[PATCH] pickles: Add new pickle for jpeg

[Andreas Klinger]

2024-01-29  Andreas Klinger  <ak@it-klinger.de>

        * pickles/jpeg.pk: New pickle for jpeg files
---

This is also a RFC as there is a topic i'm not completely satisfied:

- When uncommenting 
    byte[] image
  in JPEG_Tag it takes a long time to use the pickle.
  Maybe there is a better way to define it.

- For my purposes i don't need the image but when submitting this pickle it
  could be relevant to other users.

 ChangeLog           |   4 ++
 pickles/Makefile.am |   2 +-
 pickles/jpeg.pk     | 114 ++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 119 insertions(+), 1 deletion(-)
 create mode 100644 pickles/jpeg.pk

diff --git a/ChangeLog b/ChangeLog
index 679a1628..aa7ec183 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2024-01-29  Andreas Klinger  <ak@it-klinger.de>
+
+       * pickles/jpeg.pk: New pickle for jpeg files
+
 2024-01-28  Mohammad-Reza Nabipoor  <mnabipoor@gnu.org>
 
        * configure.ac (gl_HOST_CPU_ABI_32BIT): Emit an error instead of
diff --git a/pickles/Makefile.am b/pickles/Makefile.am
index 177aac70..eb993711 100644
--- a/pickles/Makefile.am
+++ b/pickles/Makefile.am
@@ -28,6 +28,6 @@ dist_pickles_DATA = ctf.pk ctf-dump.pk leb128.pk \
                    uuid.pk redoxfs.pk pcap.pk ieee754.pk pdap.pk \
                     iscan.pk iscan-str.pk base64.pk gpt-partition-attrs.pk \
                    gpt-partition-types.pk gpt.pk guid.pk linux.pk srec.pk \
-                   jojodiff.pk
+                   jojodiff.pk jpeg.pk
 
 EXTRA_DIST = README.elf
diff --git a/pickles/jpeg.pk b/pickles/jpeg.pk
new file mode 100644
index 00000000..ca07bf81
--- /dev/null
+++ b/pickles/jpeg.pk
@@ -0,0 +1,114 @@
+/* jpeg.pk - JPEG implementation for GNU poke */
+
+/* Copyright (C) 2024 Andreas Klinger */
+
+/* This program 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 3 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, see <http://www.gnu.org/licenses/>.
+ */
+
+/* Implemented as specified in
+ * https://en.wikipedia.org/wiki/JPEG as well as
+ * https://de.wikipedia.org/wiki/JPEG_File_Interchange_Format  */
+
+/* Marker of JPEG pictures
+ * Array id 0 ("SOF0") starts at binary marker value 0xC0:
+ *   0xC0, 0xC1, ... , 0xC7
+ *   0xC8, 0xC1, ... , 0xCF
+ *   0xD0, 0xD1, ... , 0xD7
+ *   ...
+ *   0xF8, 0xF1, ... , 0xFF
+ */
+var jpeg_marker =
+  ["SOF0", "SOF1", "SOF2", "SOF3", "DHT", "SOF5", "SOF6", "SOF7",
+   "JPG", "SOF9", "SOF10", "SOF11", "DAC", "SOF13", "SOF14", "SOF15",
+   "-", "-", "-", "-", "-", "-", "-", "-",
+   "SOI", "EOI", "SOS", "DQT", "-", "DRI", "-", "-",
+   "APP0", "APP1", "APP2", "APP3", "APP4", "APP5", "APP6", "APP7",
+   "APP8", "APP9", "APP10", "APP11", "APP12", "APP13", "APP14", "APP15",
+   "-", "-", "-", "-", "-", "-", "-", "-",
+   "-", "-", "-", "-", "-", "-", "COM", "-"];
+
+type JPEG_SOI =
+  struct
+  {
+    byte ff = 0xFF;
+    byte xx = 0xD8;
+    method _print = void:
+    {
+      printf ("\n#<tag: %u16x\tsymbol: %s>",
+                        ff:::xx, jpeg_marker[xx - 0xC0]);
+    }
+  };
+
+type JPEG_SOS =
+  struct
+  {
+    byte ff = 0xFF;
+    byte xx = 0xDA;
+    method _print = void:
+    {
+      printf ("\n#<tag: %u16x\tsymbol: %s>",
+                        ff:::xx, jpeg_marker[xx - 0xC0]);
+    }
+  };
+
+type JPEG_EOI =
+  struct
+  {
+    byte ff = 0xFF;
+    byte xx = 0xD9;
+  };
+
+type JPEG_Segment =
+  struct
+  {
+    byte ff == 0xFF;
+    byte xx : xx != 0xD8 && xx != 0xDA && xx != 0xD9 && xx >= 0xC0 && xx < 
0xFF;
+    uint16 size;
+    char[size-2] data;
+    method _print = void:
+    {
+      printf ("\n#<tag: %u16x\tsymbol: %s\tsize: %u16d>",
+                        ff:::xx, jpeg_marker[xx - 0xC0], size);
+    }
+  };
+
+fun JPEG_find_eoi = (byte[] image) int:
+  {
+    printf ("size: %u32d length: %u32d\n", image'size / 1#B, image'length);
+    for (var i = image'length - 1; i > 1; i--)
+      {
+        var ff = image[i - 1];
+        var xx = image[i];
+        if (ff == 0xFF && xx == 0xD9)
+          {
+            return i;
+          }
+      }
+    return 0;
+  }
+
+type JPEG_Tag =
+  struct
+  {
+    JPEG_SOI soi;
+    JPEG_Segment[] segments;
+    JPEG_SOS sos;
+/*    byte[] image; */  /* could take some time for loading */
+/*    var image_size = JPEG_find_eoi(image); */
+/*    JPEG_EOI eoi; */
+    method get_nsegs = int:
+    {
+      return segments'length;
+    }
+  };
-- 
2.39.2

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