convert pic_jpeg interface to pure Lua/FFI solution

pic_jpeg had a wrapper lib before that was needed because of the
libjpeg API which uses setjmp/longjmp error handling.
By using the TurboJPEG API that comes with libjpeg-turbo, we can
use a pure Lua/FFI based approach.

Makefile

@@ -11,6 +11,7 @@ all: $(OUTPUT_DIR)/libs $(if $(ANDROID),,$(LUAJIT)) \
 		$(if $(ANDROID),luacompat52 lualongnumber,) \
 		$(if $(WIN32),,$(EVERNOTE_LIB)) \
 		$(LUASERIAL_LIB) \
+		$(TURBOJPEG_LIB) \
 		$(if $(or $(ANDROID),$(WIN32)),,$(OUTPUT_DIR)/tar) \
 		$(if $(or $(ANDROID),$(WIN32)),,$(OUTPUT_DIR)/sdcv) \
 		$(if $(or $(ANDROID),$(WIN32)),,$(OUTPUT_DIR)/zsync) \
@@ -90,6 +91,9 @@ $(JPEG_LIB):
 	$(MAKE) -j$(PROCESSORS) -C $(JPEG_DIR) --silent install
 	cp -fL $(JPEG_DIR)/.libs/$(notdir $(JPEG_LIB)) $@
 
+$(TURBOJPEG_LIB): $(JPEG_LIB)
+	cp -fL $(JPEG_DIR)/.libs/$(notdir $(TURBOJPEG_LIB)) $@
+
 # libpng, fetched via GIT as a submodule
 $(PNG_LIB): $(ZLIB)
 	-cd $(PNG_DIR) && sh autogen.sh
@@ -223,7 +227,6 @@ $(K2PDFOPT_LIB) $(LEPTONICA_LIB) $(TESSERACT_LIB): $(PNG_LIB) $(ZLIB) $(MUPDF_LI
 libs: \
 	$(if $(or $(EMULATE_READER),$(ANDROID),$(WIN32)),,$(OUTPUT_DIR)/libs/libkoreader-input.so) \
 	$(OUTPUT_DIR)/libs/libkoreader-lfs.so \
-	$(OUTPUT_DIR)/libs/libpic_jpeg.so \
 	$(if $(ANDROID),,$(OUTPUT_DIR)/libs/libkoreader-djvu.so) \
 	$(OUTPUT_DIR)/libs/libkoreader-cre.so \
 	$(OUTPUT_DIR)/libs/libwrap-mupdf.so
@@ -238,9 +241,6 @@ $(OUTPUT_DIR)/libs/libkoreader-lfs.so: \
 			luafilesystem/src/lfs.c
 	$(CC) $(DYNLIB_CFLAGS) -o $@ $^
 
-$(OUTPUT_DIR)/libs/libpic_jpeg.so: pic_jpeg.c $(JPEG_LIB)
-	$(CC) -I$(JPEG_DIR) $(DYNLIB_CFLAGS) -o $@ $^
-
 # put all the libs to the end of compile command to make ubuntu's tool chain
 # happy
 $(OUTPUT_DIR)/libs/libkoreader-djvu.so: djvu.c \

Makefile.defs

@@ -273,6 +273,7 @@ FREETYPE_LIB=$(OUTPUT_DIR)/libs/libfreetype$(if $(WIN32),-6.dll,.so.6)
 FREETYPE_DIR=freetype2
 
 JPEG_LIB=$(OUTPUT_DIR)/libs/libjpeg$(if $(WIN32),-8.dll,.so.8)
+TURBOJPEG_LIB=$(OUTPUT_DIR)/libs/libturbojpeg$(if $(WIN32),.dll,.so)
 JPEG_DIR=libjpeg-turbo-1.3.1
 
 PNG_LIB=$(OUTPUT_DIR)/libs/libpng16$(if $(WIN32),-16.dll,.so.16)

ffi-cdecl/turbojpeg_decl.c

@@ -0,0 +1,14 @@
+#include <turbojpeg.h>
+
+#include "ffi-cdecl.h"
+#include "ffi-cdecl-luajit.h"
+
+cdecl_type(tjhandle)
+
+cdecl_enum(TJPF)
+
+cdecl_func(tjDestroy)
+cdecl_func(tjInitDecompress)
+cdecl_func(tjDecompressHeader2)
+cdecl_func(tjDecompress2)
+cdecl_func(tjDecompressToYUV)

ffi/pic.lua

@@ -1,14 +1,13 @@
 local ffi = require("ffi")
 local BB = require("ffi/blitbuffer")
-local pic_jpeg = ffi.load("libs/libpic_jpeg.so")
 
-ffi.cdef[[
-uint8_t *jpegLoadFile(const char *fname, int *width, int *height, int *components);
-
-void *malloc(int size);
-void free(void *ptr);
-void *memset(void *s, int c, int n);
-]]
+local dummy = require("ffi/turbojpeg_h")
+local turbojpeg
+if ffi.os == "Windows" then
+    turbojpeg = ffi.load("libs/libturbojpeg.dll")
+else
+    turbojpeg = ffi.load("libs/libturbojpeg.so")
+end
 
 local Pic = {}
 
@@ -90,38 +89,44 @@ function PicDocument:close()
         self.image_bb:free()
         self.image_bb = nil
     end
-    if self.raw_img then
-        ffi.C.free(raw_img)
-    end
 end
 
 PicDocument.__gc = PicDocument.close
 
 function Pic.openJPGDocument(filename)
-    local doc = PicDocument:new{}
-    local w_p = ffi.new("int[1]")
-    local h_p = ffi.new("int[1]")
-    local comp_p = ffi.new("int[1]")
-
-    local raw_img = pic_jpeg.jpegLoadFile(filename, w_p, h_p, comp_p)
-    if raw_img == nil then
-        error("Cannot open jpeg file")
+    local fh = io.open(filename, "r")
+    assert(fh, "couldn't open file")
+    local data = fh:read("*a")
+    fh:close()
+
+    local handle = turbojpeg.tjInitDecompress()
+    assert(handle, "no TurboJPEG API decompressor handle")
+
+    local width = ffi.new("int[1]")
+    local height = ffi.new("int[1]")
+    local jpegsubsamp = ffi.new("int[1]")
+    turbojpeg.tjDecompressHeader2(handle, ffi.cast("unsigned char*", data), #data, width, height, jpegsubsamp)
+    assert(width[0] > 0 and height[0] > 0, "image dimensions")
+
+    local doc = PicDocument:new{width=width[0], height=height[0]}
+    local format
+    if Pic.color then
+        doc.image_bb = BB.new(width[0], height[0], BB.TYPE_BBRGB24)
+        doc.components = 3
+        format = turbojpeg.TJPF_RGB
+    else
+        doc.image_bb = BB.new(width[0], height[0], BB.TYPE_BB8)
+        doc.components = 1
+        format = turbojpeg.TJPF_GRAY
     end
 
-    doc.width = w_p[0]
-    doc.height = h_p[0]
-
-    if comp_p[0] == 1 then
-        doc.image_bb = BB.new(doc.width, doc.height, BB.TYPE_BB8, raw_img)
-    elseif comp_p[0] == 3 then
-        doc.image_bb = BB.new(doc.width, doc.height, BB.TYPE_BBRGB24, raw_img)
-    else
-        ffi.C.free(raw_img)
-        error("Unsupported image format")
+    if turbojpeg.tjDecompress2(handle, ffi.cast("unsigned char*", data), #data,
+        ffi.cast("unsigned char*", doc.image_bb.data),
+        width[0], doc.image_bb.pitch, height[0], format, 0) == -1 then
+        error("decoding JPEG file")
     end
 
-    doc.raw_img = raw_img
-    doc.components = comp_p[0]
+    turbojpeg.tjDestroy(handle)
 
     return doc
 end

ffi/turbojpeg_h.lua

@@ -0,0 +1,23 @@
+local ffi = require("ffi")
+
+ffi.cdef[[
+enum TJPF {
+  TJPF_RGB = 0,
+  TJPF_BGR = 1,
+  TJPF_RGBX = 2,
+  TJPF_BGRX = 3,
+  TJPF_XBGR = 4,
+  TJPF_XRGB = 5,
+  TJPF_GRAY = 6,
+  TJPF_RGBA = 7,
+  TJPF_BGRA = 8,
+  TJPF_ABGR = 9,
+  TJPF_ARGB = 10,
+};
+typedef void *tjhandle;
+int tjDestroy(tjhandle);
+tjhandle tjInitDecompress(void);
+int tjDecompressHeader2(tjhandle, unsigned char *, long unsigned int, int *, int *, int *);
+int tjDecompress2(tjhandle, unsigned char *, long unsigned int, unsigned char *, int, int, int, int, int);
+int tjDecompressToYUV(tjhandle, unsigned char *, long unsigned int, unsigned char *, int);
+]]