From ae2a7222cea9c3417f1a54d907c8d666b55edc54 Mon Sep 17 00:00:00 2001
From: Pascal Massimino <pascal.massimino@gmail.com>
Date: Mon, 30 May 2016 21:45:38 -0700
Subject: [PATCH] collect all decoding utilities from examples/ in
 libexampledec.a

adds a generic examples/image_dec.[ch] entry point too.

WebPGuessImageType() can be used to infer image type.

Change-Id: I8337e7b6ad91863c9cf118e4791668d2d175079b
---
 CMakeLists.txt       | 40 +++++++++++++++++++++-------------
 Makefile.vc          |  1 +
 build.gradle         | 26 +++++++++++++++++-----
 examples/Android.mk  | 28 ++++++++++++++++++------
 examples/Makefile.am | 22 +++++++++++--------
 examples/cwebp.c     | 49 ++++++------------------------------------
 examples/image_dec.c | 35 ++++++++++++++++++++++++++++++
 examples/image_dec.h | 51 ++++++++++++++++++++++++++++++++++++++++++++
 makefile.unix        |  7 ++++--
 9 files changed, 180 insertions(+), 79 deletions(-)
 create mode 100644 examples/image_dec.c
 create mode 100644 examples/image_dec.h

diff --git a/CMakeLists.txt b/CMakeLists.txt
index c36c873d..3cb9c3bc 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -287,6 +287,28 @@ if(WEBP_BUILD_CWEBP OR WEBP_BUILD_DWEBP)
   target_link_libraries(exampleutil webp ${WEBP_DEP_LIBRARIES})
 endif()
 
+if(WEBP_BUILD_CWEBP)
+  # Image-decoding utility library.
+  set(exampledec_SRCS
+    ${CMAKE_CURRENT_SOURCE_DIR}/examples/image_dec.c
+    ${CMAKE_CURRENT_SOURCE_DIR}/examples/image_dec.h
+    ${CMAKE_CURRENT_SOURCE_DIR}/examples/jpegdec.c
+    ${CMAKE_CURRENT_SOURCE_DIR}/examples/jpegdec.h
+    ${CMAKE_CURRENT_SOURCE_DIR}/examples/metadata.c
+    ${CMAKE_CURRENT_SOURCE_DIR}/examples/metadata.h
+    ${CMAKE_CURRENT_SOURCE_DIR}/examples/pngdec.c
+    ${CMAKE_CURRENT_SOURCE_DIR}/examples/pngdec.h
+    ${CMAKE_CURRENT_SOURCE_DIR}/examples/tiffdec.c
+    ${CMAKE_CURRENT_SOURCE_DIR}/examples/tiffdec.h
+    ${CMAKE_CURRENT_SOURCE_DIR}/examples/webpdec.c
+    ${CMAKE_CURRENT_SOURCE_DIR}/examples/webpdec.h
+    ${CMAKE_CURRENT_SOURCE_DIR}/examples/wicdec.c
+    ${CMAKE_CURRENT_SOURCE_DIR}/examples/wicdec.h)
+  add_library(exampledec ${exampledec_SRCS})
+  target_link_libraries(exampledec webp ${WEBP_DEP_LIBRARIES}
+    ${WEBP_DEP_IMG_LIBRARIES})
+endif()
+
 if(WEBP_BUILD_DWEBP)
   # dwebp
   include_directories(${WEBP_DEP_IMG_INCLUDE_DIRS})
@@ -304,20 +326,8 @@ if(WEBP_BUILD_CWEBP)
   include_directories(${WEBP_DEP_IMG_INCLUDE_DIRS})
   add_executable(cwebp
     ${CMAKE_CURRENT_SOURCE_DIR}/examples/cwebp.c
-    ${CMAKE_CURRENT_SOURCE_DIR}/examples/metadata.c
-    ${CMAKE_CURRENT_SOURCE_DIR}/examples/metadata.h
-    ${CMAKE_CURRENT_SOURCE_DIR}/examples/stopwatch.h
-    ${CMAKE_CURRENT_SOURCE_DIR}/examples/jpegdec.c
-    ${CMAKE_CURRENT_SOURCE_DIR}/examples/jpegdec.h
-    ${CMAKE_CURRENT_SOURCE_DIR}/examples/pngdec.c
-    ${CMAKE_CURRENT_SOURCE_DIR}/examples/pngdec.h
-    ${CMAKE_CURRENT_SOURCE_DIR}/examples/tiffdec.c
-    ${CMAKE_CURRENT_SOURCE_DIR}/examples/tiffdec.h
-    ${CMAKE_CURRENT_SOURCE_DIR}/examples/webpdec.c
-    ${CMAKE_CURRENT_SOURCE_DIR}/examples/webpdec.h
-    ${CMAKE_CURRENT_SOURCE_DIR}/examples/wicdec.c
-    ${CMAKE_CURRENT_SOURCE_DIR}/examples/wicdec.h)
-  target_link_libraries(cwebp webp exampleutil ${WEBP_DEP_LIBRARIES}
-    ${WEBP_DEP_IMG_LIBRARIES}
+    ${CMAKE_CURRENT_SOURCE_DIR}/examples/stopwatch.h)
+  target_link_libraries(cwebp exampledec webp exampleutil
+    ${WEBP_DEP_LIBRARIES} ${WEBP_DEP_IMG_LIBRARIES}
   )
 endif()
diff --git a/Makefile.vc b/Makefile.vc
index df0282f8..06461a1f 100644
--- a/Makefile.vc
+++ b/Makefile.vc
@@ -244,6 +244,7 @@ EX_ANIM_UTIL_OBJS = \
     $(DIROBJ)\examples\anim_util.obj \
 
 EX_FORMAT_DEC_OBJS = \
+    $(DIROBJ)\examples\image_dec.obj \
     $(DIROBJ)\examples\jpegdec.obj \
     $(DIROBJ)\examples\metadata.obj \
     $(DIROBJ)\examples\pngdec.obj \
diff --git a/build.gradle b/build.gradle
index 85aeda3e..a498b2aa 100644
--- a/build.gradle
+++ b/build.gradle
@@ -241,10 +241,31 @@ model {
       }
     }
 
+    example_dec(NativeLibrarySpec) {
+      binaries {
+        all {
+          lib library: "webp", linkage: "static"
+        }
+      }
+      sources {
+        c {
+          source {
+            srcDir "./examples"
+            include "image_dec.c"
+            include "jpegdec.c"
+            include "metadata.c"
+            include "pngdec.c"
+            include "tiffdec.c"
+            include "webpdec.c"
+          }
+        }
+      }
+    }
     cwebp(NativeExecutableSpec) {
       binaries {
         all {
           lib library: "example_util", linkage: "static"
+          lib library: "example_dec", linkage: "static"
           lib library: "webp", linkage: "static"
         }
       }
@@ -253,11 +274,6 @@ model {
           source {
             srcDir "./examples"
             include "cwebp.c"
-            include "jpegdec.c"
-            include "metadata.c"
-            include "pngdec.c"
-            include "tiffdec.c"
-            include "webpdec.c"
           }
         }
       }
diff --git a/examples/Android.mk b/examples/Android.mk
index 5489f03b..81490f61 100644
--- a/examples/Android.mk
+++ b/examples/Android.mk
@@ -15,6 +15,27 @@ LOCAL_MODULE := example_util
 
 include $(BUILD_STATIC_LIBRARY)
 
+
+################################################################################
+# libexample_dec
+
+include $(CLEAR_VARS)
+
+LOCAL_SRC_FILES := \
+    image_dec.c \
+    jpegdec.c \
+    metadata.c \
+    pngdec.c \
+    tiffdec.c \
+    webpdec.c \
+
+LOCAL_CFLAGS := $(WEBP_CFLAGS)
+LOCAL_C_INCLUDES := $(LOCAL_PATH)/../src
+
+LOCAL_MODULE := example_dec
+
+include $(BUILD_STATIC_LIBRARY)
+
 ################################################################################
 # cwebp
 
@@ -24,15 +45,10 @@ include $(CLEAR_VARS)
 # minor modification to their Android.mk files.
 LOCAL_SRC_FILES := \
     cwebp.c \
-    jpegdec.c \
-    metadata.c \
-    pngdec.c \
-    tiffdec.c \
-    webpdec.c \
 
 LOCAL_CFLAGS := $(WEBP_CFLAGS)
 LOCAL_C_INCLUDES := $(LOCAL_PATH)/../src
-LOCAL_STATIC_LIBRARIES := example_util webp
+LOCAL_STATIC_LIBRARIES := example_util example_dec webp
 
 LOCAL_MODULE := cwebp
 
diff --git a/examples/Makefile.am b/examples/Makefile.am
index 3b9e5b20..17a3688a 100644
--- a/examples/Makefile.am
+++ b/examples/Makefile.am
@@ -12,10 +12,20 @@ if BUILD_GIF2WEBP
   bin_PROGRAMS += gif2webp
 endif
 
-noinst_LTLIBRARIES = libexampleutil.la
+noinst_LTLIBRARIES = libexampleutil.la libexampledec.la
 
 libexampleutil_la_SOURCES = example_util.c example_util.h stopwatch.h
 
+libexampledec_la_SOURCES  = image_dec.c image_dec.h
+libexampledec_la_SOURCES += jpegdec.c jpegdec.h
+libexampledec_la_SOURCES += metadata.c metadata.h
+libexampledec_la_SOURCES += pngdec.c pngdec.h
+libexampledec_la_SOURCES += tiffdec.c tiffdec.h
+libexampledec_la_SOURCES += webpdec.c webpdec.h
+libexampledec_la_SOURCES += wicdec.c wicdec.h
+libexampledec_la_CPPFLAGS = $(JPEG_INCLUDES) $(PNG_INCLUDES) $(TIFF_INCLUDES)
+libexampledec_la_CPPFLAGS += $(AM_CPPFLAGS) $(USE_EXPERIMENTAL_CODE)
+
 if BUILD_ANIMDIFF
   noinst_PROGRAMS = anim_diff
 endif
@@ -31,15 +41,9 @@ dwebp_CPPFLAGS  = $(AM_CPPFLAGS) $(USE_EXPERIMENTAL_CODE)
 dwebp_CPPFLAGS += $(JPEG_INCLUDES) $(PNG_INCLUDES)
 dwebp_LDADD = libexampleutil.la $(PNG_LIBS) $(JPEG_LIBS)
 
-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_SOURCES  = cwebp.c stopwatch.h
 cwebp_CPPFLAGS  = $(AM_CPPFLAGS) $(USE_EXPERIMENTAL_CODE)
-cwebp_CPPFLAGS += $(JPEG_INCLUDES) $(PNG_INCLUDES) $(TIFF_INCLUDES)
-cwebp_LDADD  = libexampleutil.la ../src/libwebp.la
+cwebp_LDADD  = libexampleutil.la libexampledec.la ../src/libwebp.la
 cwebp_LDADD += $(JPEG_LIBS) $(PNG_LIBS) $(TIFF_LIBS)
 
 gif2webp_SOURCES = gif2webp.c gifdec.c gifdec.h
diff --git a/examples/cwebp.c b/examples/cwebp.c
index b8d513c4..80924072 100644
--- a/examples/cwebp.c
+++ b/examples/cwebp.c
@@ -20,17 +20,10 @@
 #include "webp/config.h"
 #endif
 
-#include "webp/encode.h"
-
 #include "./example_util.h"
-#include "./metadata.h"
+#include "./image_dec.h"
 #include "./stopwatch.h"
-
-#include "./jpegdec.h"
-#include "./pngdec.h"
-#include "./tiffdec.h"
-#include "./webpdec.h"
-#include "./wicdec.h"
+#include "webp/encode.h"
 
 #ifndef WEBP_DLL
 #ifdef __cplusplus
@@ -102,34 +95,6 @@ static int ReadPicture(const char* const filename, WebPPicture* const pic,
 
 #else  // !HAVE_WINCODEC_H
 
-typedef enum {
-  PNG_ = 0,
-  JPEG_,
-  TIFF_,  // 'TIFF' clashes with libtiff
-  WEBP_,
-  UNSUPPORTED
-} InputFileFormat;
-
-static uint32_t GetBE32(const uint8_t buf[]) {
-  return ((uint32_t)buf[0] << 24) | (buf[1] << 16) | (buf[2] << 8) | buf[3];
-}
-
-static InputFileFormat GuessImageType(const uint8_t buf[12]) {
-  InputFileFormat format = UNSUPPORTED;
-  const uint32_t magic1 = GetBE32(buf + 0);
-  const uint32_t magic2 = GetBE32(buf + 8);
-  if (magic1 == 0x89504E47U) {
-    format = PNG_;
-  } else if (magic1 >= 0xFFD8FF00U && magic1 <= 0xFFD8FFFFU) {
-    format = JPEG_;
-  } else if (magic1 == 0x49492A00 || magic1 == 0x4D4D002A) {
-    format = TIFF_;
-  } else if (magic1 == 0x52494646 && magic2 == 0x57454250) {
-    format = WEBP_;
-  }
-  return format;
-}
-
 static int ReadPicture(const char* const filename, WebPPicture* const pic,
                        int keep_alpha, Metadata* const metadata) {
   const uint8_t* data = NULL;
@@ -142,14 +107,14 @@ static int ReadPicture(const char* const filename, WebPPicture* const pic,
   if (pic->width == 0 || pic->height == 0) {
     ok = 0;
     if (data_size >= 12) {
-      const InputFileFormat format = GuessImageType(data);
-      if (format == PNG_) {
+      const WebPInputFileFormat format = WebPGuessImageType(data, data_size);
+      if (format == WEBP_PNG_FORMAT) {
         ok = ReadPNG(data, data_size, pic, keep_alpha, metadata);
-      } else if (format == JPEG_) {
+      } else if (format == WEBP_JPEG_FORMAT) {
         ok = ReadJPEG(data, data_size, pic, metadata);
-      } else if (format == TIFF_) {
+      } else if (format == WEBP_TIFF_FORMAT) {
         ok = ReadTIFF(data, data_size, pic, keep_alpha, metadata);
-      } else if (format == WEBP_) {
+      } else if (format == WEBP_WEBP_FORMAT) {
         ok = ReadWebP(data, data_size, pic, keep_alpha, metadata);
       }
     }
diff --git a/examples/image_dec.c b/examples/image_dec.c
new file mode 100644
index 00000000..0b3ea160
--- /dev/null
+++ b/examples/image_dec.c
@@ -0,0 +1,35 @@
+// Copyright 2016 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.
+// -----------------------------------------------------------------------------
+//
+// Generic image-type guessing.
+
+#include "./image_dec.h"
+
+static WEBP_INLINE uint32_t GetBE32(const uint8_t buf[]) {
+  return ((uint32_t)buf[0] << 24) | (buf[1] << 16) | (buf[2] << 8) | buf[3];
+}
+
+WebPInputFileFormat WebPGuessImageType(const uint8_t* const data,
+                                       size_t data_size) {
+  WebPInputFileFormat format = WEBP_UNSUPPORTED_FORMAT;
+  if (data != NULL && data_size >= 12) {
+    const uint32_t magic1 = GetBE32(data + 0);
+    const uint32_t magic2 = GetBE32(data + 8);
+    if (magic1 == 0x89504E47U) {
+      format = WEBP_PNG_FORMAT;
+    } else if (magic1 >= 0xFFD8FF00U && magic1 <= 0xFFD8FFFFU) {
+      format = WEBP_JPEG_FORMAT;
+    } else if (magic1 == 0x49492A00 || magic1 == 0x4D4D002A) {
+      format = WEBP_TIFF_FORMAT;
+    } else if (magic1 == 0x52494646 && magic2 == 0x57454250) {
+      format = WEBP_WEBP_FORMAT;
+    }
+  }
+  return format;
+}
diff --git a/examples/image_dec.h b/examples/image_dec.h
new file mode 100644
index 00000000..b12b3a85
--- /dev/null
+++ b/examples/image_dec.h
@@ -0,0 +1,51 @@
+// Copyright 2016 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.
+// -----------------------------------------------------------------------------
+//
+//  All-in-one library to decode PNG/JPEG/WebP/TIFF/WIC input images.
+//
+// Author: Skal (pascal.massimino@gmail.com)
+
+#ifndef WEBP_EXAMPLES_IMAGE_DEC_H_
+#define WEBP_EXAMPLES_IMAGE_DEC_H_
+
+#include "webp/types.h"
+
+#ifdef HAVE_CONFIG_H
+#include "webp/config.h"
+#endif
+
+#include "./metadata.h"
+#include "./jpegdec.h"
+#include "./pngdec.h"
+#include "./tiffdec.h"
+#include "./webpdec.h"
+#include "./wicdec.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef enum {
+  WEBP_PNG_FORMAT = 0,
+  WEBP_JPEG_FORMAT,
+  WEBP_TIFF_FORMAT,
+  WEBP_WEBP_FORMAT,
+  WEBP_UNSUPPORTED_FORMAT
+} WebPInputFileFormat;
+
+// Try to infer the image format. 'data_size' should be larger than 12.
+// Returns WEBP_UNSUPPORTED_FORMAT if format can't be guess safely.
+WebPInputFileFormat WebPGuessImageType(const uint8_t* const data,
+                                       size_t data_size);
+
+#ifdef __cplusplus
+}    // extern "C"
+#endif
+
+#endif  // WEBP_EXAMPLES_IMAGE_DEC_H_
diff --git a/makefile.unix b/makefile.unix
index 20a8e841..3fa5d5f7 100644
--- a/makefile.unix
+++ b/makefile.unix
@@ -201,6 +201,7 @@ ENC_OBJS = \
     src/enc/webpenc.o \
 
 EX_FORMAT_DEC_OBJS = \
+    examples/image_dec.o \
     examples/jpegdec.o \
     examples/metadata.o \
     examples/pngdec.o \
@@ -321,6 +322,7 @@ src/utils/bit_writer.o: src/utils/endian_inl.h
 	$(CC) $(CFLAGS) $(CPPFLAGS) -c $< -o $@
 
 examples/libanim_util.a: $(ANIM_UTIL_OBJS)
+examples/libexample_dec.a: $(EX_FORMAT_DEC_OBJS)
 examples/libexample_util.a: $(EX_UTIL_OBJS)
 examples/libgifdec.a: $(GIFDEC_OBJS)
 src/libwebpdecoder.a: $(LIBWEBPDECODER_OBJS)
@@ -333,7 +335,7 @@ src/libwebpextras.a: $(LIBWEBPEXTRA_OBJS)
 	$(AR) $(ARFLAGS) $@ $^
 
 examples/anim_diff: examples/anim_diff.o $(ANIM_UTIL_OBJS) $(GIFDEC_OBJS)
-examples/cwebp: examples/cwebp.o $(EX_FORMAT_DEC_OBJS)
+examples/cwebp: examples/cwebp.o
 examples/dwebp: examples/dwebp.o
 examples/gif2webp: examples/gif2webp.o $(GIFDEC_OBJS)
 examples/vwebp: examples/vwebp.o
@@ -344,7 +346,8 @@ examples/anim_diff: src/demux/libwebpdemux.a examples/libexample_util.a
 examples/anim_diff: src/libwebp.a
 examples/anim_diff: EXTRA_LIBS += $(GIF_LIBS)
 examples/anim_diff: EXTRA_FLAGS += -DWEBP_HAVE_GIF
-examples/cwebp: examples/libexample_util.a src/libwebp.a
+examples/cwebp: examples/libexample_util.a examples/libexample_dec.a
+examples/cwebp: src/libwebp.a
 examples/cwebp: EXTRA_LIBS += $(CWEBP_LIBS)
 examples/dwebp: examples/libexample_util.a src/libwebpdecoder.a
 examples/dwebp: EXTRA_LIBS += $(DWEBP_LIBS)