From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:48512) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RiATs-0003d7-18 for qemu-devel@nongnu.org; Tue, 03 Jan 2012 14:57:09 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1RiATq-0002CA-PZ for qemu-devel@nongnu.org; Tue, 03 Jan 2012 14:57:07 -0500 Received: from mail-iy0-f173.google.com ([209.85.210.173]:63370) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RiATq-0002Bz-Kw for qemu-devel@nongnu.org; Tue, 03 Jan 2012 14:57:06 -0500 Received: by iagj37 with SMTP id j37so36406727iag.4 for ; Tue, 03 Jan 2012 11:57:06 -0800 (PST) Message-ID: <4F035D8E.2050103@redhat.com> Date: Tue, 03 Jan 2012 13:57:02 -0600 From: Anthony Liguori MIME-Version: 1.0 References: <1325604879-15862-1-git-send-email-owasserm@redhat.com> <1325604879-15862-3-git-send-email-owasserm@redhat.com> In-Reply-To: <1325604879-15862-3-git-send-email-owasserm@redhat.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v5 2/9] Add rle_encode and rle_decode functions Implement Run Length Encoding compression List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Orit Wasserman Cc: blauwirbel@gmail.com, stefanha@gmail.com, qemu-devel@nongnu.org, quintela@redhat.com On 01/03/2012 09:34 AM, Orit Wasserman wrote: > Signed-off-by: Orit Wasserman > --- > arch_init.c | 58 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > 1 files changed, 58 insertions(+), 0 deletions(-) > > diff --git a/arch_init.c b/arch_init.c > index fdda277..426b34d 100644 > --- a/arch_init.c > +++ b/arch_init.c > @@ -139,6 +139,9 @@ typedef struct XBRLEHeader { > uint32_t xh_cksum; > } XBRLEHeader; > > +static int rle_encode(uint8_t *src, int slen, uint8_t *dst, int dlen); > +static int rle_decode(uint8_t *src, int slen, uint8_t *dst, int dlen); > + > /***********************************************************/ > /* XBRLE page cache implementation */ > static CacheItem *cache_item_get(unsigned long pos, int item) > @@ -277,6 +280,61 @@ static void cache_insert(unsigned long addr, uint8_t *pdata) > it->it_addr = addr; > } > > +/* XBRLE (Xor Based Run-Length Encoding) */ > +static int rle_encode(uint8_t *src, int slen, uint8_t *dst, int dlen) > +{ > + int d = 0, ch_run = 0, i; > + uint8_t prev = 0, ch = 0; > + > + for (i = 0; i<= slen; i++) { > + if (i != slen) { > + ch = src[i]; > + } > + > + if (!i || (i != slen&& ch == prev&& ch_run< 255)) { > + ch_run++; > + } else { > + if (d+2> dlen) { > + return -1; > + } > + *dst++ = ch_run; > + *dst++ = prev; > + d += 2; > + ch_run = 1; > + } > + > + prev = ch; > + } > + return d; > +} > + > +static int rle_decode(uint8_t *src, int slen, uint8_t *dst, int dlen) > +{ > + int d = 0, s; > + > + for (s = 0; s< slen-1; s += 2) { > + uint8_t ch_run = src[s]; > + uint8_t ch = src[s+1]; > + while (ch_run--) { > + if (d == dlen) { > + return -1; > + } > + dst[d] = ch; > + d++; > + } > + } > + return d; > +} > + > +static void xor_encode(uint8_t *dst, uint8_t *src1, uint8_t *src2) > +{ > + int i; > + > + for (i = 0; i< TARGET_PAGE_SIZE; i++) { > + dst[i] = src1[i] ^ src2[i]; > + } > +} > + I don't think any of these need to be in arch_init.c. It would be nicer to make a xbzrle.c file for this stuff. Regards, Anthony Liguori > static int is_dup_page(uint8_t *page, uint8_t ch) > { > uint32_t val = ch<< 24 | ch<< 16 | ch<< 8 | ch;