Merge pull request #249 from xexyl/1994-schnitzi

1994/schnitzi/README.md

@@ -14,11 +14,15 @@
 
 	./schnitzi < textfile
 
-[Cody Boone Ferguson](/winners.html#Cody_Boone_Ferguson) fixed the entry to not
+[Cody Boone Ferguson](/winners.html#Cody_Boone_Ferguson) increased the buffer
-overflow the buffer (and segfault) by changing the call of `gets()` to
+size from 100 to 10000. Changing it to use `fgets()` instead of `gets()` is more
-`fgets()`. He also increased the buffer size. Prior to this fix one could not
+problematic because when feeding the source code to the program the output
-redirect the Makefile into this program, as an example problem. Thank you Cody
+results in compiler errors and not only that but the gets() is still there in
-for your assistance!
+the generated output. Even changing the buffer size can result in compilation
+errors if not done correctly. The generated output also does not have a changed
+buffer size. Changing it to use fgets() can happen later, maybe, but bigger
+files can now be parsed by the original code. An example is this Makefile. Thank
+you Cody!
 
 
 ## Try:

1994/schnitzi/schnitzi.c

@@ -20,12 +20,12 @@ h                   mh111 de{l)   +di (+'( d+%  c n+
  */                 n         =             0     ;
                main        (       )   {
                 char       v   [
-                1000   ]                   ,  s;
+              10000    ]                   ,  s;
-          int t[100    ]                    ,
+          int t[100     ]                    ,
-              u[100              ]     ;  u
+              u[100               ]     ;  u
                   [                   0
       ]=ftell(stdin        )       ;
-         while(fgets(v,100,stdin )&&((v[strlen(v)-1]='\0',1))                )
+         while(gets (v    )                 )
                  {t  [         r ]=
              strlen                 (
                v);y=

bugs.md

@@ -453,6 +453,63 @@ this simply does not work with them. Can you help us?
 
 # 1994
 
+## [1994/schnitzi](1994/schnitzi.c) ([README.md])(1994/schnitzi/README.md))
+## STATUS: uses gets() - change to fgets() if possible
+
+The original buffer size of this entry is 100 which is very easily overflowed
+with `gets()` which it uses. [Cody Boone
+Ferguson](/winners.html#Cody_Boone_Ferguson) changed the buffer size to 10000
+but he notes a problem in that this does not translate to the generated source
+file (when feeding the source itself). With `fgets()` it generates compiler
+errors. Without special care with changing the buffer size it would also
+generate compiler errors. Cody explains the magic below which might be used to
+change this entry to fgets() (and he'll be working on it in the coming days most
+likely).
+
+### The magic of the entry
+
+Take a look at the interesting comment as well as the `int r=0,x,y=0` at the top
+of the file. If you look at each column go down that column you can see how it
+spells out the code. For instance the first column looks like:
+
+
+```
+i
+n
+c
+l
+u
+d
+e
+ 
+<
+s
+t
+d
+i
+o
+.
+h
+>
+```
+
+If you join the lines you end up with:
+
+
+```c
+#include <stdio.h>
+```
+
+If you look at column 25 which is the end of the word 'mh111' and you go down to
+the next row you'll see a 0 and if you go one row down another 0. This is the
+buffer size, 100, for `u`. The column to the left is the same for the `t`
+variable.
+
+Thus it seems that in order to get the generated output correct one needs to
+provide the correct input in comments or possibly by rearranging some of the
+code (this was required to make the generated code compile at all when changing
+the buffer size).
+
 
 # 1995