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Fix printvideo regression and minor improvements

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This commit is contained in:
Justine Tunney 2020-08-26 09:41:07 -07:00
parent eb4bb43275
commit e86cff8ba0
25 changed files with 240 additions and 207 deletions
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61
libc/str/lz4cpy.c Normal file
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/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2020 Justine Alexandra Roberts Tunney │
│ │
│ 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; version 2 of the License. │
│ │
│ 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 "libc/bits/bits.h"
#include "libc/bits/pushpop.h"
#include "libc/intrin/repmovsb.h"
#include "libc/nexgen32e/kompressor.h"
#include "libc/str/str.h"
/**
* Decompresses LZ4 block.
*
* This is a 103 byte implementation of the LZ4 algorithm. Please note
* LZ4 files are comprised of multiple frames, which may be decoded
* together using the wrapper function lz4decode().
*
* @see rldecode() for a 16-byte decompressor
*/
textstartup void *lz4cpy(void *dest, const void *blockdata, size_t blocksize) {
unsigned char *op, *ip, *ipe, *match;
unsigned token, length, fifteen, offset, matchlen;
for (op = dest, ip = blockdata, ipe = ip + blocksize;;) {
token = *ip++;
length = token >> 4;
fifteen = pushpop(15);
if (length == fifteen) {
do {
length += *ip;
} while (*ip++ == 255);
}
repmovsb(&op, &ip, length);
if (ip >= ipe) break;
offset = read16le(ip);
matchlen = token & fifteen;
ip += 2;
if (matchlen == fifteen) {
do {
matchlen += *ip;
} while (*ip++ == 255);
}
match = op - offset;
repmovsb(&op, &match, (matchlen += 4));
}
return op;
}