Use some constants from headers

While investigating SprExtend-1_69, tidied up JPEGprint a bit.
Binary unchanged, not tagged.

c/JPEGprint

@@ -83,6 +83,7 @@
 #include <ctype.h>
 
 #include "kernel.h"
+#include "Global/FileTypes.h"
 
 #if Debug
 #  include "alarm.h"
@@ -127,9 +128,6 @@
 #define DeclareFontFlag (1<<29) /* in PDriver_Info features word */
 #define DrawPageFlags   (1<<13) /* in PDriver_Info features word */
 
-#define SpriteFileType 0xff9
-#define JPEGFileType   0xc85
-
   /* avoid code-breaking scale for very small pictures */
 #define AbsoluteMaxScale 100
 
@@ -281,7 +279,7 @@ static void check_JPEG_support(void)
   regs.r[1] = (int)"JPEG_Info";
   error = _kernel_swi(OS_SWINumberFromString, &regs, &regs);
   if (error) internal_give_up("MJSOSPX:You need SpriteExtend 0.75 or "
-                              "later to print JPEG's directly",(char *)0);
+                              "later to print JPEG's directly",NULL);
 }
 
 /* ------------------------------------------------------------------------ */
@@ -438,7 +436,7 @@ static void set_translation_table(sprite_t *sp)
   else
   {
     sp->sptrans = malloc(regs.r[4]);
-    if (sp->sptrans == NULL) internal_give_up("NoMem",(char *)0);
+    if (sp->sptrans == NULL) internal_give_up("NoMem",NULL);
     regs.r[4] = (int)sp->sptrans;  /* generate table in sized buffer */
     swi(ColourTrans_GenerateTable,&regs);
   }
@@ -477,12 +475,12 @@ static int read_sprite(char *fname, imagerec_t *im)
   regs.r[1] = (int)fname;
   swi(OS_File,&regs);
   if (regs.r[0] == 0) internal_give_up("NoFile",fname);
-  if (regs.r[6] != SpriteFileType) return 0;
+  if (regs.r[6] != FileType_Sprite) return 0;
 
-  im->image_type          = SpriteFileType;
+  im->image_type          = FileType_Sprite;
   im->image.sprite.SpSize = regs.r[4] + 4;  /* size of area = filesize + 4 */
   im->image.sprite.spbuff = malloc(im->image.sprite.SpSize);
-  if (im->image.sprite.spbuff == NULL) internal_give_up("NoMem",(char *)0);
+  if (im->image.sprite.spbuff == NULL) internal_give_up("NoMem",NULL);
 #if Debug
   tprintf("sprite file size = %1d\n",regs.r[4]);
 #endif
@@ -575,7 +573,7 @@ static void prime_spriteextend(jpeg_t *jp)
 #endif
 
   sparea = malloc(512); /* plenty for 8x8 32 bit Sprite */
-  if (sparea == NULL) internal_give_up("NoMem",(char *)0);
+  if (sparea == NULL) internal_give_up("NoMem",NULL);
 
   sparea[0] = 512; /* size */
   sparea[2] = 16;
@@ -624,12 +622,12 @@ static int read_jpeg(char *fname, imagerec_t *im)
   regs.r[1] = (int)fname;
   swi(OS_File,&regs);
   if (regs.r[0] == 0) internal_give_up("NoFile",fname);
-  if (regs.r[6] != JPEGFileType) return 0;
+  if (regs.r[6] != FileType_JPEG) return 0;
 
-  im->image_type        = JPEGFileType;
+  im->image_type        = FileType_JPEG;
   im->image.jpeg.JPSize = regs.r[4];    /* size of area required */
   im->image.jpeg.jpbuff = malloc(im->image.jpeg.JPSize);
-  if (im->image.jpeg.jpbuff == NULL) internal_give_up("NoMem",(char *)0);
+  if (im->image.jpeg.jpbuff == NULL) internal_give_up("NoMem",NULL);
 #if Debug
   tprintf("jpeg file size = %1d\n",regs.r[4]);
 #endif
@@ -727,7 +725,6 @@ static void plot_jpeg(jpeg_t *jp, int scale[4])
 {
   _kernel_swi_regs regs;
 
-
   regs.r[0] = (int)jp->jpbuff;
   regs.r[1] = 0;               /* x coord */
   regs.r[2] = 0;               /* y coord */
@@ -881,7 +878,7 @@ static void decide_printrec(int centred, char orientation, int max_scale,
     width   = margins[2] - margins[0];
     height  = margins[3] - margins[1];
     if ((width < 7200) || (height < 7200))
-      internal_give_up("MJSPATS:printable area too small",(char *)0);
+      internal_give_up("MJSPATS:printable area too small",NULL);
   }
 
   /* safety margin means we don't risk clipping the image slightly */
@@ -1105,10 +1102,10 @@ static void handle_print(imagerec_t *im)
     only_counting = (more & 0x1000000) != 0;
     switch(im->image_type)
     {
-      case JPEGFileType:
+      case FileType_JPEG:
         plot_jpeg(&(im->image.jpeg),im->scale);
         break;
-      case SpriteFileType:
+      case FileType_Sprite:
         plot_sprite(&(im->image.sprite),im->scale, only_counting);
         break;
     }
@@ -1148,7 +1145,7 @@ static void set_options(int *centred, int *max_scale, char *orientation)
   {
     regs.r[0] = (int)"JPEGprint$Options";
     regs.r[1] = (int)buff;
-    regs.r[2] = 256; /* read it (256 = size of buff) */
+    regs.r[2] = sizeof(buff);
     regs.r[3] = 0;
     regs.r[4] = 3;
     swi(OS_ReadVarVal,&regs);
@@ -1208,7 +1205,7 @@ int main(int argc, char *argv[])
 
   check_JPEG_support();
 
-  if (argc != 2) internal_give_up("BadParm",(char *)0);
+  if (argc != 2) internal_give_up("BadParm",NULL);
 
   set_options(&centred, &max_scale, &orientation);
 
@@ -1227,7 +1224,7 @@ int main(int argc, char *argv[])
 
   if (!read_jpeg(argv[argc-1], &imagerec) &&
       !read_sprite(argv[argc-1], &imagerec)  )
-    internal_give_up("MJSCPFT:cannot print file of this type",(char *)0);
+    internal_give_up("MJSCPFT:cannot print file of this type",NULL);
 
   decide_printrec(centred, orientation, max_scale, &imagerec, &printrec);