/* pipe_read.c - pipe_read */

#include 

/*------------------------------------------------------------------------
 *  pipe_read  -  Read one or more bytes of data from a pipe device
 *------------------------------------------------------------------------
 */
devcall pipe_read(
          struct dentry *devptr,        /* Entry in device switch table */
          char  *buff,                  /* Buffer for the bytes         */
          int32 count                   /* Maximum bytes to read        */
        )
{
        int32   retval;                 /* Return from pipegetc */
        int32   nbytes;                 /* Number of bytes found        */

        if (count <= 0) {
                return SYSERR;
        }

        nbytes = 0;
        while (count > 0) {
                retval = pipe_getc(devptr);
                if ( (retval == SYSERR) || (retval == EOF) ) {
                        if (nbytes > 0) {
                                /* Some data already read -- return the */
                                /*  data on this call; the next call    */
                                /*  will return EOF or SYSERR           */
                                return nbytes;
                        } else {
                                return retval;
                        }
                }

                /* Normal case: a data byte has been found */

                *buff++ = 0xff & retval;
                count--;
                nbytes++;
        }
        return nbytes;
}