Refactor native code and implement our own JNI wrapper around zlib.

The previous native cipher code has been refactored so that it may be loaded and used slightly more generically, allowing more native components to be easily added as time goes on. I have also written a new native code compression module, which wraps around zlib in the same manner that Inflater / Deflater does, however it operates directly on the memory addresses of it's input / output buffers which means that we can save one, or maybe even two copies. To support this, the VarInt decoder has been adjusted to always use a native buffer.
2015-02-01 21:05:16 +11:00
parent e6da9cbba8
commit 0d569ac0d1
29 changed files with 599 additions and 148 deletions
--- a/native/src/main/c/NativeCompressImpl.cpp
+++ b/native/src/main/c/NativeCompressImpl.cpp
@@ -0,0 +1,82 @@
+#include <string>
+#include <zlib.h>
+#include "net_md_5_bungee_jni_zlib_NativeCompressImpl.h"
+
+using namespace std;
+typedef unsigned char byte;
+
+jint throwException(JNIEnv *env, string message) {
+    jclass exClass = env->FindClass("java/lang/RuntimeException");
+    // Can never actually happen on a sane JVM, but better be safe anyway
+    if (exClass == NULL) {
+        return -1;
+    }
+
+    return env->ThrowNew(exClass, message.c_str());
+}
+
+static jfieldID consumedID;
+static jfieldID finishedID;
+
+void JNICALL Java_net_md_15_bungee_jni_zlib_NativeCompressImpl_initFields(JNIEnv* env, jclass clazz) {
+    // We trust that these fields will be there
+    consumedID = env->GetFieldID(clazz, "consumed", "I");
+    finishedID = env->GetFieldID(clazz, "finished", "Z");
+}
+
+void JNICALL Java_net_md_15_bungee_jni_zlib_NativeCompressImpl_reset(JNIEnv* env, jobject obj, jlong ctx, jboolean compress) {
+    z_stream* stream = (z_stream*) ctx;
+    int ret = (compress) ? deflateReset(stream) : inflateReset(stream);
+
+    if (ret != Z_OK) {
+        throwException(env, "Could not reset z_stream: " + to_string(ret));
+    }
+}
+
+void JNICALL Java_net_md_15_bungee_jni_zlib_NativeCompressImpl_end(JNIEnv* env, jobject obj, jlong ctx, jboolean compress) {
+    z_stream* stream = (z_stream*) ctx;
+    int ret = (compress) ? deflateEnd(stream) : inflateEnd(stream);
+
+    free(stream);
+
+    if (ret != Z_OK) {
+        throwException(env, "Could not free z_stream: " + to_string(ret));
+    }
+}
+
+jlong JNICALL Java_net_md_15_bungee_jni_zlib_NativeCompressImpl_init(JNIEnv* env, jobject obj, jboolean compress, jint level) {
+    z_stream* stream = (z_stream*) calloc(1, sizeof (z_stream));
+    int ret = (compress) ? deflateInit(stream, level) : inflateInit(stream);
+
+    if (ret != Z_OK) {
+        throwException(env, "Could not init z_stream: " + to_string(ret));
+    }
+
+    return (jlong) stream;
+}
+
+jint JNICALL Java_net_md_15_bungee_jni_zlib_NativeCompressImpl_process(JNIEnv* env, jobject obj, jlong ctx, jlong in, jint inLength, jlong out, jint outLength, jboolean compress) {
+    z_stream* stream = (z_stream*) ctx;
+
+    stream->avail_in = inLength;
+    stream->next_in = (byte*) in;
+
+    stream->avail_out = outLength;
+    stream->next_out = (byte*) out;
+
+    int ret = (compress) ? deflate(stream, Z_FINISH) : inflate(stream, Z_PARTIAL_FLUSH);
+
+    switch (ret) {
+        case Z_STREAM_END:
+            env->SetBooleanField(obj, finishedID, true);
+            break;
+        case Z_OK:
+            break;
+        default:
+            throwException(env, "Unknown z_stream return code: " + to_string(ret));
+    }
+
+    env->SetIntField(obj, consumedID, inLength - stream->avail_in);
+
+    return outLength - stream->avail_out;
+}