mirror of
https://github.com/webmproject/libwebp.git
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216 lines
6.8 KiB
C
216 lines
6.8 KiB
C
// Copyright 2011 Google Inc. All Rights Reserved.
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//
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// This code is licensed under the same terms as WebM:
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// Software License Agreement: http://www.webmproject.org/license/software/
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// Additional IP Rights Grant: http://www.webmproject.org/license/additional/
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// -----------------------------------------------------------------------------
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//
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// Everything about WebPDecBuffer
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//
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// Author: Skal (pascal.massimino@gmail.com)
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#include <stdlib.h>
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#include "./vp8i.h"
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#include "./webpi.h"
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#include "../utils/utils.h"
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#if defined(__cplusplus) || defined(c_plusplus)
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extern "C" {
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#endif
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//------------------------------------------------------------------------------
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// WebPDecBuffer
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// Number of bytes per pixel for the different color-spaces.
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static const int kModeBpp[MODE_LAST] = {
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3, 4, 3, 4, 4, 2, 2,
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4, 4, 4, 2, // pre-multiplied modes
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1, 1 };
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// Check that webp_csp_mode is within the bounds of WEBP_CSP_MODE.
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// Convert to an integer to handle both the unsigned/signed enum cases
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// without the need for casting to remove type limit warnings.
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static int IsValidColorspace(int webp_csp_mode) {
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return (webp_csp_mode >= MODE_RGB && webp_csp_mode < MODE_LAST);
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}
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static VP8StatusCode CheckDecBuffer(const WebPDecBuffer* const buffer) {
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int ok = 1;
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const WEBP_CSP_MODE mode = buffer->colorspace;
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const int width = buffer->width;
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const int height = buffer->height;
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if (!IsValidColorspace(mode)) {
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ok = 0;
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} else if (!WebPIsRGBMode(mode)) { // YUV checks
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const WebPYUVABuffer* const buf = &buffer->u.YUVA;
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const uint64_t y_size = (uint64_t)buf->y_stride * height;
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const uint64_t u_size = (uint64_t)buf->u_stride * ((height + 1) / 2);
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const uint64_t v_size = (uint64_t)buf->v_stride * ((height + 1) / 2);
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const uint64_t a_size = (uint64_t)buf->a_stride * height;
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ok &= (y_size <= buf->y_size);
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ok &= (u_size <= buf->u_size);
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ok &= (v_size <= buf->v_size);
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ok &= (buf->y_stride >= width);
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ok &= (buf->u_stride >= (width + 1) / 2);
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ok &= (buf->v_stride >= (width + 1) / 2);
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ok &= (buf->y != NULL);
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ok &= (buf->u != NULL);
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ok &= (buf->v != NULL);
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if (mode == MODE_YUVA) {
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ok &= (buf->a_stride >= width);
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ok &= (a_size <= buf->a_size);
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ok &= (buf->a != NULL);
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}
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} else { // RGB checks
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const WebPRGBABuffer* const buf = &buffer->u.RGBA;
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const uint64_t size = (uint64_t)buf->stride * height;
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ok &= (size <= buf->size);
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ok &= (buf->stride >= width * kModeBpp[mode]);
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ok &= (buf->rgba != NULL);
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}
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return ok ? VP8_STATUS_OK : VP8_STATUS_INVALID_PARAM;
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}
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static VP8StatusCode AllocateBuffer(WebPDecBuffer* const buffer) {
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const int w = buffer->width;
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const int h = buffer->height;
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const WEBP_CSP_MODE mode = buffer->colorspace;
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if (w <= 0 || h <= 0 || !IsValidColorspace(mode)) {
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return VP8_STATUS_INVALID_PARAM;
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}
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if (!buffer->is_external_memory && buffer->private_memory == NULL) {
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uint8_t* output;
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int uv_stride = 0, a_stride = 0;
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uint64_t uv_size = 0, a_size = 0, total_size;
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// We need memory and it hasn't been allocated yet.
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// => initialize output buffer, now that dimensions are known.
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const int stride = w * kModeBpp[mode];
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const uint64_t size = (uint64_t)stride * h;
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if (!WebPIsRGBMode(mode)) {
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uv_stride = (w + 1) / 2;
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uv_size = (uint64_t)uv_stride * ((h + 1) / 2);
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if (mode == MODE_YUVA) {
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a_stride = w;
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a_size = (uint64_t)a_stride * h;
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}
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}
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total_size = size + 2 * uv_size + a_size;
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// Security/sanity checks
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output = (uint8_t*)WebPSafeMalloc(total_size, sizeof(*output));
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if (output == NULL) {
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return VP8_STATUS_OUT_OF_MEMORY;
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}
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buffer->private_memory = output;
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if (!WebPIsRGBMode(mode)) { // YUVA initialization
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WebPYUVABuffer* const buf = &buffer->u.YUVA;
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buf->y = output;
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buf->y_stride = stride;
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buf->y_size = (size_t)size;
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buf->u = output + size;
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buf->u_stride = uv_stride;
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buf->u_size = (size_t)uv_size;
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buf->v = output + size + uv_size;
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buf->v_stride = uv_stride;
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buf->v_size = (size_t)uv_size;
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if (mode == MODE_YUVA) {
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buf->a = output + size + 2 * uv_size;
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}
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buf->a_size = (size_t)a_size;
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buf->a_stride = a_stride;
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} else { // RGBA initialization
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WebPRGBABuffer* const buf = &buffer->u.RGBA;
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buf->rgba = output;
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buf->stride = stride;
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buf->size = (size_t)size;
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}
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}
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return CheckDecBuffer(buffer);
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}
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VP8StatusCode WebPAllocateDecBuffer(int w, int h,
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const WebPDecoderOptions* const options,
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WebPDecBuffer* const out) {
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if (out == NULL || w <= 0 || h <= 0) {
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return VP8_STATUS_INVALID_PARAM;
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}
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if (options != NULL) { // First, apply options if there is any.
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if (options->use_cropping) {
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const int cw = options->crop_width;
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const int ch = options->crop_height;
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const int x = options->crop_left & ~1;
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const int y = options->crop_top & ~1;
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if (x < 0 || y < 0 || cw <= 0 || ch <= 0 || x + cw > w || y + ch > h) {
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return VP8_STATUS_INVALID_PARAM; // out of frame boundary.
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}
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w = cw;
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h = ch;
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}
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if (options->use_scaling) {
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if (options->scaled_width <= 0 || options->scaled_height <= 0) {
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return VP8_STATUS_INVALID_PARAM;
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}
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w = options->scaled_width;
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h = options->scaled_height;
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}
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}
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out->width = w;
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out->height = h;
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// Then, allocate buffer for real
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return AllocateBuffer(out);
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}
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//------------------------------------------------------------------------------
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// constructors / destructors
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int WebPInitDecBufferInternal(WebPDecBuffer* buffer, int version) {
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if (WEBP_ABI_IS_INCOMPATIBLE(version, WEBP_DECODER_ABI_VERSION)) {
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return 0; // version mismatch
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}
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if (buffer == NULL) return 0;
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memset(buffer, 0, sizeof(*buffer));
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return 1;
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}
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void WebPFreeDecBuffer(WebPDecBuffer* buffer) {
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if (buffer != NULL) {
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if (!buffer->is_external_memory)
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free(buffer->private_memory);
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buffer->private_memory = NULL;
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}
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}
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void WebPCopyDecBuffer(const WebPDecBuffer* const src,
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WebPDecBuffer* const dst) {
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if (src != NULL && dst != NULL) {
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*dst = *src;
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if (src->private_memory != NULL) {
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dst->is_external_memory = 1; // dst buffer doesn't own the memory.
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dst->private_memory = NULL;
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}
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}
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}
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// Copy and transfer ownership from src to dst (beware of parameter order!)
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void WebPGrabDecBuffer(WebPDecBuffer* const src, WebPDecBuffer* const dst) {
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if (src != NULL && dst != NULL) {
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*dst = *src;
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if (src->private_memory != NULL) {
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src->is_external_memory = 1; // src relinquishes ownership
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src->private_memory = NULL;
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}
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}
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}
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//------------------------------------------------------------------------------
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#if defined(__cplusplus) || defined(c_plusplus)
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} // extern "C"
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#endif
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