/*
 * JFFS2 -- Journalling Flash File System, Version 2.
 *
 * Copyright © 2001-2007 Red Hat, Inc.
 * Copyright © 2004-2010 David Woodhouse <dwmw2@infradead.org>
 *
 * Created by Arjan van de Ven <arjanv@redhat.com>
 *
 * For licensing information, see the file 'LICENCE' in this directory.
 *
 *
 *
 * Very simple lz77-ish encoder.
 *
 * Theory of operation: Both encoder and decoder have a list of "last
 * occurrences" for every possible source-value; after sending the
 * first source-byte, the second byte indicated the "run" length of
 * matches
 *
 * The algorithm is intended to only send "whole bytes", no bit-messing.
 *
 */

#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/jffs2.h>
#include "compr.h"

/* _compress returns the compressed size, -1 if bigger */
static int jffs2_rtime_compress(unsigned char *data_in,
				unsigned char *cpage_out,
				uint32_t *sourcelen, uint32_t *dstlen)
{
	unsigned short positions[256];
	int outpos = 0;
	int pos=0;

	memset(positions,0,sizeof(positions));

	while (pos < (*sourcelen) && outpos <= (*dstlen)-2) {
		int backpos, runlen=0;
		unsigned char value;

		value = data_in[pos];

		cpage_out[outpos++] = data_in[pos++];

		backpos = positions[value];
		positions[value]=pos;

		while ((backpos < pos) && (pos < (*sourcelen)) &&
		       (data_in[pos]==data_in[backpos++]) && (runlen<255)) {
			pos++;
			runlen++;
		}
		cpage_out[outpos++] = runlen;
	}

	if (outpos >= pos) {
		/* We failed */
		return -1;
	}

	/* Tell the caller how much we managed to compress, and how much space it took */
	*sourcelen = pos;
	*dstlen = outpos;
	return 0;
}


static int jffs2_rtime_decompress(unsigned char *data_in,
				  unsigned char *cpage_out,
				  uint32_t srclen, uint32_t destlen)
{
	unsigned short positions[256];
	int outpos = 0;
	int pos=0;

	memset(positions,0,sizeof(positions));

	while (outpos<destlen) {
		unsigned char value;
		int backoffs;
		int repeat;

		value = data_in[pos++];
		cpage_out[outpos++] = value; /* first the verbatim copied byte */
		repeat = data_in[pos++];
		backoffs = positions[value];

		positions[value]=outpos;
		if (repeat) {
			if (backoffs + repeat >= outpos) {
				while(repeat) {
					cpage_out[outpos++] = cpage_out[backoffs++];
					repeat--;
				}
			} else {
				memcpy(&cpage_out[outpos],&cpage_out[backoffs],repeat);
				outpos+=repeat;
			}
		}
	}
	return 0;
}

static struct jffs2_compressor jffs2_rtime_comp = {
    .priority = JFFS2_RTIME_PRIORITY,
    .name = "rtime",
    .compr = JFFS2_COMPR_RTIME,
    .compress = &jffs2_rtime_compress,
    .decompress = &jffs2_rtime_decompress,
#ifdef JFFS2_RTIME_DISABLED
    .disabled = 1,
#else
    .disabled = 0,
#endif
};

int jffs2_rtime_init(void)
{
    return jffs2_register_compressor(&jffs2_rtime_comp);
}

void jffs2_rtime_exit(void)
{
    jffs2_unregister_compressor(&jffs2_rtime_comp);
}
f='/cgit.cgi/linux/net-next.git/commit/?h=nds-private-remove&amp;id=ca92e6c7e6329029d7188487a5c32e86ef471977'>root</a>/<a href='/cgit.cgi/linux/net-next.git/commit/net?h=nds-private-remove&amp;id=ca92e6c7e6329029d7188487a5c32e86ef471977'>net</a>/<a href='/cgit.cgi/linux/net-next.git/commit/net/ipv6?h=nds-private-remove&amp;id=ca92e6c7e6329029d7188487a5c32e86ef471977'>ipv6</a>/<a href='/cgit.cgi/linux/net-next.git/commit/net/ipv6/ip6_gre.c?h=nds-private-remove&amp;id=ca92e6c7e6329029d7188487a5c32e86ef471977'>ip6_gre.c</a></div><div class='content'><div class='cgit-panel'><b>diff options</b><form method='get'><input type='hidden' name='h' value='nds-private-remove'/><input type='hidden' name='id' value='ca92e6c7e6329029d7188487a5c32e86ef471977'/><table><tr><td colspan='2'/></tr><tr><td class='label'>context:</td><td class='ctrl'><select name='context' onchange='this.form.submit();'><option value='1'>1</option><option value='2'>2</option><option value='3' selected='selected'>3</option><option value='4'>4</option><option value='5'>5</option><option value='6'>6</option><option value='7'>7</option><option value='8'>8</option><option value='9'>9</option><option value='10'>10</option><option value='15'>15</option><option value='20'>20</option><option value='25'>25</option><option value='30'>30</option><option value='35'>35</option><option value='40'>40</option></select></td></tr><tr><td class='label'>space:</td><td class='ctrl'><select name='ignorews' onchange='this.form.submit();'><option value='0' selected='selected'>include</option><option value='1'>ignore</option></select></td></tr><tr><td class='label'>mode:</td><td class='ctrl'><select name='dt' onchange='this.form.submit();'><option value='0' selected='selected'>unified</option><option value='1'>ssdiff</option><option value='2'>stat only</option></select></td></tr><tr><td/><td class='ctrl'><noscript><input type='submit' value='reload'/></noscript></td></tr></table></form></div><table summary='commit info' class='commit-info'>
<tr><th>author</th><td>Linus Torvalds &lt;torvalds@linux-foundation.org&gt;</td><td class='right'>2017-01-18 11:13:41 -0800</td></tr>
<tr><th>committer</th><td>Linus Torvalds &lt;torvalds@linux-foundation.org&gt;</td><td class='right'>2017-01-18 11:13:41 -0800</td></tr>
<tr><th>commit</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/net/ipv6/ip6_gre.c?h=nds-private-remove&amp;id=ca92e6c7e6329029d7188487a5c32e86ef471977'>ca92e6c7e6329029d7188487a5c32e86ef471977</a> (<a href='/cgit.cgi/linux/net-next.git/patch/net/ipv6/ip6_gre.c?id=ca92e6c7e6329029d7188487a5c32e86ef471977'>patch</a>)</td></tr>
<tr><th>tree</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/tree/?h=nds-private-remove&amp;id=ca92e6c7e6329029d7188487a5c32e86ef471977'>704fb5c2ca533cdb569826522eed0dbbcf31f316</a> /<a href='/cgit.cgi/linux/net-next.git/tree/net/ipv6/ip6_gre.c?h=nds-private-remove&amp;id=ca92e6c7e6329029d7188487a5c32e86ef471977'>net/ipv6/ip6_gre.c</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/net/ipv6/ip6_gre.c?h=nds-private-remove&amp;id=0b75f821ec8be459dd4dec77be39595d989d77ac'>0b75f821ec8be459dd4dec77be39595d989d77ac</a> (<a href='/cgit.cgi/linux/net-next.git/diff/net/ipv6/ip6_gre.c?h=nds-private-remove&amp;id=ca92e6c7e6329029d7188487a5c32e86ef471977&amp;id2=0b75f821ec8be459dd4dec77be39595d989d77ac'>diff</a>)</td></tr><tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/net/ipv6/ip6_gre.c?h=nds-private-remove&amp;id=4205e4786d0b9fc3b4fec7b1910cf645a0468307'>4205e4786d0b9fc3b4fec7b1910cf645a0468307</a> (<a href='/cgit.cgi/linux/net-next.git/diff/net/ipv6/ip6_gre.c?h=nds-private-remove&amp;id=ca92e6c7e6329029d7188487a5c32e86ef471977&amp;id2=4205e4786d0b9fc3b4fec7b1910cf645a0468307'>diff</a>)</td></tr></table>
<div class='commit-subject'>Merge branch 'smp-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip</div><div class='commit-msg'>Pull SMP hotplug update from Thomas Gleixner:
 "This contains a trivial typo fix and an extension to the core code for
  dynamically allocating states in the prepare stage.

  The extension is necessary right now because we need a proper way to
  unbreak LTTNG, which iscurrently non functional due to the removal of
  the notifiers. Surely it's out of tree, but it's widely used by
  distros.

  The simple solution would have been to reserve a state for LTTNG, but
  I'm not fond about unused crap in the kernel and the dynamic range,
  which we admittedly should have done right away, allows us to remove
  quite some of the hardcoded states, i.e. those which have no ordering
  requirements. So doing the right thing now is better than having an
  smaller intermediate solution which needs to be reworked anyway"

* 'smp-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  cpu/hotplug: Provide dynamic range for prepare stage
  perf/x86/amd/ibs: Fix typo after cleanup state names in cpu/hotplug
</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?h=nds-private-remove&amp;id=ca92e6c7e6329029d7188487a5c32e86ef471977'>Diffstat</a> (limited to 'net/ipv6/ip6_gre.c')</div><table summary='diffstat' class='diffstat'>