seq-range-array.c revision 90b50df264b57e0f63cd8cc6aea1ce3bb7cf5f64
/* Copyright (c) 2005-2007 Dovecot authors, see the included COPYING file */
#include "lib.h"
#include "array.h"
#include "seq-range-array.h"
static bool seq_range_lookup(const ARRAY_TYPE(seq_range) *array,
uint32_t seq, unsigned int *idx_r)
{
const struct seq_range *data;
unsigned int idx, left_idx, right_idx, count;
data = array_get(array, &count);
idx = 0; left_idx = 0; right_idx = count;
while (left_idx < right_idx) {
idx = (left_idx + right_idx) / 2;
if (data[idx].seq1 <= seq) {
if (data[idx].seq2 >= seq) {
/* it's already in the range */
*idx_r = idx;
return TRUE;
}
left_idx = idx+1;
} else {
right_idx = idx;
}
}
*idx_r = idx;
return FALSE;
}
void seq_range_array_add(ARRAY_TYPE(seq_range) *array,
unsigned int init_count, uint32_t seq)
{
struct seq_range *data, value;
unsigned int idx, count;
value.seq1 = value.seq2 = seq;
if (!array_is_created(array))
i_array_init(array, init_count);
data = array_get_modifiable(array, &count);
if (count == 0) {
array_append(array, &value, 1);
return;
}
/* quick checks */
if (data[count-1].seq2 == seq-1) {
/* grow last range */
data[count-1].seq2 = seq;
return;
}
if (data[count-1].seq2 < seq) {
array_append(array, &value, 1);
return;
}
if (data[0].seq1 == seq+1) {
/* grow down first range */
data[0].seq1 = seq;
return;
}
if (data[0].seq1 > seq) {
array_insert(array, 0, &value, 1);
return;
}
/* somewhere in the middle, array is sorted so find it with
binary search */
if (seq_range_lookup(array, seq, &idx))
return;
if (data[idx].seq2 < seq)
idx++;
/* idx == count couldn't happen because we already handle it above */
i_assert(idx < count && data[idx].seq1 >= seq);
i_assert(data[idx].seq1 > seq || data[idx].seq2 < seq);
if (data[idx].seq1 == seq+1) {
data[idx].seq1 = seq;
if (idx > 0 && data[idx-1].seq2 == seq-1) {
/* merge */
data[idx-1].seq2 = data[idx].seq2;
array_delete(array, idx, 1);
}
} else if (data[idx].seq2 == seq-1) {
i_assert(idx+1 < count); /* already handled above */
data[idx].seq2 = seq;
if (data[idx+1].seq1 == seq+1) {
/* merge */
data[idx+1].seq1 = data[idx].seq1;
array_delete(array, idx, 1);
}
} else {
array_insert(array, idx, &value, 1);
}
}
bool seq_range_array_remove(ARRAY_TYPE(seq_range) *array, uint32_t seq)
{
struct seq_range *data, value;
unsigned int idx, left_idx, right_idx, count;
if (!array_is_created(array))
return FALSE;
data = array_get_modifiable(array, &count);
if (count == 0)
return FALSE;
/* quick checks */
if (seq > data[count-1].seq2 || seq < data[0].seq1) {
/* outside the range */
return FALSE;
}
if (data[count-1].seq2 == seq) {
/* shrink last range */
if (data[count-1].seq1 != data[count-1].seq2)
data[count-1].seq2--;
else
array_delete(array, count-1, 1);
return TRUE;
}
if (data[0].seq1 == seq) {
/* shrink up first range */
if (data[0].seq1 != data[0].seq2)
data[0].seq1++;
else
array_delete(array, 0, 1);
return TRUE;
}
/* somewhere in the middle, array is sorted so find it with
binary search */
idx = 0; left_idx = 0; right_idx = count;
while (left_idx < right_idx) {
idx = (left_idx + right_idx) / 2;
if (data[idx].seq1 > seq)
right_idx = idx;
else if (data[idx].seq2 < seq)
left_idx = idx+1;
else {
/* found it */
if (data[idx].seq1 == seq) {
if (data[idx].seq1 == data[idx].seq2) {
/* a single sequence range.
remove it entirely */
array_delete(array, idx, 1);
} else {
/* shrink the range */
data[idx].seq1++;
}
} else if (data[idx].seq2 == seq) {
/* shrink the range */
data[idx].seq2--;
} else {
/* split the sequence range */
value.seq1 = seq + 1;
value.seq2 = data[idx].seq2;
data[idx].seq2 = seq - 1;
array_insert(array, idx + 1, &value, 1);
}
return TRUE;
}
}
return FALSE;
}
unsigned int seq_range_array_remove_range(ARRAY_TYPE(seq_range) *array,
uint32_t seq1, uint32_t seq2)
{
const struct seq_range *data;
unsigned int idx, idx2, count, remove_count = 0;
/* remove first and last. this makes sure that everything between
can simply be deleted with array_delete().
FIXME: it would be faster if we did only one binary lookup here
and handled the splitting ourself.. */
if (seq_range_array_remove(array, seq1++))
remove_count++;
if (seq1 > seq2)
return remove_count;
if (seq_range_array_remove(array, seq2--))
remove_count++;
if (seq1 > seq2)
return remove_count;
/* find the beginning */
data = array_get(array, &count);
(void)seq_range_lookup(array, seq1, &idx);
if (idx < count && data[idx].seq2 < seq1)
idx++;
if (idx == count)
return remove_count;
i_assert(data[idx].seq1 >= seq1);
for (idx2 = idx; idx2 < count; idx2++) {
if (data[idx2].seq1 > seq2)
break;
remove_count += data[idx2].seq2 - data[idx2].seq1 + 1;
}
array_delete(array, idx, idx2-idx);
return remove_count;
}
bool seq_range_exists(const ARRAY_TYPE(seq_range) *array, uint32_t seq)
{
unsigned int idx;
return seq_range_lookup(array, seq, &idx);
}
void seq_range_array_invert(ARRAY_TYPE(seq_range) *array,
uint32_t min_seq, uint32_t max_seq)
{
struct seq_range *range, value;
unsigned int i, count;
uint32_t next_min_seq;
if (array_is_created(array))
range = array_get_modifiable(array, &count);
else {
range = NULL;
count = 0;
}
if (count == 0) {
/* empty -> full */
if (!array_is_created(array))
i_array_init(array, 4);
value.seq1 = min_seq;
value.seq2 = max_seq;
array_append(array, &value, 1);
return;
}
i_assert(range[0].seq1 >= min_seq);
i_assert(range[count-1].seq2 <= max_seq);
if (range[0].seq1 == min_seq && range[0].seq2 == max_seq) {
/* full -> empty */
array_clear(array);
return;
}
for (i = 0; i < count; ) {
next_min_seq = range[i].seq2 + 1;
if (range[i].seq1 == min_seq) {
array_delete(array, i, 1);
range = array_get_modifiable(array, &count);
} else {
range[i].seq2 = range[i].seq1 - 1;
range[i].seq1 = min_seq;
i++;
}
min_seq = next_min_seq;
}
if (min_seq <= max_seq) {
value.seq1 = min_seq;
value.seq2 = max_seq;
array_append(array, &value, 1);
}
}