checkpoint on string realloc bug fix attempt

In preparation to fix issue #47, we:

Fix a minor typo in `Makefile.config`.

Move `stringindex(char *format, char *test)` from `str.c` into `codegen.c`
as static function.

Expand `STR_TABLECHUNK` from `1<<10` to `1<<16`.

Identify with an XXX comment, a problematic `realloc()` call in the
`addstr(STRINGHEAD *hp, char *str)` function of `str.c`.

Move the `charstr(int ch)` in `str.c` above the only function that uses
it, `addliteral(char *str)`, and make it a static function.

Improved comments about return values for `str.c` functions that
work on STRINGHEAD pointers.

Makefile.config

@@ -1358,7 +1358,7 @@ COMMON_LDFLAGS= ${EXTRA_LDFLAGS}
 # For more info see: https://github.com/google/sanitizers/wiki/AddressSanitizer
 # See also: https://developer.apple.com/documentation/xcode/diagnosing-memory-thread-and-crash-issues-early
 #
-# The following Address Sanitizer (ASAN) are common to both REHL9.2 (Linux) and macOS 14.0.
+# The following Address Sanitizer (ASAN) are common to both RHEL9.2 (Linux) and macOS 14.0.
 #
 # By default, the Address Sanitizer is NOT enabled, not compiled into calc.
 # To enable the Address Sanitizer, uncomment the appropriate lines in Makefile.local !!!

codegen.c

@@ -1,7 +1,7 @@
 /*
  * codegen - module to generate opcodes from the input tokens
  *
- * Copyright (C) 1999-2007,2017,2021-2023  David I. Bell and Ernest Bowen
+ * Copyright (C) 1999-2007,2017,2021-2023,2025  David I. Bell and Ernest Bowen
  *
  * Primary author:  David I. Bell
  *
@@ -2425,6 +2425,40 @@ getfilename(char *name, size_t namelen, bool *once)
 }
 
 
+/*
+ * Useful routine to return the index of one string within another one
+ * which has the format:  "str1\000str2\000str3\000...strn\0\0".  Index starts
+ * at one for the first string.  Returns zero if the string being checked
+ * is not contained in the formatted string.
+ *
+ * Be sure to use \000 instead of \0.  ANSI-C compilers interpret "foo\0foo..."
+ * as "foo\017oo...".
+ *
+ * given:
+ *      format          string formatted into substrings
+ *      test            string to be found in formatted string
+ */
+S_FUNC long
+stringindex(char *format, char *test)
+{
+        long index;             /* found index */
+        size_t len;             /* length of current piece of string */
+        size_t testlen;         /* length of test string */
+
+        testlen = strlen(test);
+        index = 1;
+        while (*format) {
+                len = strlen(format);
+                if ((len == testlen) && (*format == *test) &&
+                        (strcmp(format, test) == 0))
+                                return index;
+                format += (len + 1);
+                index++;
+        }
+        return 0;
+}
+
+
 /*
  * Read the show command to display useful information
  */

str.c

@@ -1,7 +1,7 @@
 /*
  * str - string list routines
  *
- * Copyright (C) 1999-2007,2021-2023  David I. Bell and Ernest Bowen
+ * Copyright (C) 1999-2007,2021-2023,2025  David I. Bell and Ernest Bowen
  *
  * Primary author:  David I. Bell
  *
@@ -42,7 +42,7 @@
 #include "banned.h"     /* include after system header <> includes */
 
 
-#define STR_TABLECHUNK  (1<<10) /* how often to reallocate string table */
+#define STR_TABLECHUNK  (1<<16) /* how often to reallocate string literal table */
 #define STR_CHUNK       (1<<16) /* size of string storage allocation */
 #define OCTET_VALUES    256     /* number of different values in a OCTET */
 #define STR_UNIQUE      (1<<7)  /* size of string to allocate separately */
@@ -97,6 +97,10 @@ initstr(STRINGHEAD *hp)
  * given:
  *      hp              header of string storage
  *      str             string to be added
+ *
+ * returns:
+ *      != NULL ==> pointer to newly added string
+ *      NULL    ==> unable to add string
  */
 char *
 addstr(STRINGHEAD *hp, char *str)
@@ -113,6 +117,10 @@ addstr(STRINGHEAD *hp, char *str)
                 /* alloc + 1 guard paranoia */
                 newsize = len + STR_CHUNK + hp->h_used + hp->h_avail + 1;
                 /* alloc + 1 guard paranoia */
+                /*
+                 * XXX - doing a realloc can cause problems if the larger list has to be
+                 *       relocated due the recalloc() call and stuff point to old location
+                 */
                 list = (char *)realloc(hp->h_list, newsize + 1);
                 if (list == NULL)
                         return NULL;
@@ -130,35 +138,6 @@ addstr(STRINGHEAD *hp, char *str)
 }
 
 
-/*
- * Return a null-terminated string which consists of a single character.
- * The table is initialized on the first call.
- */
-char *
-charstr(int ch)
-{
-        char *cp;
-        int i;
-
-        if (chartable == NULL) {
-                /* alloc + 1 guard paranoia */
-                cp = (char *)malloc((OCTET_VALUES + 1)*2);
-                if (cp == NULL) {
-                        math_error("Cannot allocate character table");
-                        not_reached();
-                }
-                for (i = 0; i < OCTET_VALUES; i++) {
-                        *cp++ = (char)i;
-                        *cp++ = '\0';
-                }
-                chartable = cp - (OCTET_VALUES*2);
-                *cp++ = '\0';   /* guard paranoia */
-                *cp++ = '\0';   /* guard paranoia */
-        }
-        return &chartable[(ch & 0xff) * 2];
-}
-
-
 /*
  * Find a string with the specified name and return its number in the
  * string list.  The first string is numbered zero.  Minus one is returned
@@ -166,7 +145,11 @@ charstr(int ch)
  *
  * given:
  *      hp              header of string storage
- *      str             string to be added
+ *      str             string to be searched for
+ *
+ * returns:
+ *      >= 0 ==> index of string
+ *      -1   ==> unable to find string
  */
 int
 findstr(STRINGHEAD *hp, char *str)
@@ -200,6 +183,10 @@ findstr(STRINGHEAD *hp, char *str)
  * given:
  *      hp              header of string storage
  *      n               string index
+ *
+ * returns:
+ *      non-empty string ==> string at index n
+ *      ""               ==> no strings or string at index n
  */
 char *
 namestr(STRINGHEAD *hp, long n)
@@ -219,36 +206,31 @@ namestr(STRINGHEAD *hp, long n)
 
 
 /*
- * Useful routine to return the index of one string within another one
+ * Return a null-terminated string which consists of a single character.
- * which has the format:  "str1\000str2\000str3\000...strn\0\0".  Index starts
+ * The table is initialized on the first call.
- * at one for the first string.  Returns zero if the string being checked
- * is not contained in the formatted string.
- *
- * Be sure to use \000 instead of \0.  ANSI-C compilers interpret "foo\0foo..."
- * as "foo\017oo...".
- *
- * given:
- *      format          string formatted into substrings
- *      test            string to be found in formatted string
  */
-long
+S_FUNC char *
-stringindex(char *format, char *test)
+charstr(int ch)
 {
-        long index;             /* found index */
+        char *cp;
-        size_t len;             /* length of current piece of string */
+        int i;
-        size_t testlen;         /* length of test string */
 
-        testlen = strlen(test);
+        if (chartable == NULL) {
-        index = 1;
+                /* alloc + 1 guard paranoia */
-        while (*format) {
+                cp = (char *)malloc((OCTET_VALUES + 1)*2);
-                len = strlen(format);
+                if (cp == NULL) {
-                if ((len == testlen) && (*format == *test) &&
+                        math_error("Cannot allocate character table");
-                        (strcmp(format, test) == 0))
+                        not_reached();
-                                return index;
+                }
-                format += (len + 1);
+                for (i = 0; i < OCTET_VALUES; i++) {
-                index++;
+                        *cp++ = (char)i;
+                        *cp++ = '\0';
+                }
+                chartable = cp - (OCTET_VALUES*2);
+                *cp++ = '\0';   /* guard paranoia */
+                *cp++ = '\0';   /* guard paranoia */
         }
-        return 0;
+        return &chartable[(ch & 0xff) * 2];
 }
 
 

str.h

@@ -1,7 +1,7 @@
 /*
  * str - string list routines
  *
- * Copyright (C) 1999-2007,2014  David I. Bell
+ * Copyright (C) 1999-2007,2014,2025  David I. Bell
  *
  * Calc is open software; you can redistribute it and/or modify it under
  * the terms of the version 2.1 of the GNU Lesser General Public License
@@ -59,9 +59,7 @@ E_FUNC void initstr(STRINGHEAD *hp);
 E_FUNC char *addstr(STRINGHEAD *hp, char *str);
 E_FUNC char *namestr(STRINGHEAD *hp, long n);
 E_FUNC int findstr(STRINGHEAD *hp, char *str);
-E_FUNC char *charstr(int ch);
 E_FUNC char *addliteral(char *str);
-E_FUNC long stringindex(char *str1, char *str2);
 E_FUNC STRING *stralloc(void);
 E_FUNC long addstring(char *str, size_t len);
 E_FUNC STRING *charstring(int ch);