Reorganise rojpeg.

Aside from moving blocks around and adding comments, decisions about numcomponents use switch/case statements to allow CMYK support in the future.
Split out (some of the) Huffman decoding to allow arithmetic support in the future.
Moved memcpy() and memset() into CSupport.
Tested in all colour depths with 1x1; 1x2; 2x1; 2x2 sampling & ChangeFSI.
Tighten up check on cinfo being NULL (was previously only checked in the colour decoder, not the monochrome).

Version 1.37. Tagged as 'SprExtend-1_37'

Sources/CSupport

@@ -16,6 +16,8 @@
 
         EXPORT  |__rt_sdiv|
         EXPORT  |__rt_udiv|
+        EXPORT  |memcpy|
+        EXPORT  |memset|
 
 |x$divide|
 |__rt_sdiv|
@@ -165,4 +167,25 @@ u_sh0   RSBS    ip, a1, a2
         MOV     a1, a3
         MOV     pc, r14
 
+|memcpy|
+; extern void *memcpy(void *a1, const void *a2, size_t a3)
+        TEQ     a3, #0
+        MOVNE   ip, a1
+mc_0
+        LDRNEB  a4, [a2], #1
+        STRNEB  a4, [ip], #1
+        SUBNES  a3, a3, #1
+        BNE     mc_0
+        MOV     pc, lr
+        
+|memset|
+; extern void *memset(void *a1, int a2, size_t a3)
+        TEQ     a3, #0
+        MOVNE   ip, a1
+ms_0
+        STRNEB  a2, [ip], #1
+        SUBNES  a3, a3, #1
+        BNE     ms_0
+        MOV     pc, lr
+
         END

VersionASM

@@ -11,13 +11,13 @@
                         GBLS    Module_HelpVersion
                         GBLS    Module_ComponentName
                         GBLS    Module_ComponentPath
-Module_MajorVersion     SETS    "1.36"
-Module_Version          SETA    136
+Module_MajorVersion     SETS    "1.37"
+Module_Version          SETA    137
 Module_MinorVersion     SETS    ""
-Module_Date             SETS    "14 Nov 2010"
-Module_ApplicationDate  SETS    "14-Nov-10"
+Module_Date             SETS    "22 Dec 2010"
+Module_ApplicationDate  SETS    "22-Dec-10"
 Module_ComponentName    SETS    "SprExtend"
 Module_ComponentPath    SETS    "mixed/RiscOS/Sources/Video/Render/SprExtend"
-Module_FullVersion      SETS    "1.36"
-Module_HelpVersion      SETS    "1.36 (14 Nov 2010)"
+Module_FullVersion      SETS    "1.37"
+Module_HelpVersion      SETS    "1.37 (22 Dec 2010)"
                         END

VersionNum

-/* (1.36)
+/* (1.37)
  *
  * This file is automatically maintained by srccommit, do not edit manually.
  * Last processed by srccommit version: 1.1.
  *
  */
-#define Module_MajorVersion_CMHG        1.36
+#define Module_MajorVersion_CMHG        1.37
 #define Module_MinorVersion_CMHG        
-#define Module_Date_CMHG                14 Nov 2010
+#define Module_Date_CMHG                22 Dec 2010
 
-#define Module_MajorVersion             "1.36"
-#define Module_Version                  136
+#define Module_MajorVersion             "1.37"
+#define Module_Version                  137
 #define Module_MinorVersion             ""
-#define Module_Date                     "14 Nov 2010"
+#define Module_Date                     "22 Dec 2010"
 
-#define Module_ApplicationDate          "14-Nov-10"
+#define Module_ApplicationDate          "22-Dec-10"
 
 #define Module_ComponentName            "SprExtend"
 #define Module_ComponentPath            "mixed/RiscOS/Sources/Video/Render/SprExtend"
 
-#define Module_FullVersion              "1.36"
-#define Module_HelpVersion              "1.36 (14 Nov 2010)"
-#define Module_LibraryVersionInfo       "1:36"
+#define Module_FullVersion              "1.37"
+#define Module_HelpVersion              "1.37 (22 Dec 2010)"
+#define Module_LibraryVersionInfo       "1:37"

h/jinclude

@@ -97,7 +97,11 @@ asm_huff_skip_blocks(decompress_info_ptr cinfo, JBLOCK block,
                  int *last_dc_val, int nblocks);
 #endif
 
+#ifdef STATS
+#define asm_j_rev_dct(i,b,c) j_rev_dct(i,b,c) /* Substitute 'Sources.jrevdct' for 'c.jrevdct4' */
+#else
 extern void asm_j_rev_dct(decompress_info_ptr cinfo, JBLOCK block, int count);
+#endif
 extern void asm_mono_convert_block(JBLOCK jblock, int *outptr, int outoffset);
 extern void asm_mono_convert_block_8(JBLOCK jblock, int *outptr, int outoffset);
 extern void asm_colour_convert_block(JBLOCK jblock, int *outptr, int outoffset);

h/jpegdata

@@ -190,16 +190,14 @@ typedef struct
 } huff_pointer;
 
 /* ------------- Error codes for various forms of unacceptable JPEG file ------------- */
-#define E_PRE_NOT_8         1            /* Data precision not 8 */
-#define E_RESTART           2            /* Restart interval not 0 */
-#define E_MULTI_SCAN        3            /* Multi-scan file */
-#define E_TOO_HIGH          4            /* Image too high, max is %i pixels */
-#define E_BAD_SAMPLE        5            /* Bad sample factor */
-#define E_HEIGHT            6            /* Height is %i, not as specified */
-#define E_WIDTH             7            /* Width is %i, not as specified */
-#define E_COLOUR            8            /* Bad colour space (%i), not grey or YUV */
-#define E_COMPONENTS        9            /* Bad number (%i) of components, only 1 or 3 allowed */
-#define E_TOO_WIDE          10           /* Image too wide, max is %i pixels */
+#define E_PRE_NOT_8         1            /* Unsupported - Data precision not 8 */
+#define E_MULTI_SCAN        2            /* Unsupported - Multi scan file */
+#define E_COMPONENTS        3            /* Unsupported - Bad number of components, only 1 or 3 allowed */
+#define E_BAD_SAMPLE        4            /* Bad sample factor */
+#define E_HEIGHT_DISAGREES  5            /* Height is not as specified */
+#define E_WIDTH_DISAGREES   6            /* Width is not as specified */
+#define E_COLOUR            7            /* Bad colour space, not grey or YUV */
+#define E_TOO_WIDE          8            /* Image too wide based on number of MCUs */
 
 /* ------------- Working data for decompression ---------------------------------- */