knetfile.h

#ifndef KNETFILE_H
#define KNETFILE_H

#include <stdint.h>
#include <fcntl.h>

#ifndef _WIN32
#define netread(fd, ptr, len) read(fd, ptr, len)
#define netwrite(fd, ptr, len) write(fd, ptr, len)
#define netclose(fd) close(fd)
#else
#include <winsock2.h>
#define netread(fd, ptr, len) recv(fd, ptr, len, 0)
#define netwrite(fd, ptr, len) send(fd, ptr, len, 0)
#define netclose(fd) closesocket(fd)
#endif

// FIXME: currently I/O is unbuffered

#define KNF_TYPE_LOCAL 1
#define KNF_TYPE_FTP   2
#define KNF_TYPE_HTTP  3

typedef struct knetFile_s {
    int type, fd;
    int64_t offset;
    char *host, *port;

    // the following are for FTP only
    int ctrl_fd, pasv_ip[4], pasv_port, max_response, no_reconnect, is_ready;
    char *response, *retr, *size_cmd;
    int64_t seek_offset; // for lazy seek
    int64_t file_size;

    // the following are for HTTP only
    char *path, *http_host;
} knetFile;

#define knet_tell(fp) ((fp)->offset)
#define knet_fileno(fp) ((fp)->fd)

#ifdef __cplusplus
extern "C" {
#endif

#ifdef _WIN32
    int knet_win32_init();
    void knet_win32_destroy();
#endif

    knetFile *knet_open(const char *fn, const char *mode);

    /* 
       This only works with local files.
     */
    knetFile *knet_dopen(int fd, const char *mode);

    /*
      If ->is_ready==0, this routine updates ->fd; otherwise, it simply
      reads from ->fd.
     */
    off_t knet_read(knetFile *fp, void *buf, off_t len);

    /*
      This routine only sets ->offset and ->is_ready=0. It does not
      communicate with the FTP server.
     */
    off_t knet_seek(knetFile *fp, int64_t off, int whence);
    int knet_close(knetFile *fp);

#ifdef __cplusplus
}
#endif

#endif