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author | Max Kellermann <max@duempel.org> | 2014-07-30 19:10:28 +0200 |
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committer | Max Kellermann <max@duempel.org> | 2014-07-30 22:12:02 +0200 |
commit | 0d0ccacdf3e154b1cc27a0840fce80ac13f9641c (patch) | |
tree | 75d25911d85f6c32e9206c2e713cc864728aad6a /src/fs/output/BufferedOutputStream.cxx | |
parent | c8858f85d8366e36c588b1dcc7ef7eff40832dd0 (diff) | |
download | mpd-0d0ccacdf3e154b1cc27a0840fce80ac13f9641c.tar.gz mpd-0d0ccacdf3e154b1cc27a0840fce80ac13f9641c.tar.xz mpd-0d0ccacdf3e154b1cc27a0840fce80ac13f9641c.zip |
fs/OutputStream: new infrastructure for writing to files
Diffstat (limited to '')
-rw-r--r-- | src/fs/output/BufferedOutputStream.cxx | 143 |
1 files changed, 143 insertions, 0 deletions
diff --git a/src/fs/output/BufferedOutputStream.cxx b/src/fs/output/BufferedOutputStream.cxx new file mode 100644 index 000000000..088a3e279 --- /dev/null +++ b/src/fs/output/BufferedOutputStream.cxx @@ -0,0 +1,143 @@ +/* + * Copyright (C) 2003-2014 The Music Player Daemon Project + * http://www.musicpd.org + * + * This program 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 2 of the License, or + * (at your option) any later version. + * + * This program 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 this program; if not, write to the Free Software Foundation, Inc., + * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + */ + +#include "config.h" +#include "BufferedOutputStream.hxx" +#include "OutputStream.hxx" + +#include <stdarg.h> +#include <string.h> +#include <stdio.h> + +bool +BufferedOutputStream::AppendToBuffer(const void *data, size_t size) +{ + auto r = buffer.Write(); + if (r.size < size) + return false; + + memcpy(r.data, data, size); + buffer.Append(size); + return true; +} + +bool +BufferedOutputStream::Write(const void *data, size_t size) +{ + if (gcc_unlikely(last_error.IsDefined())) + return false; + + if (AppendToBuffer(data, size)) + return true; + + if (!Flush()) + return false; + + if (AppendToBuffer(data, size)) + return true; + + return os.Write(data, size, last_error); +} + +bool +BufferedOutputStream::Write(const char *p) +{ + return Write(p, strlen(p)); +} + +bool +BufferedOutputStream::Format(const char *fmt, ...) +{ + if (gcc_unlikely(last_error.IsDefined())) + return false; + + auto r = buffer.Write(); + if (r.IsEmpty()) { + if (!Flush()) + return false; + + r = buffer.Write(); + } + + /* format into the buffer */ + va_list ap; + va_start(ap, fmt); + size_t size = vsnprintf(r.data, r.size, fmt, ap); + va_end(ap); + + if (gcc_unlikely(size >= r.size)) { + /* buffer was not large enough; flush it and try + again */ + + if (!Flush()) + return false; + + r = buffer.Write(); + + if (gcc_unlikely(size >= r.size)) { + /* still not enough space: grow the buffer and + try again */ + r.size = size + 1; + r.data = buffer.Write(r.size); + } + + /* format into the new buffer */ + va_start(ap, fmt); + size = vsnprintf(r.data, r.size, fmt, ap); + va_end(ap); + + /* this time, it must fit */ + assert(size < r.size); + } + + buffer.Append(size); + return true; +} + +bool +BufferedOutputStream::Flush() +{ + if (!Check()) + return false; + + auto r = buffer.Read(); + if (r.IsEmpty()) + return true; + + bool success = os.Write(r.data, r.size, last_error); + if (gcc_likely(success)) + buffer.Consume(r.size); + return success; +} + +bool +BufferedOutputStream::Flush(Error &error) +{ + if (!Check(error)) + return false; + + auto r = buffer.Read(); + if (r.IsEmpty()) + return true; + + bool success = os.Write(r.data, r.size, error); + if (gcc_likely(success)) + buffer.Consume(r.size); + return success; +} |