ *
+ * Created by Charles Manning <charles@aleph1.co.uk>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+/*
+ * This simple implementation of a name-value store assumes a small number of values and fits
+ * into a small finite buffer.
+ *
+ * Each attribute is stored as a record:
+ *  sizeof(int) bytes   record size.
+ *  strnlen+1 bytes name null terminated.
+ *  nbytes    value.
+ *  ----------
+ *  total size  stored in record size 
+ */
+
+
+#include "yaffs_nameval.h"
+
+#include "yportenv.h"
+ 
+static int nval_find(const char *xb, int xb_size, const char *name)
+{
+	int pos=0;
+	int size;
+
+	memcpy(&size,xb,sizeof(int));
+	while(size > 0 && (size < xb_size) && (pos + size < xb_size)){
+		if(strncmp(xb+pos+sizeof(int),name,size) == 0)
+			return pos;
+		pos += size;
+		if(pos < xb_size -sizeof(int))
+			memcpy(&size,xb + pos,sizeof(int));
+		else
+			size = 0;
+	}
+	return -1;
+}
+
+static int nval_used(const char *xb, int xb_size)
+{
+	int pos=0;
+	int size;
+
+	memcpy(&size,xb + pos,sizeof(int));
+	while(size > 0 && (size < xb_size) && (pos + size < xb_size)){
+		pos += size;
+		if(pos < xb_size -sizeof(int))
+			memcpy(&size,xb + pos,sizeof(int));
+		else
+			size = 0;
+	}
+	return pos;
+}
+
+int nval_del(char *xb, int xb_size, const char *name)
+{
+	int pos  = nval_find(xb, xb_size, name);
+	int size;
+	
+	if(pos >= 0 && pos < xb_size){
+		/* Find size, shift rest over this record, then zero out the rest of buffer */
+		memcpy(&size,xb+pos,sizeof(int));
+		memcpy(xb + pos, xb + pos + size, xb_size - (pos + size));
+		memset(xb + (xb_size - size),0,size);
+		return 0;
+	} else
+		return -ENOENT;
+}
+
+int nval_set(char *xb, int xb_size, const char *name, const char *buf, int bsize, int flags)
+{
+	int pos = nval_find(xb,xb_size,name);
+	int namelen = strnlen(name,xb_size);
+	int reclen;
+
+	if(flags & NVAL_CREATE && pos >= 0)
+		return -EEXIST;
+	if(flags & NVAL_REPLACE && pos < 0)
+		return -ENOENT;
+
+	nval_del(xb,xb_size,name);
+
+	pos = nval_used(xb, xb_size);
+	
+	if(pos < xb_size && bsize < xb_size && namelen < xb_size){
+		reclen = (sizeof(int) + namelen + 1 + bsize);
+		if( pos + reclen < xb_size){
+			memcpy(xb + pos,&reclen,sizeof(int));
+			pos +=sizeof(int);
+			strncpy(xb + pos, name, reclen);
+			pos+= (namelen+1);
+			memcpy(xb + pos,buf,bsize);
+			pos+= bsize;
+			return 0;
+		}
+	}
+	return -ENOSPC;
+}
+
+int nval_get(const char *xb, int xb_size, const char *name, char *buf, int bsize)
+{
+	int pos = nval_find(xb,xb_size,name);
+	int size;
+	
+	if(pos >= 0 && pos< xb_size){
+		
+		memcpy(&size,xb +pos,sizeof(int));
+		pos+=sizeof(int); /* advance past record length */
+		size -= sizeof(int);
+
+		/* Advance over name string */
+		while(xb[pos] && size > 0 && pos < xb_size){
+			pos++;
+			size--;
+		}
+		/*Advance over NUL */
+		pos++;
+		size--;
+
+		if(size <= bsize){
+			memcpy(buf,xb + pos,size);
+			return size;
+		}
+		
+	}
+	return -ENOENT;
+}
+
+int nval_list(const char *xb, int xb_size, char *buf, int bsize)
+{
+	int pos = 0;
+	int size;
+	int name_len;
+	int ncopied = 0;
+	int filled = 0;
+
+	memcpy(&size,xb + pos,sizeof(int));
+	while(size > sizeof(int) && size <= xb_size && (pos + size) < xb_size && !filled){
+		pos+= sizeof(int);
+		size-=sizeof(int);
+		name_len = strnlen(xb + pos, size);
+		if(ncopied + name_len + 1 < bsize){
+			memcpy(buf,xb+pos,name_len);
+			buf+= name_len;
+			*buf = '\0';
+			buf++;
+			ncopied += (name_len+1);
+		} else
+			filled = 1;
+		pos+=size;
+		if(pos < xb_size -sizeof(int))
+			memcpy(&size,xb + pos,sizeof(int));
+		else
+			size = 0;
+	}
+	return ncopied;
+}
+
+int nval_load(char *xb, int xb_size, const char *src, int src_size)
+{
+	int tx_size;
+	int used;
+	
+	tx_size = xb_size;
+	if(tx_size > src_size)
+		tx_size = src_size;
+
+	memcpy(xb,src,tx_size);
+	used = nval_used(xb, xb_size);
+	
+	if( used < xb_size)
+		memset(xb+ used, 0, xb_size - used);
+	return used;	
+}
+
+int nval_save(const char *xb, int xb_size, char *dest, int dest_size)
+{
+	int tx_size;
+	
+	tx_size = xb_size;
+	if(tx_size > dest_size)
+		tx_size = dest_size;
+
+	memcpy(dest,xb,tx_size);
+	return tx_size;
+}