src/rio.h

   1 #ifndef __REDIS_RIO_H
   2 #define __REDIS_RIO_H
   3
   4 #include <stdio.h>
   5 #include <stdint.h>
   6 #include "sds.h"
   7
   8 struct _rio {
   9     /* Backend functions.
  10      * Since this functions do not tolerate short writes or reads the return
  11      * value is simplified to: zero on error, non zero on complete success. */
  12     size_t (*read)(struct _rio *, void *buf, size_t len);
  13     size_t (*write)(struct _rio *, const void *buf, size_t len);
  14     off_t (*tell)(struct _rio *);
  15     /* The update_cksum method if not NULL is used to compute the checksum of all the
  16      * data that was read or written so far. The method should be designed so that
  17      * can be called with the current checksum, and the buf and len fields pointing
  18      * to the new block of data to add to the checksum computation. */
  19     void (*update_cksum)(struct _rio *, const void *buf, size_t len);
  20
  21     /* The current checksum */
  22     uint64_t cksum;
  23
  24     /* Backend-specific vars. */
  25     union {
  26         struct {
  27             sds ptr;
  28             off_t pos;
  29         } buffer;
  30         struct {
  31             FILE *fp;
  32         } file;
  33     } io;
  34 };
  35
  36 typedef struct _rio rio;
  37
  38 /* The following functions are our interface with the stream. They'll call the
  39  * actual implementation of read / write / tell, and will update the checksum
  40  * if needed. */
  41
  42 static inline size_t rioWrite(rio *r, const void *buf, size_t len) {
  43     if (r->update_cksum) r->update_cksum(r,buf,len);
  44     return r->write(r,buf,len);
  45 }
  46
  47 static inline size_t rioRead(rio *r, void *buf, size_t len) {
  48     if (r->read(r,buf,len) == 1) {
  49         if (r->update_cksum) r->update_cksum(r,buf,len);
  50         return 1;
  51     }
  52     return 0;
  53 }
  54
  55 static inline off_t rioTell(rio *r) {
  56     return r->tell(r);
  57 }
  58
  59 void rioInitWithFile(rio *r, FILE *fp);
  60 void rioInitWithBuffer(rio *r, sds s);
  61
  62 size_t rioWriteBulkCount(rio *r, char prefix, int count);
  63 size_t rioWriteBulkString(rio *r, const char *buf, size_t len);
  64 size_t rioWriteBulkLongLong(rio *r, long long l);
  65 size_t rioWriteBulkDouble(rio *r, double d);
  66
  67 void rioGenericUpdateChecksum(rio *r, const void *buf, size_t len);
  68
  69 #endif