Allowed character code zero to be remapped with other character codes.

doc/ca65.sgml

@@ -4,7 +4,7 @@
 <title>ca65 Users Guide
 <author><url url="mailto:uz@cc65.org" name="Ullrich von Bassewitz">,<newline>
 <url url="mailto:greg.king5@verizon.net" name="Greg King">
-<date>2015-11-17
+<date>2016-06-11
 
 <abstract>
 ca65 is a powerful macro assembler for the 6502, 65C02, and 65816 CPUs. It is
@@ -2170,16 +2170,15 @@ Here's a list of all control commands and a description, what they do:
 <sect1><tt>.CHARMAP</tt><label id=".CHARMAP"><p>
 
   Apply a custom mapping for characters. The command is followed by two
-  numbers. The first one is the index of the source character (range 1..255),
+  numbers. The first one is the index of the source character (range 0..255);
   the second one is the mapping (range 0..255). The mapping applies to all
-  character and string constants when they generate output, and overrides a
+  character and string constants <em/when/ they generate output; and, overrides
-  mapping table specified with the <tt><ref id="option-t" name="-t"></tt>
+  a mapping table specified with the <tt><ref id="option-t" name="-t"></tt>
   command line switch.
 
   Example:
-
   <tscreen><verb>
-       	.charmap        $41, $61        ; Map 'A' to 'a'
+  .charmap        $41, $61        ; Map 'A' to 'a'
   </verb></tscreen>
 
 

doc/cc65.sgml

@@ -4,7 +4,7 @@
 <title>cc65 Users Guide
 <author><url url="mailto:uz@cc65.org" name="Ullrich von Bassewitz">,<newline>
 <url url="mailto:gregdk@users.sf.net" name="Greg King">
-<date>2016-04-22
+<date>2016-06-11
 
 <abstract>
 cc65 is a C compiler for 6502 targets. It supports several 6502 based home
@@ -478,15 +478,15 @@ Here is a description of all the command line options:
 
 
   <label id="option-W">
-  <tag><tt>-W name[,name]</tt></tag>
+  <tag><tt>-W name[,name,...]</tt></tag>
 
   This option allows to control warnings generated by the compiler. It is
-  followed by a comma separated list of warnings that should be enabled or
+  followed by a comma-separated list of warnings that should be enabled or
   disabled. To disable a warning, its name is prefixed by a minus sign. If
   no such prefix exists, or the name is prefixed by a plus sign, the warning
   is enabled.
 
-  The following warning names are currently recognized:
+  The following warning names currently are recognized:
   <descrip>
   <tag><tt/const-comparison/</tag>
         Warn if the result of a comparison is constant.
@@ -494,10 +494,13 @@ Here is a description of all the command line options:
         Treat all warnings as errors.
   <tag><tt/no-effect/</tag>
         Warn about statements that don't have an effect.
+  <tag><tt/remap-zero/</tag>
+        Warn about a <tt/<ref id="pragma-charmap" name="#pragma charmap()">/
+        that changes a character's code number from/to 0x00.
   <tag><tt/struct-param/</tag>
         Warn when passing structs by value.
   <tag><tt/unknown-pragma/</tag>
-        Warn about known #pragmas.
+        Warn about #pragmas that aren't recognized by cc65.
   <tag><tt/unused-label/</tag>
         Warn about unused labels.
   <tag><tt/unused-param/</tag>
@@ -506,11 +509,11 @@ Here is a description of all the command line options:
         Warn about unused variables.
   </descrip>
 
-  The full list of available warning names may be retrieved by using the
+  The full list of available warning names can be retrieved by using the
   option <tt><ref id="option-list-warnings" name="--list-warnings"></tt>.
 
-  You may also use <tt><ref id="pragma-warn" name="#pragma&nbsp;warn"></tt> to
+  You may use also <tt><ref id="pragma-warn" name="#pragma&nbsp;warn"></tt> to
-  control this setting for smaller pieces of code from within your code.
+  control this setting, for smaller pieces of code, from within your sources.
 
 </descrip><p>
 
@@ -931,34 +934,38 @@ parameter with the <tt/#pragma/.
 <sect1><tt>#pragma charmap (&lt;index&gt;, &lt;code&gt;)</tt><label id="pragma-charmap"><p>
 
   Each literal string and each literal character in the source is translated
-  by use of a translation table. This translation table is preset when the
+  by use of a translation table. That translation table is preset when the
-  compiler is started depending on the target system, for example to map
+  compiler is started, depending on the target system; for example, to map
-  ISO-8859-1 characters into PETSCII if the target is a commodore machine.
+  ISO-8859-1 characters into PETSCII if the target is a Commodore machine.
 
   This pragma allows to change entries in the translation table, so the
   translation for individual characters, or even the complete table may be
-  adjusted.
+  adjusted. Both arguments are assumed to be unsigned characters with a valid
+  range of 0-255.
 
-  Both arguments are assumed to be unsigned characters with a valid range of
+  Beware of some pitfalls:
-  1-255.
+  <itemize>
-
+  <item>The character index is actually the code of the character in the
-  Beware of two pitfalls:
+        C source; so, character mappings do always depend on the source
-
+        character set. That means that <tt/#pragma&nbsp;charmap()/ is not
-    <itemize>
+        portable -- it depends on the build environment.
-    <item>The character index is actually the code of the character in the
+  <item>While it is possible to use character literals as indices, the
-      	  C source, so character mappings do always depend on the source
+        result may be somewhat unexpected, since character literals are
-      	  character set. This means that <tt/#pragma&nbsp;charmap/ is not
+        themselves translated. For that reason, I would suggest to avoid
-	  portable -- it depends on the build environment.
+        character literals, and use numeric character codes instead.
-    <item>While it is possible to use character literals as indices, the
+  <item>It is risky to change index <tt/0x00/, because string functions depend
-      	  result may be somewhat unexpected, since character literals are
+        on it. If it is changed, then the <tt/'\0'/ at the end of string
-      	  itself translated. For this reason I would suggest to avoid
+        literals will become non-zero. Functions that are used on those
-      	  character literals and use numeric character codes instead.
+        literals won't stop at the end of them. cc65 will warn you if you do
-    </itemize>
+        change that code number. You can turn off that <tt/remap-zero/ warning
+        if you are certain that you know what you are doing (see <tt/<ref
+        id="pragma-warn" name="#pragma&nbsp;warn()">/).
+  </itemize>
 
   Example:
   <tscreen><verb>
-        /* Use a space wherever an 'a' occurs in ISO-8859-1 source */
+  /* Use a space wherever an 'a' occurs in ISO-8859-1 source */
-       	#pragma charmap (0x61, 0x20);
+  #pragma charmap (0x61, 0x20);
   </verb></tscreen>
 
 
@@ -1129,7 +1136,7 @@ parameter with the <tt/#pragma/.
 
   Switch compiler warnings on or off. "name" is the name of a warning (see the
   <tt/<ref name="-W" id="option-W">/ compiler option for a list). The name is
-  either followed by "pop", which restores the last pushed state, or by "on" or
+  followed either by "pop", which restores the last pushed state, or by "on" or
   "off", optionally preceeded by "push" to push the current state before
   changing it.
 
@@ -1144,6 +1151,7 @@ parameter with the <tt/#pragma/.
         #pragma warn (unused-param, pop)
   </verb></tscreen>
 
+
 <sect1><tt>#pragma writable-strings ([push,] on|off)</tt><label id="pragma-writable-strings"><p>
 
   Changes the storage location of string literals. For historical reasons,

src/ca65/pseudo.c

@@ -618,16 +618,16 @@ static void DoCase (void)
 
 
 static void DoCharMap (void)
-/* Allow custome character mappings */
+/* Allow custom character mappings */
 {
     long Index;
     long Code;
 
     /* Read the index as numerical value */
     Index = ConstExpression ();
-    if (Index <= 0 || Index > 255) {
+    if (Index < 0 || Index > 255) {
         /* Value out of range */
-        ErrorSkip ("Range error");
+        ErrorSkip ("Index range error");
         return;
     }
 
@@ -638,7 +638,7 @@ static void DoCharMap (void)
     Code = ConstExpression ();
     if (Code < 0 || Code > 255) {
         /* Value out of range */
-        ErrorSkip ("Range error");
+        ErrorSkip ("Code range error");
         return;
     }
 

src/cc65/error.c

@@ -66,11 +66,12 @@ IntStack WarningsAreErrors  = INTSTACK(0);  /* Treat warnings as errors */
                                             /* Warn about: */
 IntStack WarnConstComparison= INTSTACK(1);  /* - constant comparison results */
 IntStack WarnNoEffect       = INTSTACK(1);  /* - statements without an effect */
+IntStack WarnRemapZero      = INTSTACK(1);  /* - remapping character code zero */
 IntStack WarnStructParam    = INTSTACK(1);  /* - structs passed by val */
+IntStack WarnUnknownPragma  = INTSTACK(1);  /* - unknown #pragmas */
 IntStack WarnUnusedLabel    = INTSTACK(1);  /* - unused labels */
 IntStack WarnUnusedParam    = INTSTACK(1);  /* - unused parameters */
 IntStack WarnUnusedVar      = INTSTACK(1);  /* - unused variables */
-IntStack WarnUnknownPragma  = INTSTACK(1);  /* - unknown #pragmas */
 
 /* Map the name of a warning to the intstack that holds its state */
 typedef struct WarnMapEntry WarnMapEntry;
@@ -79,10 +80,11 @@ struct WarnMapEntry {
     const char* Name;
 };
 static WarnMapEntry WarnMap[] = {
-    /* Keep sorted, even if this isn't used for now */
+    /* Keep names sorted, even if it isn't used for now */
-    { &WarningsAreErrors,       "error"                 },
     { &WarnConstComparison,     "const-comparison"      },
+    { &WarningsAreErrors,       "error"                 },
     { &WarnNoEffect,            "no-effect"             },
+    { &WarnRemapZero,           "remap-zero"            },
     { &WarnStructParam,         "struct-param"          },
     { &WarnUnknownPragma,       "unknown-pragma"        },
     { &WarnUnusedLabel,         "unused-label"          },

src/cc65/error.h

@@ -65,11 +65,12 @@ extern IntStack WarningsAreErrors;      /* Treat warnings as errors */
                                         /* Warn about: */
 extern IntStack WarnConstComparison;    /* - constant comparison results */
 extern IntStack WarnNoEffect;           /* - statements without an effect */
+extern IntStack WarnRemapZero;          /* - remapping character code zero */
 extern IntStack WarnStructParam;        /* - structs passed by val */
+extern IntStack WarnUnknownPragma;      /* - unknown #pragmas */
 extern IntStack WarnUnusedLabel;        /* - unused labels */
 extern IntStack WarnUnusedParam;        /* - unused parameters */
 extern IntStack WarnUnusedVar;          /* - unused variables */
-extern IntStack WarnUnknownPragma;      /* - unknown #pragmas */
 
 
 

src/cc65/pragma.c

@@ -453,13 +453,14 @@ static void CharMapPragma (StrBuf* B)
         return;
     }
     if (Index < 1 || Index > 255) {
-        if (Index == 0) {
+        if (Index != 0) {
-            /* For groepaz */
-            Error ("Remapping 0 is not allowed");
-        } else {
             Error ("Character index out of range");
+            return;
+        }
+        /* For groepaz and Christian */
+        if (IS_Get (&WarnRemapZero)) {
+            Warning ("Remapping from 0 is dangerous with string functions");
         }
-        return;
     }
 
     /* Comma follows */
@@ -472,13 +473,14 @@ static void CharMapPragma (StrBuf* B)
         return;
     }
     if (C < 1 || C > 255) {
-        if (C == 0) {
+        if (C != 0) {
-            /* For groepaz */
-            Error ("Remapping 0 is not allowed");
-        } else {
             Error ("Character code out of range");
+            return;
+        }
+        /* For groepaz and Christian */
+        if (IS_Get (&WarnRemapZero)) {
+            Warning ("Remapping to 0 can make string functions stop unexpectedly");
         }
-        return;
     }
 
     /* Remap the character */

src/cc65/pragma.h

@@ -6,10 +6,10 @@
 /*                                                                           */
 /*                                                                           */
 /*                                                                           */
-/* (C) 1998-2002 Ullrich von Bassewitz                                       */
+/* (C) 1998-2002, Ullrich von Bassewitz                                      */
-/*               Wacholderweg 14                                             */
+/*                Roemerstrasse 52                                           */
-/*               D-70597 Stuttgart                                           */
+/*                D-70794 Filderstadt                                        */
-/* EMail:        uz@cc65.org                                                 */
+/* EMail:         uz@cc65.org                                                */
 /*                                                                           */
 /*                                                                           */
 /* This software is provided 'as-is', without any expressed or implied       */

src/common/tgttrans.c

@@ -124,6 +124,6 @@ void TgtTranslateStrBuf (StrBuf* Buf)
 void TgtTranslateSet (unsigned Index, unsigned char C)
 /* Set the translation code for the given character */
 {
-    CHECK (Index > 0 && Index < sizeof (Tab));
+    CHECK (Index < sizeof (Tab));
     Tab[Index] = C;
 }