From 56d571d2405284a7ab79dcea2ee677d0e75a2244 Mon Sep 17 00:00:00 2001 From: Michael R Sweet Date: Sun, 16 May 2004 13:45:56 +0000 Subject: [PATCH] Implement index sorting internally to avoid multithreading issues with qsort(). --- doc/reference.html | 10 --- mxml-index.c | 209 +++++++++++++++++++++++++-------------------- mxml.xml | 4 - 3 files changed, 117 insertions(+), 106 deletions(-) diff --git a/doc/reference.html b/doc/reference.html index b0ac0de..f39d325 100644 --- a/doc/reference.html +++ b/doc/reference.html @@ -1212,7 +1212,6 @@ union mxml_value_u

Variables

num_callbacks

@@ -1221,14 +1220,5 @@ union mxml_value_u 
 static int num_callbacks = 1;
- -

sort_attr_name

-
-

Description

-

Current attribute to sort on

-

Definition

-
-static const char * sort_attr_name;
-
diff --git a/mxml-index.c b/mxml-index.c index 0438b96..632a841 100644 --- a/mxml-index.c +++ b/mxml-index.c @@ -1,5 +1,5 @@ /* - * "$Id: mxml-index.c,v 1.2 2004/05/16 13:09:44 mike Exp $" + * "$Id: mxml-index.c,v 1.3 2004/05/16 13:45:56 mike Exp $" * * Index support code for Mini-XML, a small XML-like file parsing library. * @@ -23,9 +23,9 @@ * mxmlIndexNew() - Create a new index. * mxmlIndexReset() - Reset the enumeration/find pointer in the index and * return the first node in the index. - * sort_attr() - Sort by attribute value... - * sort_attr() - Sort by element name... - * sort_element_attr() - Sort by element name and attribute value... + * index_compare() - Compare two nodes. + * index_find() - Compare a node with index values. + * index_sort() - Sort the nodes in the index... */ /* @@ -40,18 +40,11 @@ * Sort functions... */ -static int index_compare(mxml_index_t *ind, const char *element, - const char *value, mxml_node_t *node); -static int sort_attr(const void *a, const void *b); -static int sort_element(const void *a, const void *b); -static int sort_element_attr(const void *a, const void *b); - - -/* - * Sort attribute... - */ - -static const char *sort_attr_name; /* Current attribute to sort on */ +static int index_compare(mxml_index_t *ind, mxml_node_t *first, + mxml_node_t *second); +static int index_find(mxml_index_t *ind, const char *element, + const char *value, mxml_node_t *node); +static void index_sort(mxml_index_t *ind, int left, int right); /* @@ -168,14 +161,14 @@ mxmlIndexFind(mxml_index_t *ind, /* I - Index to search */ { current = (first + last) / 2; - if ((diff = index_compare(ind, element, value, ind->nodes[current])) == 0) + if ((diff = index_find(ind, element, value, ind->nodes[current])) == 0) { /* * Found a match, move back to find the first... */ while (current > 0 && - !index_compare(ind, element, value, ind->nodes[current - 1])) + !index_find(ind, element, value, ind->nodes[current - 1])) current --; /* @@ -199,7 +192,7 @@ mxmlIndexFind(mxml_index_t *ind, /* I - Index to search */ current = (first + last) / 2; ind->cur_node = ind->num_nodes; - if (!index_compare(ind, element, value, ind->nodes[current])) + if (!index_find(ind, element, value, ind->nodes[current])) { /* * Found exactly one match... @@ -217,7 +210,7 @@ mxmlIndexFind(mxml_index_t *ind, /* I - Index to search */ } } else if (ind->cur_node < ind->num_nodes && - !index_compare(ind, element, value, ind->nodes[ind->cur_node])) + !index_find(ind, element, value, ind->nodes[ind->cur_node])) { /* * Return the next matching node... @@ -306,42 +299,8 @@ mxmlIndexNew(mxml_node_t *node, /* I - XML node tree */ * Sort nodes based upon the search criteria... */ - if (ind->num_nodes > 0) - { - if (!element && attr) - { - /* - * Sort based upon the element name and attribute value... - */ - - sort_attr_name = attr; - ind->attr = strdup(attr); - - qsort(ind->nodes, ind->num_nodes, sizeof(mxml_node_t *), - sort_element_attr); - } - else if (!element && !attr) - { - /* - * Sort based upon the element name... - */ - - qsort(ind->nodes, ind->num_nodes, sizeof(mxml_node_t *), - sort_element); - } - else if (attr) - { - /* - * Sort based upon the attribute value... - */ - - sort_attr_name = attr; - ind->attr = strdup(attr); - - qsort(ind->nodes, ind->num_nodes, sizeof(mxml_node_t *), - sort_attr); - } - } + if (ind->num_nodes > 1) + index_sort(ind, 0, ind->num_nodes - 1); /* * Return the new index... @@ -387,14 +346,53 @@ mxmlIndexReset(mxml_index_t *ind) /* I - Index to reset */ /* - * 'index_compare()' - Compare a node with index values. + * 'index_compare()' - Compare two nodes. */ static int /* O - Result of comparison */ index_compare(mxml_index_t *ind, /* I - Index */ - const char *element, /* I - Element name or NULL */ - const char *value, /* I - Attribute value or NULL */ - mxml_node_t *node) /* I - Node */ + mxml_node_t *first, /* I - First node */ + mxml_node_t *second) /* I - Second node */ +{ + int diff; /* Difference */ + + + /* + * Check the element name... + */ + + if ((diff = strcmp(first->value.element.name, + second->value.element.name)) != 0) + return (diff); + + /* + * Check the attribute value... + */ + + if (ind->attr) + { + if ((diff = strcmp(mxmlElementGetAttr(first, ind->attr), + mxmlElementGetAttr(second, ind->attr))) != 0) + return (diff); + } + + /* + * No difference, return 0... + */ + + return (0); +} + + +/* + * 'index_find()' - Compare a node with index values. + */ + +static int /* O - Result of comparison */ +index_find(mxml_index_t *ind, /* I - Index */ + const char *element, /* I - Element name or NULL */ + const char *value, /* I - Attribute value or NULL */ + mxml_node_t *node) /* I - Node */ { int diff; /* Difference */ @@ -428,51 +426,78 @@ index_compare(mxml_index_t *ind, /* I - Index */ /* - * 'sort_attr()' - Sort by attribute value... + * 'index_sort()' - Sort the nodes in the index... + * + * This function implements the classic quicksort algorithm... */ -static int /* O - Result of comparison */ -sort_attr(const void *a, /* I - First node */ - const void *b) /* I - Second node */ +static void +index_sort(mxml_index_t *ind, /* I - Index to sort */ + int left, /* I - Left node in partition */ + int right) /* I - Right node in partition */ { - return (strcmp(mxmlElementGetAttr((mxml_node_t *)a, sort_attr_name), - mxmlElementGetAttr((mxml_node_t *)b, sort_attr_name))); -} + mxml_node_t *pivot, /* Pivot node */ + *temp; /* Swap node */ + int templ, /* Temporary left node */ + tempr; /* Temporary right node */ -/* - * 'sort_element()' - Sort by element name... - */ + /* + * Sort the pivot in the current partition... + */ -static int /* O - Result of comparison */ -sort_element(const void *a, /* I - First node */ - const void *b) /* I - Second node */ -{ - return (strcmp(((mxml_node_t *)a)->value.element.name, - ((mxml_node_t *)b)->value.element.name)); -} + pivot = ind->nodes[left]; + + for (templ = left, tempr = right; templ < tempr;) + { + /* + * Move left while left node <= pivot node... + */ + while ((templ < right) && + index_compare(ind, ind->nodes[templ], pivot) <= 0) + templ ++; -/* - * 'sort_element_attr()' - Sort by element name and attribute value... - */ + /* + * Move right while right node > pivot node... + */ -static int /* O - Result of comparison */ -sort_element_attr(const void *a, /* I - First node */ - const void *b) /* I - Second node */ -{ - int i; /* Result of comparison */ + while ((tempr > left) && + index_compare(ind, ind->nodes[tempr], pivot) > 0) + tempr --; + /* + * Swap nodes if needed... + */ - if ((i = strcmp(((mxml_node_t *)a)->value.element.name, - ((mxml_node_t *)b)->value.element.name)) != 0) - return (i); - else - return (strcmp(mxmlElementGetAttr((mxml_node_t *)a, sort_attr_name), - mxmlElementGetAttr((mxml_node_t *)b, sort_attr_name))); + if (templ < tempr) + { + temp = ind->nodes[templ]; + ind->nodes[templ] = ind->nodes[tempr]; + ind->nodes[tempr] = temp; + } + } + + /* + * When we get here, the right (tempr) node is the new position for the + * pivot node... + */ + + ind->nodes[left] = ind->nodes[tempr]; + ind->nodes[tempr] = pivot; + + /* + * Recursively sort the left and right partitions as needed... + */ + + if (left < (tempr - 1)) + index_sort(ind, left, tempr - 1); + + if (right > (tempr + 1)) + index_sort(ind, tempr + 1, right); } /* - * End of "$Id: mxml-index.c,v 1.2 2004/05/16 13:09:44 mike Exp $". + * End of "$Id: mxml-index.c,v 1.3 2004/05/16 13:45:56 mike Exp $". */ diff --git a/mxml.xml b/mxml.xml index 83938de..a19c082 100644 --- a/mxml.xml +++ b/mxml.xml @@ -841,8 +841,4 @@ the walk to the node's children. static int - - static const char * - Current attribute to sort on -