恢复删除照片（JPEG格式）
想要恢复图片首先需要了解图片文件格式头和尾
- JPEG头：
0xFFD8FFE0/0xFFD8FFE1 - JPEG结尾
0xFFD9在data镜像文件中存放JPEG得所有头都是对齐得，判断是否为JPEG格式的图片：
bool findNewImage(void) {
return (memcmp(bufcpy, "\xFF\xD8\xFF\xE0", 4) == 0 ||
memcmp(bufcpy, "\xFF\xD8\xFF\xE1", 4) == 0) ? true : false;
}
大概过程如下：
#define _LARGEFILE64_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <unistd.h>
#include <errno.h>
#include <fcntl.h>
#include <stdbool.h>
typedef uint8_t BYTE;
const char *ACTION_HELP = "--help";
const char *ACTION_SIZE = "--length";
const char *ACTION_GET_DATA = "--getData";
const char *ACTION_SCANNING = "--scanning";
const char *HELP = "recover [filePath] <blockSize> <start> <end> <outPath> [--action]\nfilePath:文件路径；\nblockSize：块大小 -- 扫描文件时传入blockSize，默认512\nstart end：获取图片byte[]时必须传入开始和结尾位置，outPath ：文件输出路径\n --action: 1、length:文件长度；2、getData:获取图片byte[];3、scanning：扫描文件\n";
BYTE *buffer = NULL;
BYTE *bufcpy = NULL;
unsigned int blockSize = 512;
int64_t getFileLength(const char *filePath);
int fseek_64(FILE *stream, int64_t offset, int origin);
void getData(const char *filePath, const char *outPath, long long start, long long end);
void writeToImage(const char *outPath, BYTE *byte, unsigned int block);
bool findNewImage(void);
void recover(const char *filePath, const char *outPath);
int main(int argc, char **argv) {
if (argc < 2) {
printf("recover [--help]\n");
return 0;
}
const char *action = argv[argc - 1];
if (strcmp(action, ACTION_HELP) == 0 || argc <= 2) {
printf(HELP);
return 0;
}
const char *filePath = argv[1];
if (strcmp(action, ACTION_SIZE) == 0) {
const long long length = getFileLength(filePath);
printf("length %lld \n", length);
return 1;
}
if (strcmp(action, ACTION_SCANNING) == 0) {
if (argc > 3) {
int b = atoi(argv[2]);
blockSize = (unsigned int) (b * 1000);
} else blockSize = 512 * 1000;
const char *outPath = argv[3];
recover(filePath, outPath);
return 1;
}
if (strcmp(action, ACTION_GET_DATA) == 0) {
long long start = atoll(argv[2]);
long long end = atoll(argv[3]);
char *outPath = argv[4];
int strLength = (int) strlen(outPath);
printf("outPath length = %d\n", strLength);
getData(filePath, outPath, start, end);
return 1;
}
}
int64_t getFileLength(const char *filePath) {
FILE *file = fopen(filePath, "rb");
if (file == NULL) {
return errno;
}
int fd = fileno(file);
long long length = lseek64(fd, 0, SEEK_END);
fclose(file);
return length;
}
void recover(const char *filePath, const char *outPath) {
long long start = 0;//图片起始位置
long long end = 0;//图片结束位置
FILE *inptr = fopen(filePath, "rb");
// create counter to track how many images received and use as counter.jpg as file name (first image is 001.jpg)
int jpegCount = 1;
// starts off initially with no images found
bool foundJpeg = false;
if (inptr == NULL) {
printf("Could not open %s\n", filePath);
return;
}
// create buffer which we will read to
fseek(inptr, 0, SEEK_SET);
buffer = malloc(sizeof(BYTE) * blockSize);
unsigned int perSize = blockSize / 1000;
bufcpy = malloc(sizeof(BYTE) * perSize);
unsigned long long index = 0;
int readsize = 0;
// we read 512 bytes at a time and only check the first 4 bytes of the buffer for jpeg signatures
while ((readsize = fread(buffer, 1, blockSize, inptr)) != 0) {
if (readsize == blockSize) {
long long length = index * blockSize;
printf("progress %lld \n", length);
int i = 0;
int totalsize = 0;
for (i; i < 1000; ++i) {
memcpy(bufcpy, buffer + totalsize, perSize);
totalsize += perSize;
if (foundJpeg == true) {
if (findNewImage() == true) {
end = index * blockSize + i * perSize;
long long len = end - start;
if (len < 5 * 1024 * 1024) {
char fileName[100] = {0};
sprintf(fileName, "%s%lld%d", outPath, index, i);
getData(filePath, fileName, start, end);
printf("save path %s %lld %lld\n", fileName, start, end);
}
start = index * blockSize + i * perSize;
}
}
else if (findNewImage() ==
true) // keep reading the card until we find the first image
{
foundJpeg = true;
start = index * blockSize + i * perSize;
}
}
} else {
printf("scanning end\n");
break;
}
index++;
}
// free buffer since we used malloc to allocate memory for it in the heap
free(buffer);
fclose(inptr);
printf("scanning end\n");
}
void getData(const char *filePath, const char *outPath, long long start, long long end) {
BYTE *buf = NULL;
long long poor = end - start;
printf(" ===== poor %lld ======== start %lld ======== end %lld\n", poor, start, end);
// TODO
FILE *file = fopen(filePath, "rb");
if (file == NULL)
return;
buf = malloc(sizeof(BYTE) * poor);
if (buf == NULL) {
printf("== %s 打开失败！\n", filePath);
fclose(file);
return;
}
fseek_64(file, start, SEEK_SET);
fread(buf, sizeof(BYTE) * poor, 1, file);
FILE *outptr = fopen(outPath, "wb");
if (outptr == NULL) {
printf("couldn't open the outfile\n");
return;
}
fwrite(buf, sizeof(BYTE) * poor, 1, outptr); // write contents from buffer to the outfile
printf("write file is true\n");
fclose(outptr);
free(buf);
fclose(file);
}
int fseek_64(FILE *stream, int64_t offset, int origin) {
if (feof(stream)) {
rewind(stream);
}
else {
setbuf(stream, NULL); //清空fread的缓存
}
int fd = fileno(stream);
if (lseek64(fd, offset, origin) == -1) {
return errno;
}
return 0;
}
bool findNewImage(void) {
// return (buffer[0] == 0xff && buffer[1] == 0xd8 && buffer[2]== 0xff && (buffer[3]== 0xe0 || buffer[3]==0xe1) ) ? true : false;
return (memcmp(bufcpy, "\xFF\xD8\xFF\xE0", 4) == 0 ||
memcmp(bufcpy, "\xFF\xD8\xFF\xE1", 4) == 0) ? true : false;
}
void writeToImage(const char *outPath, BYTE *byte, unsigned int block) {
// name found files as ###.jpg so need an extra for null character
FILE *outptr = fopen(outPath, "a");
if (outptr == NULL) {
printf("couldn't open the outfile\n");
return;
}
fwrite(byte, block, 1, outptr); // write contents from buffer to the outfile
fclose(outptr);
printf("save path %s\n", outPath);
}