Changeset 37ceccb for libcfa

Timestamp:

Oct 17, 2023, 12:12:00 PM (18 months ago)

Author:

Michael Brooks <mlbrooks@…>

Branches:

master

Children:

5e0bba5

Parents:

1b41219

Message:

Change string-read semantics so that reading nothing leaves the original value unmodified.

Logically revert #8cffa4f21, and apply the change onto work done since.

At cstring layer, libcfa change is a simplification, and test suite change is merely a different expectation.

At var-len-string layer, libcfa change is a patch to enable detecting the nothing-read case,
and test sute change (shows the different expectation but also) puts a similar patch into its "stop trying if nothing read" loop exits.

Location:

libcfa/src

Files:

• collections/string_res.cfa (modified) (3 diffs)
• iostream.cfa (modified) (1 diff)

libcfa/src/collections/string_res.cfa ¶

@@ -236 +236 @@
         // get bytes
         try {
+                        *(temp.Handle.ulink->EndVbyte) = '\0';   // pre-assign empty cstring
             in | wdi( lenReadable, temp.Handle.ulink->EndVbyte );
         } catch (cstring_length*) {
@@ -247 +248 @@
     }
 
-    s = temp;
+        if ( temp.Handle.lnth > 0 ) s = temp;
     return in;
 }
@@ -268 +269 @@
         cstr[wd] = '\0';                                                                        // guard null terminate string
         try {
+                cstr[0] = '\0';                                                                 // pre-assign as empty cstring
                 is | cf;
         } catch( cstring_length * ) {
                 cont = true;
         } finally {
-        if ( ! cf.flags.ignore ) *(f.s) = cstr;                 // ok to initialize string
+                if ( ! cf.flags.ignore &&                                               // ok to initialize string
+                                cstr[0] != '\0' ) {                                             // something was read
+                        *(f.s) = cstr;
+                }
         } // try
         for ( ; cont; )  {                                                                      // overflow read ?
                 cont = false;
                 try {
+                        cstr[0] = '\0';                                                         // pre-assign as empty cstring
                         is | cf;
                 } catch( cstring_length * ) {
                         cont = true;                                                            // continue not allowed
                 } finally {
-                        if ( ! cf.flags.ignore ) *(f.s) += cstr;        // build string chunk at a time
+                        if ( ! cf.flags.ignore &&
+                                        cstr[0] != '\0' ) {                                     // something was read
+                                *(f.s) += cstr;                                                 // build string chunk at a time
+                        }
                 } // try
         } // for

libcfa/src/iostream.cfa ¶

@@ -1021 +1021 @@
                 int check = f.wd - 2;
                 if (! f.flags.ignore ) {
-                        f.s[0] = '\0';
                         if ( ! f.flags.rwd ) f.s[check] = '\0';         // insert sentinel
                 }