add basic support for .ase/.aseprite files from LibreSprite and Aseprite

src/Makefile.am

@@ -74,6 +74,7 @@ file_C			= filegen.c \
 			  file_apple.c \
 			  file_ari.c \
 			  file_arj.c \
+			  file_aseprite.c \
 			  file_asf.c \
 			  file_asl.c \
 			  file_asm.c \

src/file_aseprite.c

@@ -0,0 +1,135 @@
+/*
+
+    File: file_aseprite.c
+
+    Copyright (C) 2006-2009,2021 Christophe GRENIER <[email protected]>
+
+    This software is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License along
+    with this program; if not, write the Free Software Foundation, Inc., 51
+    Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+
+ */
+
+#if !defined(SINGLE_FORMAT) || defined(SINGLE_FORMAT_aseprite)
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+#ifdef HAVE_STRING_H
+#include <string.h>
+#endif
+#include <stdio.h>
+#include "types.h"
+#include "filegen.h"
+#include "common.h"
+
+#ifdef DEBUG_ASEPRITE
+#include "log.h"
+#endif
+
+/* file format spec: https://github.com/aseprite/aseprite/blob/main/docs/ase-file-specs.md */
+
+/*@ requires valid_register_header_check(file_stat); */
+static void register_header_check_aseprite(file_stat_t *file_stat);
+
+const file_hint_t file_hint_aseprite= {
+  .extension="aseprite",
+  .description="LibreSprite/Aseprite .ase/.aseprite Files.",
+  .max_filesize=PHOTOREC_MAX_FILE_SIZE,
+  .recover=1,
+  .enable_by_default=1,
+  .register_header_check=&register_header_check_aseprite
+};
+
+struct aseprite_file_header
+{
+  uint32_t file_size;
+  uint16_t magic;	/* must be 0xA5E0 */
+  uint16_t frames;	/* number of frames */
+  uint16_t width;	/* Width in pixels */
+  uint16_t height;	/* Height in pixels */
+  uint16_t color_depth;	/* Bits per pixel (32 bpp = RGBA; 16 bpp GRAYSCALE; 8 bpp INDEXED;) */
+  uint32_t flags; /* flags */
+  uint16_t speed; /* speed (miliseconds between frames) 
+    DEPRECATED: frame's frame duration field used instead. */
+  uint32_t reserved1; /* must be 0 */
+  uint32_t reserved2; /* must be 0 */
+  uint8_t pallete; /* Pallete entry (index). Only for indexed sprites. */
+  uint8_t reserved3[3]; /* must be 0 */
+  uint16_t ncolors; /* Number of colors (0 means 256 for old sprites) */
+  uint8_t pixel_width; /* Pixel ratio = pixel_width/pixel_height; 
+    If this or pixel_height equals to 0, pixel ratio = 1:1 */
+  uint8_t pixel_height; /* Pixel Height */
+  int16_t x_grid; /* X position on grid. */
+  int16_t y_grid; /* Y position on grid. */
+  uint16_t grid_w; /* Grid width. Zero if no grid. */
+  uint16_t grid_h; /* Grid Height. Zero if no grid. */
+  uint8_t reserved4[84]; /* For future. Set to zero (0). */
+} __attribute__ ((gcc_struct, __packed__));
+
+/*@
+  @ requires buffer_size >= sizeof(struct aseprite_file_header);
+  @ requires separation: \separated(&file_hint_aseprite, buffer+(..), file_recovery, file_recovery_new);
+  @ requires valid_header_check_param(buffer, buffer_size, safe_header_only, file_recovery, file_recovery_new);
+  @ ensures  valid_header_check_result(\result, file_recovery_new);
+  @ assigns  *file_recovery_new;
+*/
+static int header_check_aseprite(const unsigned char *buffer, const unsigned int buffer_size, const unsigned int safe_header_only, const file_recovery_t *file_recovery, file_recovery_t *file_recovery_new)
+{
+  const struct aseprite_file_header *hdr= (const struct aseprite_file_header *)buffer;
+
+  const unsigned int file_size = le32(hdr->file_size);
+  const unsigned int frames = le16(hdr->frames);
+  const unsigned int width = le16(hdr->width);
+  const unsigned int height = le16(hdr->height);
+  const unsigned int reserved1 = le32(hdr->reserved1);
+  const unsigned int reserved2 = le32(hdr->reserved2);
+  const unsigned int color_depth = le16(hdr->color_depth);
+
+#ifdef DEBUG_ASEPRITE
+  log_info("file size %u\n", file_size);
+  log_info("frames %u\n", frames);
+  log_info("height %u\n", height);
+  log_info("width  %u\n", width);
+  log_info("depth  %u\n", color_depth);
+#endif
+
+  if (file_size < sizeof(struct aseprite_file_header) || 
+      frames==0 || frames > 65535 || 
+      width==0 || width > 65535 || 
+      height==0 || height > 65535 || 
+      reserved1!=0 || reserved2!=0 || 
+      (color_depth!=8 && color_depth!=16 && color_depth!=32)  
+  ) 
+    return 0;
+
+  reset_file_recovery(file_recovery_new);
+  file_recovery_new->min_filesize=sizeof(struct aseprite_file_header);
+  file_recovery_new->extension=file_hint_aseprite.extension;
+  if (file_recovery_new->blocksize < 16) 
+    return 1;
+  file_recovery_new->calculated_file_size=file_size;
+  file_recovery_new->data_check=&data_check_size;
+  file_recovery_new->file_check=&file_check_size_min;
+  return 1;
+}
+
+/*
+    Will register specific file header check function.
+*/
+static void register_header_check_aseprite(file_stat_t *file_stat)
+{
+  static const unsigned char aseprite_header[2]={ 0xE0, 0xA5 };
+  register_header_check(4, aseprite_header,sizeof(aseprite_header), &header_check_aseprite, file_stat);
+}
+
+#endif

src/file_list.c

@@ -100,6 +100,9 @@ extern const file_hint_t file_hint_ari;
 #if !defined(SINGLE_FORMAT) || defined(SINGLE_FORMAT_arj)
 extern const file_hint_t file_hint_arj;
 #endif
+#if !defined(SINGLE_FORMAT) || defined(SINGLE_FOMART_aseprite)
+extern const file_hint_t file_hint_aseprite;
+#endif
 #if !defined(SINGLE_FORMAT) || defined(SINGLE_FORMAT_asf)
 extern const file_hint_t file_hint_asf;
 #endif
@@ -1160,6 +1163,9 @@ file_enable_t array_file_enable[]=
 #if !defined(SINGLE_FORMAT) || defined(SINGLE_FORMAT_arj)
   { .enable=0, .file_hint=&file_hint_arj  },
 #endif
+#if !defined(SINGLE_FORMAT) || defined(SINGLE_FORMAT_aseprite)
+  { .enable=0, .file_hint=&file_hint_aseprite },
+#endif
 #if !defined(SINGLE_FORMAT) || defined(SINGLE_FORMAT_asf)
   { .enable=0, .file_hint=&file_hint_asf  },
 #endif