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-rw-r--r--media/libwebp/src/dsp/rescaler.c251
1 files changed, 251 insertions, 0 deletions
diff --git a/media/libwebp/src/dsp/rescaler.c b/media/libwebp/src/dsp/rescaler.c
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+// Copyright 2014 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.
+// -----------------------------------------------------------------------------
+//
+// Rescaling functions
+//
+// Author: Skal (pascal.massimino@gmail.com)
+
+#include <assert.h>
+
+#include "src/dsp/dsp.h"
+#include "src/utils/rescaler_utils.h"
+
+//------------------------------------------------------------------------------
+// Implementations of critical functions ImportRow / ExportRow
+
+#define ROUNDER (WEBP_RESCALER_ONE >> 1)
+#define MULT_FIX(x, y) (((uint64_t)(x) * (y) + ROUNDER) >> WEBP_RESCALER_RFIX)
+#define MULT_FIX_FLOOR(x, y) (((uint64_t)(x) * (y)) >> WEBP_RESCALER_RFIX)
+
+//------------------------------------------------------------------------------
+// Row import
+
+void WebPRescalerImportRowExpand_C(WebPRescaler* const wrk,
+ const uint8_t* src) {
+ const int x_stride = wrk->num_channels;
+ const int x_out_max = wrk->dst_width * wrk->num_channels;
+ int channel;
+ assert(!WebPRescalerInputDone(wrk));
+ assert(wrk->x_expand);
+ for (channel = 0; channel < x_stride; ++channel) {
+ int x_in = channel;
+ int x_out = channel;
+ // simple bilinear interpolation
+ int accum = wrk->x_add;
+ rescaler_t left = (rescaler_t)src[x_in];
+ rescaler_t right =
+ (wrk->src_width > 1) ? (rescaler_t)src[x_in + x_stride] : left;
+ x_in += x_stride;
+ while (1) {
+ wrk->frow[x_out] = right * wrk->x_add + (left - right) * accum;
+ x_out += x_stride;
+ if (x_out >= x_out_max) break;
+ accum -= wrk->x_sub;
+ if (accum < 0) {
+ left = right;
+ x_in += x_stride;
+ assert(x_in < wrk->src_width * x_stride);
+ right = (rescaler_t)src[x_in];
+ accum += wrk->x_add;
+ }
+ }
+ assert(wrk->x_sub == 0 /* <- special case for src_width=1 */ || accum == 0);
+ }
+}
+
+void WebPRescalerImportRowShrink_C(WebPRescaler* const wrk,
+ const uint8_t* src) {
+ const int x_stride = wrk->num_channels;
+ const int x_out_max = wrk->dst_width * wrk->num_channels;
+ int channel;
+ assert(!WebPRescalerInputDone(wrk));
+ assert(!wrk->x_expand);
+ for (channel = 0; channel < x_stride; ++channel) {
+ int x_in = channel;
+ int x_out = channel;
+ uint32_t sum = 0;
+ int accum = 0;
+ while (x_out < x_out_max) {
+ uint32_t base = 0;
+ accum += wrk->x_add;
+ while (accum > 0) {
+ accum -= wrk->x_sub;
+ assert(x_in < wrk->src_width * x_stride);
+ base = src[x_in];
+ sum += base;
+ x_in += x_stride;
+ }
+ { // Emit next horizontal pixel.
+ const rescaler_t frac = base * (-accum);
+ wrk->frow[x_out] = sum * wrk->x_sub - frac;
+ // fresh fractional start for next pixel
+ sum = (int)MULT_FIX(frac, wrk->fx_scale);
+ }
+ x_out += x_stride;
+ }
+ assert(accum == 0);
+ }
+}
+
+//------------------------------------------------------------------------------
+// Row export
+
+void WebPRescalerExportRowExpand_C(WebPRescaler* const wrk) {
+ int x_out;
+ uint8_t* const dst = wrk->dst;
+ rescaler_t* const irow = wrk->irow;
+ const int x_out_max = wrk->dst_width * wrk->num_channels;
+ const rescaler_t* const frow = wrk->frow;
+ assert(!WebPRescalerOutputDone(wrk));
+ assert(wrk->y_accum <= 0);
+ assert(wrk->y_expand);
+ assert(wrk->y_sub != 0);
+ if (wrk->y_accum == 0) {
+ for (x_out = 0; x_out < x_out_max; ++x_out) {
+ const uint32_t J = frow[x_out];
+ const int v = (int)MULT_FIX(J, wrk->fy_scale);
+ dst[x_out] = (v > 255) ? 255u : (uint8_t)v;
+ }
+ } else {
+ const uint32_t B = WEBP_RESCALER_FRAC(-wrk->y_accum, wrk->y_sub);
+ const uint32_t A = (uint32_t)(WEBP_RESCALER_ONE - B);
+ for (x_out = 0; x_out < x_out_max; ++x_out) {
+ const uint64_t I = (uint64_t)A * frow[x_out]
+ + (uint64_t)B * irow[x_out];
+ const uint32_t J = (uint32_t)((I + ROUNDER) >> WEBP_RESCALER_RFIX);
+ const int v = (int)MULT_FIX(J, wrk->fy_scale);
+ dst[x_out] = (v > 255) ? 255u : (uint8_t)v;
+ }
+ }
+}
+
+void WebPRescalerExportRowShrink_C(WebPRescaler* const wrk) {
+ int x_out;
+ uint8_t* const dst = wrk->dst;
+ rescaler_t* const irow = wrk->irow;
+ const int x_out_max = wrk->dst_width * wrk->num_channels;
+ const rescaler_t* const frow = wrk->frow;
+ const uint32_t yscale = wrk->fy_scale * (-wrk->y_accum);
+ assert(!WebPRescalerOutputDone(wrk));
+ assert(wrk->y_accum <= 0);
+ assert(!wrk->y_expand);
+ if (yscale) {
+ for (x_out = 0; x_out < x_out_max; ++x_out) {
+ const uint32_t frac = (uint32_t)MULT_FIX_FLOOR(frow[x_out], yscale);
+ const int v = (int)MULT_FIX(irow[x_out] - frac, wrk->fxy_scale);
+ dst[x_out] = (v > 255) ? 255u : (uint8_t)v;
+ irow[x_out] = frac; // new fractional start
+ }
+ } else {
+ for (x_out = 0; x_out < x_out_max; ++x_out) {
+ const int v = (int)MULT_FIX(irow[x_out], wrk->fxy_scale);
+ dst[x_out] = (v > 255) ? 255u : (uint8_t)v;
+ irow[x_out] = 0;
+ }
+ }
+}
+
+#undef MULT_FIX_FLOOR
+#undef MULT_FIX
+#undef ROUNDER
+
+//------------------------------------------------------------------------------
+// Main entry calls
+
+void WebPRescalerImportRow(WebPRescaler* const wrk, const uint8_t* src) {
+ assert(!WebPRescalerInputDone(wrk));
+ if (!wrk->x_expand) {
+ WebPRescalerImportRowShrink(wrk, src);
+ } else {
+ WebPRescalerImportRowExpand(wrk, src);
+ }
+}
+
+void WebPRescalerExportRow(WebPRescaler* const wrk) {
+ if (wrk->y_accum <= 0) {
+ assert(!WebPRescalerOutputDone(wrk));
+ if (wrk->y_expand) {
+ WebPRescalerExportRowExpand(wrk);
+ } else if (wrk->fxy_scale) {
+ WebPRescalerExportRowShrink(wrk);
+ } else { // special case
+ int i;
+ assert(wrk->src_height == wrk->dst_height && wrk->x_add == 1);
+ assert(wrk->src_width == 1 && wrk->dst_width <= 2);
+ for (i = 0; i < wrk->num_channels * wrk->dst_width; ++i) {
+ wrk->dst[i] = wrk->irow[i];
+ wrk->irow[i] = 0;
+ }
+ }
+ wrk->y_accum += wrk->y_add;
+ wrk->dst += wrk->dst_stride;
+ ++wrk->dst_y;
+ }
+}
+
+//------------------------------------------------------------------------------
+
+WebPRescalerImportRowFunc WebPRescalerImportRowExpand;
+WebPRescalerImportRowFunc WebPRescalerImportRowShrink;
+
+WebPRescalerExportRowFunc WebPRescalerExportRowExpand;
+WebPRescalerExportRowFunc WebPRescalerExportRowShrink;
+
+extern void WebPRescalerDspInitSSE2(void);
+extern void WebPRescalerDspInitMIPS32(void);
+extern void WebPRescalerDspInitMIPSdspR2(void);
+extern void WebPRescalerDspInitMSA(void);
+extern void WebPRescalerDspInitNEON(void);
+
+WEBP_DSP_INIT_FUNC(WebPRescalerDspInit) {
+#if !defined(WEBP_REDUCE_SIZE)
+#if !WEBP_NEON_OMIT_C_CODE
+ WebPRescalerExportRowExpand = WebPRescalerExportRowExpand_C;
+ WebPRescalerExportRowShrink = WebPRescalerExportRowShrink_C;
+#endif
+
+ WebPRescalerImportRowExpand = WebPRescalerImportRowExpand_C;
+ WebPRescalerImportRowShrink = WebPRescalerImportRowShrink_C;
+
+ if (VP8GetCPUInfo != NULL) {
+#if defined(WEBP_HAVE_SSE2)
+ if (VP8GetCPUInfo(kSSE2)) {
+ WebPRescalerDspInitSSE2();
+ }
+#endif
+#if defined(WEBP_USE_MIPS32)
+ if (VP8GetCPUInfo(kMIPS32)) {
+ WebPRescalerDspInitMIPS32();
+ }
+#endif
+#if defined(WEBP_USE_MIPS_DSP_R2)
+ if (VP8GetCPUInfo(kMIPSdspR2)) {
+ WebPRescalerDspInitMIPSdspR2();
+ }
+#endif
+#if defined(WEBP_USE_MSA)
+ if (VP8GetCPUInfo(kMSA)) {
+ WebPRescalerDspInitMSA();
+ }
+#endif
+ }
+
+#if defined(WEBP_HAVE_NEON)
+ if (WEBP_NEON_OMIT_C_CODE ||
+ (VP8GetCPUInfo != NULL && VP8GetCPUInfo(kNEON))) {
+ WebPRescalerDspInitNEON();
+ }
+#endif
+
+ assert(WebPRescalerExportRowExpand != NULL);
+ assert(WebPRescalerExportRowShrink != NULL);
+ assert(WebPRescalerImportRowExpand != NULL);
+ assert(WebPRescalerImportRowShrink != NULL);
+#endif // WEBP_REDUCE_SIZE
+}
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