diff options
Diffstat (limited to 'base/circlebuf.cc')
| -rw-r--r-- | base/circlebuf.cc | 187 |
1 files changed, 187 insertions, 0 deletions
diff --git a/base/circlebuf.cc b/base/circlebuf.cc new file mode 100644 index 000000000..482c97f84 --- /dev/null +++ b/base/circlebuf.cc @@ -0,0 +1,187 @@ +/* + * Copyright (c) 2003 The Regents of The University of Michigan + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are + * met: redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer; + * redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution; + * neither the name of the copyright holders nor the names of its + * contributors may be used to endorse or promote products derived from + * this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR + * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT + * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT + * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE + * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +#include <algorithm> +#include <string> + +#include <stdio.h> +#include <string.h> +#include <unistd.h> + +#include "cprintf.hh" +#include "circlebuf.hh" +#include "intmath.h" + +using namespace std; + +CircleBuf::CircleBuf(int l) + : rollover(false), buflen(l), size(0), start(0), stop(0) +{ buf = new char[buflen]; } + +CircleBuf::~CircleBuf() +{ if (buf) delete [] buf; } + +void +CircleBuf::dump() +{ + cprintf("start = %10d, stop = %10d, buflen = %10d\n", start, stop, buflen); + fflush(stdout); + ::write(STDOUT_FILENO, buf, buflen); + ::write(STDOUT_FILENO, "<\n", 2); +} + +void +CircleBuf::flush() +{ + start = 0; + stop = 0; + rollover = false; +} + +void +CircleBuf::read(char *b, int len) +{ + size -= len; + if (size < 0) + size = 0; + + if (stop > start) { + len = min(len, stop - start); + memcpy(b, buf + start, len); + start += len; + } + else { + int endlen = buflen - start; + if (endlen > len) { + memcpy(b, buf + start, len); + start += len; + } + else { + memcpy(b, buf + start, endlen); + start = min(len - endlen, stop); + memcpy(b + endlen, buf, start); + } + } +} + +void +CircleBuf::read(int fd, int len) +{ + size -= len; + if (size < 0) + size = 0; + + if (stop > start) { + len = min(len, stop - start); + ::write(fd, buf + start, len); + start += len; + } + else { + int endlen = buflen - start; + if (endlen > len) { + ::write(fd, buf + start, len); + start += len; + } + else { + ::write(fd, buf + start, endlen); + start = min(len - endlen, stop); + ::write(fd, buf, start); + } + } +} + +void +CircleBuf::read(int fd) +{ + size = 0; + + if (stop > start) { + ::write(fd, buf + start, stop - start); + } + else { + ::write(fd, buf + start, buflen - start); + ::write(fd, buf, stop); + } + + start = stop; +} + +void +CircleBuf::readall(int fd) +{ + if (rollover) + ::write(fd, buf + stop, buflen - stop); + + ::write(fd, buf, stop); + start = stop; +} + +void +CircleBuf::write(char b) +{ write(&b, 1); } + +void +CircleBuf::write(const char *b) +{ write(b, strlen(b)); } + +void +CircleBuf::write(const char *b, int len) +{ + if (len <= 0) + return; + + size += len; + if (size > buflen) + size = buflen; + + int old_start = start; + int old_stop = stop; + + if (len >= buflen) { + start = 0; + stop = buflen; + rollover = true; + memcpy(buf, b + (len - buflen), buflen); + return; + } + + if (stop + len <= buflen) { + memcpy(buf + stop, b, len); + stop += len; + } else { + int end_len = buflen - old_stop; + stop = len - end_len; + memcpy(buf + old_stop, b, end_len); + memcpy(buf, b + end_len, stop); + rollover = true; + } + + if (old_start > old_stop && old_start < stop || + old_start < old_stop && stop < old_stop) + start = stop + 1; +} |