sys/src/libstdio/fwrite.c

   1 /*
   2  * pANS stdio -- fwrite
   3  */
   4 #include "iolib.h"
   5
   6 #define BIGN (BUFSIZ/2)
   7
   8 long fwrite(const void *p, long recl, long nrec, FILE *f){
   9         char *s;
  10         int n, d;
  11
  12         s=(char *)p;
  13         n=recl*nrec;
  14         while(n>0){
  15                 d=f->rp-f->wp;
  16                 if(d>0){
  17                         if(d>n)
  18                                 d=n;
  19                         memmove(f->wp, s, d);
  20                         f->wp+=d;
  21                 }else{
  22                         if(n>=BIGN && f->state==WR && !(f->flags&(STRING|LINEBUF)) && f->buf!=f->unbuf){
  23                                 d=f->wp-f->buf;
  24                                 if(d>0){
  25                                         if(f->flags&APPEND)
  26                                                 seek(f->fd, 0L, 2);
  27                                         if(write(f->fd, f->buf, d)!=d){
  28                                                 f->state=ERR;
  29                                                 goto ret;
  30                                         }
  31                                         f->wp=f->rp=f->buf;
  32                                 }
  33                                 if(f->flags&APPEND)
  34                                         seek(f->fd, 0L, 2);
  35                                 d=write(f->fd, s, n);
  36                                 if(d<=0){
  37                                         f->state=ERR;
  38                                         goto ret;
  39                                 }
  40                         }else{
  41                                 if(_IO_putc(*s, f)==EOF)
  42                                         goto ret;
  43                                 d=1;
  44                         }
  45                 }
  46                 s+=d;
  47                 n-=d;
  48         }
  49     ret:
  50         return (s-(char *)p)/(recl?recl:1);
  51 }