cwebp: add webpdec

simple webp decoding, no metadata support

Change-Id: I2752fd1442c87513922878cbf72f001d45b631bc

examples/Makefile.am

@@ -25,10 +25,12 @@ cwebp_SOURCES  = cwebp.c metadata.c metadata.h stopwatch.h
 cwebp_SOURCES += jpegdec.c jpegdec.h
 cwebp_SOURCES += pngdec.c pngdec.h
 cwebp_SOURCES += tiffdec.c tiffdec.h
+cwebp_SOURCES += webpdec.c webpdec.h
 cwebp_SOURCES += wicdec.c wicdec.h
 cwebp_CPPFLAGS  = $(AM_CPPFLAGS) $(USE_EXPERIMENTAL_CODE)
 cwebp_CPPFLAGS += $(JPEG_INCLUDES) $(PNG_INCLUDES) $(TIFF_INCLUDES)
-cwebp_LDADD = ../src/libwebp.la $(JPEG_LIBS) $(PNG_LIBS) $(TIFF_LIBS)
+cwebp_LDADD  = libexampleutil.la ../src/libwebp.la
+cwebp_LDADD += $(JPEG_LIBS) $(PNG_LIBS) $(TIFF_LIBS)
 
 gif2webp_SOURCES = gif2webp.c gif2webp_util.c
 gif2webp_CPPFLAGS = $(AM_CPPFLAGS) $(USE_EXPERIMENTAL_CODE) $(GIF_INCLUDES)

examples/cwebp.c

@@ -28,6 +28,7 @@
 #include "./jpegdec.h"
 #include "./pngdec.h"
 #include "./tiffdec.h"
+#include "./webpdec.h"
 #include "./wicdec.h"
 
 #ifndef WEBP_DLL
@@ -106,26 +107,30 @@ typedef enum {
   PNG_ = 0,
   JPEG_,
   TIFF_,  // 'TIFF' clashes with libtiff
+  WEBP_,
   UNSUPPORTED
 } InputFileFormat;
 
 static InputFileFormat GetImageType(FILE* in_file) {
   InputFileFormat format = UNSUPPORTED;
-  uint32_t magic;
-  uint8_t buf[4];
+  uint32_t magic1, magic2;
+  uint8_t buf[12];
 
-  if ((fread(&buf[0], 4, 1, in_file) != 1) ||
+  if ((fread(&buf[0], 12, 1, in_file) != 1) ||
       (fseek(in_file, 0, SEEK_SET) != 0)) {
     return format;
   }
 
-  magic = ((uint32_t)buf[0] << 24) | (buf[1] << 16) | (buf[2] << 8) | buf[3];
-  if (magic == 0x89504E47U) {
+  magic1 = ((uint32_t)buf[0] << 24) | (buf[1] << 16) | (buf[2] << 8) | buf[3];
+  magic2 = ((uint32_t)buf[8] << 24) | (buf[9] << 16) | (buf[10] << 8) | buf[11];
+  if (magic1 == 0x89504E47U) {
     format = PNG_;
-  } else if (magic >= 0xFFD8FF00U && magic <= 0xFFD8FFFFU) {
+  } else if (magic1 >= 0xFFD8FF00U && magic1 <= 0xFFD8FFFFU) {
     format = JPEG_;
-  } else if (magic == 0x49492A00 || magic == 0x4D4D002A) {
+  } else if (magic1 == 0x49492A00 || magic1 == 0x4D4D002A) {
     format = TIFF_;
+  } else if (magic1 == 0x52494646 && magic2 == 0x57454250) {
+    format = WEBP_;
   }
   return format;
 }
@@ -148,6 +153,8 @@ static int ReadPicture(const char* const filename, WebPPicture* const pic,
       ok = ReadJPEG(in_file, pic, metadata);
     } else if (format == TIFF_) {
       ok = ReadTIFF(filename, pic, keep_alpha, metadata);
+    } else if (format == WEBP_) {
+      ok = ReadWebP(filename, pic, keep_alpha, metadata);
     }
   } else {
     // If image size is specified, infer it as YUV format.
@@ -553,7 +560,7 @@ static void HelpLong(void) {
   printf("Usage:\n");
   printf(" cwebp [-preset <...>] [options] in_file [-o out_file]\n\n");
   printf("If input size (-s) for an image is not specified, "
-         "it is assumed to be a PNG, JPEG or TIFF file.\n");
+         "it is assumed to be a PNG, JPEG, TIFF or WebP file.\n");
 #ifdef HAVE_WINCODEC_H
   printf("Windows builds can take as input any of the files handled by WIC\n");
 #endif

examples/webpdec.c

@@ -0,0 +1,67 @@
+// 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.
+// -----------------------------------------------------------------------------
+//
+// WebP decode.
+
+#include "./webpdec.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "webp/decode.h"
+#include "webp/encode.h"
+#include "./example_util.h"
+#include "./metadata.h"
+
+int ReadWebP(const char* const in_file, WebPPicture* const pic,
+             int keep_alpha, Metadata* const metadata) {
+  int ok = 0;
+  size_t data_size = 0;
+  const uint8_t* data = NULL;
+  VP8StatusCode status = VP8_STATUS_OK;
+  WebPDecoderConfig config;
+  WebPDecBuffer* const output_buffer = &config.output;
+  WebPBitstreamFeatures* const bitstream = &config.input;
+
+  // TODO(jzern): add Exif/XMP/ICC extraction.
+  if (metadata != NULL) {
+    fprintf(stderr, "Warning: metadata extraction from WebP is unsupported.\n");
+  }
+
+  if (!WebPInitDecoderConfig(&config)) {
+    fprintf(stderr, "Library version mismatch!\n");
+    return 0;
+  }
+
+  if (ExUtilLoadWebP(in_file, &data, &data_size, bitstream)) {
+    const int has_alpha = keep_alpha && bitstream->has_alpha;
+    output_buffer->colorspace = has_alpha ? MODE_RGBA : MODE_RGB;
+
+    status = ExUtilDecodeWebP(data, data_size, 0, 0, &config);
+    if (status == VP8_STATUS_OK) {
+      const uint8_t* const rgba = output_buffer->u.RGBA.rgba;
+      const int stride = output_buffer->u.RGBA.stride;
+      pic->width = output_buffer->width;
+      pic->height = output_buffer->height;
+      pic->use_argb = 1;
+      ok = has_alpha ? WebPPictureImportRGBA(pic, rgba, stride)
+                     : WebPPictureImportRGB(pic, rgba, stride);
+    }
+  }
+
+  if (status != VP8_STATUS_OK) {
+    ExUtilPrintWebPError(in_file, status);
+  }
+
+  free((void*)data);
+  WebPFreeDecBuffer(output_buffer);
+  return ok;
+}
+
+// -----------------------------------------------------------------------------

examples/webpdec.h

@@ -0,0 +1,33 @@
+// 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.
+// -----------------------------------------------------------------------------
+//
+// WebP decode.
+
+#ifndef WEBP_EXAMPLES_WEBPDEC_H_
+#define WEBP_EXAMPLES_WEBPDEC_H_
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct Metadata;
+struct WebPPicture;
+
+// Reads a WebP from 'in_file', returning the decoded output in 'pic'.
+// If 'keep_alpha' is true and the WebP has an alpha channel, the output is
+// RGBA otherwise it will be RGB.
+// Returns true on success.
+int ReadWebP(const char* const in_file, struct WebPPicture* const pic,
+             int keep_alpha, struct Metadata* const metadata);
+
+#ifdef __cplusplus
+}    // extern "C"
+#endif
+
+#endif  // WEBP_EXAMPLES_WEBPDEC_H_