Introduce new file read path

app/src/main/cpp/fdutils.c

@@ -1,4 +1,13 @@
 #include <jni.h>
+#include <sys/mman.h>
+
+#include <android/log.h>
+#include <string.h>
+#include <errno.h>
+
+#define LOG_TAG "mmap_utils"
+
+#include "ehviewer.h"
 
 JNIEXPORT jint JNICALL
 Java_com_hippo_Native_getFd(JNIEnv *env, jclass clazz, jobject fileDescriptor) {
@@ -13,4 +22,22 @@ Java_com_hippo_Native_getFd(JNIEnv *env, jclass clazz, jobject fileDescriptor) {
     }
 
     return fd;
-}
+}
+
+JNIEXPORT jobject JNICALL
+Java_com_hippo_Native_mapFd(JNIEnv *env, jclass clazz, jint fd, jlong capability) {
+    void *addr = mmap(0, capability, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
+    if (addr != MAP_FAILED) {
+        return (*env)->NewDirectByteBuffer(env, addr, capability);
+    } else {
+        LOGE("%s%s", "mmap failed with error ", strerror(errno));
+        return NULL;
+    }
+}
+
+JNIEXPORT void JNICALL
+Java_com_hippo_Native_unmapDirectByteBuffer(JNIEnv *env, jclass clazz, jobject buffer) {
+    void *addr = (*env)->GetDirectBufferAddress(env, buffer);
+    size_t size = (*env)->GetDirectBufferCapacity(env, buffer);
+    if (munmap(addr, size)) LOGE("munmap addr:%p, size%d failed!", addr, size);
+}