Use the upstream version of libwebp, v0.4.3.

third_party/libwebp/utils/rescaler.c

+// Copyright 2012 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 <stdlib.h>
+#include "./rescaler.h"
+#include "../dsp/dsp.h"
+
+//------------------------------------------------------------------------------
+// Implementations of critical functions ImportRow / ExportRow
+
+void (*WebPRescalerImportRow)(WebPRescaler* const wrk,
+                              const uint8_t* const src, int channel) = NULL;
+void (*WebPRescalerExportRow)(WebPRescaler* const wrk, int x_out) = NULL;
+
+#define RFIX 30
+#define MULT_FIX(x, y) (((int64_t)(x) * (y) + (1 << (RFIX - 1))) >> RFIX)
+
+static void ImportRowC(WebPRescaler* const wrk,
+                       const uint8_t* const src, int channel) {
+  const int x_stride = wrk->num_channels;
+  const int x_out_max = wrk->dst_width * wrk->num_channels;
+  int x_in = channel;
+  int x_out;
+  int accum = 0;
+  if (!wrk->x_expand) {
+    int sum = 0;
+    for (x_out = channel; x_out < x_out_max; x_out += x_stride) {
+      accum += wrk->x_add;
+      for (; accum > 0; accum -= wrk->x_sub) {
+        sum += src[x_in];
+        x_in += x_stride;
+      }
+      {        // Emit next horizontal pixel.
+        const int32_t base = src[x_in];
+        const int32_t frac = base * (-accum);
+        x_in += x_stride;
+        wrk->frow[x_out] = (sum + base) * wrk->x_sub - frac;
+        // fresh fractional start for next pixel
+        sum = (int)MULT_FIX(frac, wrk->fx_scale);
+      }
+    }
+  } else {        // simple bilinear interpolation
+    int left = src[channel], right = src[channel];
+    for (x_out = channel; x_out < x_out_max; x_out += x_stride) {
+      if (accum < 0) {
+        left = right;
+        x_in += x_stride;
+        right = src[x_in];
+        accum += wrk->x_add;
+      }
+      wrk->frow[x_out] = right * wrk->x_add + (left - right) * accum;
+      accum -= wrk->x_sub;
+    }
+  }
+  // Accumulate the contribution of the new row.
+  for (x_out = channel; x_out < x_out_max; x_out += x_stride) {
+    wrk->irow[x_out] += wrk->frow[x_out];
+  }
+}
+
+static void ExportRowC(WebPRescaler* const wrk, int x_out) {
+  if (wrk->y_accum <= 0) {
+    uint8_t* const dst = wrk->dst;
+    int32_t* const irow = wrk->irow;
+    const int32_t* const frow = wrk->frow;
+    const int yscale = wrk->fy_scale * (-wrk->y_accum);
+    const int x_out_max = wrk->dst_width * wrk->num_channels;
+    for (; x_out < x_out_max; ++x_out) {
+      const int frac = (int)MULT_FIX(frow[x_out], yscale);
+      const int v = (int)MULT_FIX(irow[x_out] - frac, wrk->fxy_scale);
+      dst[x_out] = (!(v & ~0xff)) ? v : (v < 0) ? 0 : 255;
+      irow[x_out] = frac;   // new fractional start
+    }
+    wrk->y_accum += wrk->y_add;
+    wrk->dst += wrk->dst_stride;
+  }
+}
+
+//------------------------------------------------------------------------------
+// MIPS version
+
+#if defined(WEBP_USE_MIPS32)
+
+static void ImportRowMIPS(WebPRescaler* const wrk,
+                          const uint8_t* const src, int channel) {
+  const int x_stride = wrk->num_channels;
+  const int x_out_max = wrk->dst_width * wrk->num_channels;
+  const int fx_scale = wrk->fx_scale;
+  const int x_add = wrk->x_add;
+  const int x_sub = wrk->x_sub;
+  int* frow = wrk->frow + channel;
+  int* irow = wrk->irow + channel;
+  const uint8_t* src1 = src + channel;
+  int temp1, temp2, temp3;
+  int base, frac, sum;
+  int accum, accum1;
+  const int x_stride1 = x_stride << 2;
+  int loop_c = x_out_max - channel;
+
+  if (!wrk->x_expand) {
+    __asm__ volatile (
+      "li     %[temp1],   0x8000                    \n\t"
+      "li     %[temp2],   0x10000                   \n\t"
+      "li     %[sum],     0                         \n\t"
+      "li     %[accum],   0                         \n\t"
+    "1:                                             \n\t"
+      "addu   %[accum],   %[accum],   %[x_add]      \n\t"
+      "blez   %[accum],   3f                        \n\t"
+    "2:                                             \n\t"
+      "lbu    %[temp3],   0(%[src1])                \n\t"
+      "subu   %[accum],   %[accum],   %[x_sub]      \n\t"
+      "addu   %[src1],    %[src1],    %[x_stride]   \n\t"
+      "addu   %[sum],     %[sum],     %[temp3]      \n\t"
+      "bgtz   %[accum],   2b                        \n\t"
+    "3:                                             \n\t"
+      "lbu    %[base],    0(%[src1])                \n\t"
+      "addu   %[src1],    %[src1],    %[x_stride]   \n\t"
+      "negu   %[accum1],  %[accum]                  \n\t"
+      "mul    %[frac],    %[base],    %[accum1]     \n\t"
+      "addu   %[temp3],   %[sum],     %[base]       \n\t"
+      "mul    %[temp3],   %[temp3],   %[x_sub]      \n\t"
+      "lw     %[base],    0(%[irow])                \n\t"
+      "subu   %[loop_c],  %[loop_c],  %[x_stride]   \n\t"
+      "sll    %[accum1],  %[frac],    2             \n\t"
+      "mult   %[temp1],   %[temp2]                  \n\t"
+      "madd   %[accum1],  %[fx_scale]               \n\t"
+      "mfhi   %[sum]                                \n\t"
+      "subu   %[temp3],   %[temp3],   %[frac]       \n\t"
+      "sw     %[temp3],   0(%[frow])                \n\t"
+      "add    %[base],    %[base],    %[temp3]      \n\t"
+      "sw     %[base],    0(%[irow])                \n\t"
+      "addu   %[irow],    %[irow],    %[x_stride1]  \n\t"
+      "addu   %[frow],    %[frow],    %[x_stride1]  \n\t"
+      "bgtz   %[loop_c],  1b                        \n\t"
+
+      : [accum] "=&r" (accum), [src1] "+r" (src1), [temp3] "=&r" (temp3),
+        [sum] "=&r" (sum), [base] "=&r" (base), [frac] "=&r" (frac),
+        [frow] "+r" (frow), [irow] "+r" (irow), [accum1] "=&r" (accum1),
+        [temp2] "=&r" (temp2), [temp1] "=&r" (temp1)
+      : [x_stride] "r" (x_stride), [fx_scale] "r" (fx_scale),
+        [x_sub] "r" (x_sub), [x_add] "r" (x_add),
+        [loop_c] "r" (loop_c), [x_stride1] "r" (x_stride1)
+      : "memory", "hi", "lo"
+    );
+  } else {
+    __asm__ volatile (
+      "lbu    %[temp1],   0(%[src1])                \n\t"
+      "move   %[temp2],   %[temp1]                  \n\t"
+      "li     %[accum],   0                         \n\t"
+    "1:                                             \n\t"
+      "bgez   %[accum],   2f                        \n\t"
+      "move   %[temp2],   %[temp1]                  \n\t"
+      "addu   %[src1],    %[x_stride]               \n\t"
+      "lbu    %[temp1],   0(%[src1])                \n\t"
+      "addu   %[accum],   %[x_add]                  \n\t"
+    "2:                                             \n\t"
+      "subu   %[temp3],   %[temp2],   %[temp1]      \n\t"
+      "mul    %[temp3],   %[temp3],   %[accum]      \n\t"
+      "mul    %[base],    %[temp1],   %[x_add]      \n\t"
+      "subu   %[accum],   %[accum],   %[x_sub]      \n\t"
+      "lw     %[frac],    0(%[irow])                \n\t"
+      "subu   %[loop_c],  %[loop_c],  %[x_stride]   \n\t"
+      "addu   %[temp3],   %[base],    %[temp3]      \n\t"
+      "sw     %[temp3],   0(%[frow])                \n\t"
+      "addu   %[frow],    %[x_stride1]              \n\t"
+      "addu   %[frac],    %[temp3]                  \n\t"
+      "sw     %[frac],    0(%[irow])                \n\t"
+      "addu   %[irow],    %[x_stride1]              \n\t"
+      "bgtz   %[loop_c],  1b                        \n\t"
+
+      : [src1] "+r" (src1), [accum] "=&r" (accum), [temp1] "=&r" (temp1),
+        [temp2] "=&r" (temp2), [temp3] "=&r" (temp3), [base] "=&r" (base),
+        [frac] "=&r" (frac), [frow] "+r" (frow), [irow] "+r" (irow)
+      : [x_stride] "r" (x_stride), [x_add] "r" (x_add), [x_sub] "r" (x_sub),
+        [x_stride1] "r" (x_stride1), [loop_c] "r" (loop_c)
+      : "memory", "hi", "lo"
+    );
+  }
+}
+
+static void ExportRowMIPS(WebPRescaler* const wrk, int x_out) {
+  if (wrk->y_accum <= 0) {
+    uint8_t* const dst = wrk->dst;
+    int32_t* const irow = wrk->irow;
+    const int32_t* const frow = wrk->frow;
+    const int yscale = wrk->fy_scale * (-wrk->y_accum);
+    const int x_out_max = wrk->dst_width * wrk->num_channels;
+    // if wrk->fxy_scale can fit into 32 bits use optimized code,
+    // otherwise use C code
+    if ((wrk->fxy_scale >> 32) == 0) {
+      int temp0, temp1, temp3, temp4, temp5, temp6, temp7, loop_end;
+      const int temp2 = (int)(wrk->fxy_scale);
+      const int temp8 = x_out_max << 2;
+      uint8_t* dst_t = (uint8_t*)dst;
+      int32_t* irow_t = (int32_t*)irow;
+      const int32_t* frow_t = (const int32_t*)frow;
+
+      __asm__ volatile(
+        "addiu    %[temp6],    $zero,       -256          \n\t"
+        "addiu    %[temp7],    $zero,       255           \n\t"
+        "li       %[temp3],    0x10000                    \n\t"
+        "li       %[temp4],    0x8000                     \n\t"
+        "addu     %[loop_end], %[frow_t],   %[temp8]      \n\t"
+      "1:                                                 \n\t"
+        "lw       %[temp0],    0(%[frow_t])               \n\t"
+        "mult     %[temp3],    %[temp4]                   \n\t"
+        "addiu    %[frow_t],   %[frow_t],   4             \n\t"
+        "sll      %[temp0],    %[temp0],    2             \n\t"
+        "madd     %[temp0],    %[yscale]                  \n\t"
+        "mfhi     %[temp1]                                \n\t"
+        "lw       %[temp0],    0(%[irow_t])               \n\t"
+        "addiu    %[dst_t],    %[dst_t],    1             \n\t"
+        "addiu    %[irow_t],   %[irow_t],   4             \n\t"
+        "subu     %[temp0],    %[temp0],    %[temp1]      \n\t"
+        "mult     %[temp3],    %[temp4]                   \n\t"
+        "sll      %[temp0],    %[temp0],    2             \n\t"
+        "madd     %[temp0],    %[temp2]                   \n\t"
+        "mfhi     %[temp5]                                \n\t"
+        "sw       %[temp1],    -4(%[irow_t])              \n\t"
+        "and      %[temp0],    %[temp5],    %[temp6]      \n\t"
+        "slti     %[temp1],    %[temp5],    0             \n\t"
+        "beqz     %[temp0],    2f                         \n\t"
+        "xor      %[temp5],    %[temp5],    %[temp5]      \n\t"
+        "movz     %[temp5],    %[temp7],    %[temp1]      \n\t"
+      "2:                                                 \n\t"
+        "sb       %[temp5],    -1(%[dst_t])               \n\t"
+        "bne      %[frow_t],   %[loop_end], 1b            \n\t"
+
+        : [temp0]"=&r"(temp0), [temp1]"=&r"(temp1), [temp3]"=&r"(temp3),
+          [temp4]"=&r"(temp4), [temp5]"=&r"(temp5), [temp6]"=&r"(temp6),
+          [temp7]"=&r"(temp7), [frow_t]"+r"(frow_t), [irow_t]"+r"(irow_t),
+          [dst_t]"+r"(dst_t), [loop_end]"=&r"(loop_end)
+        : [temp2]"r"(temp2), [yscale]"r"(yscale), [temp8]"r"(temp8)
+        : "memory", "hi", "lo"
+      );
+      wrk->y_accum += wrk->y_add;
+      wrk->dst += wrk->dst_stride;
+    } else {
+      ExportRowC(wrk, x_out);
+    }
+  }
+}
+#endif   // WEBP_USE_MIPS32
+
+//------------------------------------------------------------------------------
+
+void WebPRescalerInit(WebPRescaler* const wrk, int src_width, int src_height,
+                      uint8_t* const dst, int dst_width, int dst_height,
+                      int dst_stride, int num_channels, int x_add, int x_sub,
+                      int y_add, int y_sub, int32_t* const work) {
+  wrk->x_expand = (src_width < dst_width);
+  wrk->src_width = src_width;
+  wrk->src_height = src_height;
+  wrk->dst_width = dst_width;
+  wrk->dst_height = dst_height;
+  wrk->dst = dst;
+  wrk->dst_stride = dst_stride;
+  wrk->num_channels = num_channels;
+  // for 'x_expand', we use bilinear interpolation
+  wrk->x_add = wrk->x_expand ? (x_sub - 1) : x_add - x_sub;
+  wrk->x_sub = wrk->x_expand ? (x_add - 1) : x_sub;
+  wrk->y_accum = y_add;
+  wrk->y_add = y_add;
+  wrk->y_sub = y_sub;
+  wrk->fx_scale = (1 << RFIX) / x_sub;
+  wrk->fy_scale = (1 << RFIX) / y_sub;
+  wrk->fxy_scale = wrk->x_expand ?
+      ((int64_t)dst_height << RFIX) / (x_sub * src_height) :
+      ((int64_t)dst_height << RFIX) / (x_add * src_height);
+  wrk->irow = work;
+  wrk->frow = work + num_channels * dst_width;
+
+  if (WebPRescalerImportRow == NULL) {
+    WebPRescalerImportRow = ImportRowC;
+    WebPRescalerExportRow = ExportRowC;
+    if (VP8GetCPUInfo != NULL) {
+#if defined(WEBP_USE_MIPS32)
+      if (VP8GetCPUInfo(kMIPS32)) {
+        WebPRescalerImportRow = ImportRowMIPS;
+        WebPRescalerExportRow = ExportRowMIPS;
+      }
+#endif
+    }
+  }
+}
+
+#undef MULT_FIX
+#undef RFIX
+
+//------------------------------------------------------------------------------
+// all-in-one calls
+
+int WebPRescaleNeededLines(const WebPRescaler* const wrk, int max_num_lines) {
+  const int num_lines = (wrk->y_accum + wrk->y_sub - 1) / wrk->y_sub;
+  return (num_lines > max_num_lines) ? max_num_lines : num_lines;
+}
+
+int WebPRescalerImport(WebPRescaler* const wrk, int num_lines,
+                       const uint8_t* src, int src_stride) {
+  int total_imported = 0;
+  while (total_imported < num_lines && wrk->y_accum > 0) {
+    int channel;
+    for (channel = 0; channel < wrk->num_channels; ++channel) {
+      WebPRescalerImportRow(wrk, src, channel);
+    }
+    src += src_stride;
+    ++total_imported;
+    wrk->y_accum -= wrk->y_sub;
+  }
+  return total_imported;
+}
+
+int WebPRescalerExport(WebPRescaler* const rescaler) {
+  int total_exported = 0;
+  while (WebPRescalerHasPendingOutput(rescaler)) {
+    WebPRescalerExportRow(rescaler, 0);
+    ++total_exported;
+  }
+  return total_exported;
+}
+
+//------------------------------------------------------------------------------