MINOR: cache: Improve accept_encoding_normalizer
Turn the "Accept-Encoding" value to lower case before processing it.
Calculate the CRC on every token instead of a sorted concatenation of
them all (in order to avoir copying them) then XOR all the CRCs into a
single hash (while ignoring duplicates).
diff --git a/src/cache.c b/src/cache.c
index 6489f16..1b86ccd 100644
--- a/src/cache.c
+++ b/src/cache.c
@@ -1791,10 +1791,14 @@
int accept_encoding_cmp(const void *a, const void *b)
{
- const struct ist ist_a = *(const struct ist*)a;
- const struct ist ist_b = *(const struct ist*)b;
+ unsigned int int_a = *(unsigned int*)a;
+ unsigned int int_b = *(unsigned int*)b;
- return istdiff(ist_a, ist_b);
+ if (int_a < int_b)
+ return -1;
+ if (int_a > int_b)
+ return 1;
+ return 0;
}
#define ACCEPT_ENCODING_MAX_ENTRIES 16
@@ -1804,33 +1808,38 @@
* for the newly constructed buffer.
* Returns 0 in case of success.
*/
-static int accept_encoding_normalizer(struct ist value, char *buf, unsigned int *buf_len)
+static int accept_encoding_normalizer(struct ist full_value, char *buf, unsigned int *buf_len)
{
- struct ist values[ACCEPT_ENCODING_MAX_ENTRIES] = {{}};
+ unsigned int values[ACCEPT_ENCODING_MAX_ENTRIES] = {};
size_t count = 0;
char *comma = NULL;
- struct buffer *trash = get_trash_chunk();
- int hash_value = 0;
+ unsigned int hash_value = 0;
+ unsigned int prev = 0, curr = 0;
+
+ /* Turn accept-encoding value to lower case */
+ full_value = ist2bin_lc(istptr(full_value), full_value);
/* The hash will be built out of a sorted list of accepted encodings. */
- while (count < (ACCEPT_ENCODING_MAX_ENTRIES - 1) && (comma = istchr(value, ',')) != NULL) {
- size_t length = comma - istptr(value);
+ while (count < (ACCEPT_ENCODING_MAX_ENTRIES - 1) && (comma = istchr(full_value, ',')) != NULL) {
+ size_t length = comma - istptr(full_value);
- values[count++] = isttrim(value, length);
- value = istadv(value, length + 1);
- }
- values[count++] = value;
+ values[count++] = hash_crc32(istptr(full_value), length);
- if (count == ACCEPT_ENCODING_MAX_ENTRIES)
- return 1;
+ full_value = istadv(full_value, length + 1);
- /* Sort the values alphabetically. */
- qsort(values, count, sizeof(struct ist), &accept_encoding_cmp);
+ }
+ values[count++] = hash_crc32(istptr(full_value), istlen(full_value));
- while (count)
- chunk_istcat(trash, values[--count]);
+ /* Sort the values alphabetically. */
+ qsort(values, count, sizeof(*values), &accept_encoding_cmp);
- hash_value = hash_crc32(b_orig(trash), b_data(trash));
+ while (count) {
+ curr = values[--count];
+ if (curr != prev) {
+ hash_value ^= curr;
+ }
+ prev = curr;
+ }
memcpy(buf, &hash_value, sizeof(hash_value));
*buf_len = sizeof(hash_value);