添加源码
在官网下载源码后，将其中的C目录拷贝到src/main/cpp，并重命名为lzma
精简文件
删除lzma/Util，并新建文件夹lzma/jni，在其下写入如下文件lzma.c，内容见下节。lzma目录下只需保留如下文件即可
添加JNI函数
该文件提供可供JNI调用的函数lzma(sf: String, df: String, isEncode: Boolean): String，以实现压缩/解压缩某目录文件的功能
//
// lzma.c
// Created by rumia on 2021/3/12.
//
/* Edit from LzmaUtil.c -- Test application for LZMA compression
2018-07-04 : Igor Pavlov : Public domain */
#include <jni.h>
#include "../Precomp.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "../CpuArch.h"
#include "../Alloc.h"
#include "../7zFile.h"
#include "../7zVersion.h"
#include "../LzmaDec.h"
#include "../LzmaEnc.h"
static const char * const kCantReadMessage = "Can not read input file";
static const char * const kCantWriteMessage = "Can not write output file";
static const char * const kCantAllocateMessage = "Can not allocate memory";
static const char * const kDataErrorMessage = "Data error";
static int PrintError(char *buffer, const char *message) {
strcat(buffer, "\nError: ");
strcat(buffer, message);
strcat(buffer, "\n");
return 1;
}
static int PrintErrorNumber(char *buffer, SRes val) {
sprintf(buffer + strlen(buffer), "\nError code: %x\n", (unsigned)val);
return 1;
}
#define IN_BUF_SIZE (1 << 16)
#define OUT_BUF_SIZE (1 << 16)
static SRes Decode2(CLzmaDec *state, ISeqOutStream *outStream, ISeqInStream *inStream, UInt64 unpackSize) {
int thereIsSize = (unpackSize != (UInt64)(Int64)-1);
Byte inBuf[IN_BUF_SIZE];
Byte outBuf[OUT_BUF_SIZE];
size_t inPos = 0, inSize = 0, outPos = 0;
LzmaDec_Init(state);
for (;;)
{
if (inPos == inSize)
{
inSize = IN_BUF_SIZE;
RINOK(inStream->Read(inStream, inBuf, &inSize));
inPos = 0;
}
{
SRes res;
SizeT inProcessed = inSize - inPos;
SizeT outProcessed = OUT_BUF_SIZE - outPos;
ELzmaFinishMode finishMode = LZMA_FINISH_ANY;
ELzmaStatus status;
if (thereIsSize && outProcessed > unpackSize)
{
outProcessed = (SizeT)unpackSize;
finishMode = LZMA_FINISH_END;
}
res = LzmaDec_DecodeToBuf(state, outBuf + outPos, &outProcessed,
inBuf + inPos, &inProcessed, finishMode, &status);
inPos += inProcessed;
outPos += outProcessed;
unpackSize -= outProcessed;
if (outStream)
if (outStream->Write(outStream, outBuf, outPos) != outPos)
return SZ_ERROR_WRITE;
outPos = 0;
if (res != SZ_OK || (thereIsSize && unpackSize == 0))
return res;
if (inProcessed == 0 && outProcessed == 0)
{
if (thereIsSize || status != LZMA_STATUS_FINISHED_WITH_MARK)
return SZ_ERROR_DATA;
return res;
}
}
}
}
static SRes Decode(ISeqOutStream *outStream, ISeqInStream *inStream) {
UInt64 unpackSize;
int i;
SRes res = 0;
CLzmaDec state;
/* header: 5 bytes of LZMA properties and 8 bytes of uncompressed size */
unsigned char header[LZMA_PROPS_SIZE + 8];
/* Read and parse header */
RINOK(SeqInStream_Read(inStream, header, sizeof(header)));
unpackSize = 0;
for (i = 0; i < 8; i++)
unpackSize += (UInt64)header[LZMA_PROPS_SIZE + i] << (i * 8);
LzmaDec_Construct(&state);
RINOK(LzmaDec_Allocate(&state, header, LZMA_PROPS_SIZE, &g_Alloc));
res = Decode2(&state, outStream, inStream, unpackSize);
LzmaDec_Free(&state, &g_Alloc);
return res;
}
static SRes Encode(ISeqOutStream *outStream, ISeqInStream *inStream, UInt64 fileSize, char *rs) {
CLzmaEncHandle enc;
SRes res;
CLzmaEncProps props;
UNUSED_VAR(rs);
enc = LzmaEnc_Create(&g_Alloc);
if (enc == 0)
return SZ_ERROR_MEM;
LzmaEncProps_Init(&props);
res = LzmaEnc_SetProps(enc, &props);
if (res == SZ_OK)
{
Byte header[LZMA_PROPS_SIZE + 8];
size_t headerSize = LZMA_PROPS_SIZE;
int i;
res = LzmaEnc_WriteProperties(enc, header, &headerSize);
for (i = 0; i < 8; i++)
header[headerSize++] = (Byte)(fileSize >> (8 * i));
if (outStream->Write(outStream, header, headerSize) != headerSize)
res = SZ_ERROR_WRITE;
else
{
if (res == SZ_OK)
res = LzmaEnc_Encode(enc, outStream, inStream, NULL, &g_Alloc, &g_Alloc);
}
}
LzmaEnc_Destroy(enc, &g_Alloc, &g_Alloc);
return res;
}
extern JNIEXPORT jstring JNICALL
Java_com_my_app_MainActivity_lzma(JNIEnv* env, jobject obj, jstring sf, jstring df, jboolean encodeMode) {
char rs[800] = {
0 };
const char *inputFileDir = (*env)->GetStringUTFChars(env, sf, JNI_FALSE);
const char *outputFileDir = (*env)->GetStringUTFChars(env, df, JNI_FALSE);
CFileSeqInStream inStream;
CFileOutStream outStream;
FileSeqInStream_CreateVTable(&inStream);
File_Construct(&inStream.file);
FileOutStream_CreateVTable(&outStream);
File_Construct(&outStream.file);
if (InFile_Open(&inStream.file, inputFileDir) != 0) PrintError(rs, "Can not open input file");
else if (OutFile_Open(&outStream.file, outputFileDir) != 0) PrintError(rs, "Can not open output file");
else {
int res;
if (encodeMode) {
UInt64 fileSize;
File_GetLength(&inStream.file, &fileSize);
res = Encode(&outStream.vt, &inStream.vt, fileSize, rs);
} else res = Decode(&outStream.vt, &inStream.vt);
File_Close(&outStream.file);
File_Close(&inStream.file);
if (res != SZ_OK) {
if (res == SZ_ERROR_MEM) PrintError(rs, kCantAllocateMessage);
else if (res == SZ_ERROR_DATA) PrintError(rs, kDataErrorMessage);
else if (res == SZ_ERROR_WRITE) PrintError(rs, kCantWriteMessage);
else if (res == SZ_ERROR_READ) PrintError(rs, kCantReadMessage);
PrintErrorNumber(rs, res);
}
}
return (*env)->NewStringUTF(env, rs);
}
添加CMakeLists
- 在
cpp目录下新建CMakeLists.txt，写入如下内容
cmake_minimum_required(VERSION 3.10.2)
project("myapp")
add_subdirectory(lzma)
- 在
cpp/lzma目录下新建CMakeLists.txt，写入如下内容
cmake_minimum_required(VERSION 3.10.2)
project("myapp")
set(CMAKE_C_FLAGS "${
CMAKE_C_FLAGS} -D_7ZIP_ST")
add_library(
lzma
SHARED
jni/lzma.c Alloc.c LzFind.c LzmaDec.c LzmaEnc.c 7zFile.c 7zStream.c
)
配置gradle
在模块级build.gradle中增加如下内容
android {
externalNativeBuild {
cmake {
path "src/main/cpp/CMakeLists.txt"
version "3.10.2"
}
}
......
}
加载库
在MainActivity增加
class MainActivity : Activity() {
......
private external fun lzma(sf: String, df: String, isEncode: Boolean): String
companion object {
// Used to load the 'native-lib' library on application startup.
init {
System.loadLibrary("lzma")
}
}
}
之后即可在代码中调用