Prompt to embedded mujs engine
This commit is contained in:
kamkow1
341
mujs/jsproperty.c
Normal file
341
mujs/jsproperty.c
Normal file
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#include "jsi.h"
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#include <assert.h>
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/*
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Use an AA-tree to quickly look up properties in objects:
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The level of every leaf node is one.
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The level of every left child is one less than its parent.
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The level of every right child is equal or one less than its parent.
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The level of every right grandchild is less than its grandparent.
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Every node of level greater than one has two children.
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A link where the child's level is equal to that of its parent is called a horizontal link.
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Individual right horizontal links are allowed, but consecutive ones are forbidden.
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Left horizontal links are forbidden.
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skew() fixes left horizontal links.
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split() fixes consecutive right horizontal links.
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*/
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static js_Property sentinel = {
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&sentinel, &sentinel,
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0, 0,
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{ { {0}, JS_TUNDEFINED } },
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NULL, NULL, ""
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};
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static js_Property *newproperty(js_State *J, js_Object *obj, const char *name)
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{
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int n = strlen(name) + 1;
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js_Property *node = js_malloc(J, offsetof(js_Property, name) + n);
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node->left = node->right = &sentinel;
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node->level = 1;
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node->atts = 0;
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node->value.t.type = JS_TUNDEFINED;
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node->value.u.number = 0;
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node->getter = NULL;
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node->setter = NULL;
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memcpy(node->name, name, n);
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++obj->count;
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++J->gccounter;
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return node;
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}
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static js_Property *lookup(js_Property *node, const char *name)
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{
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while (node != &sentinel) {
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int c = strcmp(name, node->name);
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if (c == 0)
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return node;
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else if (c < 0)
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node = node->left;
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else
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node = node->right;
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}
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return NULL;
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}
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static js_Property *skew(js_Property *node)
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{
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if (node->left->level == node->level) {
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js_Property *temp = node;
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node = node->left;
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temp->left = node->right;
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node->right = temp;
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}
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return node;
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}
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static js_Property *split(js_Property *node)
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{
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if (node->right->right->level == node->level) {
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js_Property *temp = node;
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node = node->right;
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temp->right = node->left;
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node->left = temp;
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++node->level;
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}
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return node;
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}
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static js_Property *insert(js_State *J, js_Object *obj, js_Property *node, const char *name, js_Property **result)
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{
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if (node != &sentinel) {
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int c = strcmp(name, node->name);
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if (c < 0)
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node->left = insert(J, obj, node->left, name, result);
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else if (c > 0)
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node->right = insert(J, obj, node->right, name, result);
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else
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return *result = node;
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node = skew(node);
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node = split(node);
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return node;
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}
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return *result = newproperty(J, obj, name);
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}
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static void freeproperty(js_State *J, js_Object *obj, js_Property *node)
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{
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js_free(J, node);
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--obj->count;
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}
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static js_Property *unlinkproperty(js_Property *node, const char *name, js_Property **garbage)
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{
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js_Property *temp, *a, *b;
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if (node != &sentinel) {
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int c = strcmp(name, node->name);
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if (c < 0) {
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node->left = unlinkproperty(node->left, name, garbage);
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} else if (c > 0) {
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node->right = unlinkproperty(node->right, name, garbage);
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} else {
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*garbage = node;
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if (node->left == &sentinel && node->right == &sentinel) {
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return &sentinel;
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}
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else if (node->left == &sentinel) {
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a = node->right;
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while (a->left != &sentinel)
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a = a->left;
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b = unlinkproperty(node->right, a->name, &temp);
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temp->level = node->level;
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temp->left = node->left;
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temp->right = b;
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node = temp;
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}
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else {
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a = node->left;
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while (a->right != &sentinel)
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a = a->right;
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b = unlinkproperty(node->left, a->name, &temp);
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temp->level = node->level;
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temp->left = b;
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temp->right = node->right;
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node = temp;
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}
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}
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if (node->left->level < node->level - 1 || node->right->level < node->level - 1)
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{
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if (node->right->level > --node->level)
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node->right->level = node->level;
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node = skew(node);
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node->right = skew(node->right);
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node->right->right = skew(node->right->right);
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node = split(node);
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node->right = split(node->right);
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}
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}
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return node;
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}
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static js_Property *deleteproperty(js_State *J, js_Object *obj, js_Property *tree, const char *name)
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{
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js_Property *garbage = &sentinel;
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tree = unlinkproperty(tree, name, &garbage);
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if (garbage != &sentinel)
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freeproperty(J, obj, garbage);
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return tree;
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}
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js_Object *jsV_newobject(js_State *J, enum js_Class type, js_Object *prototype)
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{
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js_Object *obj = js_malloc(J, sizeof *obj);
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memset(obj, 0, sizeof *obj);
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obj->gcmark = 0;
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obj->gcnext = J->gcobj;
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J->gcobj = obj;
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++J->gccounter;
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obj->type = type;
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obj->properties = &sentinel;
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obj->prototype = prototype;
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obj->extensible = 1;
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return obj;
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}
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js_Property *jsV_getownproperty(js_State *J, js_Object *obj, const char *name)
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{
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return lookup(obj->properties, name);
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}
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js_Property *jsV_getpropertyx(js_State *J, js_Object *obj, const char *name, int *own)
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{
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*own = 1;
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do {
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js_Property *ref = lookup(obj->properties, name);
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if (ref)
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return ref;
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obj = obj->prototype;
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*own = 0;
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} while (obj);
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return NULL;
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}
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js_Property *jsV_getproperty(js_State *J, js_Object *obj, const char *name)
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{
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do {
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js_Property *ref = lookup(obj->properties, name);
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if (ref)
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return ref;
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obj = obj->prototype;
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} while (obj);
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return NULL;
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}
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static js_Property *jsV_getenumproperty(js_State *J, js_Object *obj, const char *name)
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{
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do {
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js_Property *ref = lookup(obj->properties, name);
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if (ref && !(ref->atts & JS_DONTENUM))
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return ref;
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obj = obj->prototype;
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} while (obj);
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return NULL;
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}
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js_Property *jsV_setproperty(js_State *J, js_Object *obj, const char *name)
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{
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js_Property *result;
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if (!obj->extensible) {
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result = lookup(obj->properties, name);
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if (J->strict && !result)
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js_typeerror(J, "object is non-extensible");
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return result;
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}
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obj->properties = insert(J, obj, obj->properties, name, &result);
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return result;
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}
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void jsV_delproperty(js_State *J, js_Object *obj, const char *name)
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{
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obj->properties = deleteproperty(J, obj, obj->properties, name);
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}
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/* Flatten hierarchy of enumerable properties into an iterator object */
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static js_Iterator *itnewnode(js_State *J, const char *name, js_Iterator *next) {
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int n = strlen(name) + 1;
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js_Iterator *node = js_malloc(J, offsetof(js_Iterator, name) + n);
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node->next = next;
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memcpy(node->name, name, n);
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return node;
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}
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static js_Iterator *itwalk(js_State *J, js_Iterator *iter, js_Property *prop, js_Object *seen)
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{
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if (prop->right != &sentinel)
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iter = itwalk(J, iter, prop->right, seen);
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if (!(prop->atts & JS_DONTENUM)) {
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if (!seen || !jsV_getenumproperty(J, seen, prop->name)) {
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iter = itnewnode(J, prop->name, iter);
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}
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}
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if (prop->left != &sentinel)
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iter = itwalk(J, iter, prop->left, seen);
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return iter;
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}
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static js_Iterator *itflatten(js_State *J, js_Object *obj)
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{
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js_Iterator *iter = NULL;
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if (obj->prototype)
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iter = itflatten(J, obj->prototype);
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if (obj->properties != &sentinel)
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iter = itwalk(J, iter, obj->properties, obj->prototype);
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return iter;
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}
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js_Object *jsV_newiterator(js_State *J, js_Object *obj, int own)
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{
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js_Object *io = jsV_newobject(J, JS_CITERATOR, NULL);
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io->u.iter.target = obj;
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io->u.iter.i = 0;
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io->u.iter.n = 0;
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if (own) {
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io->u.iter.head = NULL;
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if (obj->properties != &sentinel)
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io->u.iter.head = itwalk(J, io->u.iter.head, obj->properties, NULL);
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} else {
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io->u.iter.head = itflatten(J, obj);
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}
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io->u.iter.current = io->u.iter.head;
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if (obj->type == JS_CSTRING)
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io->u.iter.n = obj->u.s.length;
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if (obj->type == JS_CARRAY && obj->u.a.simple)
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io->u.iter.n = obj->u.a.flat_length;
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return io;
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}
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const char *jsV_nextiterator(js_State *J, js_Object *io)
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{
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if (io->type != JS_CITERATOR)
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js_typeerror(J, "not an iterator");
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if (io->u.iter.i < io->u.iter.n) {
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js_itoa(J->scratch, io->u.iter.i);
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io->u.iter.i++;
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return J->scratch;
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}
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while (io->u.iter.current) {
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const char *name = io->u.iter.current->name;
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io->u.iter.current = io->u.iter.current->next;
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if (jsV_getproperty(J, io->u.iter.target, name))
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return name;
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}
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return NULL;
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}
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/* Walk all the properties and delete them one by one for arrays */
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void jsV_resizearray(js_State *J, js_Object *obj, int newlen)
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{
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char buf[32];
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const char *s;
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int k;
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assert(!obj->u.a.simple);
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if (newlen < obj->u.a.length) {
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if (obj->u.a.length > obj->count * 2) {
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js_Object *it = jsV_newiterator(J, obj, 1);
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while ((s = jsV_nextiterator(J, it))) {
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k = jsV_numbertointeger(jsV_stringtonumber(J, s));
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if (k >= newlen && !strcmp(s, jsV_numbertostring(J, buf, k)))
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jsV_delproperty(J, obj, s);
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}
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} else {
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for (k = newlen; k < obj->u.a.length; ++k) {
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jsV_delproperty(J, obj, js_itoa(buf, k));
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}
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}
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}
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obj->u.a.length = newlen;
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}
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