Generalize image file support for ccv and png2smzx. (#309)

* Add image_file.c image loading abstraction (PNG, BMP, NetPBM, farbfeld, raw; file or stdin).
* Relicense ccv to GPL 2+ (with permission of Lancer-X).
* Add image_file unit tests.

.gitignore

@@ -149,6 +149,7 @@ unit/.build/
 unit/editor/.build/
 unit/io/.build/
 unit/network/.build/
+unit/utils/.build/
 /*.js
 /*.js.mem
 /*.js.orig.js

Makefile

@@ -492,17 +492,14 @@ ifeq (${BUILD_UTILS},1)
 	${MKDIR} ${build}/utils
 	${CP} ${checkres} ${downver} ${build}/utils
 	${CP} ${hlp2txt} ${txt2hlp} ${build}/utils
-	${CP} ${ccv} ${build}/utils
+	${CP} ${ccv} ${png2smzx} ${build}/utils
 	@if [ -f "${checkres}.debug" ]; then cp ${checkres}.debug ${build}/utils; fi
 	@if [ -f "${downver}.debug" ]; then cp ${downver}.debug ${build}/utils; fi
 	@if [ -f "${hlp2txt}.debug" ]; then cp ${hlp2txt}.debug ${build}/utils; fi
 	@if [ -f "${txt2hlp}.debug" ]; then cp ${txt2hlp}.debug ${build}/utils; fi
 	@if [ -f "${ccv}.debug" ]; then cp ${ccv}.debug ${build}/utils; fi
-ifeq (${LIBPNG},1)
-	${CP} ${png2smzx} ${build}/utils
 	@if [ -f "${png2smzx}.debug" ]; then cp ${png2smzx}.debug ${build}/utils; fi
 endif
-endif
 
 ${build}/docs: ${build}
 	${MKDIR} -p ${build}/docs

arch/install.inc

@@ -178,6 +178,7 @@ ifeq (${BUILD_UTILS},1)
 		${DESTDIR}${BINDIR}/downver \
 		${DESTDIR}${BINDIR}/hlp2txt \
 		${DESTDIR}${BINDIR}/txt2hlp \
+		${DESTDIR}${BINDIR}/png2smzx \
 		${DESTDIR}${BINDIR}/ccv
 endif
 	@echo Done.

docs/changelog.txt

@@ -150,6 +150,13 @@ USERS
   intermediate render and skipping pixel checks for blank chars.
 + libxmp playback improvements for GDM, AMF, and OctaMED modules
   as well as general stability improvements.
++ ccv and png2smzx now both support the following image formats:
+  PNG (with libpng enabled), BMP (uncompressed, RLE8, RLE4),
+  NetPBM (PBM, PGM, PPM, PNM, PAM), farbfeld. png2smzx will now
+  build when libpng support is disabled, though it won't support
+  loading PNGs with this configuration.
++ ccv and png2smzx now both support streaming image data from
+  stdin using the input filename "-".
 - Removed GL4ES from the GLSL blacklist.
 - Removed 3DS CIA support. (asie)
 
@@ -177,6 +184,8 @@ DEVELOPERS
 + Replaced the macro-based mixers in sampled_stream.c with more
   maintainable template-based mixers.
 + Updated libxmp to 4.5.0.
++ Relicensed ccv from GPL 3 to GPL 2+ to match the rest of MZX.
+  (Lancer-X)
 
 
 November 22nd, 2020 - MZX 2.92f

src/pngops.c

@@ -61,7 +61,7 @@ int png_write_screen(uint8_t *pixels, struct rgb_color *pal, int count,
    PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_DEFAULT,
    PNG_FILTER_TYPE_DEFAULT);
 
-  pal_ptr = cmalloc(count * sizeof(png_color));
+  pal_ptr = (png_colorp)cmalloc(count * sizeof(png_color));
   if(!pal_ptr)
     goto exit_free_close;
 
@@ -77,7 +77,7 @@ int png_write_screen(uint8_t *pixels, struct rgb_color *pal, int count,
   png_write_info(png_ptr, info_ptr);
   png_set_packing(png_ptr);
 
-  row_ptrs = cmalloc(sizeof(png_bytep) * 350);
+  row_ptrs = (png_bytep *)cmalloc(sizeof(png_bytep) * 350);
   if(!row_ptrs)
     goto exit_free_close;
 
@@ -137,7 +137,7 @@ int png_write_screen_32bpp(uint32_t *pixels, const char *name)
   png_write_info(png_ptr, info_ptr);
   png_set_packing(png_ptr);
 
-  row_ptrs = cmalloc(sizeof(png_bytep) * 350);
+  row_ptrs = (png_bytep *)cmalloc(sizeof(png_bytep) * 350);
   if(!row_ptrs)
     goto exit_free_close;
 
@@ -165,33 +165,41 @@ int png_write_screen_32bpp(uint32_t *pixels, const char *name)
 
 #ifdef NEED_PNG_READ_FILE
 
-void *png_read_file(const char *name, png_uint_32 *_w, png_uint_32 *_h,
+static boolean png_check_stream(FILE *fp)
+{
+  png_byte header[8];
+
+  if(fread(header, 1, 8, fp) < 8)
+    return false;
+
+  if(png_sig_cmp(header, 0, 8))
+    return false;
+
+  return true;
+}
+
+/**
+ * If `checked` is true, the first 8 bytes of the stream have already been
+ * read and verified to be the PNG signature.
+ */
+void *png_read_stream(FILE *fp, png_uint_32 *_w, png_uint_32 *_h, boolean checked,
  check_w_h_constraint_t constraint, rgba_surface_allocator_t allocator)
 {
   png_uint_32 i, w, h, stride;
-  png_byte header[8];
   png_structp png_ptr = NULL;
   png_infop info_ptr = NULL;
   png_bytep * volatile row_ptrs = NULL;
   void * volatile s = NULL;
   void *pixels;
   int type;
   int bpp;
-  FILE *f;
 
-  f = fopen_unsafe(name, "rb");
-  if(!f)
+  if(!checked && !png_check_stream(fp))
     goto exit_out;
 
-  if(fread(header, 1, 8, f) < 8)
-    goto exit_close;
-
-  if(png_sig_cmp(header, 0, 8))
-    goto exit_close;
-
   png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
   if(!png_ptr)
-    goto exit_close;
+    goto exit_out;
 
   info_ptr = png_create_info_struct(png_ptr);
   if(!info_ptr)
@@ -200,14 +208,14 @@ void *png_read_file(const char *name, png_uint_32 *_w, png_uint_32 *_h,
   if(setjmp(png_jmpbuf(png_ptr)))
     goto exit_free_close;
 
-  png_init_io(png_ptr, f);
+  png_init_io(png_ptr, fp);
   png_set_sig_bytes(png_ptr, 8);
   png_read_info(png_ptr, info_ptr);
   png_get_IHDR(png_ptr, info_ptr, &w, &h, &bpp, &type, NULL, NULL, NULL);
 
   if(!constraint(w, h))
   {
-    warn("Requested image '%s' failed dimension checks.\n", name);
+    warn("Requested image failed dimension checks.\n");
     goto exit_free_close;
   }
 
@@ -235,7 +243,7 @@ void *png_read_file(const char *name, png_uint_32 *_w, png_uint_32 *_h,
   png_read_update_info(png_ptr, info_ptr);
   png_get_IHDR(png_ptr, info_ptr, &w, &h, &bpp, &type, NULL, NULL, NULL);
 
-  row_ptrs = cmalloc(sizeof(png_bytep) * h);
+  row_ptrs = (png_bytep *)cmalloc(sizeof(png_bytep) * h);
   if(!row_ptrs)
     goto exit_free_close;
 
@@ -256,10 +264,26 @@ void *png_read_file(const char *name, png_uint_32 *_w, png_uint_32 *_h,
 exit_free_close:
   png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
   free(row_ptrs);
-exit_close:
-  fclose(f);
 exit_out:
   return s;
 }
 
+void *png_read_file(const char *name, png_uint_32 *_w, png_uint_32 *_h,
+ check_w_h_constraint_t constraint, rgba_surface_allocator_t allocator)
+{
+  void *s;
+
+  FILE *fp = fopen_unsafe(name, "rb");
+  if(!fp)
+    return NULL;
+
+  s = png_read_stream(fp, _w, _h, false, constraint, allocator);
+  fclose(fp);
+
+  if(!s)
+    warn("Failed to load '%s'\n", name);
+
+  return s;
+}
+
 #endif // NEED_PNG_READ_FILE

src/pngops.h

@@ -35,6 +35,7 @@ __M_BEGIN_DECLS
 
 #include "graphics.h"
 #include <stdint.h>
+#include <stdio.h>
 
 int png_write_screen(uint8_t *pixels, struct rgb_color *pal, int count,
  const char *name);
@@ -48,6 +49,9 @@ typedef boolean (*check_w_h_constraint_t)(png_uint_32 w, png_uint_32 h);
 typedef void *(*rgba_surface_allocator_t)(png_uint_32 w, png_uint_32 h,
                                           png_uint_32 *stride, void **pixels);
 
+void *png_read_stream(FILE *fp, png_uint_32 *_w, png_uint_32 *_h, boolean checked,
+ check_w_h_constraint_t constraint, rgba_surface_allocator_t allocator);
+
 void *png_read_file(const char *name, png_uint_32 *_w, png_uint_32 *_h,
  check_w_h_constraint_t constraint, rgba_surface_allocator_t allocator);
 

src/utils/Makefile.in

@@ -17,6 +17,13 @@ utils_obj = src/utils/.build
 utils_cflags := ${LIBPNG_CFLAGS} -DUTILS_LIBSPEC=
 
 zip_objs  := ${io_obj}/vio.o ${io_obj}/zip.o ${io_obj}/zip_stream.o
+img_objs  := ${utils_obj}/image_file.o
+img_flags :=
+
+ifneq (${LIBPNG},)
+img_objs  += ${core_obj}/pngops.o
+img_flags += ${LIBPNG_LDFLAGS} ${ZLIB_LDFLAGS}
+endif
 
 checkres := ${utils_src}/checkres${BINEXT}
 checkres_objs := ${utils_obj}/checkres.o \
@@ -39,12 +46,14 @@ txt2hlp_objs := ${utils_obj}/txt2hlp.o
 
 png2smzx := ${utils_src}/png2smzx${BINEXT}
 png2smzx_objs := ${utils_obj}/png2smzx.o ${utils_obj}/smzxconv.o
-png2smzx_objs += ${core_obj}/pngops.o
+png2smzx_objs += ${img_objs}
 png2smzx_objs += ${io_obj}/path.o ${io_obj}/vio.o
-png2smzx_ldflags := ${LIBPNG_LDFLAGS} ${ZLIB_LDFLAGS}
+png2smzx_ldflags := ${img_flags}
 
 ccv := ${utils_src}/ccv${BINEXT}
 ccv_objs := ${utils_obj}/ccv.o
+ccv_objs += ${img_objs}
+ccv_ldflags := ${img_flags}
 
 ${utils_obj}/%.o: ${utils_src}/%.c src/config.h
 	$(if ${V},,@echo "  CC      " $<)
@@ -91,19 +100,16 @@ ${png2smzx}: ${png2smzx_objs}
 ${ccv}: ${ccv_objs}
 	$(if ${V},,@echo "  LINK    " ${ccv})
 	${CC} ${ccv_objs} -o ${ccv} \
-	  ${ARCH_EXE_LDFLAGS} ${LDFLAGS}
+	  ${ARCH_EXE_LDFLAGS} ${LDFLAGS} ${ccv_ldflags}
 
 utils: $(filter-out $(wildcard ${utils_obj}), ${utils_obj})
 
-utils: ${checkres} ${downver} ${hlp2html} ${hlp2txt} ${txt2hlp} ${ccv}
-
-ifeq (${LIBPNG},1)
-utils: ${png2smzx}
-utils.debug: ${png2smzx}.debug
-endif
+utils: ${checkres} ${downver} ${hlp2html} ${hlp2txt} ${txt2hlp}
+utils: ${ccv} ${png2smzx}
 
 utils.debug: ${checkres}.debug ${downver}.debug ${ccv}.debug
 utils.debug: ${hlp2html}.debug ${hlp2txt}.debug ${txt2hlp}.debug
+utils.debug: ${png2smzx}.debug
 
 utils_clean:
 	$(if ${V},,@echo "  RM      " ${utils_obj})