For #1659, #307, add ffmpeg-4.2-fit for rtc

trunk/3rdparty/ffmpeg-4.2-fit/libavutil/fifo.c

@@ -0,0 +1,240 @@
+/*
+ * a very simple circular buffer FIFO implementation
+ * Copyright (c) 2000, 2001, 2002 Fabrice Bellard
+ * Copyright (c) 2006 Roman Shaposhnik
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "avassert.h"
+#include "common.h"
+#include "fifo.h"
+
+static AVFifoBuffer *fifo_alloc_common(void *buffer, size_t size)
+{
+    AVFifoBuffer *f;
+    if (!buffer)
+        return NULL;
+    f = av_mallocz(sizeof(AVFifoBuffer));
+    if (!f) {
+        av_free(buffer);
+        return NULL;
+    }
+    f->buffer = buffer;
+    f->end    = f->buffer + size;
+    av_fifo_reset(f);
+    return f;
+}
+
+AVFifoBuffer *av_fifo_alloc(unsigned int size)
+{
+    void *buffer = av_malloc(size);
+    return fifo_alloc_common(buffer, size);
+}
+
+AVFifoBuffer *av_fifo_alloc_array(size_t nmemb, size_t size)
+{
+    void *buffer = av_malloc_array(nmemb, size);
+    return fifo_alloc_common(buffer, nmemb * size);
+}
+
+void av_fifo_free(AVFifoBuffer *f)
+{
+    if (f) {
+        av_freep(&f->buffer);
+        av_free(f);
+    }
+}
+
+void av_fifo_freep(AVFifoBuffer **f)
+{
+    if (f) {
+        av_fifo_free(*f);
+        *f = NULL;
+    }
+}
+
+void av_fifo_reset(AVFifoBuffer *f)
+{
+    f->wptr = f->rptr = f->buffer;
+    f->wndx = f->rndx = 0;
+}
+
+int av_fifo_size(const AVFifoBuffer *f)
+{
+    return (uint32_t)(f->wndx - f->rndx);
+}
+
+int av_fifo_space(const AVFifoBuffer *f)
+{
+    return f->end - f->buffer - av_fifo_size(f);
+}
+
+int av_fifo_realloc2(AVFifoBuffer *f, unsigned int new_size)
+{
+    unsigned int old_size = f->end - f->buffer;
+
+    if (old_size < new_size) {
+        int len          = av_fifo_size(f);
+        AVFifoBuffer *f2 = av_fifo_alloc(new_size);
+
+        if (!f2)
+            return AVERROR(ENOMEM);
+        av_fifo_generic_read(f, f2->buffer, len, NULL);
+        f2->wptr += len;
+        f2->wndx += len;
+        av_free(f->buffer);
+        *f = *f2;
+        av_free(f2);
+    }
+    return 0;
+}
+
+int av_fifo_grow(AVFifoBuffer *f, unsigned int size)
+{
+    unsigned int old_size = f->end - f->buffer;
+    if(size + (unsigned)av_fifo_size(f) < size)
+        return AVERROR(EINVAL);
+
+    size += av_fifo_size(f);
+
+    if (old_size < size)
+        return av_fifo_realloc2(f, FFMAX(size, 2*old_size));
+    return 0;
+}
+
+/* src must NOT be const as it can be a context for func that may need
+ * updating (like a pointer or byte counter) */
+int av_fifo_generic_write(AVFifoBuffer *f, void *src, int size,
+                          int (*func)(void *, void *, int))
+{
+    int total = size;
+    uint32_t wndx= f->wndx;
+    uint8_t *wptr= f->wptr;
+
+    do {
+        int len = FFMIN(f->end - wptr, size);
+        if (func) {
+            len = func(src, wptr, len);
+            if (len <= 0)
+                break;
+        } else {
+            memcpy(wptr, src, len);
+            src = (uint8_t *)src + len;
+        }
+// Write memory barrier needed for SMP here in theory
+        wptr += len;
+        if (wptr >= f->end)
+            wptr = f->buffer;
+        wndx    += len;
+        size    -= len;
+    } while (size > 0);
+    f->wndx= wndx;
+    f->wptr= wptr;
+    return total - size;
+}
+
+int av_fifo_generic_peek_at(AVFifoBuffer *f, void *dest, int offset, int buf_size, void (*func)(void*, void*, int))
+{
+    uint8_t *rptr = f->rptr;
+
+    av_assert2(offset >= 0);
+
+    /*
+     * *ndx are indexes modulo 2^32, they are intended to overflow,
+     * to handle *ndx greater than 4gb.
+     */
+    av_assert2(buf_size + (unsigned)offset <= f->wndx - f->rndx);
+
+    if (offset >= f->end - rptr)
+        rptr += offset - (f->end - f->buffer);
+    else
+        rptr += offset;
+
+    while (buf_size > 0) {
+        int len;
+
+        if (rptr >= f->end)
+            rptr -= f->end - f->buffer;
+
+        len = FFMIN(f->end - rptr, buf_size);
+        if (func)
+            func(dest, rptr, len);
+        else {
+            memcpy(dest, rptr, len);
+            dest = (uint8_t *)dest + len;
+        }
+
+        buf_size -= len;
+        rptr     += len;
+    }
+
+    return 0;
+}
+
+int av_fifo_generic_peek(AVFifoBuffer *f, void *dest, int buf_size,
+                         void (*func)(void *, void *, int))
+{
+// Read memory barrier needed for SMP here in theory
+    uint8_t *rptr = f->rptr;
+
+    do {
+        int len = FFMIN(f->end - rptr, buf_size);
+        if (func)
+            func(dest, rptr, len);
+        else {
+            memcpy(dest, rptr, len);
+            dest = (uint8_t *)dest + len;
+        }
+// memory barrier needed for SMP here in theory
+        rptr += len;
+        if (rptr >= f->end)
+            rptr -= f->end - f->buffer;
+        buf_size -= len;
+    } while (buf_size > 0);
+
+    return 0;
+}
+
+int av_fifo_generic_read(AVFifoBuffer *f, void *dest, int buf_size,
+                         void (*func)(void *, void *, int))
+{
+// Read memory barrier needed for SMP here in theory
+    do {
+        int len = FFMIN(f->end - f->rptr, buf_size);
+        if (func)
+            func(dest, f->rptr, len);
+        else {
+            memcpy(dest, f->rptr, len);
+            dest = (uint8_t *)dest + len;
+        }
+// memory barrier needed for SMP here in theory
+        av_fifo_drain(f, len);
+        buf_size -= len;
+    } while (buf_size > 0);
+    return 0;
+}
+
+/** Discard data from the FIFO. */
+void av_fifo_drain(AVFifoBuffer *f, int size)
+{
+    av_assert2(av_fifo_size(f) >= size);
+    f->rptr += size;
+    if (f->rptr >= f->end)
+        f->rptr -= f->end - f->buffer;
+    f->rndx += size;
+}