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marlin "String is truncated when SDSUPPORT is enabled

Positioning of string terminator to truncate checksum from the commands is off by one, causing the last letter of the actual command to be truncated instead of just the checksum. This caused checksummed commands targeting existing files to fail since the last letter of the filename was truncated. Issue 520 on Octoprint though it is a Marlin bug: https://github.com/foosel/OctoPrint/issues/520 Discussion thread: https://groups.google.com/forum/#!topic/octoprint/C7e_HRaflUM"

Bug fixed by commit 2d22902d080

Type	BehaviorViolation
Config	"SDSUPPORT" (1st degree)
Fix-in	code
Location	main

#include <string.h>

static char *strchr_pointer = "eiffel~1.gco*57";

void process_commands()
{
  char *starpos = NULL;
#ifdef SDSUPPORT
    starpos = (strchr(strchr_pointer + 4,'*'));
    if(starpos!=NULL)
        *(starpos-1)='\0'; //ERROR
    assert(strcmp(strchr_pointer,"eiffel~1.gco"));
#endif
}

int main(int argc, char** argv)
{
    process_commands();
    return 0;
}

diff --git a/simple/2d22902.c b/simple/2d22902.c
--- a/simple/2d22902.c
+++ b/simple/2d22902.c
@@ -8,7 +8,7 @@ void process_commands()
 #ifdef SDSUPPORT
 	starpos = (strchr(strchr_pointer + 4,'*'));
 	if(starpos!=NULL)
-		*(starpos-1)='\0'; //ERROR
+		*(starpos)='\0';
 #endif
 }

#include <string.h>

int main(int argc, char** argv)
{
static char *strchr_pointer = "eiffel~1.gco*57";
char *starpos = NULL;
#ifdef SDSUPPORT
	starpos = (strchr(strchr_pointer + 4,'*'));
	if(starpos!=NULL)
		*(starpos-1)='\0'; //ERROR
#endif
return 0;
}

. call  Marlin_main.cpp:1155: void process_commands()
. 1635: else if(code_seen('M'))
. ERROR 1696: *(starpos-1)='\0';