Always use isascii() with isspace()

isspace() must only used with an unsigned char or EOF argument,
and even then its result can depend on the current locale settings.

While this is not a problem for C/C++ executables which use the default
"C" locale, it becomes a problem when the Tesseract API is called from
languages like Python or Java which don't use the "C" locale.

By calling isasci() before calling isspace() this uncertainty can be
avoided, because any locale will hopefully give identical results for
the basic ASCII character set.

Signed-off-by: Stefan Weil <sw@weilnetz.de>

src/ccmain/paragraphs.cpp

@@ -2455,7 +2455,7 @@ static void InitializeRowInfo(bool after_recognition,
   int trailing_ws_idx = strlen(text.get());  // strip trailing space
   while (trailing_ws_idx > 0 &&
          // isspace() only takes ASCII
-         ((text[trailing_ws_idx - 1] & 0x80) == 0) &&
+         isascii(text[trailing_ws_idx - 1]) &&
          isspace(text[trailing_ws_idx - 1]))
     trailing_ws_idx--;
   if (trailing_ws_idx > 0) {

src/ccutil/scanutils.cpp

@@ -75,7 +75,7 @@ inline size_t LongBit() {
 static inline int
 SkipSpace(FILE *s) {
   int p;
-  while (isspace(p = fgetc(s)));
+  while (isascii(p = fgetc(s)) && isspace(p));
   ungetc(p, s);  // Make sure next char is available for reading
   return p;
 }
@@ -108,9 +108,7 @@ static uintmax_t streamtoumax(FILE* s, int base) {
   uintmax_t v = 0;
   int d, c = 0;
 
-  for (c = fgetc(s);
-    isspace(static_cast<unsigned char>(c)) && (c != EOF);
-    c = fgetc(s)) {}
+  for (c = fgetc(s); isascii(c) && isspace(c); c = fgetc(s));
 
   // Single optional + or -
   if (c == '-' || c == '+') {
@@ -151,9 +149,7 @@ static double streamtofloat(FILE* s) {
   int k = 1;
   int w = 0;
 
-  for (c = fgetc(s);
-    isspace(static_cast<unsigned char>(c)) && (c != EOF);
-    c = fgetc(s));
+  for (c = fgetc(s); isascii(c) && isspace(c); c = fgetc(s));
 
   // Single optional + or -
   if (c == '-' || c == '+') {
@@ -265,7 +261,7 @@ static int tvfscanf(FILE* stream, const char *format, va_list ap) {
         if (ch == '%') {
           state = ST_FLAGS;
           flags = 0; rank = RANK_INT; width = UINT_MAX;
-        } else if (isspace(static_cast<unsigned char>(ch))) {
+        } else if (isascii(ch) && isspace(ch)) {
           SkipSpace(stream);
         } else {
           if (fgetc(stream) != ch)
@@ -445,7 +441,7 @@ static int tvfscanf(FILE* stream, const char *format, va_list ap) {
               unsigned length = 0;
               while (width--) {
                 q = fgetc(stream);
-                if (isspace(static_cast<unsigned char>(q)) || q <= 0) {
+                if (isascii(q) && isspace(q) || q <= 0) {
                   ungetc(q, stream);
                   break;
                 }

src/wordrec/params_model.cpp

@@ -58,7 +58,10 @@ bool ParamsModel::ParseLine(char *line, char** key, float *val) {
   if (line[0] == '#')
     return false;
   int end_of_key = 0;
-  while (line[end_of_key] && !isspace(line[end_of_key])) end_of_key++;
+  while (line[end_of_key] &&
+         !(isascii(line[end_of_key]) && isspace(line[end_of_key]))) {
+    end_of_key++;
+  }
   if (!line[end_of_key]) {
     tprintf("ParamsModel::Incomplete line %s\n", line);
     return false;