Add doc

Author: mattn

doc.go

@@ -0,0 +1,95 @@
+/*
+Package sqlite3 provides interface to SQLite3 databases.
+
+This works as driver for database/sql.
+
+Installation
+
+    go get github.com/mattn/go-sqlite3
+
+Supported Types
+
+Currently, go-sqlite3 support following data types.
+
+    +------------------------------+
+    |go        | sqlite3           |
+    |----------|-------------------|
+    |nil       | null              |
+    |int       | integer           |
+    |int64     | integer           |
+    |float64   | float             |
+    |bool      | integer           |
+    |[]byte    | blob              |
+    |string    | text              |
+    |time.Time | timestamp/datetime|
+    +------------------------------+
+
+SQLite3 Extension
+
+You can write your own extension module for sqlite3. For example, below is a
+extension for Regexp matcher operation.
+
+    #include <pcre.h>
+    #include <string.h>
+    #include <stdio.h>
+    #include <sqlite3ext.h>
+    
+    SQLITE_EXTENSION_INIT1
+    static void regexp_func(sqlite3_context *context, int argc, sqlite3_value **argv) {
+      if (argc >= 2) {
+        const char *target  = (const char *)sqlite3_value_text(argv[1]);
+        const char *pattern = (const char *)sqlite3_value_text(argv[0]);
+        const char* errstr = NULL;
+        int erroff = 0;
+        int vec[500];
+        int n, rc;
+        pcre* re = pcre_compile(pattern, 0, &errstr, &erroff, NULL);
+        rc = pcre_exec(re, NULL, target, strlen(target), 0, 0, vec, 500); 
+        if (rc <= 0) {
+          sqlite3_result_error(context, errstr, 0);
+          return;
+        }
+        sqlite3_result_int(context, 1);
+      }
+    }
+    
+    #ifdef _WIN32
+    __declspec(dllexport)
+    #endif
+    int sqlite3_extension_init(sqlite3 *db, char **errmsg,
+          const sqlite3_api_routines *api) {
+      SQLITE_EXTENSION_INIT2(api);
+      return sqlite3_create_function(db, "regexp", 2, SQLITE_UTF8,
+          (void*)db, regexp_func, NULL, NULL);
+    }
+
+It need to build as so/dll shared library. And you need to register
+extension module like below.
+
+	sql.Register("sqlite3_with_extensions",
+		&sqlite3.SQLiteDriver{
+			Extensions: []string{
+				"sqlite3_mod_regexp",
+			},
+		})
+
+Then, you can use this extension.
+
+	rows, err := db.Query("select text from mytable where name regexp '^golang'")
+
+Connection Hook
+
+You can hook and inject your codes when connection established. database/sql
+doesn't provide the way to get native go-sqlite3 interfaces. So if you want,
+you need to hook ConnectHook and get the SQLiteConn.
+
+	sql.Register("sqlite3_with_hook_example",
+			&sqlite3.SQLiteDriver{
+					ConnectHook: func(conn *sqlite3.SQLiteConn) error {
+						sqlite3conn = append(sqlite3conn, conn)
+						return nil
+					},
+			})
+
+*/
+package sqlite3