1 files changed, 138 insertions, 0 deletions
diff --git a/libnetdata/adaptive_resortable_list/adaptive_resortable_list.h b/libnetdata/adaptive_resortable_list/adaptive_resortable_list.h
new file mode 100644
index 000000000..011ee73d9
--- /dev/null
+++ b/libnetdata/adaptive_resortable_list/adaptive_resortable_list.h
@@ -0,0 +1,138 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#include "../libnetdata.h"
+
+#ifndef NETDATA_ADAPTIVE_RESORTABLE_LIST_H
+#define NETDATA_ADAPTIVE_RESORTABLE_LIST_H 1
+
+#define ARL_ENTRY_FLAG_FOUND    0x01    // the entry has been found in the source data
+#define ARL_ENTRY_FLAG_EXPECTED 0x02    // the entry is expected by the program
+#define ARL_ENTRY_FLAG_DYNAMIC  0x04    // the entry was dynamically allocated, from source data
+
+typedef struct arl_entry {
+    char *name;             // the keywords
+    uint32_t hash;          // the hash of the keyword
+
+    void *dst;              // the dst to pass to the processor
+
+    uint8_t flags;          // ARL_ENTRY_FLAG_*
+
+    // the processor to do the job
+    void (*processor)(const char *name, uint32_t hash, const char *value, void *dst);
+
+    // double linked list for fast re-linkings
+    struct arl_entry *prev, *next;
+} ARL_ENTRY;
+
+typedef struct arl_base {
+    char *name;
+
+    size_t iteration;   // incremented on each iteration (arl_begin())
+    size_t found;       // the number of expected keywords found in this iteration
+    size_t expected;    // the number of expected keywords
+    size_t wanted;      // the number of wanted keywords
+                        // i.e. the number of keywords found and expected
+
+    size_t relinkings;  // the number of relinkings we have made so far
+
+    size_t allocated;   // the number of keywords allocated
+    size_t fred;        // the number of keywords cleaned up
+
+    size_t rechecks;    // the number of iterations between re-checks of the
+                        // wanted number of keywords
+                        // this is only needed in cases where the source
+                        // is having less lines over time.
+
+    size_t added;       // it is non-zero if new keywords have been added
+                        // this is only needed to detect new lines have
+                        // been added to the file, over time.
+
+#ifdef NETDATA_INTERNAL_CHECKS
+    size_t fast;        // the number of times we have taken the fast path
+    size_t slow;        // the number of times we have taken the slow path
+#endif
+
+    // the processor to do the job
+    void (*processor)(const char *name, uint32_t hash, const char *value, void *dst);
+
+    // the linked list of the keywords
+    ARL_ENTRY *head;
+
+    // since we keep the list of keywords sorted (as found in the source data)
+    // this is next keyword that we expect to find in the source data.
+    ARL_ENTRY *next_keyword;
+} ARL_BASE;
+
+// create a new ARL
+extern ARL_BASE *arl_create(const char *name, void (*processor)(const char *, uint32_t, const char *, void *), size_t rechecks);
+
+// free an ARL
+extern void arl_free(ARL_BASE *arl_base);
+
+// register an expected keyword to the ARL
+// together with its destination ( i.e. the output of the processor() )
+extern ARL_ENTRY *arl_expect_custom(ARL_BASE *base, const char *keyword, void (*processor)(const char *name, uint32_t hash, const char *value, void *dst), void *dst);
+#define arl_expect(base, keyword, dst) arl_expect_custom(base, keyword, NULL, dst)
+
+// an internal call to complete the check() call
+extern int arl_find_or_create_and_relink(ARL_BASE *base, const char *s, const char *value);
+
+// begin an ARL iteration
+extern void arl_begin(ARL_BASE *base);
+
+extern void arl_callback_str2ull(const char *name, uint32_t hash, const char *value, void *dst);
+extern void arl_callback_str2kernel_uint_t(const char *name, uint32_t hash, const char *value, void *dst);
+extern void arl_callback_ssize_t(const char *name, uint32_t hash, const char *value, void *dst);
+
+// check a keyword against the ARL
+// this is to be called for each keyword read from source data
+// s = the keyword, as collected
+// src = the src data to be passed to the processor
+// it is defined in the header file in order to be inlined
+static inline int arl_check(ARL_BASE *base, const char *keyword, const char *value) {
+    ARL_ENTRY *e = base->next_keyword;
+
+#ifdef NETDATA_INTERNAL_CHECKS
+    if(unlikely((base->fast + base->slow) % (base->expected + base->allocated) == 0 && (base->fast + base->slow) > (base->expected + base->allocated) * base->iteration))
+        info("ARL '%s': Did you forget to call arl_begin()?", base->name);
+#endif
+
+    // it should be the first entry (pointed by base->next_keyword)
+    if(likely(!strcmp(keyword, e->name))) {
+        // it is
+
+#ifdef NETDATA_INTERNAL_CHECKS
+        base->fast++;
+#endif
+
+        e->flags |= ARL_ENTRY_FLAG_FOUND;
+
+        // execute the processor
+        if(unlikely(e->dst)) {
+            e->processor(e->name, e->hash, value, e->dst);
+            base->found++;
+        }
+
+        // be prepared for the next iteration
+        base->next_keyword = e->next;
+        if(unlikely(!base->next_keyword))
+            base->next_keyword = base->head;
+
+        // stop if we collected all the values for this iteration
+        if(unlikely(base->found == base->wanted)) {
+            // fprintf(stderr, "FOUND ALL WANTED 2: found = %zu, wanted = %zu, expected %zu\n", base->found, base->wanted, base->expected);
+            return 1;
+        }
+
+        return 0;
+    }
+
+#ifdef NETDATA_INTERNAL_CHECKS
+    base->slow++;
+#endif
+
+    // we read from source, a not-expected keyword
+    return arl_find_or_create_and_relink(base, keyword, value);
+}
+
+#endif //NETDATA_ADAPTIVE_RESORTABLE_LIST_H