Revert "Revert "Cut down on object allocation in CipherInputStream""

This reverts commit 6b3f9499cf6647263b51741e4187a26a54500072.

Bug: 6523748
Bug: 6478569
Change-Id: Ic422e5fa320995600bdae7a42816652e16b8728b

2 files changed, 42 insertions, 32 deletions

diff --git a/luni/src/main/java/javax/crypto/Cipher.java b/luni/src/main/java/javax/crypto/Cipher.java
index c8cb601..1dacd46 100644
--- a/luni/src/main/java/javax/crypto/Cipher.java
+++ b/luni/src/main/java/javax/crypto/Cipher.java
@@ -886,17 +886,25 @@ public class Cipher {
         if (input == null) {
             throw new IllegalArgumentException("input == null");
         }
-        if (inputOffset < 0 || inputLen < 0
-                || inputLen > input.length
-                || inputOffset > input.length - inputLen) {
-            throw new IllegalArgumentException("Incorrect inputOffset/inputLen parameters");
-        }
+        checkInputOffsetAndCount(input.length, inputOffset, inputLen);
         if (input.length == 0) {
             return null;
         }
         return spiImpl.engineUpdate(input, inputOffset, inputLen);
     }
 
+    private static void checkInputOffsetAndCount(int inputArrayLength,
+                                                 int inputOffset,
+                                                 int inputLen) {
+        if ((inputOffset | inputLen) < 0
+                || inputOffset > inputArrayLength
+                || inputArrayLength - inputOffset < inputLen) {
+            throw new IllegalArgumentException("input.length=" + inputArrayLength
+                                               + "; inputOffset=" + inputOffset
+                                               + "; inputLen=" + inputLen);
+        }
+    }
+
     /**
      * Continues a multi-part transformation (encryption or decryption). The
      * transformed bytes are stored in the {@code output} buffer.
@@ -972,12 +980,9 @@ public class Cipher {
             throw new IllegalArgumentException("output == null");
         }
         if (outputOffset < 0) {
-            throw new IllegalArgumentException("outputOffset < 0");
-        }
-        if (inputOffset < 0 || inputLen < 0 || inputLen > input.length
-                || inputOffset > input.length - inputLen) {
-            throw new IllegalArgumentException("Incorrect inputOffset/inputLen parameters");
+            throw new IllegalArgumentException("outputOffset < 0. outputOffset=" + outputOffset);
         }
+        checkInputOffsetAndCount(input.length, inputOffset, inputLen);
         if (input.length == 0) {
             return 0;
         }
@@ -1075,7 +1080,7 @@ public class Cipher {
             throw new IllegalStateException();
         }
         if (outputOffset < 0) {
-            throw new IllegalArgumentException("outputOffset < 0");
+            throw new IllegalArgumentException("outputOffset < 0. outputOffset=" + outputOffset);
         }
         return spiImpl.engineDoFinal(null, 0, 0, output, outputOffset);
     }
@@ -1137,9 +1142,7 @@ public class Cipher {
         if (mode != ENCRYPT_MODE && mode != DECRYPT_MODE) {
             throw new IllegalStateException();
         }
-        if (inputOffset < 0 || inputLen < 0 || inputOffset + inputLen > input.length) {
-            throw new IllegalArgumentException("Incorrect inputOffset/inputLen parameters");
-        }
+        checkInputOffsetAndCount(input.length, inputOffset, inputLen);
         return spiImpl.engineDoFinal(input, inputOffset, inputLen);
     }
 
@@ -1217,9 +1220,7 @@ public class Cipher {
         if (mode != ENCRYPT_MODE && mode != DECRYPT_MODE) {
             throw new IllegalStateException();
         }
-        if (inputOffset < 0 || inputLen < 0 || inputOffset + inputLen > input.length) {
-            throw new IllegalArgumentException("Incorrect inputOffset/inputLen parameters");
-        }
+        checkInputOffsetAndCount(input.length, inputOffset, inputLen);
         return spiImpl.engineDoFinal(input, inputOffset, inputLen, output,
                 outputOffset);
     }
diff --git a/luni/src/main/java/javax/crypto/CipherInputStream.java b/luni/src/main/java/javax/crypto/CipherInputStream.java
index 4de37db..39dcfda 100644
--- a/luni/src/main/java/javax/crypto/CipherInputStream.java
+++ b/luni/src/main/java/javax/crypto/CipherInputStream.java
@@ -39,8 +39,9 @@ public class CipherInputStream extends FilterInputStream {
 
     private final Cipher cipher;
     private final byte[] inputBuffer = new byte[I_BUFFER_SIZE];
-    private int index; // index of the bytes to return from outputBuffer
     private byte[] outputBuffer;
+    private int outputIndex; // index of the first byte to return from outputBuffer
+    private int outputLength; // count of the bytes to return from outputBuffer
     private boolean finished;
 
     /**
@@ -84,27 +85,35 @@ public class CipherInputStream extends FilterInputStream {
     @Override
     public int read() throws IOException {
         if (finished) {
-            return ((outputBuffer == null) || (index == outputBuffer.length))
-                            ? -1
-                            : outputBuffer[index++] & 0xFF;
+            return (outputIndex == outputLength) ? -1 : outputBuffer[outputIndex++] & 0xFF;
         }
-        if ((outputBuffer != null) && (index < outputBuffer.length)) {
-            return outputBuffer[index++] & 0xFF;
+        if (outputIndex < outputLength) {
+            return outputBuffer[outputIndex++] & 0xFF;
         }
-        index = 0;
-        outputBuffer = null;
-        int byteCount;
-        while (outputBuffer == null) {
-            if ((byteCount = in.read(inputBuffer)) == -1) {
+        outputIndex = 0;
+        outputLength = 0;
+        while (outputLength == 0) {
+            // check output size on each iteration since pending state
+            // in the cipher can cause this to vary from call to call
+            int outputSize = cipher.getOutputSize(inputBuffer.length);
+            if ((outputBuffer == null) || (outputBuffer.length < outputSize)) {
+                this.outputBuffer = new byte[outputSize];
+            }
+            int byteCount = in.read(inputBuffer);
+            if (byteCount == -1) {
                 try {
-                    outputBuffer = cipher.doFinal();
+                    outputLength = cipher.doFinal(outputBuffer, 0);
                 } catch (Exception e) {
                     throw new IOException(e.getMessage());
                 }
                 finished = true;
                 break;
             }
-            outputBuffer = cipher.update(inputBuffer, 0, byteCount);
+            try {
+                outputLength = cipher.update(inputBuffer, 0, byteCount, outputBuffer, 0);
+            } catch (ShortBufferException e) {
+                throw new AssertionError(e);  // should not happen since we sized with getOutputSize
+            }
         }
         return read();
     }
@@ -113,10 +122,10 @@ public class CipherInputStream extends FilterInputStream {
      * Reads the next {@code len} bytes from this input stream into buffer
      * {@code buf} starting at offset {@code off}.
      * <p>
-     * if {@code b} is {@code null}, the next {@code len} bytes are read and
+     * if {@code buf} is {@code null}, the next {@code len} bytes are read and
      * discarded.
      *
-     * @return the number of bytes filled into buffer {@code b}, or {@code -1}
+     * @return the number of bytes filled into buffer {@code buf}, or {@code -1}
      *         of the of the stream is reached.
      * @throws IOException
      *             if an error occurs.