{

struct stat st;

if (stat(filename, &st) < 0) {

printf("st init err\n");

};

return st.st_size;

char *filename,

int begin_pos,

int end_pos,

string &header)

{

int src_fd = open(filename, O_RDONLY, 0);

int file_size = get_file_size(filename);

if (src_fd < 2)

printf("open %s error\n", filename);

// TODO: sendfile（）

char buffer[NORMAL_SIZE];

memset(buffer, 0, NORMAL_SIZE);

// 传输header

int wcnt = write(fd, header.c_str(), header.size());

cout << "wcnt:" << wcnt << endl;

if (begin_pos != 0) {

lseek(src_fd, begin_pos * NORMAL_SIZE, SEEK_SET);

}

int rcnt = 0;

int cnt = 0;

int total = 0;

if (end_pos <= 0) {

do {

rcnt = read(src_fd, buffer, NORMAL_SIZE);

file_size -= NORMAL_SIZE;

int res = write(fd, buffer, rcnt);

} while (rcnt == NORMAL_SIZE && file_size > 0);

} else {

int size = end_pos - begin_pos;

do {

rcnt = read(src_fd, buffer, NORMAL_SIZE);

write(fd, buffer, rcnt);

size -= NORMAL_SIZE;

} while (size > 0);

}

close(src_fd);

{

int src_fd = open(filename, O_RDONLY, 0);

int file_size = get_file_size(filename);

std::cout << file_size << endl;

if (src_fd < 2)

printf("open %s error\n", filename);

// TODO: sendfile（）

char chunk[C_SIZE + 2];

memset(chunk, 0, C_SIZE + 2);

// 传输header

write(fd, header.c_str(), header.size());

int rcnt = 0;

const char *eof = "0\r\n\r\n";

char s[6];

// itoa(C_SIZE, s, 10);

sprintf(s, "%d", C_SIZE);

s[4] = '\r';

s[5] = '\n';

// const char *s = std::to_string(C_SIZE).c_str() + '\r' + '\n';

std::cout << "length of s:" << strlen(s) << std::endl;

while (1) {

if (file_size <= C_SIZE) {

rcnt = read(src_fd, chunk, file_size);

const char *ss = std::to_string(file_size).c_str() + '\r' + '\n';

write(fd, s, strlen(ss));

write(fd, chunk, rcnt);

write(fd, eof, strlen(eof));

break;

} else {

rcnt = read(src_fd, chunk, C_SIZE);

write(fd, s, strlen(s));

chunk[C_SIZE] = '\r';

chunk[C_SIZE + 1] = '\n';

// cout << "chunksize:" << strlen(chunk) << endl;

write(fd, chunk, strlen(chunk));

}

file_size -= C_SIZE;

}

close(src_fd);