/* [<][>][^][v][top][bottom][index][help] */
DEFINITIONS
This source file includes following definitions.
- phpdbg_btree_init
- phpdbg_btree_find
- phpdbg_btree_find_closest
- phpdbg_btree_find_between
- phpdbg_btree_next
- phpdbg_btree_insert_or_update
- phpdbg_btree_delete
/*
+----------------------------------------------------------------------+
| PHP Version 5 |
+----------------------------------------------------------------------+
| Copyright (c) 1997-2015 The PHP Group |
+----------------------------------------------------------------------+
| This source file is subject to version 3.01 of the PHP license, |
| that is bundled with this package in the file LICENSE, and is |
| available through the world-wide-web at the following url: |
| http://www.php.net/license/3_01.txt |
| If you did not receive a copy of the PHP license and are unable to |
| obtain it through the world-wide-web, please send a note to |
| license@php.net so we can mail you a copy immediately. |
+----------------------------------------------------------------------+
| Authors: Felipe Pena <felipe@php.net> |
| Authors: Joe Watkins <joe.watkins@live.co.uk> |
| Authors: Bob Weinand <bwoebi@php.net> |
+----------------------------------------------------------------------+
*/
#include "phpdbg_btree.h"
#include "phpdbg.h"
#define CHOOSE_BRANCH(n) \
branch = branch->branches[!!(n)];
#ifdef _Win32
# define emalloc malloc
# define efree free
#endif
/* depth in bits */
void phpdbg_btree_init(phpdbg_btree *tree, zend_ulong depth) {
tree->depth = depth;
tree->branch = NULL;
tree->count = 0;
}
phpdbg_btree_result *phpdbg_btree_find(phpdbg_btree *tree, zend_ulong idx) {
phpdbg_btree_branch *branch = tree->branch;
int i = tree->depth - 1;
if (branch == NULL) {
return NULL;
}
do {
if ((idx >> i) % 2 == 1) {
if (branch->branches[1]) {
CHOOSE_BRANCH(1);
} else {
return NULL;
}
} else {
if (branch->branches[0]) {
CHOOSE_BRANCH(0);
} else {
return NULL;
}
}
} while (i--);
return &branch->result;
}
phpdbg_btree_result *phpdbg_btree_find_closest(phpdbg_btree *tree, zend_ulong idx) {
phpdbg_btree_branch *branch = tree->branch;
int i = tree->depth - 1, last_superior_i = -1;
zend_bool had_alternative_branch = 0;
if (branch == NULL) {
return NULL;
}
/* find nearest watchpoint */
do {
/* an impossible branch was found if: */
if (!had_alternative_branch && (idx >> i) % 2 == 0 && !branch->branches[0]) {
/* there's no lower branch than idx */
if (last_superior_i == -1) {
/* failure */
return NULL;
}
/* reset state */
branch = tree->branch;
i = tree->depth - 1;
/* follow branch according to bits in idx until the last lower branch before the impossible branch */
do {
CHOOSE_BRANCH((idx >> i) % 2 == 1 && branch->branches[1]);
} while (--i > last_superior_i);
/* use now the lower branch of which we can be sure that it contains only branches lower than idx */
CHOOSE_BRANCH(0);
/* and choose the highest possible branch in the branch containing only branches lower than idx */
while (i--) {
CHOOSE_BRANCH(branch->branches[1]);
}
break;
}
/* follow branch according to bits in idx until having found an impossible branch */
if (had_alternative_branch || (idx >> i) % 2 == 1) {
if (branch->branches[1]) {
if (branch->branches[0]) {
last_superior_i = i;
}
CHOOSE_BRANCH(1);
} else {
CHOOSE_BRANCH(0);
had_alternative_branch = 1;
}
} else {
CHOOSE_BRANCH(0);
}
} while (i--);
return &branch->result;
}
phpdbg_btree_position phpdbg_btree_find_between(phpdbg_btree *tree, zend_ulong lower_idx, zend_ulong higher_idx) {
phpdbg_btree_position pos;
pos.tree = tree;
pos.end = lower_idx;
pos.cur = higher_idx;
return pos;
}
phpdbg_btree_result *phpdbg_btree_next(phpdbg_btree_position *pos) {
phpdbg_btree_result *result = phpdbg_btree_find_closest(pos->tree, pos->cur);
if (result == NULL || result->idx < pos->end) {
return NULL;
}
pos->cur = result->idx - 1;
return result;
}
int phpdbg_btree_insert_or_update(phpdbg_btree *tree, zend_ulong idx, void *ptr, int flags) {
int i = tree->depth - 1;
phpdbg_btree_branch **branch = &tree->branch;
do {
if (*branch == NULL) {
break;
}
branch = &(*branch)->branches[(idx >> i) % 2];
} while (i--);
if (*branch == NULL) {
if (!(flags & PHPDBG_BTREE_INSERT)) {
return FAILURE;
}
{
phpdbg_btree_branch *memory = *branch = emalloc((i + 2) * sizeof(phpdbg_btree_branch));
do {
(*branch)->branches[!((idx >> i) % 2)] = NULL;
branch = &(*branch)->branches[(idx >> i) % 2];
*branch = ++memory;
} while (i--);
tree->count++;
}
} else if (!(flags & PHPDBG_BTREE_UPDATE)) {
return FAILURE;
}
(*branch)->result.idx = idx;
(*branch)->result.ptr = ptr;
return SUCCESS;
}
int phpdbg_btree_delete(phpdbg_btree *tree, zend_ulong idx) {
int i = tree->depth;
phpdbg_btree_branch *branch = tree->branch;
int i_last_dual_branch = -1, last_dual_branch_branch;
phpdbg_btree_branch *last_dual_branch = NULL;
goto check_branch_existence;
do {
if (branch->branches[0] && branch->branches[1]) {
last_dual_branch = branch;
i_last_dual_branch = i;
last_dual_branch_branch = (idx >> i) % 2;
}
branch = branch->branches[(idx >> i) % 2];
check_branch_existence:
if (branch == NULL) {
return FAILURE;
}
} while (i--);
tree->count--;
if (i_last_dual_branch == -1) {
efree(tree->branch);
tree->branch = NULL;
} else {
if (last_dual_branch->branches[last_dual_branch_branch] == last_dual_branch + 1) {
phpdbg_btree_branch *original_branch = last_dual_branch->branches[!last_dual_branch_branch];
memcpy(last_dual_branch + 1, last_dual_branch->branches[!last_dual_branch_branch], (i_last_dual_branch + 1) * sizeof(phpdbg_btree_branch));
efree(last_dual_branch->branches[!last_dual_branch_branch]);
last_dual_branch->branches[!last_dual_branch_branch] = last_dual_branch + 1;
branch = last_dual_branch->branches[!last_dual_branch_branch];
for (i = i_last_dual_branch; i--;) {
branch = (branch->branches[branch->branches[1] == ++original_branch] = last_dual_branch + i_last_dual_branch - i + 1);
}
} else {
efree(last_dual_branch->branches[last_dual_branch_branch]);
}
last_dual_branch->branches[last_dual_branch_branch] = NULL;
}
return SUCCESS;
}