Initial Commit

src/frame_queue.c

@@ -0,0 +1,112 @@
+#include "frame_queue.h"
+
+#include <stdlib.h>
+#include <string.h>
+
+void frame_data_free(FrameData *frame) {
+    if (!frame) {
+        return;
+    }
+
+    free(frame->pixels);
+    memset(frame, 0, sizeof(*frame));
+}
+
+int frame_queue_init(FrameQueue *queue) {
+    if (!queue) {
+        return -1;
+    }
+
+    memset(queue, 0, sizeof(*queue));
+    queue->mutex = SDL_CreateMutex();
+    queue->cond = SDL_CreateCond();
+
+    return (queue->mutex && queue->cond) ? 0 : -1;
+}
+
+void frame_queue_clear(FrameQueue *queue) {
+    if (!queue || !queue->mutex) {
+        return;
+    }
+
+    SDL_LockMutex(queue->mutex);
+    while (queue->count > 0) {
+        frame_data_free(&queue->frames[queue->head]);
+        queue->head = (queue->head + 1) % FRAME_QUEUE_CAPACITY;
+        queue->count -= 1;
+    }
+    queue->head = 0;
+    SDL_UnlockMutex(queue->mutex);
+}
+
+void frame_queue_destroy(FrameQueue *queue) {
+    if (!queue) {
+        return;
+    }
+
+    frame_queue_clear(queue);
+    if (queue->cond) {
+        SDL_DestroyCond(queue->cond);
+    }
+    if (queue->mutex) {
+        SDL_DestroyMutex(queue->mutex);
+    }
+    memset(queue, 0, sizeof(*queue));
+}
+
+int frame_queue_push(FrameQueue *queue, FrameData *frame) {
+    int tail;
+
+    if (!queue || !frame || !queue->mutex) {
+        return -1;
+    }
+
+    SDL_LockMutex(queue->mutex);
+
+    if (queue->count == FRAME_QUEUE_CAPACITY) {
+        frame_data_free(&queue->frames[queue->head]);
+        queue->head = (queue->head + 1) % FRAME_QUEUE_CAPACITY;
+        queue->count -= 1;
+    }
+
+    tail = (queue->head + queue->count) % FRAME_QUEUE_CAPACITY;
+    queue->frames[tail] = *frame;
+    memset(frame, 0, sizeof(*frame));
+    queue->count += 1;
+    SDL_CondSignal(queue->cond);
+    SDL_UnlockMutex(queue->mutex);
+    return 0;
+}
+
+int frame_queue_pop_latest(FrameQueue *queue, FrameData *out) {
+    int latest_index;
+
+    if (!queue || !out || !queue->mutex) {
+        return 0;
+    }
+
+    SDL_LockMutex(queue->mutex);
+    if (queue->count == 0) {
+        SDL_UnlockMutex(queue->mutex);
+        return 0;
+    }
+
+    latest_index = (queue->head + queue->count - 1) % FRAME_QUEUE_CAPACITY;
+    *out = queue->frames[latest_index];
+    memset(&queue->frames[latest_index], 0, sizeof(queue->frames[latest_index]));
+
+    while (queue->count > 0) {
+        if (queue->head == latest_index) {
+            queue->head = 0;
+            queue->count = 0;
+            break;
+        }
+
+        frame_data_free(&queue->frames[queue->head]);
+        queue->head = (queue->head + 1) % FRAME_QUEUE_CAPACITY;
+        queue->count -= 1;
+    }
+
+    SDL_UnlockMutex(queue->mutex);
+    return 1;
+}