Squashed 'external/toxcore/c-toxcore/' content from commit 67badf69

git-subtree-dir: external/toxcore/c-toxcore
git-subtree-split: 67badf69416a74e74f6d7eb51dd96f37282b8455

toxcore/ping_array.c

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+/* SPDX-License-Identifier: GPL-3.0-or-later
+ * Copyright © 2016-2018 The TokTok team.
+ * Copyright © 2014 Tox project.
+ */
+
+/**
+ * Implementation of an efficient array to store that we pinged something.
+ */
+#include "ping_array.h"
+
+#include <stdlib.h>
+#include <string.h>
+
+#include "ccompat.h"
+#include "crypto_core.h"
+#include "mono_time.h"
+#include "util.h"
+
+typedef struct Ping_Array_Entry {
+    uint8_t *data;
+    uint32_t length;
+    uint64_t ping_time;
+    uint64_t ping_id;
+} Ping_Array_Entry;
+
+struct Ping_Array {
+    Ping_Array_Entry *entries;
+
+    uint32_t last_deleted; /* number representing the next entry to be deleted. */
+    uint32_t last_added;   /* number representing the last entry to be added. */
+    uint32_t total_size;   /* The length of entries */
+    uint32_t timeout;      /* The timeout after which entries are cleared. */
+};
+
+Ping_Array *ping_array_new(uint32_t size, uint32_t timeout)
+{
+    if (size == 0 || timeout == 0) {
+        return nullptr;
+    }
+
+    if ((size & (size - 1)) != 0) {
+        // Not a power of 2.
+        return nullptr;
+    }
+
+    Ping_Array *const empty_array = (Ping_Array *)calloc(1, sizeof(Ping_Array));
+
+    if (empty_array == nullptr) {
+        return nullptr;
+    }
+
+    empty_array->entries = (Ping_Array_Entry *)calloc(size, sizeof(Ping_Array_Entry));
+
+    if (empty_array->entries == nullptr) {
+        free(empty_array);
+        return nullptr;
+    }
+
+    empty_array->last_deleted = 0;
+    empty_array->last_added = 0;
+    empty_array->total_size = size;
+    empty_array->timeout = timeout;
+    return empty_array;
+}
+
+non_null()
+static void clear_entry(Ping_Array *array, uint32_t index)
+{
+    const Ping_Array_Entry empty = {nullptr};
+    free(array->entries[index].data);
+    array->entries[index] = empty;
+}
+
+void ping_array_kill(Ping_Array *array)
+{
+    if (array == nullptr) {
+        return;
+    }
+
+    while (array->last_deleted != array->last_added) {
+        const uint32_t index = array->last_deleted % array->total_size;
+        clear_entry(array, index);
+        ++array->last_deleted;
+    }
+
+    free(array->entries);
+    free(array);
+}
+
+/** Clear timed out entries. */
+non_null()
+static void ping_array_clear_timedout(Ping_Array *array, const Mono_Time *mono_time)
+{
+    while (array->last_deleted != array->last_added) {
+        const uint32_t index = array->last_deleted % array->total_size;
+
+        if (!mono_time_is_timeout(mono_time, array->entries[index].ping_time, array->timeout)) {
+            break;
+        }
+
+        clear_entry(array, index);
+        ++array->last_deleted;
+    }
+}
+
+uint64_t ping_array_add(Ping_Array *array, const Mono_Time *mono_time, const Random *rng,
+                        const uint8_t *data, uint32_t length)
+{
+    ping_array_clear_timedout(array, mono_time);
+    const uint32_t index = array->last_added % array->total_size;
+
+    if (array->entries[index].data != nullptr) {
+        array->last_deleted = array->last_added - array->total_size;
+        clear_entry(array, index);
+    }
+
+    array->entries[index].data = (uint8_t *)malloc(length);
+
+    if (array->entries[index].data == nullptr) {
+        return 0;
+    }
+
+    memcpy(array->entries[index].data, data, length);
+    array->entries[index].length = length;
+    array->entries[index].ping_time = mono_time_get(mono_time);
+    ++array->last_added;
+    uint64_t ping_id = random_u64(rng);
+    ping_id /= array->total_size;
+    ping_id *= array->total_size;
+    ping_id += index;
+
+    if (ping_id == 0) {
+        ping_id += array->total_size;
+    }
+
+    array->entries[index].ping_id = ping_id;
+    return ping_id;
+}
+
+int32_t ping_array_check(Ping_Array *array, const Mono_Time *mono_time, uint8_t *data,
+                         size_t length, uint64_t ping_id)
+{
+    if (ping_id == 0) {
+        return -1;
+    }
+
+    const uint32_t index = ping_id % array->total_size;
+
+    if (array->entries[index].ping_id != ping_id) {
+        return -1;
+    }
+
+    if (mono_time_is_timeout(mono_time, array->entries[index].ping_time, array->timeout)) {
+        return -1;
+    }
+
+    if (array->entries[index].length > length) {
+        return -1;
+    }
+
+    // TODO(iphydf): This can't happen? If it indeed can't, turn it into an assert.
+    if (array->entries[index].data == nullptr) {
+        return -1;
+    }
+
+    memcpy(data, array->entries[index].data, array->entries[index].length);
+    const uint32_t len = array->entries[index].length;
+    clear_entry(array, index);
+    return len;
+}