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Alpha coding: reorganize the filter/unfiltering code

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Move the filtering code to their own dsp/ spot
New function: VP8FiltersInit()

Change-Id: I0b2041eab42346c59b972f2575b05509e6a8f7b1
This commit is contained in:
Pascal Massimino 2015-01-28 08:02:41 +01:00
parent ec0d1be577
commit 7afdaf8496
12 changed files with 291 additions and 233 deletions
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1
Android.mk
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@ -51,6 +51,7 @@ LOCAL_SRC_FILES := \
src/dsp/enc_mips_dsp_r2.c \
src/dsp/enc_neon.$(NEON) \
src/dsp/enc_sse2.c \
src/dsp/filters.c \
src/dsp/filters_mips_dsp_r2.c \
src/dsp/lossless.c \
src/dsp/lossless_mips32.c \

1
Makefile.vc
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@ -195,6 +195,7 @@ DSP_DEC_OBJS = \
$(DIROBJ)\dsp\dec_mips_dsp_r2.obj \
$(DIROBJ)\dsp\dec_neon.obj \
$(DIROBJ)\dsp\dec_sse2.obj \
$(DIROBJ)\dsp\filters.obj \
$(DIROBJ)\dsp\filters_mips_dsp_r2.obj \
$(DIROBJ)\dsp\lossless.obj \
$(DIROBJ)\dsp\lossless_mips32.obj \

1
makefile.unix
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@ -119,6 +119,7 @@ DSP_DEC_OBJS = \
src/dsp/dec_mips_dsp_r2.o \
src/dsp/dec_neon.o \
src/dsp/dec_sse2.o \
src/dsp/filters.o \
src/dsp/filters_mips_dsp_r2.o \
src/dsp/lossless.o \
src/dsp/lossless_mips32.o \

2
src/dec/alpha.c
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@ -15,6 +15,7 @@
#include "./alphai.h"
#include "./vp8i.h"
#include "./vp8li.h"
#include "../dsp/dsp.h"
#include "../utils/quant_levels_dec.h"
#include "../utils/utils.h"
#include "../webp/format_constants.h"
@ -78,6 +79,7 @@ static int ALPHInit(ALPHDecoder* const dec, const uint8_t* data,
assert(dec->method_ == ALPHA_LOSSLESS_COMPRESSION);
ok = VP8LDecodeAlphaHeader(dec, alpha_data, alpha_data_size, output);
}
VP8FiltersInit();
return ok;
}

1
src/dsp/Makefile.am
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@ -18,6 +18,7 @@ COMMON_SOURCES += dec_mips32.c
COMMON_SOURCES += dec_mips_dsp_r2.c
COMMON_SOURCES += dec_neon.c
COMMON_SOURCES += dsp.h
COMMON_SOURCES += filters.c
COMMON_SOURCES += filters_mips_dsp_r2.c
COMMON_SOURCES += lossless.c
COMMON_SOURCES += lossless.h

2
src/dsp/alpha_processing.c
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@ -343,7 +343,6 @@ int (*WebPExtractAlpha)(const uint8_t*, int, int, int, uint8_t*, int);
//------------------------------------------------------------------------------
// Init function
extern void VP8FiltersInitMIPSdspR2(void);
extern void WebPInitAlphaProcessingMIPSdspR2(void);
extern void WebPInitAlphaProcessingSSE2(void);
@ -370,7 +369,6 @@ WEBP_TSAN_IGNORE_FUNCTION void WebPInitAlphaProcessing(void) {
#endif
#if defined(WEBP_USE_MIPS_DSP_R2)
if (VP8GetCPUInfo(kMIPSdspR2)) {
VP8FiltersInitMIPSdspR2();
WebPInitAlphaProcessingMIPSdspR2();
}
#endif

33
src/dsp/dsp.h
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@ -373,6 +373,39 @@ extern void (*VP8PackRGB)(const uint8_t* r, const uint8_t* g, const uint8_t* b,
// To be called first before using the above.
WEBP_TSAN_IGNORE_FUNCTION void VP8EncDspARGBInit(void);
//------------------------------------------------------------------------------
// Filter functions
typedef enum { // Filter types.
WEBP_FILTER_NONE = 0,
WEBP_FILTER_HORIZONTAL,
WEBP_FILTER_VERTICAL,
WEBP_FILTER_GRADIENT,
WEBP_FILTER_LAST = WEBP_FILTER_GRADIENT + 1, // end marker
WEBP_FILTER_BEST, // meta-types
WEBP_FILTER_FAST
} WEBP_FILTER_TYPE;
typedef void (*WebPFilterFunc)(const uint8_t* in, int width, int height,
int stride, uint8_t* out);
typedef void (*WebPUnfilterFunc)(int width, int height, int stride,
int row, int num_rows, uint8_t* data);
// Filter the given data using the given predictor.
// 'in' corresponds to a 2-dimensional pixel array of size (stride * height)
// in raster order.
// 'stride' is number of bytes per scan line (with possible padding).
// 'out' should be pre-allocated.
extern WebPFilterFunc WebPFilters[WEBP_FILTER_LAST];
// In-place reconstruct the original data from the given filtered data.
// The reconstruction will be done for 'num_rows' rows starting from 'row'
// (assuming rows upto 'row - 1' are already reconstructed).
extern WebPUnfilterFunc WebPUnfilters[WEBP_FILTER_LAST];
// To be called first before using the above.
WEBP_TSAN_IGNORE_FUNCTION void VP8FiltersInit(void);
#ifdef __cplusplus
} // extern "C"
#endif

234
src/dsp/filters.c Normal file
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@ -0,0 +1,234 @@
// Copyright 2011 Google Inc. All Rights Reserved.
//
// Use of this source code is governed by a BSD-style license
// that can be found in the COPYING file in the root of the source
// tree. An additional intellectual property rights grant can be found
// in the file PATENTS. All contributing project authors may
// be found in the AUTHORS file in the root of the source tree.
// -----------------------------------------------------------------------------
//
// Spatial prediction using various filters
//
// Author: Urvang (urvang@google.com)
#include "./dsp.h"
#include <assert.h>
#include <stdlib.h>
#include <string.h>
//------------------------------------------------------------------------------
// Helpful macro.
# define SANITY_CHECK(in, out) \
assert(in != NULL); \
assert(out != NULL); \
assert(width > 0); \
assert(height > 0); \
assert(stride >= width); \
assert(row >= 0 && num_rows > 0 && row + num_rows <= height); \
(void)height; // Silence unused warning.
static WEBP_INLINE void PredictLine(const uint8_t* src, const uint8_t* pred,
uint8_t* dst, int length, int inverse) {
int i;
if (inverse) {
for (i = 0; i < length; ++i) dst[i] = src[i] + pred[i];
} else {
for (i = 0; i < length; ++i) dst[i] = src[i] - pred[i];
}
}
//------------------------------------------------------------------------------
// Horizontal filter.
static WEBP_INLINE void DoHorizontalFilter(const uint8_t* in,
int width, int height, int stride,
int row, int num_rows,
int inverse, uint8_t* out) {
const uint8_t* preds;
const size_t start_offset = row * stride;
const int last_row = row + num_rows;
SANITY_CHECK(in, out);
in += start_offset;
out += start_offset;
preds = inverse ? out : in;
if (row == 0) {
// Leftmost pixel is the same as input for topmost scanline.
out[0] = in[0];
PredictLine(in + 1, preds, out + 1, width - 1, inverse);
row = 1;
preds += stride;
in += stride;
out += stride;
}
// Filter line-by-line.
while (row < last_row) {
// Leftmost pixel is predicted from above.
PredictLine(in, preds - stride, out, 1, inverse);
PredictLine(in + 1, preds, out + 1, width - 1, inverse);
++row;
preds += stride;
in += stride;
out += stride;
}
}
//------------------------------------------------------------------------------
// Vertical filter.
static WEBP_INLINE void DoVerticalFilter(const uint8_t* in,
int width, int height, int stride,
int row, int num_rows,
int inverse, uint8_t* out) {
const uint8_t* preds;
const size_t start_offset = row * stride;
const int last_row = row + num_rows;
SANITY_CHECK(in, out);
in += start_offset;
out += start_offset;
preds = inverse ? out : in;
if (row == 0) {
// Very first top-left pixel is copied.
out[0] = in[0];
// Rest of top scan-line is left-predicted.
PredictLine(in + 1, preds, out + 1, width - 1, inverse);
row = 1;
in += stride;
out += stride;
} else {
// We are starting from in-between. Make sure 'preds' points to prev row.
preds -= stride;
}
// Filter line-by-line.
while (row < last_row) {
PredictLine(in, preds, out, width, inverse);
++row;
preds += stride;
in += stride;
out += stride;
}
}
//------------------------------------------------------------------------------
// Gradient filter.
static WEBP_INLINE int GradientPredictor(uint8_t a, uint8_t b, uint8_t c) {
const int g = a + b - c;
return ((g & ~0xff) == 0) ? g : (g < 0) ? 0 : 255; // clip to 8bit
}
static WEBP_INLINE void DoGradientFilter(const uint8_t* in,
int width, int height, int stride,
int row, int num_rows,
int inverse, uint8_t* out) {
const uint8_t* preds;
const size_t start_offset = row * stride;
const int last_row = row + num_rows;
SANITY_CHECK(in, out);
in += start_offset;
out += start_offset;
preds = inverse ? out : in;
// left prediction for top scan-line
if (row == 0) {
out[0] = in[0];
PredictLine(in + 1, preds, out + 1, width - 1, inverse);
row = 1;
preds += stride;
in += stride;
out += stride;
}
// Filter line-by-line.
while (row < last_row) {
int w;
// leftmost pixel: predict from above.
PredictLine(in, preds - stride, out, 1, inverse);
for (w = 1; w < width; ++w) {
const int pred = GradientPredictor(preds[w - 1],
preds[w - stride],
preds[w - stride - 1]);
out[w] = in[w] + (inverse ? pred : -pred);
}
++row;
preds += stride;
in += stride;
out += stride;
}
}
#undef SANITY_CHECK
//------------------------------------------------------------------------------
static void HorizontalFilter(const uint8_t* data, int width, int height,
int stride, uint8_t* filtered_data) {
DoHorizontalFilter(data, width, height, stride, 0, height, 0, filtered_data);
}
static void VerticalFilter(const uint8_t* data, int width, int height,
int stride, uint8_t* filtered_data) {
DoVerticalFilter(data, width, height, stride, 0, height, 0, filtered_data);
}
static void GradientFilter(const uint8_t* data, int width, int height,
int stride, uint8_t* filtered_data) {
DoGradientFilter(data, width, height, stride, 0, height, 0, filtered_data);
}
//------------------------------------------------------------------------------
static void VerticalUnfilter(int width, int height, int stride, int row,
int num_rows, uint8_t* data) {
DoVerticalFilter(data, width, height, stride, row, num_rows, 1, data);
}
static void HorizontalUnfilter(int width, int height, int stride, int row,
int num_rows, uint8_t* data) {
DoHorizontalFilter(data, width, height, stride, row, num_rows, 1, data);
}
static void GradientUnfilter(int width, int height, int stride, int row,
int num_rows, uint8_t* data) {
DoGradientFilter(data, width, height, stride, row, num_rows, 1, data);
}
//------------------------------------------------------------------------------
// Init function
WebPFilterFunc WebPFilters[WEBP_FILTER_LAST];
WebPUnfilterFunc WebPUnfilters[WEBP_FILTER_LAST];
extern void VP8FiltersInitMIPSdspR2(void);
static volatile VP8CPUInfo filters_last_cpuinfo_used =
(VP8CPUInfo)&filters_last_cpuinfo_used;
WEBP_TSAN_IGNORE_FUNCTION void VP8FiltersInit(void) {
if (filters_last_cpuinfo_used == VP8GetCPUInfo) return;
WebPUnfilters[WEBP_FILTER_NONE] = NULL;
WebPUnfilters[WEBP_FILTER_HORIZONTAL] = HorizontalUnfilter;
WebPUnfilters[WEBP_FILTER_VERTICAL] = VerticalUnfilter;
WebPUnfilters[WEBP_FILTER_GRADIENT] = GradientUnfilter;
WebPFilters[WEBP_FILTER_NONE] = NULL;
WebPFilters[WEBP_FILTER_HORIZONTAL] = HorizontalFilter;
WebPFilters[WEBP_FILTER_VERTICAL] = VerticalFilter;
WebPFilters[WEBP_FILTER_GRADIENT] = GradientFilter;
if (VP8GetCPUInfo != NULL) {
#if defined(WEBP_USE_MIPS_DSP_R2)
if (VP8GetCPUInfo(kMIPSdspR2)) {
VP8FiltersInitMIPSdspR2();
}
#endif
}
filters_last_cpuinfo_used = VP8GetCPUInfo;
}

2
src/dsp/filters_mips_dsp_r2.c
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@ -16,7 +16,7 @@
#if defined(WEBP_USE_MIPS_DSP_R2)
#include "../utils/filters.h"
#include "../dsp/dsp.h"
#include <assert.h>
#include <stdlib.h>
#include <string.h>

8
src/enc/alpha.c
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@ -15,6 +15,7 @@
#include <stdlib.h>
#include "./vp8enci.h"
#include "../dsp/dsp.h"
#include "../utils/filters.h"
#include "../utils/quant_levels.h"
#include "../utils/utils.h"
@ -208,8 +209,9 @@ static uint32_t GetFilterMap(const uint8_t* alpha, int width, int height,
const int kMaxColorsForFilterNone = 192;
const int num_colors = GetNumColors(alpha, width, height, width);
// For low number of colors, NONE yields better compression.
filter = (num_colors <= kMinColorsForFilterNone) ? WEBP_FILTER_NONE :
EstimateBestFilter(alpha, width, height, width);
filter = (num_colors <= kMinColorsForFilterNone)
? WEBP_FILTER_NONE
: WebPEstimateBestFilter(alpha, width, height, width);
bit_map |= 1 << filter;
// For large number of colors, try FILTER_NONE in addition to the best
// filter as well.
@ -240,6 +242,7 @@ static int ApplyFiltersAndEncode(const uint8_t* alpha, int width, int height,
uint32_t try_map =
GetFilterMap(alpha, width, height, filter, effort_level);
InitFilterTrial(&best);
if (try_map != FILTER_TRY_NONE) {
uint8_t* filtered_alpha = (uint8_t*)WebPSafeMalloc(1ULL, data_size);
if (filtered_alpha == NULL) return 0;
@ -326,6 +329,7 @@ static int EncodeAlpha(VP8Encoder* const enc,
}
if (ok) {
VP8FiltersInit();
ok = ApplyFiltersAndEncode(quant_alpha, width, height, data_size, method,
filter, reduce_levels, effort_level, output,
output_size, pic->stats);

206
src/utils/filters.c
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@ -7,200 +7,27 @@
// be found in the AUTHORS file in the root of the source tree.
// -----------------------------------------------------------------------------
//
// Spatial prediction using various filters
// filter estimation
//
// Author: Urvang (urvang@google.com)
#include "./filters.h"
#include <assert.h>
#include <stdlib.h>
#include <string.h>
//------------------------------------------------------------------------------
// Helpful macro.
# define SANITY_CHECK(in, out) \
assert(in != NULL); \
assert(out != NULL); \
assert(width > 0); \
assert(height > 0); \
assert(stride >= width); \
assert(row >= 0 && num_rows > 0 && row + num_rows <= height); \
(void)height; // Silence unused warning.
static WEBP_INLINE void PredictLine(const uint8_t* src, const uint8_t* pred,
uint8_t* dst, int length, int inverse) {
int i;
if (inverse) {
for (i = 0; i < length; ++i) dst[i] = src[i] + pred[i];
} else {
for (i = 0; i < length; ++i) dst[i] = src[i] - pred[i];
}
}
//------------------------------------------------------------------------------
// Horizontal filter.
static WEBP_INLINE void DoHorizontalFilter(const uint8_t* in,
int width, int height, int stride,
int row, int num_rows,
int inverse, uint8_t* out) {
const uint8_t* preds;
const size_t start_offset = row * stride;
const int last_row = row + num_rows;
SANITY_CHECK(in, out);
in += start_offset;
out += start_offset;
preds = inverse ? out : in;
if (row == 0) {
// Leftmost pixel is the same as input for topmost scanline.
out[0] = in[0];
PredictLine(in + 1, preds, out + 1, width - 1, inverse);
row = 1;
preds += stride;
in += stride;
out += stride;
}
// Filter line-by-line.
while (row < last_row) {
// Leftmost pixel is predicted from above.
PredictLine(in, preds - stride, out, 1, inverse);
PredictLine(in + 1, preds, out + 1, width - 1, inverse);
++row;
preds += stride;
in += stride;
out += stride;
}
}
static void HorizontalFilter(const uint8_t* data, int width, int height,
int stride, uint8_t* filtered_data) {
DoHorizontalFilter(data, width, height, stride, 0, height, 0, filtered_data);
}
static void HorizontalUnfilter(int width, int height, int stride, int row,
int num_rows, uint8_t* data) {
DoHorizontalFilter(data, width, height, stride, row, num_rows, 1, data);
}
//------------------------------------------------------------------------------
// Vertical filter.
static WEBP_INLINE void DoVerticalFilter(const uint8_t* in,
int width, int height, int stride,
int row, int num_rows,
int inverse, uint8_t* out) {
const uint8_t* preds;
const size_t start_offset = row * stride;
const int last_row = row + num_rows;
SANITY_CHECK(in, out);
in += start_offset;
out += start_offset;
preds = inverse ? out : in;
if (row == 0) {
// Very first top-left pixel is copied.
out[0] = in[0];
// Rest of top scan-line is left-predicted.
PredictLine(in + 1, preds, out + 1, width - 1, inverse);
row = 1;
in += stride;
out += stride;
} else {
// We are starting from in-between. Make sure 'preds' points to prev row.
preds -= stride;
}
// Filter line-by-line.
while (row < last_row) {
PredictLine(in, preds, out, width, inverse);
++row;
preds += stride;
in += stride;
out += stride;
}
}
static void VerticalFilter(const uint8_t* data, int width, int height,
int stride, uint8_t* filtered_data) {
DoVerticalFilter(data, width, height, stride, 0, height, 0, filtered_data);
}
static void VerticalUnfilter(int width, int height, int stride, int row,
int num_rows, uint8_t* data) {
DoVerticalFilter(data, width, height, stride, row, num_rows, 1, data);
}
//------------------------------------------------------------------------------
// Gradient filter.
static WEBP_INLINE int GradientPredictor(uint8_t a, uint8_t b, uint8_t c) {
const int g = a + b - c;
return ((g & ~0xff) == 0) ? g : (g < 0) ? 0 : 255; // clip to 8bit
}
static WEBP_INLINE void DoGradientFilter(const uint8_t* in,
int width, int height, int stride,
int row, int num_rows,
int inverse, uint8_t* out) {
const uint8_t* preds;
const size_t start_offset = row * stride;
const int last_row = row + num_rows;
SANITY_CHECK(in, out);
in += start_offset;
out += start_offset;
preds = inverse ? out : in;
// left prediction for top scan-line
if (row == 0) {
out[0] = in[0];
PredictLine(in + 1, preds, out + 1, width - 1, inverse);
row = 1;
preds += stride;
in += stride;
out += stride;
}
// Filter line-by-line.
while (row < last_row) {
int w;
// leftmost pixel: predict from above.
PredictLine(in, preds - stride, out, 1, inverse);
for (w = 1; w < width; ++w) {
const int pred = GradientPredictor(preds[w - 1],
preds[w - stride],
preds[w - stride - 1]);
out[w] = in[w] + (inverse ? pred : -pred);
}
++row;
preds += stride;
in += stride;
out += stride;
}
}
static void GradientFilter(const uint8_t* data, int width, int height,
int stride, uint8_t* filtered_data) {
DoGradientFilter(data, width, height, stride, 0, height, 0, filtered_data);
}
static void GradientUnfilter(int width, int height, int stride, int row,
int num_rows, uint8_t* data) {
DoGradientFilter(data, width, height, stride, row, num_rows, 1, data);
}
#undef SANITY_CHECK
// -----------------------------------------------------------------------------
// Quick estimate of a potentially interesting filter mode to try.
#define SMAX 16
#define SDIFF(a, b) (abs((a) - (b)) >> 4) // Scoring diff, in [0..SMAX)
WEBP_FILTER_TYPE EstimateBestFilter(const uint8_t* data,
int width, int height, int stride) {
static WEBP_INLINE int GradientPredictor(uint8_t a, uint8_t b, uint8_t c) {
const int g = a + b - c;
return ((g & ~0xff) == 0) ? g : (g < 0) ? 0 : 255; // clip to 8bit
}
WEBP_FILTER_TYPE WebPEstimateBestFilter(const uint8_t* data,
int width, int height, int stride) {
int i, j;
int bins[WEBP_FILTER_LAST][SMAX];
memset(bins, 0, sizeof(bins));
@ -247,20 +74,3 @@ WEBP_FILTER_TYPE EstimateBestFilter(const uint8_t* data,
#undef SDIFF
//------------------------------------------------------------------------------
WebPFilterFunc WebPFilters[WEBP_FILTER_LAST] = {
NULL, // WEBP_FILTER_NONE
HorizontalFilter, // WEBP_FILTER_HORIZONTAL
VerticalFilter, // WEBP_FILTER_VERTICAL
GradientFilter // WEBP_FILTER_GRADIENT
};
WebPUnfilterFunc WebPUnfilters[WEBP_FILTER_LAST] = {
NULL, // WEBP_FILTER_NONE
HorizontalUnfilter, // WEBP_FILTER_HORIZONTAL
VerticalUnfilter, // WEBP_FILTER_VERTICAL
GradientUnfilter // WEBP_FILTER_GRADIENT
};
//------------------------------------------------------------------------------

33
src/utils/filters.h
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@ -15,42 +15,15 @@
#define WEBP_UTILS_FILTERS_H_
#include "../webp/types.h"
#include "../dsp/dsp.h"
#ifdef __cplusplus
extern "C" {
#endif
// Filters.
typedef enum {
WEBP_FILTER_NONE = 0,
WEBP_FILTER_HORIZONTAL,
WEBP_FILTER_VERTICAL,
WEBP_FILTER_GRADIENT,
WEBP_FILTER_LAST = WEBP_FILTER_GRADIENT + 1, // end marker
WEBP_FILTER_BEST,
WEBP_FILTER_FAST
} WEBP_FILTER_TYPE;
typedef void (*WebPFilterFunc)(const uint8_t* in, int width, int height,
int stride, uint8_t* out);
typedef void (*WebPUnfilterFunc)(int width, int height, int stride,
int row, int num_rows, uint8_t* data);
// Filter the given data using the given predictor.
// 'in' corresponds to a 2-dimensional pixel array of size (stride * height)
// in raster order.
// 'stride' is number of bytes per scan line (with possible padding).
// 'out' should be pre-allocated.
extern WebPFilterFunc WebPFilters[WEBP_FILTER_LAST];
// In-place reconstruct the original data from the given filtered data.
// The reconstruction will be done for 'num_rows' rows starting from 'row'
// (assuming rows upto 'row - 1' are already reconstructed).
extern WebPUnfilterFunc WebPUnfilters[WEBP_FILTER_LAST];
// Fast estimate of a potentially good filter.
WEBP_FILTER_TYPE EstimateBestFilter(const uint8_t* data,
int width, int height, int stride);
WEBP_FILTER_TYPE WebPEstimateBestFilter(const uint8_t* data,
int width, int height, int stride);
#ifdef __cplusplus
} // extern "C"