genmodule.c: Fix edge cases in string handling.

svn path=/trunk/yasm/; revision=1664

diff --git a/libyasm/genmodule.c b/libyasm/genmodule.c
index f34fa1c7a8cadb6e097c785597bbf64074148fb3..ee35c830125719783e0461b7e7a013f6f3222206 100644 (file)
--- a/libyasm/genmodule.c
+++ b/libyasm/genmodule.c
@@ -92,10 +92,12 @@ main(int argc, char *argv[])
        while (fgets(str, MAXLINE, in)) {
            /* Strip off any trailing whitespace */
            len = strlen(str);
-           strp = &str[len-1];
-           while (isspace(*strp)) {
-               *strp-- = '\0';
-               len--;
+           if (len > 0) {
+               strp = &str[len-1];
+               while (len > 0 && isspace(*strp)) {
+                   *strp-- = '\0';
+                   len--;
+               }
            }
 
            strp = str;
@@ -141,7 +143,7 @@ main(int argc, char *argv[])
 
 keepgoing:
            /* Check for continuation */
-           if (str[len-1] == '\\') {
+           if (len > 0 && str[len-1] == '\\') {
                str[len-1] = '\0';
                while (isspace(*strp))
                    *strp-- = '\0';
@@ -204,10 +206,8 @@ keepgoing:
            for (i=0; i<num_modules; i++) {
                strcpy(str, modules[i]);
                strp = str;
-               while (*strp != '\0' && *strp != '_') {
-                   len++;
+               while (*strp != '\0' && *strp != '_')
                    strp++;
-               }
                *strp++ = '\0';
 
                fprintf(out, "extern yasm_%s_module yasm_%s_LTX_%s;\n",