diff options
Diffstat (limited to 'java/src/main/java/com/google/protobuf/CodedInputStream.java')
-rw-r--r-- | java/src/main/java/com/google/protobuf/CodedInputStream.java | 50 |
1 files changed, 35 insertions, 15 deletions
diff --git a/java/src/main/java/com/google/protobuf/CodedInputStream.java b/java/src/main/java/com/google/protobuf/CodedInputStream.java index ad43f96d..b3e08555 100644 --- a/java/src/main/java/com/google/protobuf/CodedInputStream.java +++ b/java/src/main/java/com/google/protobuf/CodedInputStream.java @@ -67,7 +67,25 @@ public final class CodedInputStream { */ public static CodedInputStream newInstance(final byte[] buf, final int off, final int len) { - return new CodedInputStream(buf, off, len); + CodedInputStream result = new CodedInputStream(buf, off, len); + try { + // Some uses of CodedInputStream can be more efficient if they know + // exactly how many bytes are available. By pushing the end point of the + // buffer as a limit, we allow them to get this information via + // getBytesUntilLimit(). Pushing a limit that we know is at the end of + // the stream can never hurt, since we can never past that point anyway. + result.pushLimit(len); + } catch (InvalidProtocolBufferException ex) { + // The only reason pushLimit() might throw an exception here is if len + // is negative. Normally pushLimit()'s parameter comes directly off the + // wire, so it's important to catch exceptions in case of corrupt or + // malicious data. However, in this case, we expect that len is not a + // user-supplied value, so we can assume that it being negative indicates + // a programming error. Therefore, throwing an unchecked exception is + // appropriate. + throw new IllegalArgumentException(ex); + } + return result; } // ----------------------------------------------------------------- @@ -263,7 +281,9 @@ public final class CodedInputStream { /** Read a {@code bytes} field value from the stream. */ public ByteString readBytes() throws IOException { final int size = readRawVarint32(); - if (size <= (bufferSize - bufferPos) && size > 0) { + if (size == 0) { + return ByteString.EMPTY; + } else if (size <= (bufferSize - bufferPos) && size > 0) { // Fast path: We already have the bytes in a contiguous buffer, so // just copy directly from it. final ByteString result = ByteString.copyFrom(buffer, bufferPos, size); @@ -368,8 +388,8 @@ public final class CodedInputStream { * has already read one byte. This allows the caller to determine if EOF * has been reached before attempting to read. */ - static int readRawVarint32(final int firstByte, - final InputStream input) throws IOException { + public static int readRawVarint32( + final int firstByte, final InputStream input) throws IOException { if ((firstByte & 0x80) == 0) { return firstByte; } @@ -847,19 +867,19 @@ public final class CodedInputStream { } else { // Skipping more bytes than are in the buffer. First skip what we have. int pos = bufferSize - bufferPos; - totalBytesRetired += pos; - bufferPos = 0; - bufferSize = 0; + bufferPos = bufferSize; - // Then skip directly from the InputStream for the rest. - while (pos < size) { - final int n = (input == null) ? -1 : (int) input.skip(size - pos); - if (n <= 0) { - throw InvalidProtocolBufferException.truncatedMessage(); - } - pos += n; - totalBytesRetired += n; + // Keep refilling the buffer until we get to the point we wanted to skip + // to. This has the side effect of ensuring the limits are updated + // correctly. + refillBuffer(true); + while (size - pos > bufferSize) { + pos += bufferSize; + bufferPos = bufferSize; + refillBuffer(true); } + + bufferPos = size - pos; } } } |