142 lines
5.1 KiB
C
142 lines
5.1 KiB
C
//----------------------------------------------------------------------------//
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// GNU GPL OS/K //
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// //
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// Desc: Buffer library //
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// //
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// //
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// Copyright © 2018-2019 The OS/K Team //
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// //
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// This file is part of OS/K. //
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// //
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// OS/K is free software: you can redistribute it and/or modify //
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// it under the terms of the GNU General Public License as published by //
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// the Free Software Foundation, either version 3 of the License, or //
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// any later version. //
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// //
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// OS/K is distributed in the hope that it will be useful, //
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// but WITHOUT ANY WARRANTY//without even the implied warranty of //
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the //
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// GNU General Public License for more details. //
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// //
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// You should have received a copy of the GNU General Public License //
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// along with OS/K. If not, see <https://www.gnu.org/licenses/>. //
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//----------------------------------------------------------------------------//
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#include <kernel/buf.h>
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error_t bputc(Buffer_t *buf, uchar ch);
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//
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// Writes a character on a buffer
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//
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error_t BPutOnBuf(Buffer_t *buf, uchar ch)
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{
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error_t rc;
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assert(buf && buf->initDone == INITOK);
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if (!buf) return EINVAL;
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if (buf->state != BS_RDWR && buf->state != BS_WRONLY) {
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return EBADF;
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}
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ExAcquireLock(&buf->lock);
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rc = bputc(buf, ch);
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ExReleaseLock(&buf->lock);
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return rc;
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}
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//
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// Internal, unlocked version of BPutOnBuf
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//
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error_t bputc(Buffer_t *buf, uchar ch)
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{
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error_t rc = EOK;
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size_t bufSize, pbCount;
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// Implements playback / scrolling up when line buffering
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// Note that '\n', '\r' and '\t' can never occur in the buffer
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// That should change; there should be a flag for it
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if (buf->flags & BF_LINE) {
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// Deal with carriage returns
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if (ch == '\r') {
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buf->wp -= buf->lastLF;
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buf->lastLF = 0;
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assert(buf->wp >= buf->buf);
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}
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// Deal with tabs... we need a tabSize field
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// We assume tabs are 4 characters long for now
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else if (ch == '\t') {
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rc = bputc(buf, ' ');
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while (buf->lastLF % 4 > 0) {
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rc = bputc(buf, ' ');
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}
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if (rc > 0) return rc;
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}
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// Deal with line feeds by filling the rest of the line with spaces
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// We need a field for choosing a different filler, e.g. '\0'
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else if (ch == '\n') {
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assert(buf->lastLF < buf->lineLen);
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while (buf->lastLF > 0) {
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rc = bputc(buf, ' ');
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}
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if (rc > 0) return rc;
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if (buf->flusher) buf->flusher(buf);
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}
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// Just a regular character
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else {
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// Do we have to scroll up?
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if (buf->wp == buf->buf + buf->size) {
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// Yes, so we give up a whole playback buffer worth
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// of lines so we don't have to do this too often
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// (basically we make the current buffer a pb one)
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bufSize = buf->nLines * buf->lineLen;
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pbCount = (buf->size / bufSize) - 1;
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// Paranoia check
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assert(buf->size >= (size_t)(buf->nLines * buf->lineLen));
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// If we only have one playback buffer we just give up a line
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if (pbCount == 0) {
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// Use of memcpy() is safe because the source occur
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// after the destination
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memcpy(buf->buf, buf->buf + buf->lineLen,
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buf->size - buf->lineLen);
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buf->wp -= buf->lineLen;
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}
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// We do have a playback buffer worth of lines to give up
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else {
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memcpy(buf->buf, buf->buf + bufSize,
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buf->size - bufSize);
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buf->wp -= buf->lineLen;
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}
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}
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// Write it
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*buf->wp++ = ch;
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// Did we reach the end of line?
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if (++buf->lastLF == buf->lineLen) {
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buf->lastLF = 0;
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}
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}
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return EOK;
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}
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// No scrolling up when not line-buffering
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else {
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if (buf->wp == buf->buf + buf->size) {
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buf->state = BS_EOF;
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}
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return ENOSYS;
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}
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}
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