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70 lines
2.2 KiB
C++
70 lines
2.2 KiB
C++
/* -*- mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*- */
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// vim: ft=cpp:expandtab:ts=8:sw=4:softtabstop=4:
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#ident "$Id$"
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/*======
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This file is part of TokuDB
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Copyright (c) 2006, 2015, Percona and/or its affiliates. All rights reserved.
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TokuDBis is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License, version 2,
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as published by the Free Software Foundation.
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TokuDB 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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You should have received a copy of the GNU General Public License
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along with TokuDB. If not, see <http://www.gnu.org/licenses/>.
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======= */
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#ident "Copyright (c) 2006, 2015, Percona and/or its affiliates. All rights reserved."
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#ifndef _TOKUDB_VLQ_H
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#define _TOKUDB_VLQ_H
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namespace tokudb {
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// Variable length encode an unsigned integer into a buffer with limit s.
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// Returns the number of bytes used to encode n in the buffer.
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// Returns 0 if the buffer is too small.
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template <class T> size_t vlq_encode_ui(T n, void *p, size_t s) {
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unsigned char *pp = (unsigned char *)p;
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size_t i = 0;
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while (n >= 128) {
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if (i >= s)
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return 0; // not enough space
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pp[i++] = n%128;
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n = n/128;
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}
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if (i >= s)
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return 0; // not enough space
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pp[i++] = 128+n;
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return i;
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}
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// Variable length decode an unsigned integer from a buffer with limit s.
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// Returns the number of bytes used to decode the buffer.
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// Returns 0 if the buffer is too small.
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template <class T> size_t vlq_decode_ui(T *np, void *p, size_t s) {
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unsigned char *pp = (unsigned char *)p;
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T n = 0;
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size_t i = 0;
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while (1) {
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if (i >= s)
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return 0; // not a full decode
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T m = pp[i];
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n |= (m & 127) << (7*i);
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i++;
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if ((m & 128) != 0)
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break;
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}
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*np = n;
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return i;
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}
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}
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#endif
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