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atom: separate lookup logic from atom_intern 

This would allow us to add a non-interning xkb_atom_lookup function.

Signed-off-by: Ran Benita <ran234@gmail.com>
master
Ran Benita 2012-08-31 18:47:28 +03:00
parent f205d0f9b6
commit 651e1dab04
1 changed files with 51 additions and 31 deletions
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76
src/atom.c
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@ -139,6 +139,52 @@ atom_strdup(struct atom_table *table, xkb_atom_t atom)
return strdup_safe(atom_text(table, atom));
}
static bool
find_node_pointer(struct atom_table *table, const char *string,
struct atom_node ***np_out, unsigned int *fingerprint_out)
{
struct atom_node **np;
unsigned i;
int comp;
unsigned int fp = 0;
size_t len;
bool found = false;
len = strlen(string);
np = &table->root;
for (i = 0; i < (len + 1) / 2; i++) {
fp = fp * 27 + string[i];
fp = fp * 27 + string[len - 1 - i];
}
while (*np) {
if (fp < (*np)->fingerprint) {
np = &((*np)->left);
}
else if (fp > (*np)->fingerprint) {
np = &((*np)->right);
}
else {
/* now start testing the strings */
comp = strncmp(string, (*np)->string, len);
if (comp < 0 || (comp == 0 && len < strlen((*np)->string))) {
np = &((*np)->left);
}
else if (comp > 0) {
np = &((*np)->right);
}
else {
found = true;
break;
}
}
}
*fingerprint_out = fp;
*np_out = np;
return found;
}
/*
* If steal is true, we do not strdup @string; therefore it must be
* dynamically allocated, not be free'd by the caller and not be used
@ -150,42 +196,16 @@ atom_intern(struct atom_table *table, const char *string,
{
struct atom_node **np;
struct atom_node *nd;
unsigned i;
int comp;
unsigned int fp = 0;
size_t len;
unsigned int fp;
if (!string)
return XKB_ATOM_NONE;
len = strlen(string);
np = &table->root;
for (i = 0; i < (len + 1) / 2; i++) {
fp = fp * 27 + string[i];
fp = fp * 27 + string[len - 1 - i];
}
while (*np) {
if (fp < (*np)->fingerprint)
np = &((*np)->left);
else if (fp > (*np)->fingerprint)
np = &((*np)->right);
else {
/* now start testing the strings */
comp = strncmp(string, (*np)->string, len);
if (comp < 0 || (comp == 0 && len < strlen((*np)->string))) {
np = &((*np)->left);
}
else if (comp > 0) {
np = &((*np)->right);
}
else {
if (find_node_pointer(table, string, &np, &fp)) {
if (steal)
free(UNCONSTIFY(string));
return (*np)->atom;
}
}
}
nd = malloc(sizeof(*nd));
if (!nd)