Merge commit 'dec0d4ec4153bf9fc2b78ae6c2df45b6ea8dde7a' as 'external/sdl/SDL'

external/sdl/SDL/src/SDL_dataqueue.c

@@ -0,0 +1,318 @@
+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2023 Sam Lantinga <slouken@libsdl.org>
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+#include "SDL_internal.h"
+
+#include "./SDL_dataqueue.h"
+
+typedef struct SDL_DataQueuePacket
+{
+    size_t datalen;                        /* bytes currently in use in this packet. */
+    size_t startpos;                       /* bytes currently consumed in this packet. */
+    struct SDL_DataQueuePacket *next;      /* next item in linked list. */
+    Uint8 data[SDL_VARIABLE_LENGTH_ARRAY]; /* packet data */
+} SDL_DataQueuePacket;
+
+struct SDL_DataQueue
+{
+    SDL_Mutex *lock;
+    SDL_DataQueuePacket *head; /* device fed from here. */
+    SDL_DataQueuePacket *tail; /* queue fills to here. */
+    SDL_DataQueuePacket *pool; /* these are unused packets. */
+    size_t packet_size;        /* size of new packets */
+    size_t queued_bytes;       /* number of bytes of data in the queue. */
+};
+
+static void SDL_FreeDataQueueList(SDL_DataQueuePacket *packet)
+{
+    while (packet) {
+        SDL_DataQueuePacket *next = packet->next;
+        SDL_free(packet);
+        packet = next;
+    }
+}
+
+SDL_DataQueue *SDL_CreateDataQueue(const size_t _packetlen, const size_t initialslack)
+{
+    SDL_DataQueue *queue = (SDL_DataQueue *)SDL_calloc(1, sizeof(SDL_DataQueue));
+
+    if (queue == NULL) {
+        SDL_OutOfMemory();
+    } else {
+        const size_t packetlen = _packetlen ? _packetlen : 1024;
+        const size_t wantpackets = (initialslack + (packetlen - 1)) / packetlen;
+        size_t i;
+
+        queue->packet_size = packetlen;
+
+        queue->lock = SDL_CreateMutex();
+        if (!queue->lock) {
+            SDL_free(queue);
+            return NULL;
+        }
+
+        for (i = 0; i < wantpackets; i++) {
+            SDL_DataQueuePacket *packet = (SDL_DataQueuePacket *)SDL_malloc(sizeof(SDL_DataQueuePacket) + packetlen);
+            if (packet) { /* don't care if this fails, we'll deal later. */
+                packet->datalen = 0;
+                packet->startpos = 0;
+                packet->next = queue->pool;
+                queue->pool = packet;
+            }
+        }
+    }
+
+    return queue;
+}
+
+void SDL_DestroyDataQueue(SDL_DataQueue *queue)
+{
+    if (queue) {
+        SDL_FreeDataQueueList(queue->head);
+        SDL_FreeDataQueueList(queue->pool);
+        SDL_DestroyMutex(queue->lock);
+        SDL_free(queue);
+    }
+}
+
+void SDL_ClearDataQueue(SDL_DataQueue *queue, const size_t slack)
+{
+    const size_t packet_size = queue ? queue->packet_size : 1;
+    const size_t slackpackets = (slack + (packet_size - 1)) / packet_size;
+    SDL_DataQueuePacket *packet;
+    SDL_DataQueuePacket *prev = NULL;
+    size_t i;
+
+    if (queue == NULL) {
+        return;
+    }
+
+    SDL_LockMutex(queue->lock);
+
+    packet = queue->head;
+
+    /* merge the available pool and the current queue into one list. */
+    if (packet) {
+        queue->tail->next = queue->pool;
+    } else {
+        packet = queue->pool;
+    }
+
+    /* Remove the queued packets from the device. */
+    queue->tail = NULL;
+    queue->head = NULL;
+    queue->queued_bytes = 0;
+    queue->pool = packet;
+
+    /* Optionally keep some slack in the pool to reduce memory allocation pressure. */
+    for (i = 0; packet && (i < slackpackets); i++) {
+        prev = packet;
+        packet = packet->next;
+    }
+
+    if (prev) {
+        prev->next = NULL;
+    } else {
+        queue->pool = NULL;
+    }
+
+    SDL_UnlockMutex(queue->lock);
+
+    SDL_FreeDataQueueList(packet); /* free extra packets */
+}
+
+/* You must hold queue->lock before calling this! */
+static SDL_DataQueuePacket *AllocateDataQueuePacket(SDL_DataQueue *queue)
+{
+    SDL_DataQueuePacket *packet;
+
+    SDL_assert(queue != NULL);
+
+    packet = queue->pool;
+    if (packet != NULL) {
+        /* we have one available in the pool. */
+        queue->pool = packet->next;
+    } else {
+        /* Have to allocate a new one! */
+        packet = (SDL_DataQueuePacket *)SDL_malloc(sizeof(SDL_DataQueuePacket) + queue->packet_size);
+        if (packet == NULL) {
+            return NULL;
+        }
+    }
+
+    packet->datalen = 0;
+    packet->startpos = 0;
+    packet->next = NULL;
+
+    SDL_assert((queue->head != NULL) == (queue->queued_bytes != 0));
+    if (queue->tail == NULL) {
+        queue->head = packet;
+    } else {
+        queue->tail->next = packet;
+    }
+    queue->tail = packet;
+    return packet;
+}
+
+int SDL_WriteToDataQueue(SDL_DataQueue *queue, const void *_data, const size_t _len)
+{
+    size_t len = _len;
+    const Uint8 *data = (const Uint8 *)_data;
+    const size_t packet_size = queue ? queue->packet_size : 0;
+    SDL_DataQueuePacket *orighead;
+    SDL_DataQueuePacket *origtail;
+    size_t origlen;
+    size_t datalen;
+
+    if (queue == NULL) {
+        return SDL_InvalidParamError("queue");
+    }
+
+    SDL_LockMutex(queue->lock);
+
+    orighead = queue->head;
+    origtail = queue->tail;
+    origlen = origtail ? origtail->datalen : 0;
+
+    while (len > 0) {
+        SDL_DataQueuePacket *packet = queue->tail;
+        SDL_assert(packet == NULL || (packet->datalen <= packet_size));
+        if (packet == NULL || (packet->datalen >= packet_size)) {
+            /* tail packet missing or completely full; we need a new packet. */
+            packet = AllocateDataQueuePacket(queue);
+            if (packet == NULL) {
+                /* uhoh, reset so we've queued nothing new, free what we can. */
+                if (origtail == NULL) {
+                    packet = queue->head; /* whole queue. */
+                } else {
+                    packet = origtail->next; /* what we added to existing queue. */
+                    origtail->next = NULL;
+                    origtail->datalen = origlen;
+                }
+                queue->head = orighead;
+                queue->tail = origtail;
+                queue->pool = NULL;
+
+                SDL_UnlockMutex(queue->lock);
+                SDL_FreeDataQueueList(packet); /* give back what we can. */
+                return SDL_OutOfMemory();
+            }
+        }
+
+        datalen = SDL_min(len, packet_size - packet->datalen);
+        SDL_memcpy(packet->data + packet->datalen, data, datalen);
+        data += datalen;
+        len -= datalen;
+        packet->datalen += datalen;
+        queue->queued_bytes += datalen;
+    }
+
+    SDL_UnlockMutex(queue->lock);
+
+    return 0;
+}
+
+size_t SDL_PeekIntoDataQueue(SDL_DataQueue *queue, void *_buf, const size_t _len)
+{
+    size_t len = _len;
+    Uint8 *buf = (Uint8 *)_buf;
+    Uint8 *ptr = buf;
+    SDL_DataQueuePacket *packet;
+
+    if (queue == NULL) {
+        return 0;
+    }
+
+    SDL_LockMutex(queue->lock);
+
+    for (packet = queue->head; len && packet; packet = packet->next) {
+        const size_t avail = packet->datalen - packet->startpos;
+        const size_t cpy = SDL_min(len, avail);
+        SDL_assert(queue->queued_bytes >= avail);
+
+        SDL_memcpy(ptr, packet->data + packet->startpos, cpy);
+        ptr += cpy;
+        len -= cpy;
+    }
+
+    SDL_UnlockMutex(queue->lock);
+
+    return (size_t)(ptr - buf);
+}
+
+size_t SDL_ReadFromDataQueue(SDL_DataQueue *queue, void *_buf, const size_t _len)
+{
+    size_t len = _len;
+    Uint8 *buf = (Uint8 *)_buf;
+    Uint8 *ptr = buf;
+    SDL_DataQueuePacket *packet;
+
+    if (queue == NULL) {
+        return 0;
+    }
+
+    SDL_LockMutex(queue->lock);
+
+    while ((len > 0) && ((packet = queue->head) != NULL)) {
+        const size_t avail = packet->datalen - packet->startpos;
+        const size_t cpy = SDL_min(len, avail);
+        SDL_assert(queue->queued_bytes >= avail);
+
+        SDL_memcpy(ptr, packet->data + packet->startpos, cpy);
+        packet->startpos += cpy;
+        ptr += cpy;
+        queue->queued_bytes -= cpy;
+        len -= cpy;
+
+        if (packet->startpos == packet->datalen) { /* packet is done, put it in the pool. */
+            queue->head = packet->next;
+            SDL_assert((packet->next != NULL) || (packet == queue->tail));
+            packet->next = queue->pool;
+            queue->pool = packet;
+        }
+    }
+
+    SDL_assert((queue->head != NULL) == (queue->queued_bytes != 0));
+
+    if (queue->head == NULL) {
+        queue->tail = NULL; /* in case we drained the queue entirely. */
+    }
+
+    SDL_UnlockMutex(queue->lock);
+
+    return (size_t)(ptr - buf);
+}
+
+size_t SDL_GetDataQueueSize(SDL_DataQueue *queue)
+{
+    size_t retval = 0;
+    if (queue) {
+        SDL_LockMutex(queue->lock);
+        retval = queue->queued_bytes;
+        SDL_UnlockMutex(queue->lock);
+    }
+    return retval;
+}
+
+SDL_Mutex *SDL_GetDataQueueMutex(SDL_DataQueue *queue)
+{
+    return queue ? queue->lock : NULL;
+}
+