content/vectorIndex/verify from Buffer

binding/java/src/main/java/org/lionsoul/ip2region/xdb/Searcher.java

@@ -11,6 +11,7 @@ import java.io.File;
 // @Date   2022/06/23
 
 import java.io.IOException;
+import java.io.InputStream;
 import java.io.RandomAccessFile;
 
 public class Searcher {
@@ -195,7 +196,9 @@ public class Searcher {
         );
     }
 
+    // ---
     // --- static util function
+    // --- read xdb header
 
     public static Header loadHeader(RandomAccessFile handle) throws IOException {
         handle.seek(0);
@@ -215,6 +218,12 @@ public class Searcher {
         return loadHeaderFromFile(new File(xdbPath));
     }
 
+    public static Header loadHeaderFromBuffer(LongByteArray cBuffer) throws IOException {
+        return new Header(cBuffer.slice(0, HeaderInfoLength));
+    }
+
+    // --- read xdb vector index
+
     public static byte[] loadVectorIndex(RandomAccessFile handle) throws IOException {
         handle.seek(HeaderInfoLength);
         int len = VectorIndexRows * VectorIndexCols * VectorIndexSize;
@@ -238,6 +247,13 @@ public class Searcher {
         return loadVectorIndexFromFile(new File(xdbPath));
     }
 
+    public static byte[] loadVectorIndexFromBuffer(LongByteArray cBuffer) throws IOException {
+        final int len = VectorIndexRows * VectorIndexCols * VectorIndexSize;
+        return cBuffer.slice(HeaderInfoLength, len);
+    }
+
+    // --- read xdb content
+
     public static LongByteArray loadContent(RandomAccessFile handle) throws IOException {
         handle.seek(0);
         // check the length and do the buff load
@@ -268,6 +284,45 @@ public class Searcher {
         return loadContentFromFile(new File(xdbPath));
     }
 
+    public static LongByteArray loadContentFromInputStream(InputStream is) throws IOException {
+        final LongByteArray byteArray = new LongByteArray();
+        while (true) {
+            boolean done = false;
+
+            // read at most MAX_WRITE_BYTES bytes
+            int rLen, tBytes = 0;
+            final byte[] buff = new byte[MAX_WRITE_BYTES];
+            while (true) {
+                rLen = is.read(buff, tBytes, buff.length - tBytes);
+                if (rLen == -1) {
+                    // reach the end of the stream
+                    done = true;
+                    break;
+                } else if (rLen == 0) {
+                    // the entire buff was filled
+                    break;
+                }
+
+                tBytes += rLen;
+            }
+
+            // check and copy the buffer with its actual filled bytes
+            if (tBytes == buff.length) {
+                byteArray.append(buff);
+            } else {
+                final byte[] nBuff = new byte[tBytes];
+                System.arraycopy(buff, 0, nBuff, 0, tBytes);
+                byteArray.append(nBuff);
+            }
+
+            if (done) {
+                break;
+            }
+        }
+
+        return byteArray;
+    }
+
     // --- verify util function
 
     // Verify if the current Searcher could be used to search the specified xdb file.
@@ -276,9 +331,7 @@ public class Searcher {
     //
     // @Note: You Just need to check this ONCE when the service starts
     // Or use another process (eg, A command) to check once Just to confirm the suitability.
-    public static void verify(RandomAccessFile handle) throws IOException, XdbException {
+    public static void verify(Header header, long fileBytes) throws IOException, XdbException {
-        final Header header = loadHeader(handle);
-
         // get the runtime ptr bytes
         int runtimePtrBytes = 0;
         if (header.version == STRUCTURE_20) {
@@ -292,11 +345,15 @@ public class Searcher {
         // 1, confirm the xdb file size
         // to ensure that the maximum file pointer does not overflow
         final long maxFilePtr = (1L << (runtimePtrBytes * 8)) - 1;
-        if (handle.length() > maxFilePtr) {
+        if (fileBytes > maxFilePtr) {
             throw new XdbException("xdb file exceeds the maximum supported bytes: "+maxFilePtr+"");
         }
     }
 
+    public static void verify(RandomAccessFile handle) throws IOException, XdbException {
+        verify(loadHeader(handle), handle.length());
+    }
+
     public static void verifyFromFile(File xdbFile) throws IOException, XdbException {
         final RandomAccessFile handle = new RandomAccessFile(xdbFile, "r");
         verify(handle);