Added mutable max buffer size for Encryptor and Decryptor

src/main/java/org/c02e/jpgpj/Decryptor.java

@@ -12,10 +12,9 @@
 import java.util.Iterator;
 import java.util.List;
 import java.util.NoSuchElementException;
-import org.bouncycastle.bcpg.ArmoredOutputStream;
+
 import org.bouncycastle.openpgp.PGPCompressedData;
 import org.bouncycastle.openpgp.PGPDataValidationException;
-import org.bouncycastle.openpgp.PGPEncryptedData;
 import org.bouncycastle.openpgp.PGPEncryptedDataList;
 import org.bouncycastle.openpgp.PGPException;
 import org.bouncycastle.openpgp.PGPLiteralData;
@@ -71,7 +70,7 @@
 public class Decryptor {
     protected boolean verificationRequired;
     protected String symmetricPassphrase;
-    protected int maxBufferSize = 0x100000; //1MB
+    protected int maxFileBufferSize = 0x100000; //1MB
     protected Ring ring;
     protected Logger log = LoggerFactory.getLogger(Decryptor.class.getName());
 
@@ -119,17 +118,16 @@ public void setSymmetricPassphrase(String x) {
         symmetricPassphrase = x != null ? x : "";
     }
 
-    public int getMaxBufferSize() {
-        return maxBufferSize;
+    public int getMaxFileBufferSize() {
+        return maxFileBufferSize;
     }
 
     /**
      * Decryptor will choose the most appropriate read/write buffer size
-     * for each file. You can set the maximum value here and it must be
-     * power of 2. Defaults to 1MB.
+     * for each file. You can set the maximum value here. Defaults to 1MB.
      */
-    public void setMaxBufferSize(int maxBufferSize) {
-        this.maxBufferSize = maxBufferSize;
+    public void setMaxFileBufferSize(int maxFileBufferSize) {
+        this.maxFileBufferSize = maxFileBufferSize;
     }
 
   /** Keys to use for decryption and verification. */
@@ -178,7 +176,7 @@ public FileMetadata decrypt(File ciphertext, File plaintext)
         OutputStream output = null;
         try {
             int bestBufferSize =
-                Util.bestBufferSize(plaintext.length(), maxBufferSize);
+                Util.bestFileBufferSize(ciphertext.length(), maxFileBufferSize);
             input = new BufferedInputStream(
                 new FileInputStream(ciphertext), bestBufferSize);
             output = new BufferedOutputStream(

src/main/java/org/c02e/jpgpj/Encryptor.java

@@ -13,7 +13,6 @@
 import java.util.Date;
 import java.util.List;
 import org.bouncycastle.bcpg.ArmoredOutputStream;
-import org.bouncycastle.bcpg.BCPGOutputStream;
 import org.bouncycastle.openpgp.PGPCompressedDataGenerator;
 import org.bouncycastle.openpgp.PGPEncryptedDataGenerator;
 import org.bouncycastle.openpgp.PGPException;
@@ -23,13 +22,13 @@
 import org.bouncycastle.openpgp.PGPSignatureSubpacketGenerator;
 import org.bouncycastle.openpgp.operator.PBEKeyEncryptionMethodGenerator;
 import org.bouncycastle.openpgp.operator.PGPContentSignerBuilder;
-import org.bouncycastle.openpgp.operator.PGPDataEncryptorBuilder;
 import org.bouncycastle.openpgp.operator.PublicKeyKeyEncryptionMethodGenerator;
 import org.bouncycastle.openpgp.operator.bc.BcPBEKeyEncryptionMethodGenerator;
 import org.bouncycastle.openpgp.operator.bc.BcPGPContentSignerBuilder;
 import org.bouncycastle.openpgp.operator.bc.BcPGPDataEncryptorBuilder;
 import org.bouncycastle.openpgp.operator.bc.BcPGPDigestCalculatorProvider;
 import org.bouncycastle.openpgp.operator.bc.BcPublicKeyKeyEncryptionMethodGenerator;
+import org.bouncycastle.util.Strings;
 import org.c02e.jpgpj.util.Util;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -79,7 +78,7 @@ public class Encryptor {
     protected HashingAlgorithm keyDerivationAlgorithm;
     protected int keyDerivationWorkFactor;
 
-    protected int maxBufferSize = 0x100000; //1MB
+    protected int maxFileBufferSize = 0x100000; //1MB
 
     protected Ring ring;
     protected Logger log = LoggerFactory.getLogger(Encryptor.class.getName());
@@ -227,17 +226,17 @@ public void setKeyDeriviationWorkFactor(int x) {
         keyDerivationWorkFactor = x;
     }
 
-    public int getMaxBufferSize() {
-        return maxBufferSize;
+    public int getMaxFileBufferSize() {
+        return maxFileBufferSize;
     }
 
     /**
      * Encryptor will choose the most appropriate read/write buffer size
      * for each file. You can set the maximum value here and it must be
      * power of 2. Defaults to 1MB.
      */
-    public void setMaxBufferSize(int maxBufferSize) {
-        this.maxBufferSize = maxBufferSize;
+    public void setMaxFileBufferSize(int maxFileBufferSize) {
+        this.maxFileBufferSize = maxFileBufferSize;
     }
 
   /** Keys to use for encryption and signing. */
@@ -281,12 +280,13 @@ public void encrypt(File plaintext, File ciphertext)
         InputStream input = null;
         OutputStream output = null;
         try {
-            int bestBufferSize =
-                Util.bestBufferSize(plaintext.length(), maxBufferSize);
+            int bestFileBufferSize =
+                Util.bestFileBufferSize(plaintext.length(), maxFileBufferSize);
             input = new BufferedInputStream(
-                new FileInputStream(plaintext), bestBufferSize);
+                new FileInputStream(plaintext), bestFileBufferSize);
             output = new BufferedOutputStream(
-                new FileOutputStream(ciphertext), bestBufferSize);
+                new FileOutputStream(ciphertext),
+                estimateOutFileSize(plaintext.length()));
             encrypt(input, output, new FileMetadata(plaintext));
         } catch (Exception e) {
             // delete output file if anything went wrong
@@ -601,6 +601,22 @@ protected int bestPacketSize(FileMetadata meta) {
         return len;
     }
 
+    private int estimateOutFileSize(long inFileSize) {
+        if (inFileSize > Integer.MAX_VALUE) return maxFileBufferSize;
+        else {
+            long outFileSize = inFileSize;
+            outFileSize += (1 + getRing().getEncryptionKeys().size() +
+                getRing().getSigningKeys().size()) * 512;
+            if (isAsciiArmored()) {
+                outFileSize *= (4 / 3) *
+                    ((64 + Strings.lineSeparator().length()) / 64);
+                outFileSize += 80;
+            }
+            return (outFileSize >= maxFileBufferSize) ?
+                maxFileBufferSize : Math.toIntExact(outFileSize);
+        }
+    }
+
     protected class SigningOutputStream extends FilterOutputStream {
         protected FileMetadata meta;
         protected List<PGPSignatureGenerator> sigs;

src/main/java/org/c02e/jpgpj/util/Util.java

@@ -54,14 +54,12 @@ public static String formatAsHex(byte[] bytes) {
     }
 
   /**
-   * Returns the fileSize rounded up to exact power of 2 with a maximum
-   * of maxBufferSize (which should be power of 2).
+   * Returns the exact fileSize with a maximum of maxFileBufferSize.
    */
-    public static int bestBufferSize(long fileSize, int maxBufferSize) {
-        if (fileSize>=maxBufferSize) return maxBufferSize;
-        else {
-            return 1 << (32 - Long.numberOfLeadingZeros(fileSize));
-        }
+    public static int bestFileBufferSize(long fileSize, int maxFileBufferSize) {
+        return (fileSize>=maxFileBufferSize) ?
+            maxFileBufferSize :
+            Math.toIntExact(fileSize);
     }
 
 }