About

This is a c lib to treat xml as a native database. You can access, modify or replace a node. This is c version of go project- https://github.com/LIJUCHACKO/XmlDB

Usage

Include Header.

include "xmldb_lib/XmlDB.h"
Declare Database.

struct Database *DB=init_Database(0);
Load Database.

Load_db(DB,"sample.html");

Content of sample.html

<!DOCTYPE html>
<html>
   <head>
      <title>This is document title</title>
   </head>	
   <body style="123">
      <h1>This is a heading</h1>
      <p>Hello World!</p>
   </body>	
</html>

Identifying Nodes using Query.

struct ResultStruct * result= GetNode(DB, 0, "head*/title[This is document title]");
- 'identifiedNodes' contains list of nodes ids(<head>) identified under parent node with id '0' (<html> ..</html>).
- '*' marks the node we require.
- [] encloses attribute or value of the node as additional search criteria.
Getting Content of identified nodes.

    for(int i=0;i<result->nodeids.length;i++){
        printf("\n%s", GetNodeContents(DB, result->nodeids.items[i])->charbuf);
    }

Output

    <head>
          <title>This is document title</title>
    </head>

Getting Value of identified nodes.

   result= GetNode(DB, 0, "head/title*");
    for(int i=0;i<result->nodeids.length;i++){
        printf("\n%s", GetNodeValue(DB, result->nodeids.items[i])->charbuf);
    }

Output

This is document title

Searching using attribute value.

result = GetNode(DB, 0, "body*[style=\"123\"]/h1");
Updating node

   printf("\n### Updating node ##\n");
    result = GetNode(DB, 0, "head/title");
    for(int i=0;i<result->nodeids.length;i++){
        struct ResultStruct *newnodes = ReplaceNode(DB, result->nodeids.items[i], "<title>test</title>");
        printf("After updation\n");
        printf("old node value- %s", GetNodeValue(DB, result->nodeids.items[i])->charbuf); //no output, existing id is removed and new id added
        printf("\nnew node value- %s", GetNodeValue(DB, newnodes->nodeids.items[0])->charbuf);
    }
    printf("\n### Updating node attribute##\n");
    result = GetNode(DB, 0, "<x>*[style=\"123\"]/h1");
    for(int i=0;i<result->nodeids.length;i++){
        printf("\n%s", GetNodeAttribute(DB, result->nodeids.items[i], "style")->charbuf);
        UpdateAttributevalue(DB, result->nodeids.items[i], "style", "test2");
        printf("\nafter updating Attribute-\n%s", GetNodeContents(DB, result->nodeids.items[i])->charbuf);
        UpdateAttributevalue(DB, result->nodeids.items[i], "label", "value");
        printf("\nafter adding Attribute-\n%s", GetNodeContents(DB, result->nodeids.items[i])->charbuf);

    }

Output

### Updating node ##
After updation
Warning :node  doesnot exist
old node value- 
new node value- test
### Updating node attribute##

123
after updating Attribute-
<body style="test2">
  <h1>This is a heading with style</h1>
  <p>Hello World!</p>
</body>

after adding Attribute-
<body style="test2" label="value">
  <h1>This is a heading with style</h1>
  <p>Hello World!</p>
</body>

Recursive search.

result = GetNode(DB, 0, "../h1");
List Functions to be used to free the return pointers.

Memory deallocation function	Deallocates Return type	Functions that return the structure
free_StringReturn()	struct String	GetNodeName()
"	"	GetNodeContents()
"	"	GetNodeValue()
"	"	GetNodeAttribute()

free_ResultStruct()	struct ResultStruct	GetNode()
"	"	UpdateNodevalue()
"	"	UpdateAttributevalue()
"	"	ReplaceNode()
"	"	InserSubNode()
"	"	AppendBeforeNode()
"	"	AppendAfterNode()

free_VectorIntReturn()	struct VectorInt	RemoveNode()
"	"	ChildNodes()

-Last but not the least don't forget to free Database pointer.

'free(DB)'

-I have not used memory dealocation functions in the example inorder to keep the example simple.

Working/Software Design

INPUT(sample)

<!DOCTYPE html>
<html>
   <head><title>This is document title</title></head>	
   <body style="123">
      <h1>This is a heading</h1>
      <p>Hello World!</p>
   </body>	
</html>

After parsing- global variables are filled as shown

global_dbLines	global_ids	global_paths	global_values	global_attributes
`<!DOCTYPE html>`	-1
`<head>`	0	/head
`<title>This is document title</title>`	1	/head/title	This is document title
`<\head>`	2	/head/~
`<body style="123" font="arial">`	3	/body		style="123"\|\| font="arial"
`<h1>This is a heading</h1>`	4	/body/h1
`<p>Hello World!</p>`	5	/body/p	This is a heading
`</body>`	6	/body/~	Hello World!

Note:- If a new node is inserted in between, global_id '7' will be assigned to it. global_id will be unique and will be retained till the node is deleted.

'nodeNoToLineno' contains line no for every global id.

index/global_id	nodeNoToLineno[index]
0	1
1	2
2	3
3	4

'Nodeendlookup' contains global_id of the node end.

index/global_id	Nodeendlookup[index]
0	2
1	1
2	2
3	6
4	4
5	5

'pathKeylookup' is for quick lookup for line nos corresponding to innermost node.

-Say the path is '/head/title' then hash is calculated for 'title'.

-Corresponding to the hash value a list of global_ids ,arranged in the increasing order of lineno, is stored.

Hash no	global id list corresponding to the hash
0
1
2	[id1,id2,id3,id4]

-Binary search is utilised to find ids, under a parent node, from this list.

LIJUCHACKO / XmlDB_C

About

Usage

Working/Software Design

INPUT(sample)

After parsing- global variables are filled as shown

'nodeNoToLineno' contains line no for every global id.

'Nodeendlookup' contains global_id of the node end.

'pathKeylookup' is for quick lookup for line nos corresponding to innermost node.

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