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os-k/kaleid/libbuf/bgetc.c
2020-09-27 17:33:48 +02:00

92 lines
3.3 KiB
C

//----------------------------------------------------------------------------//
// OS on Kaleid //
// //
// Desc: Buffer library //
// //
// //
// Copyright © 2018-2020 The OS/K Team //
// //
// This file is part of OS/K. //
// //
// OS/K is free software: you can redistribute it and/or modify //
// it under the terms of the GNU General Public License as published by //
// the Free Software Foundation, either version 3 of the License, or //
// any later version. //
// //
// OS/K is distributed in the hope that it will be useful, //
// but WITHOUT ANY WARRANTY//without even the implied warranty of //
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the //
// GNU General Public License for more details. //
// //
// You should have received a copy of the GNU General Public License //
// along with OS/K. If not, see <https://www.gnu.org/licenses/>. //
//----------------------------------------------------------------------------//
#include <libbuf.h>
#ifdef _KALEID_KERNEL
#include <ke/time.h>
#endif
error_t BGetFromBuf(Buffer_t *buf, uchar *ch)
{
error_t rc;
if (!buf) return EINVAL;
if (buf->flags & BF_TERM) return EBADF;
if (buf->state != BS_RDWR && buf->state != BS_RDONLY) {
return EBADF;
}
ExAcquireLock(&buf->lock);
rc = bgetc(buf, ch);
ExReleaseLock(&buf->lock);
return rc;
}
// Note: any change to this must be done while
// keeping in mind vbscanf()'s workaround for ungetc()
error_t bgetc(Buffer_t *buf, uchar *ch)
{
error_t rc = EOK;
if (buf->flags & (BF_EOF|BF_ERR)) return EENDF;
assert(!(buf->rp > buf->wp)); // Shouldn't be possible right now
if (buf->rp == buf->buf + buf->size) {
buf->flags |= BF_EOF;
return EENDF;
}
// Are there things to read at all?
if (buf->rp < buf->wp) {
*ch = *buf->rp++;
return EOK;
}
// We need to fill the buffer
else {
// We need a BFiller_t
// For now we wait until something is in there
// (so that BStdIn works; don't make anything else)
while (buf->rp >= buf->wp) {
#ifdef _KALEID_KERNEL
KeSleep(1); // XXX synchronization with keyboard driver
#else
buf->flags |= BF_EOF;
return EENDF; // Currently empty
#endif
}
*ch = *buf->rp++;
}
if (rc != EOK) {
// buf->flags |= BF_ERR;
}
return rc;
}