From 863337c789dd28997e59192641b8d60a1aaa3d5a Mon Sep 17 00:00:00 2001
From: tarsin <yuanqingxiang233@163.com>
Date: Mon, 23 May 2022 17:34:59 +0800
Subject: [PATCH] Support fskip for better decompress perf

* Actually the whole impl can't be more sucks, will import algorithm to manage buffer and read strategy further
---
 .../gallery/ArchiveGalleryProvider.java       |  2 +-
 .../java/com/hippo/UriArchiveAccessor.java    | 20 +++++++++++++++++++
 native/src/main/jni/archive.c                 | 12 +++++++++++
 3 files changed, 33 insertions(+), 1 deletion(-)

diff --git a/app/src/main/java/com/hippo/ehviewer/gallery/ArchiveGalleryProvider.java b/app/src/main/java/com/hippo/ehviewer/gallery/ArchiveGalleryProvider.java
index 252f807f9..5fd9bc3a8 100644
--- a/app/src/main/java/com/hippo/ehviewer/gallery/ArchiveGalleryProvider.java
+++ b/app/src/main/java/com/hippo/ehviewer/gallery/ArchiveGalleryProvider.java
@@ -194,7 +194,7 @@ public class ArchiveGalleryProvider extends GalleryProvider2 {
                     continue;
                 }
 
-                Pipe pipe = new Pipe(32 * 2048);
+                Pipe pipe = new Pipe(4096);
 
                 synchronized (streams) {
                     if (streams.get(index) != null) {
diff --git a/native/src/main/java/com/hippo/UriArchiveAccessor.java b/native/src/main/java/com/hippo/UriArchiveAccessor.java
index 22c47a3f5..1087a8392 100644
--- a/native/src/main/java/com/hippo/UriArchiveAccessor.java
+++ b/native/src/main/java/com/hippo/UriArchiveAccessor.java
@@ -72,6 +72,26 @@ public class UriArchiveAccessor implements Closeable {
             Os.lseek(fd, 0, OsConstants.SEEK_SET);
         }
 
+        public long skip(long n) throws IOException, ErrnoException {
+            long pos;
+            long len;
+            long newpos;
+
+            if (n <= 0) {
+                return 0;
+            }
+            pos = Os.lseek(fd, 0L, OsConstants.SEEK_CUR);
+            len = length();
+            newpos = pos + n;
+            if (newpos > len) {
+                newpos = len;
+            }
+            seek(newpos, OsConstants.SEEK_SET);
+
+            /* return the actual number of bytes skipped */
+            return newpos - pos;
+        }
+
         public void close() throws IOException {
             pfd.close();
             try {
diff --git a/native/src/main/jni/archive.c b/native/src/main/jni/archive.c
index 1e293eb38..e5d0a1b38 100644
--- a/native/src/main/jni/archive.c
+++ b/native/src/main/jni/archive.c
@@ -61,6 +61,7 @@ static void archive_list_all_entries(struct archive_inst_sc *inst)
     while (archive_read_next_header(a, &entry) == ARCHIVE_OK) {
         if(filename_is_playable_file(archive_entry_pathname(entry)))
             count++;
+        archive_read_data_skip(a);
     }
     inst->entry_num = count;
 }
@@ -90,17 +91,26 @@ la_int64_t ins_seek(struct archive *a, void *client_data, la_int64_t offset, int
     return ret;
 }
 
+la_int64_t ins_skip(struct archive *a, void *client_data, la_int64_t request)
+{
+    archive_inst *arc = client_data;
+    jlong ret = (*arc->env)->CallLongMethod(arc->env, arc->file, arc->skipID, request);
+    return ret;
+}
+
 static archive_inst *archive_create_inst(JNIEnv *env, jobject file)
 {
     archive_inst *inst = malloc(sizeof(archive_inst));
     inst->archive = archive_read_new();
     archive_read_set_seek_callback(inst->archive, ins_seek);
+    archive_read_set_skip_callback(inst->archive, ins_skip);
     archive_read_support_format_all(inst->archive);
     archive_read_support_filter_all(inst->archive);
     inst->env = env;
     inst->file = file;
     inst->readID = (*env)->GetMethodID(env, (*env)->GetObjectClass(env, file), "read", "([B)I");
     inst->seekID = (*env)->GetMethodID(env, (*env)->GetObjectClass(env, file), "seek", "(JI)J");
+    inst->skipID = (*env)->GetMethodID(env, (*env)->GetObjectClass(env, file), "skip", "(J)J");
     inst->jbr = (*env)->NewByteArray(env, BLOCK_SIZE);
     inst->read_buffer = malloc(BLOCK_SIZE);
     inst->output_buffer = malloc(BLOCK_SIZE);
@@ -158,6 +168,8 @@ Java_com_hippo_UriArchiveAccessor_extracttoOutputStream(JNIEnv *env, jobject thi
                 (*arc->env)->CallVoidMethod(env, os, flushID);
             }
             break;
+        } else {
+            archive_read_data_skip(arc->archive);
         }
         count++;
     }