move src/extras to the top-level

reserve src/ for the code of the main libraries: libwebp, libwebpdemux
and libwebpmux

+ demote this library to internal only; i.e., don't install the header +
lib with make install

Change-Id: I8c9844db8f494be0fa0a2549a5b75b5cebcf666d

extras/extras.c

@@ -0,0 +1,111 @@
+// Copyright 2015 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.
+// -----------------------------------------------------------------------------
+//
+//  Additional WebP utilities.
+//
+
+#include "./extras.h"
+
+#include <string.h>
+
+#define XTRA_MAJ_VERSION 0
+#define XTRA_MIN_VERSION 0
+#define XTRA_REV_VERSION 0
+
+//------------------------------------------------------------------------------
+
+int WebPGetExtrasVersion(void) {
+  return (XTRA_MAJ_VERSION << 16) | (XTRA_MIN_VERSION << 8) | XTRA_REV_VERSION;
+}
+
+//------------------------------------------------------------------------------
+
+int WebPImportGray(const uint8_t* gray_data, WebPPicture* pic) {
+  int y, width, uv_width;
+  if (pic == NULL || gray_data == NULL) return 0;
+  pic->colorspace = WEBP_YUV420;
+  if (!WebPPictureAlloc(pic)) return 0;
+  width = pic->width;
+  uv_width = (width + 1) >> 1;
+  for (y = 0; y < pic->height; ++y) {
+    memcpy(pic->y + y * pic->y_stride, gray_data, width);
+    gray_data += width;    // <- we could use some 'data_stride' here if needed
+    if ((y & 1) == 0) {
+      memset(pic->u + (y >> 1) * pic->uv_stride, 128, uv_width);
+      memset(pic->v + (y >> 1) * pic->uv_stride, 128, uv_width);
+    }
+  }
+  return 1;
+}
+
+int WebPImportRGB565(const uint8_t* rgb565, WebPPicture* pic) {
+  int x, y;
+  if (pic == NULL || rgb565 == NULL) return 0;
+  pic->colorspace = WEBP_YUV420;
+  pic->use_argb = 1;
+  if (!WebPPictureAlloc(pic)) return 0;
+  for (y = 0; y < pic->height; ++y) {
+    const int width = pic->width;
+    uint32_t* dst = pic->argb + y * pic->argb_stride;
+    for (x = 0; x < width; ++x) {
+#ifdef WEBP_SWAP_16BIT_CSP
+      const uint32_t rg = rgb565[2 * x + 1];
+      const uint32_t gb = rgb565[2 * x + 0];
+#else
+      const uint32_t rg = rgb565[2 * x + 0];
+      const uint32_t gb = rgb565[2 * x + 1];
+#endif
+      uint32_t r = rg & 0xf8;
+      uint32_t g = ((rg << 5) | (gb >> 3)) & 0xfc;
+      uint32_t b = (gb << 5);
+      // dithering
+      r = r | (r >> 5);
+      g = g | (g >> 6);
+      b = b | (b >> 5);
+      dst[x] = (r << 16) | (g << 8) | b;
+    }
+    rgb565 += 2 * width;
+  }
+  return 1;
+}
+
+int WebPImportRGB4444(const uint8_t* rgb4444, WebPPicture* pic) {
+  int x, y;
+  if (pic == NULL || rgb4444 == NULL) return 0;
+  pic->colorspace = WEBP_YUV420;
+  pic->use_argb = 1;
+  if (!WebPPictureAlloc(pic)) return 0;
+  for (y = 0; y < pic->height; ++y) {
+    const int width = pic->width;
+    uint32_t* dst = pic->argb + y * pic->argb_stride;
+    for (x = 0; x < width; ++x) {
+#ifdef WEBP_SWAP_16BIT_CSP
+      const uint32_t rg = rgb4444[2 * x + 1];
+      const uint32_t ba = rgb4444[2 * x + 0];
+#else
+      const uint32_t rg = rgb4444[2 * x + 0];
+      const uint32_t ba = rgb4444[2 * x + 1];
+#endif
+      uint32_t r = rg & 0xf0;
+      uint32_t g = (rg << 4);
+      uint32_t b = (ba & 0xf0);
+      uint32_t a = (ba << 4);
+      // dithering
+      r = r | (r >> 4);
+      g = g | (g >> 4);
+      b = b | (b >> 4);
+      a = a | (a >> 4);
+      dst[x] = (a << 24) | (r << 16) | (g << 8) | b;
+    }
+    rgb4444 += 2 * width;
+  }
+  return 1;
+}
+
+//------------------------------------------------------------------------------