void match_ctx_init(match_ctx ctx, /* IN/OUT */
struct membuf *inbuf, /* IN */
int max_offset)
{
struct match_node *np;
struct progress prog[1];
int buf_len = membuf_memlen(inbuf);
const unsigned char *buf = membuf_get(inbuf);
int c, i;
int val;
ctx->info = calloc(buf_len + 1, sizeof(*ctx->info));
ctx->rle = calloc(buf_len + 1, sizeof(*ctx->rle));
ctx->rle_r = calloc(buf_len + 1, sizeof(*ctx->rle_r));
chunkpool_init(ctx->m_pool, sizeof(match));
ctx->max_offset = max_offset;
ctx->buf = buf;
ctx->len = buf_len;
val = buf[0];
for (i = 1; i < buf_len; ++i)
{
if (buf[i] == val)
{
int len = ctx->rle[i - 1] + 1;
if(len > 65535)
{
len = 0;
}
ctx->rle[i] = len;
} else
{
ctx->rle[i] = 0;
}
val = buf[i];
}
for (i = buf_len - 2; i >= 0; --i)
{
if (ctx->rle[i] < ctx->rle[i + 1])
{
ctx->rle_r[i] = ctx->rle_r[i + 1] + 1;
} else
{
ctx->rle_r[i] = 0;
}
}
/* add extra nodes to rle sequences */
for(c = 0; c < 256; ++c)
{
static char rle_map[65536];
struct match_node *prev_np;
unsigned short int rle_len;
/* for each possible rle char */
memset(rle_map, 0, sizeof(rle_map));
prev_np = NULL;
for (i = 0; i < buf_len; ++i)
{
/* must be the correct char */
if(buf[i] != c)
{
continue;
}
rle_len = ctx->rle[i];
if(!rle_map[rle_len] && ctx->rle_r[i] > 16)
{
/* no previous lengths and not our primary length*/
continue;
}
np = chunkpool_malloc(ctx->m_pool);
np->index = i;
np->next = NULL;
rle_map[rle_len] = 1;
LOG(LOG_DUMP, ("0) c = %d, added np idx %d -> %d\n", c, i, 0));
/* if we have a previous entry, let's chain it together */
if(prev_np != NULL)
{
LOG(LOG_DUMP, ("1) c = %d, pointed np idx %d -> %d\n",
c, prev_np->index, i));
prev_np->next = np;
}
ctx->info[i]->single = np;
prev_np = np;
}
memset(rle_map, 0, sizeof(rle_map));
prev_np = NULL;
for (i = buf_len - 1; i >= 0; --i)
{
/* must be the correct char */
if(buf[i] != c)
{
continue;
}
rle_len = ctx->rle_r[i];
np = ctx->info[i]->single;
if(np == NULL)
{
if(rle_map[rle_len] && prev_np != NULL && rle_len > 0)
{
np = chunkpool_malloc(ctx->m_pool);
np->index = i;
np->next = prev_np;
ctx->info[i]->single = np;
LOG(LOG_DEBUG, ("2) c = %d, added np idx %d -> %d\n",
c, i, prev_np->index));
}
}
else
{
prev_np = np;
}
if(ctx->rle_r[i] > 0)
{
continue;
}
rle_len = ctx->rle[i] + 1;
rle_map[rle_len] = 1;
}
}
progress_init(prog, "building.directed.acyclic.graph.", buf_len - 1, 0);
for (i = buf_len - 1; i >= 0; --i)
{
const_matchp matches;
/* let's populate the cache */
matches = matches_calc(ctx, i);
/* add to cache */
ctx->info[i]->cache = matches;
progress_bump(prog, i);
}
LOG(LOG_NORMAL, ("\n"));
progress_free(prog);
}
struct search_node*
search_buffer(match_ctx ctx, /* IN */
encode_match_f * f, /* IN */
encode_match_data emd, /* IN */
int use_literal_sequences)
{
struct progress prog[1];
struct search_node *sn_arr;
const_matchp mp = NULL;
struct search_node *snp;
struct search_node *best_copy_snp;
int best_copy_len;
struct search_node *best_rle_snp;
int len = ctx->len + 1;
progress_init(prog, "finding.shortest.path.",len, 0);
sn_arr = malloc(len * sizeof(struct search_node));
memset(sn_arr, 0, len * sizeof(struct search_node));
--len;
snp = &sn_arr[len];
snp->index = len;
snp->match->offset = 0;
snp->match->len = 0;
snp->total_offset = 0;
snp->total_score = 0;
snp->prev = NULL;
best_copy_snp = snp;
best_copy_len = 0.0;
best_rle_snp = NULL;
/* think twice about changing this code,
* it works the way it is. The last time
* I examined this code I was certain it was
* broken and broke it myself, trying to fix it. */
while (len > 0 && (mp = matches_get(ctx, len - 1)) != NULL)
{
float prev_score;
float prev_offset_sum;
if(use_literal_sequences)
{
/* check if we can do even better with copy */
snp = &sn_arr[len];
if(best_copy_snp->total_score+best_copy_len * 8.0 -
snp->total_score > 0.0 || best_copy_len > 65535)
{
/* found a better copy endpoint */
LOG(LOG_DEBUG,
("best copy start moved to index %d\n", snp->index));
best_copy_snp = snp;
best_copy_len = 0.0;
} else
{
float copy_score = best_copy_len * 8.0 + (1.0 + 17.0 + 17.0);
float total_copy_score = best_copy_snp->total_score +
copy_score;
LOG(LOG_DEBUG,
("total score %0.1f, copy total score %0.1f\n",
snp->total_score, total_copy_score));
if(snp->total_score > total_copy_score )
{
match local_mp;
/* here it is good to just copy instead of crunch */
LOG(LOG_DEBUG,
("copy index %d, len %d, total %0.1f, copy %0.1f\n",
snp->index, best_copy_len,
snp->total_score, total_copy_score));
local_mp->len = best_copy_len;
local_mp->offset = 0;
local_mp->next = NULL;
snp->total_score = total_copy_score;
snp->total_offset = best_copy_snp->total_offset;
snp->prev = best_copy_snp;
*snp->match = *local_mp;
}
}
/* end of copy optimization */
}
/* check if we can do rle */
snp = &sn_arr[len];
if(best_rle_snp == NULL ||
snp->index + 65535 < best_rle_snp->index ||
snp->index + ctx->rle_r[snp->index] < best_rle_snp->index)
{
/* best_rle_snp can't be reached by rle from snp, reset it*/
if(ctx->rle[snp->index] > 0)
{
best_rle_snp = snp;
LOG(LOG_DEBUG, ("resetting best_rle at index %d, len %d\n",
snp->index, ctx->rle[snp->index]));
}
else
{
best_rle_snp = NULL;
}
}
else if(ctx->rle[snp->index] > 0 &&
snp->index + ctx->rle_r[snp->index] >= best_rle_snp->index)
{
float best_rle_score;
float total_best_rle_score;
float snp_rle_score;
float total_snp_rle_score;
match rle_mp;
LOG(LOG_DEBUG, ("challenger len %d, index %d, "
"ruling len %d, index %d\n",
ctx->rle_r[snp->index], snp->index,
ctx->rle_r[best_rle_snp->index],
best_rle_snp->index));
/* snp and best_rle_snp is the same rle area,
* let's see which is best */
rle_mp->len = ctx->rle[best_rle_snp->index];
rle_mp->offset = 1;
best_rle_score = f(rle_mp, emd, NULL);
total_best_rle_score = best_rle_snp->total_score +
best_rle_score;
rle_mp->len = ctx->rle[snp->index];
rle_mp->offset = 1;
snp_rle_score = f(rle_mp, emd, NULL);
total_snp_rle_score = snp->total_score + snp_rle_score;
if(total_snp_rle_score <= total_best_rle_score)
{
/* yes, the snp is a better rle than best_rle_snp */
LOG(LOG_DEBUG, ("prospect len %d, index %d, (%0.1f+%0.1f) "
"ruling len %d, index %d (%0.1f+%0.1f)\n",
ctx->rle[snp->index], snp->index,
snp->total_score, snp_rle_score,
ctx->rle[best_rle_snp->index],
best_rle_snp->index,
best_rle_snp->total_score, best_rle_score));
best_rle_snp = snp;
LOG(LOG_DEBUG, ("setting current best_rle: "
"index %d, len %d\n",
snp->index, rle_mp->len));
}
}
if(best_rle_snp != NULL && best_rle_snp != snp)
{
float rle_score;
float total_rle_score;
/* check if rle is better */
match local_mp;
local_mp->len = best_rle_snp->index - snp->index;
local_mp->offset = 1;
rle_score = f(local_mp, emd, NULL);
total_rle_score = best_rle_snp->total_score + rle_score;
LOG(LOG_DEBUG, ("comparing index %d (%0.1f) with "
"rle index %d, len %d, total score %0.1f %0.1f\n",
snp->index, snp->total_score,
best_rle_snp->index, local_mp->len,
best_rle_snp->total_score, rle_score));
if(snp->total_score > total_rle_score)
{
/*here it is good to do rle instead of crunch */
LOG(LOG_DEBUG,
("rle index %d, len %d, total %0.1f, rle %0.1f\n",
snp->index, local_mp->len,
snp->total_score, total_rle_score));
snp->total_score = total_rle_score;
snp->total_offset = best_rle_snp->total_offset + 1;
snp->prev = best_rle_snp;
*snp->match = *local_mp;
}
}
/* end of rle optimization */
LOG(LOG_DUMP,
("matches for index %d with total score %0.1f\n",
len - 1, snp->total_score));
prev_score = sn_arr[len].total_score;
prev_offset_sum = sn_arr[len].total_offset;
while (mp != NULL)
{
matchp next;
int end_len;
match tmp;
int bucket_len_start;
float score;
next = mp->next;
end_len = 1;
*tmp = *mp;
tmp->next = NULL;
bucket_len_start = 0;
for(tmp->len = mp->len; tmp->len >= end_len; --(tmp->len))
{
float total_score;
unsigned int total_offset;
struct encode_match_buckets match_buckets;
LOG(LOG_DUMP, ("mp[%d, %d], tmp[%d, %d]\n",
mp->offset, mp->len,
tmp->offset, tmp->len));
if (bucket_len_start == 0 ||
tmp->len < 3 ||
tmp->len < bucket_len_start)
{
score = f(tmp, emd, &match_buckets);
bucket_len_start = match_buckets.len.start;
}
total_score = prev_score + score;
total_offset = prev_offset_sum + tmp->offset;
snp = &sn_arr[len - tmp->len];
LOG(LOG_DUMP,
("[%05d] cmp [%05d, %05d score %.1f + %.1f] with %.1f",
len, tmp->offset, tmp->len,
prev_score, score, snp->total_score));
if ((total_score < 100000000.0) &&
(snp->match->len == 0 ||
total_score < snp->total_score ||
(total_score == snp->total_score &&
(tmp->offset == 0 ||
(snp->match->len == tmp->len &&
(total_offset <= snp->total_offset))))))
{
LOG(LOG_DUMP, (", replaced"));
snp->index = len - tmp->len;
*snp->match = *tmp;
snp->total_offset = total_offset;
snp->total_score = total_score;
snp->prev = &sn_arr[len];
}
LOG(LOG_DUMP, ("\n"));
}
LOG(LOG_DUMP, ("tmp->len %d, ctx->rle[%d] %d\n",
tmp->len, len - tmp->len,
ctx->rle[len - tmp->len]));
mp = next;
}
/* slow way to get to the next node for cur */
--len;
++best_copy_len;
if(sn_arr[len].match == NULL)
{
LOG(LOG_ERROR, ("Found unreachable node at len %d.\n", len));
}
progress_bump(prog, len);
}
if(len > 0 && mp == NULL)
{
LOG(LOG_ERROR, ("No matches at len %d.\n", len));
}
LOG(LOG_NORMAL, ("\n"));
progress_free(prog);
return sn_arr;
}