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-rw-r--r--dimension/parse.c455
1 files changed, 309 insertions, 146 deletions
diff --git a/dimension/parse.c b/dimension/parse.c
index 5756659..bc57cef 100644
--- a/dimension/parse.c
+++ b/dimension/parse.c
@@ -20,6 +20,313 @@
#include "parse.h"
#include "utility.h"
+/*
+ * Symbol table
+ */
+
+typedef struct dmnsn_patricia_trie {
+ char *prefix;
+
+ bool leaf;
+ dmnsn_array *children;
+ dmnsn_astnode value;
+} dmnsn_patricia_trie;
+
+void
+dmnsn_delete_patricia_trie(dmnsn_patricia_trie *trie)
+{
+ if (trie) {
+ free(trie->prefix);
+
+ if (trie->leaf)
+ dmnsn_delete_astnode(trie->value);
+
+ unsigned int i;
+ for (i = 0; i < dmnsn_array_size(trie->children); ++i) {
+ dmnsn_patricia_trie *subtrie;
+ dmnsn_array_get(trie->children, i, &subtrie);
+ dmnsn_delete_patricia_trie(subtrie);
+ }
+ dmnsn_delete_array(trie->children);
+
+ free(trie);
+ }
+}
+
+dmnsn_patricia_trie *
+dmnsn_new_patricia_trie()
+{
+ dmnsn_patricia_trie *trie = malloc(sizeof(dmnsn_patricia_trie));
+ if (!trie) {
+ dmnsn_error(DMNSN_SEVERITY_HIGH, "Couldn't allocate PATRICIA trie.");
+ }
+
+ trie->prefix = strdup("");
+ if (!trie->prefix) {
+ dmnsn_error(DMNSN_SEVERITY_HIGH, "Couldn't allocate PATRICIA trie.");
+ }
+
+ trie->leaf = false;
+ trie->children = dmnsn_new_array(sizeof(dmnsn_patricia_trie *));
+ return trie;
+}
+
+void
+dmnsn_patricia_insert(dmnsn_patricia_trie *trie,
+ const char *id, dmnsn_astnode value)
+{
+ /*
+ * PATRICIA trie insertion: O(k), where k is the length of the longest string
+ * in the trie.
+ */
+
+ ++*value.refcount;
+
+ while (true) {
+ if (trie->prefix[0] == '\0'&& !trie->leaf
+ && dmnsn_array_size(trie->children) == 0)
+ {
+ /* Replace an empty tree with a single-element tree */
+ trie->prefix = realloc(trie->prefix, strlen(id) + 1);
+ if (!trie->prefix)
+ dmnsn_error(DMNSN_SEVERITY_HIGH, "Couldn't allocate room for prefix.");
+ strcpy(trie->prefix, id);
+
+ trie->leaf = true;
+ trie->value = value;
+ break;
+ }
+
+ char *prefix = trie->prefix;
+ while (*prefix == *id && *prefix && *id) {
+ ++prefix;
+ ++id;
+ }
+
+ if (*id == '\0' && *prefix == '\0') {
+ /* Complete match */
+ if (trie->leaf) {
+ dmnsn_delete_astnode(trie->value);
+ }
+ trie->leaf = true;
+ trie->value = value;
+ break;
+ } else if (*prefix == '\0') {
+ /* Partial match; id starts with prefix */
+ size_t i, size = dmnsn_array_size(trie->children);
+ for (i = 0; i < size; ++i) {
+ dmnsn_patricia_trie *subtrie;
+ dmnsn_array_get(trie->children, i, &subtrie);
+
+ if (subtrie->prefix[0] == id[0]) {
+ trie = subtrie;
+ break;
+ }
+ }
+
+ if (i == size) {
+ /* No submatch found, add a new child */
+ dmnsn_patricia_trie *subtrie = dmnsn_new_patricia_trie();
+ dmnsn_array_push(trie->children, &subtrie);
+ trie = subtrie;
+ }
+ } else {
+ /* Split the tree */
+ dmnsn_patricia_trie *copy = dmnsn_new_patricia_trie();
+ copy->prefix = realloc(copy->prefix, strlen(prefix) + 1);
+ strcpy(copy->prefix, prefix);
+ *prefix = '\0';
+
+ if (trie->leaf) {
+ copy->leaf = true;
+ copy->value = trie->value;
+ trie->leaf = false;
+ }
+
+ dmnsn_delete_array(copy->children);
+ copy->children = trie->children;
+ trie->children = dmnsn_new_array(sizeof(dmnsn_patricia_trie *));
+
+ dmnsn_patricia_trie *subtrie = dmnsn_new_patricia_trie();
+ dmnsn_array_push(trie->children, &copy);
+ dmnsn_array_push(trie->children, &subtrie);
+ trie = subtrie;
+ }
+ }
+}
+
+bool
+dmnsn_patricia_remove(dmnsn_patricia_trie *trie, const char *id)
+{
+ /*
+ * PATRICIA trie removal: O(k), where k is the length of the longest string
+ * in the trie.
+ *
+ * This implementation doesn't actually collapse the tree back upwards if a
+ * node is left with only one child, to reduce complexity.
+ */
+
+ size_t len = strlen(trie->prefix);
+ if (strncmp(id, trie->prefix, len) != 0)
+ return false;
+ id += len;
+
+ while (true) {
+ if (*id == '\0' && trie->leaf) {
+ dmnsn_delete_astnode(trie->value);
+ trie->leaf = false;
+ return true;
+ } else {
+ size_t i, size = dmnsn_array_size(trie->children);
+ for (i = 0; i < size; ++i) {
+ dmnsn_patricia_trie *subtrie;
+ dmnsn_array_get(trie->children, i, &subtrie);
+
+ len = strlen(subtrie->prefix);
+ if (strncmp(id, subtrie->prefix, len) == 0) {
+ trie = subtrie;
+ id += len;
+ break;
+ }
+ }
+
+ if (i == size)
+ break;
+ }
+ }
+
+ return false;
+}
+
+dmnsn_astnode *
+dmnsn_patricia_find(dmnsn_patricia_trie *trie, const char *id)
+{
+ /*
+ * PATRICIA trie search: O(k), where k is the length of the longest string
+ * in the trie.
+ */
+
+ size_t len = strlen(trie->prefix);
+ if (strncmp(id, trie->prefix, len) != 0)
+ return NULL;
+ id += len;
+
+ while (true) {
+ if (*id == '\0' && trie->leaf) {
+ return &trie->value;
+ } else {
+ size_t i, size = dmnsn_array_size(trie->children);
+ for (i = 0; i < size; ++i) {
+ dmnsn_patricia_trie *subtrie;
+ dmnsn_array_get(trie->children, i, &subtrie);
+
+ len = strlen(subtrie->prefix);
+ if (strncmp(id, subtrie->prefix, len) == 0) {
+ trie = subtrie;
+ id += len;
+ break;
+ }
+ }
+
+ if (i == size)
+ break;
+ }
+ }
+
+ return NULL;
+}
+
+dmnsn_symbol_table *
+dmnsn_new_symbol_table()
+{
+ dmnsn_symbol_table *symtable = dmnsn_new_array(sizeof(dmnsn_patricia_trie *));
+ dmnsn_push_scope(symtable);
+ return symtable;
+}
+
+void
+dmnsn_delete_symbol_table(dmnsn_symbol_table *symtable)
+{
+ while (dmnsn_array_size(symtable) > 0) {
+ dmnsn_pop_scope(symtable);
+ }
+ dmnsn_delete_array(symtable);
+}
+
+void
+dmnsn_push_scope(dmnsn_symbol_table *symtable)
+{
+ dmnsn_patricia_trie *scope = dmnsn_new_patricia_trie();
+ dmnsn_array_push(symtable, &scope);
+}
+
+void dmnsn_pop_scope(dmnsn_symbol_table *symtable)
+{
+ dmnsn_patricia_trie *scope;
+ dmnsn_array_pop(symtable, &scope);
+ dmnsn_delete_patricia_trie(scope);
+}
+
+void dmnsn_local_symbol(dmnsn_symbol_table *symtable,
+ const char *id, dmnsn_astnode value)
+{
+ dmnsn_patricia_trie *trie;
+ dmnsn_array_get(symtable, dmnsn_array_size(symtable) - 1, &trie);
+ dmnsn_patricia_insert(trie, id, value);
+}
+
+void
+dmnsn_declare_symbol(dmnsn_symbol_table *symtable,
+ const char *id, dmnsn_astnode value)
+{
+ dmnsn_astnode *node = dmnsn_find_symbol(symtable, id);
+ if (node) {
+ /* Always update the most local symbol */
+ dmnsn_delete_astnode(*node);
+ ++*value.refcount;
+ *node = value;
+ } else {
+ /* but create new ones at the least local scope */
+ dmnsn_patricia_trie *trie;
+ dmnsn_array_get(symtable, 0, &trie);
+ dmnsn_patricia_insert(trie, id, value);
+ }
+}
+
+void
+dmnsn_undef_symbol(dmnsn_symbol_table *symtable, const char *id)
+{
+ unsigned int i;
+ for (i = 0; i < dmnsn_array_size(symtable); ++i) {
+ dmnsn_patricia_trie *trie;
+ dmnsn_array_get(symtable, dmnsn_array_size(symtable) - i - 1, &trie);
+ if (dmnsn_patricia_remove(trie, id))
+ break;
+ }
+}
+
+dmnsn_astnode *
+dmnsn_find_symbol(dmnsn_symbol_table *symtable, const char *id)
+{
+ dmnsn_astnode *symbol = NULL;
+
+ unsigned int i;
+ for (i = 0; i < dmnsn_array_size(symtable); ++i) {
+ dmnsn_patricia_trie *trie;
+ dmnsn_array_get(symtable, dmnsn_array_size(symtable) - i - 1, &trie);
+
+ symbol = dmnsn_patricia_find(trie, id);
+ if (symbol)
+ break;
+ }
+
+ return symbol;
+}
+
+/*
+ * Abstract syntax tree
+ */
+
static dmnsn_astnode
dmnsn_new_astnode(dmnsn_astnode_type type)
{
@@ -132,6 +439,8 @@ dmnsn_new_ast_string(const char *value)
{
dmnsn_astnode astnode = dmnsn_new_astnode(DMNSN_AST_STRING);
astnode.ptr = strdup(value);
+ if (!astnode.ptr)
+ dmnsn_error(DMNSN_SEVERITY_HIGH, "Couldn't allocate room for string.");
return astnode;
}
@@ -161,152 +470,6 @@ dmnsn_delete_astree(dmnsn_astree *astree)
}
}
-/* TODO: use a hash table for symbol tables rather than an array */
-
-typedef struct dmnsn_symbol {
- char *id;
- dmnsn_astnode value;
-} dmnsn_symbol;
-
-dmnsn_symbol_table *
-dmnsn_new_symbol_table()
-{
- dmnsn_symbol_table *symtable = dmnsn_new_array(sizeof(dmnsn_array *));
- dmnsn_push_scope(symtable);
- return symtable;
-}
-
-static void
-dmnsn_delete_symbol(dmnsn_symbol symbol)
-{
- free(symbol.id);
- dmnsn_delete_astnode(symbol.value);
-}
-
-static void
-dmnsn_delete_scope(dmnsn_array *scope)
-{
- while (dmnsn_array_size(scope) > 0) {
- dmnsn_symbol symbol;
- dmnsn_array_pop(scope, &symbol);
- dmnsn_delete_symbol(symbol);
- }
- dmnsn_delete_array(scope);
-}
-
-void
-dmnsn_delete_symbol_table(dmnsn_symbol_table *symtable)
-{
- while (dmnsn_array_size(symtable) > 0) {
- dmnsn_array *scope;
- dmnsn_array_pop(symtable, &scope);
- dmnsn_delete_scope(scope);
- }
- dmnsn_delete_array(symtable);
-}
-
-void
-dmnsn_push_scope(dmnsn_symbol_table *symtable)
-{
- dmnsn_array *scope = dmnsn_new_array(sizeof(dmnsn_symbol));
- dmnsn_array_push(symtable, &scope);
-}
-
-void dmnsn_pop_scope(dmnsn_symbol_table *symtable)
-{
- dmnsn_array *scope;
- dmnsn_array_pop(symtable, &scope);
- dmnsn_delete_scope(scope);
-}
-
-void dmnsn_local_symbol(dmnsn_symbol_table *symtable,
- const char *id, dmnsn_astnode value)
-{
- ++*value.refcount;
-
- dmnsn_array *scope;
- dmnsn_array_get(symtable, dmnsn_array_size(symtable) - 1, &scope);
-
- unsigned int i;
- for (i = 0; i < dmnsn_array_size(scope); ++i) {
- dmnsn_symbol *symbol = dmnsn_array_at(scope,
- dmnsn_array_size(scope) - i - 1);
-
- if (strcmp(id, symbol->id) == 0) {
- dmnsn_delete_astnode(symbol->value);
- symbol->value = value;
- return;
- }
- }
-
- dmnsn_symbol symbol = { .id = strdup(id), .value = value };
- dmnsn_array_push(scope, &symbol);
-}
-
-void
-dmnsn_declare_symbol(dmnsn_symbol_table *symtable,
- const char *id, dmnsn_astnode value)
-{
- ++*value.refcount;
-
- dmnsn_astnode *node = dmnsn_find_symbol(symtable, id);
- if (node) {
- /* Always update the most local symbol */
- dmnsn_delete_astnode(*node);
- *node = value;
- } else {
- /* but create new ones at the least local scope */
- dmnsn_array *scope;
- dmnsn_array_get(symtable, 0, &scope);
-
- dmnsn_symbol symbol = { .id = strdup(id), .value = value };
- dmnsn_array_push(scope, &symbol);
- }
-}
-
-void
-dmnsn_undef_symbol(dmnsn_symbol_table *symtable, const char *id)
-{
- unsigned int i;
- for (i = 0; i < dmnsn_array_size(symtable); ++i) {
- dmnsn_array *scope;
- dmnsn_array_get(symtable, dmnsn_array_size(symtable) - i - 1, &scope);
-
- unsigned int j;
- for (j = 0; j < dmnsn_array_size(scope); ++j) {
- dmnsn_symbol *symbol = dmnsn_array_at(scope,
- dmnsn_array_size(scope) - j - 1);
-
- if (strcmp(id, symbol->id) == 0) {
- dmnsn_delete_symbol(*symbol);
- dmnsn_array_remove(scope, dmnsn_array_size(scope) - j - 1);
- return;
- }
- }
- }
-}
-
-dmnsn_astnode *
-dmnsn_find_symbol(dmnsn_symbol_table *symtable, const char *id)
-{
- unsigned int i;
- for (i = 0; i < dmnsn_array_size(symtable); ++i) {
- dmnsn_array *scope;
- dmnsn_array_get(symtable, dmnsn_array_size(symtable) - i - 1, &scope);
-
- unsigned int j;
- for (j = 0; j < dmnsn_array_size(scope); ++j) {
- dmnsn_symbol *symbol = dmnsn_array_at(scope,
- dmnsn_array_size(scope) - j - 1);
-
- if (strcmp(id, symbol->id) == 0)
- return &symbol->value;
- }
- }
-
- return NULL;
-}
-
static dmnsn_astnode
dmnsn_copy_astnode(dmnsn_astnode astnode)
{
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-14 16:44:44 +0000