some more compiler attributes

make sure all textcode/scan_* routines work if dest or destlen is NULL

compiler.h

@@ -191,11 +191,18 @@
 // __strout: Argument idx (counted left to right from 1) is a non-NULL string the function writes
 // Currently we can't tell the compiler that the output will be 0-terminated.
 #define __strout(idx) __attribute__((nonnull(idx),__access(write_only,idx)))
+// __strout_ornull: Argument idx (counted left to right from 1) is a string the function writes (may be NULL)
+// Currently we can't tell the compiler that the output will be 0-terminated.
+#define __strout_ornull(idx) __attribute__((__access(write_only,idx)))
 // __strnout: Argument idx (counted left to right from 1) is a non-NULL string the function writes, buffer size given in szidx'th function argument (in array elements, not necessarily bytes)
 // Currently we can't tell the compiler that the output will be 0-terminated.
 #define __strnout(idx,szidx) __attribute__((nonnull(idx),__access3(write_only,idx,szidx)))
 // __bufout: Argument idx (counted left to right from 1) is a non-NULL buffer the function writes, buffer size given in szidx'th function argument (in array elements, not necessarily bytes)
 #define __bufout(bufidx,szidx) __attribute__((nonnull(bufidx),__access3(write_only,bufidx,szidx)))
+// __retarg: Returns value in argument idx (counted left to right from 1) which must be non-NULL
+#define __retarg(bufidx) __attribute__((nonnull(bufidx),__access(write_only,bufidx)))
+// __retarg_ornull: Returns value in argument idx (counted left to right from 1) which can be NULL
+#define __retarg_ornull(bufidx) __attribute__((__access(write_only,bufidx)))
 // __strinout: Argument idx (counted left to right from 1) is a non-NULL string the function reads and writes
 // Currently we can't tell the compiler that the output will be 0-terminated.
 #define __strinout(idx) __attribute__((nonnull(idx),__access(read_write,idx),null_terminated_string_arg(idx)))

textcode.h

@@ -3,6 +3,7 @@
 #define TEXTCODE_H
 
 #include <stddef.h>
+#include <libowfat/compiler.h>
 
 #ifdef __cplusplus
 extern "C" {
@@ -11,120 +12,125 @@ extern "C" {
 /* These take len bytes from src and write them in encoded form to
  * dest (if dest != NULL), returning the number of bytes written. */
 
-/* dietlibc defines these in sys/cdefs.h, which is included from stddef.h */
-#ifndef __readmemsz__
-#define __readmemsz__(a,b)
-#endif
-
-#ifndef __writemem__
-#define __writemem__(a)
-#endif
-
 /* Needs len/3*4 bytes */
-__writemem__(1) __readmemsz__(2,3)
+__strout_ornull(1) __bufin(2,3)
 size_t fmt_uuencoded(char* dest,const char* src,size_t len);
 
 /* Needs len/3*4 bytes */
-__writemem__(1) __readmemsz__(2,3)
+__strout_ornull(1) __bufin(2,3)
 size_t fmt_base64(char* dest,const char* src,size_t len);
 
-__writemem__(1) __readmemsz__(2,3)
+__strout_ornull(1) __bufin(2,3)
 size_t fmt_base64url(char* dest,const char* src,size_t len);
 
 /* Worst case: len*3 */
-__writemem__(1) __readmemsz__(2,3)
+__strout_ornull(1) __bufin(2,3)
 size_t fmt_quotedprintable(char* dest,const char* src,size_t len);
 
 /* Worst case: len*3 */
-__writemem__(1) __readmemsz__(2,3)
+__strout_ornull(1) __bufin(2,3)
 size_t fmt_quotedprintable2(char* dest,const char* src,size_t len,const char* escapeme);
 
 /* Worst case: len*3 */
-__writemem__(1) __readmemsz__(2,3)
+__strout_ornull(1) __bufin(2,3)
 size_t fmt_urlencoded(char* dest,const char* src,size_t len);
 
 /* Worst case: len*3 */
-__writemem__(1) __readmemsz__(2,3)
+__strout_ornull(1) __bufin(2,3)
 size_t fmt_urlencoded2(char* dest,const char* src,size_t len,const char* escapeme);
 
 /* Worst case: len*2 */
-__writemem__(1) __readmemsz__(2,3)
+__strout_ornull(1) __bufin(2,3)
 size_t fmt_yenc(char* dest,const char* src,size_t len);
 
 /* Needs len*2 bytes */
-__writemem__(1) __readmemsz__(2,3)
+__strout_ornull(1) __bufin(2,3)
 size_t fmt_hexdump(char* dest,const char* src,size_t len);
 
 /* Change '<' to '&lt;' and '&' to '&amp;' and '\n' to '<br>'; worst case: len*5 */
 /* This is meant for outputting text that goes between tags */
-__writemem__(1) __readmemsz__(2,3)
+__strout_ornull(1) __bufin(2,3)
 size_t fmt_html(char* dest,const char* src,size_t len);
 
 /* Change '<' to '&lt;' and '&' to '&amp;' and '"' to '&quot;'; worst case: len*6 */
 /* This is meant for outputting text that goes in a tag argument between double quotes*/
-__writemem__(1) __readmemsz__(2,3)
+__strout_ornull(1) __bufin(2,3)
 size_t fmt_html_tagarg(char* dest,const char* src,size_t len);
 
 /* Change '<' to '&lt;' and '&' to '&amp;'; worst case: len*5 */
-__writemem__(1) __readmemsz__(2,3)
+__strout_ornull(1) __bufin(2,3)
 size_t fmt_xml(char* dest,const char* src,size_t len);
 
 /* Change '\' to "\\", '\n' to "\n", ^A to "\x01" etc; worst case: len*4 */
-__writemem__(1) __readmemsz__(2,3)
+__strout_ornull(1) __bufin(2,3)
 size_t fmt_cescape(char* dest,const char* src,size_t len);
 
 /* Worst case: len*4 */
-__writemem__(1) __readmemsz__(2,3)
+__strout_ornull(1) __bufin(2,3)
 size_t fmt_cescape2(char* dest,const char* src,size_t len,const char* escapeme);
 
 /* Fold whitespace to '_'; this is great for writing fields with
  * white spaces to a log file and still allow awk to do log analysis */
 /* Worst case: same size */
-__writemem__(1) __readmemsz__(2,3)
+__strout_ornull(1) __bufin(2,3)
 size_t fmt_foldwhitespace(char* dest,const char* src,size_t len);
 
 /* Worst case: len*3 */
-__writemem__(1) __readmemsz__(2,3)
+__strout_ornull(1) __bufin(2,3)
 size_t fmt_ldapescape(char* dest,const char* src,size_t len);
 
-__writemem__(1) __readmemsz__(2,3)
+__strout_ornull(1) __bufin(2,3)
 size_t fmt_ldapescape2(char* dest,const char* src,size_t len,const char* escapeme);
 
 /* Encode JSON string from UTF-8; will backslash-escape the bare minimum.
  * Invalid UTF-8 in input will output as valid UTF-8 for each byte
  * Worst case: len*6 */
-__writemem__(1) __readmemsz__(2,3)
+__strout_ornull(1) __bufin(2,3)
 size_t fmt_jsonescape(char* dest,const char* src,size_t len);
 
-__writemem__(1) __readmemsz__(2,3)
+__strout_ornull(1) __bufin(2,3)
 size_t fmt_base85(char* dest,const char* src,size_t len);
 
 /* These read one line from src, decode it, and write the result to
  * dest.  The number of decoded bytes is written to destlen.  dest
  * should be able to hold strlen(src) bytes as a rule of thumb. */
+__strin(1) __strout_ornull(2) __retarg_ornull(3)
 size_t scan_uuencoded(const char* src,char* dest,size_t* destlen);
+__strin(1) __strout_ornull(2) __retarg_ornull(3)
 size_t scan_base64(const char* src,char* dest,size_t* destlen);
+__strin(1) __strout_ornull(2) __retarg_ornull(3)
 size_t scan_base64url(const char* src,char* dest,size_t* destlen);
+__strin(1) __strout_ornull(2) __retarg_ornull(3)
 size_t scan_quotedprintable(const char* src,char* dest,size_t* destlen);
+__strin(1) __strout_ornull(2) __retarg_ornull(3)
 size_t scan_urlencoded(const char* src,char* dest,size_t* destlen);
+__strin(1) __strout_ornull(2) __retarg_ornull(3)
 size_t scan_urlencoded2(const char* src,char* dest,size_t* destlen);
+__strin(1) __strout_ornull(2) __retarg_ornull(3)
 size_t scan_yenc(const char* src,char* dest,size_t* destlen);
+__strin(1) __strout_ornull(2) __retarg_ornull(3)
 size_t scan_hexdump(const char* src,char* dest,size_t* destlen);
 /* decodes all html5-standardized &foo; escapes, and also
  * "<br>" to "\n" and "<p>" to "\n\n", leaves the rest of the tags alone */
+__strin(1) __strout_ornull(2) __retarg_ornull(3)
 size_t scan_html(const char* src,char* dest,size_t* destlen);
 /* decodes all html5-standardized &foo; escapes, but leaves all tags
  * alone */
+__strin(1) __strout_ornull(2) __retarg_ornull(3)
 size_t scan_html_tagarg(const char* src,char* dest,size_t* destlen);
 /* Decodes escaped C string text, turning e.g. \n into newline */
+__strin(1) __strout_ornull(2) __retarg_ornull(3)
 size_t scan_cescape(const char* src,char* dest,size_t* destlen);
 /* Decodes escaped LDIF text, turning e.g. \5C into \ */
+__strin(1) __strout_ornull(2) __retarg_ornull(3)
 size_t scan_ldapescape(const char* src,char* dest,size_t* destlen);
 /* Decodes escaped JSON strings (like \"\r\n\u0013), turns escaped
  * surrogate pairs into UTF-8. Expects input to be valid UTF-8. Ends at
  * \0 or unescaped double quote. */
+__strin(1) __strout_ornull(2) __retarg_ornull(3)
 size_t scan_jsonescape(const char* src,char* dest,size_t* destlen);
 
+__strin(1) __strout_ornull(2) __retarg_ornull(3)
 size_t scan_base85(const char* src,char* dest,size_t* destlen);
 
 #ifdef STRALLOC_H

textcode/scan_jsonescape.c

@@ -63,11 +63,11 @@ size_t scan_jsonescape(const char *src,char *dest,size_t *destlen) {
     ++written;
   }
 done:
-  *destlen=written;
+  if (destlen) *destlen=written;
   return i;
 abort:
   if (prev!=(unsigned int)-1) i-=6; // if we abort and there still was an open surrogate pair, cancel it
-  *destlen=written;
+  if (destlen) *destlen=written;
   return i;
 }
 

textcode/scan_quotedprintable.c

@@ -8,16 +8,16 @@ size_t scan_quotedprintable(const char *src,char *dest,size_t *destlen) {
     if (s[i]=='=') {
       int j=scan_fromhex(s[i+1]);
       if (j<0) break;
-      dest[written]=j<<4;
+      if (dest) dest[written]=j<<4;
       j=scan_fromhex(s[i+2]);
       if (j<0) break;
-      dest[written]|=j;
+      if (dest) dest[written]|=j;
       i+=2;
     } else {
-      dest[written]=s[i];
+      if (dest) dest[written]=s[i];
     }
     ++written;
   }
-  *destlen=written;
+  if (destlen) *destlen=written;
   return i;
 }

textcode/scan_urlencoded.c

@@ -12,17 +12,17 @@ static size_t inner_scan_urlencoded(const char *src,char *dest,size_t *destlen,i
       c=j<<4;
       j=scan_fromhex(s[i+2]);
       if (j<0) break;
-      dest[written]=c|j;
+      if (dest) dest[written]=c|j;
       i+=2;
-    } else if (s[i]=='+' && plus)
-      dest[written]=' ';
-    else if (s[i]<=' ' || s[i]=='?' || s[i]=='&')
+    } else if (s[i]=='+' && plus) {
+      if (dest) dest[written]=' ';
+    } else if (s[i]<=' ' || s[i]=='?' || s[i]=='&')
       break;	/* invalid input */
     else
-      dest[written]=s[i];
+      if (dest) dest[written]=s[i];
     ++written;
   }
-  *destlen=written;
+  if (destlen) *destlen=written;
   return i;
 }
 

textcode/scan_yenc.c

@@ -8,13 +8,13 @@ size_t scan_yenc(const char *src,char *dest,size_t *destlen) {
     if (s[i]=='=') {
       ++i;
       if (s[i]=='y') break;
-      dest[written]=s[i]-64-42;
+      if (dest) dest[written]=s[i]-64-42;
     } else if (s[i]=='\n' || s[i]=='\r' || s[i]=='\0')
       break;
     else
-      dest[written]=s[i]-42;
+      if (dest) dest[written]=s[i]-42;
     ++written;
   }
-  *destlen=written;
+  if (destlen) *destlen=written;
   return i;
 }