diff --git a/src/print.c b/src/print.c
index f0de9f3..71abbf6 100644
--- a/src/print.c
+++ b/src/print.c
@@ -140,14 +140,14 @@ window_fill(int window_identifier,
 					if (opts->ignore_case || (opts->ignore_lower_case && !scrdesc->has_upperchr))
 					{
 						if (opts->force8bit)
-							str = strstr(str, scrdesc->searchterm);
+							str = nstrstr(str, scrdesc->searchterm);
 						else
 							str = utf8_nstrstr(str, scrdesc->searchterm);
 					}
 					else if (opts->ignore_lower_case && scrdesc->has_upperchr)
 					{
 						if (opts->force8bit)
-							str = strstr(str, scrdesc->searchterm);
+							str = nstrstr_ignore_lower_case(str, scrdesc->searchterm);
 						else
 							str = utf8_nstrstr_ignore_lower_case(str, scrdesc->searchterm);
 					}
@@ -194,14 +194,14 @@ window_fill(int window_identifier,
 				if (opts->ignore_case || (opts->ignore_lower_case && !scrdesc->has_upperchr))
 				{
 					if (opts->force8bit)
-						str = strstr(str, scrdesc->searchterm);
+						str = nstrstr(str, scrdesc->searchterm);
 					else
 						str = utf8_nstrstr(str, scrdesc->searchterm);
 				}
 				else if (opts->ignore_lower_case && scrdesc->has_upperchr)
 				{
 					if (opts->force8bit)
-						str = strstr(str, scrdesc->searchterm);
+						str = nstrstr_ignore_lower_case(str, scrdesc->searchterm);
 					else
 						str = utf8_nstrstr_ignore_lower_case(str, scrdesc->searchterm);
 				}
diff --git a/src/pspg.c b/src/pspg.c
index 1a5d4cd..2f849da 100644
--- a/src/pspg.c
+++ b/src/pspg.c
@@ -49,6 +49,103 @@ min_int(int a, int b)
 		return b;
 }
 
+/*
+ * special case insensitive searching routines
+ */
+const char *
+nstrstr(const char *haystack, const char *needle)
+{
+	const char *haystack_cur, *needle_cur, *needle_prev;
+	int		f1 = 0, f2 = 0;
+
+	needle_cur = needle;
+	needle_prev = NULL;
+	haystack_cur = haystack;
+
+	while (*needle_cur != '\0')
+	{
+		if (*haystack_cur == '\0')
+			return NULL;
+
+		if (needle_prev != needle_cur)
+		{
+			needle_prev = needle_cur;
+			f1 = toupper(*needle_cur);
+		}
+
+		f2 = toupper(*haystack_cur);
+		if (f1 == f2)
+		{
+			needle_cur += 1;
+			haystack_cur += 1;
+		}
+		else
+		{
+			needle_cur = needle;
+			haystack_cur = haystack += 1;
+		}
+	}
+
+	return haystack;
+}
+
+/*
+ * Special string searching, lower chars are case insensitive,
+ * upper chars are case sensitive.
+ */
+const char *
+nstrstr_ignore_lower_case(const char *haystack, const char *needle)
+{
+	const char *haystack_cur, *needle_cur, *needle_prev;
+	int		f1 = 0;
+	bool	eq;
+
+	needle_cur = needle;
+	needle_prev = NULL;
+	haystack_cur = haystack;
+
+	while (*needle_cur != '\0')
+	{
+		bool	needle_char_is_upper;
+
+		if (*haystack_cur == '\0')
+			return NULL;
+
+		if (needle_prev != needle_cur)
+		{
+			needle_prev = needle_cur;
+			needle_char_is_upper = isupper(*needle_cur);
+			f1 = toupper(*needle_cur);
+		}
+
+		if (needle_char_is_upper)
+		{
+			/* case sensitive */
+			eq = *haystack_cur == *needle_cur;
+		}
+		else
+		{
+			/* case insensitive */
+			eq = f1 == toupper(*haystack_cur);
+		}
+
+		if (eq)
+		{
+			needle_cur += 1;
+			haystack_cur += 1;
+		}
+		else
+		{
+			needle_cur = needle;
+			haystack_cur = haystack += 1;
+		}
+	}
+
+	return haystack;
+}
+
+
+
 static const char *
 strcasestr(const char *s1, const char *s2)
 {
@@ -2435,7 +2532,7 @@ main(int argc, char *argv[])
 							if (opts.ignore_case || (opts.ignore_lower_case && !scrdesc.has_upperchr))
 							{
 								if (opts.force8bit)
-									str = strcasestr(lnb->rows[rownum_cursor_row] + skip_bytes, scrdesc.searchterm);
+									str = nstrstr(lnb->rows[rownum_cursor_row] + skip_bytes, scrdesc.searchterm);
 								else
 									str = utf8_nstrstr(lnb->rows[rownum_cursor_row] + skip_bytes, scrdesc.searchterm);
 							}
@@ -2443,7 +2540,7 @@ main(int argc, char *argv[])
 							{
 								if (opts.force8bit)
 									/* isn't correct */
-									str = strcasestr(lnb->rows[rownum_cursor_row] + skip_bytes, scrdesc.searchterm);
+									str = nstrstr_ignore_lower_case(lnb->rows[rownum_cursor_row] + skip_bytes, scrdesc.searchterm);
 								else
 									str = utf8_nstrstr_ignore_lower_case(lnb->rows[rownum_cursor_row] + skip_bytes,
 																	 scrdesc.searchterm);
@@ -2589,9 +2686,15 @@ main(int argc, char *argv[])
 						while (str != NULL)
 						{
 							if (opts.ignore_case || (opts.ignore_lower_case && !scrdesc.has_upperchr))
-								str = utf8_nstrstr(str, scrdesc.searchterm);
+								if (opts.force8bit)
+									nstrstr(str, scrdesc.searchterm);
+								else
+									str = utf8_nstrstr(str, scrdesc.searchterm);
 							else if (opts.ignore_lower_case && scrdesc.has_upperchr)
-								str = utf8_nstrstr_ignore_lower_case(str, scrdesc.searchterm);
+								if (opts.force8bit)
+									nstrstr_ignore_lower_case(str, scrdesc.searchterm);
+								else
+									str = utf8_nstrstr_ignore_lower_case(str, scrdesc.searchterm);
 							else
 								str = str = strstr(str, scrdesc.searchterm);
 
diff --git a/src/pspg.h b/src/pspg.h
index f64c8bc..cd3e0d4 100644
--- a/src/pspg.h
+++ b/src/pspg.h
@@ -140,11 +140,13 @@ typedef struct
 #define		w_bottom_bar(scrdesc)	((scrdesc)->wins[WINDOW_BOTTOM_BAR])
 
 /* from print.c */
-void window_fill(int window_identifier, int srcy, int srcx, int cursor_row, DataDesc *desc, ScrDesc *scrdesc, Options *opts);
-void draw_data(Options *opts, ScrDesc *scrdesc, DataDesc *desc, int first_data_row, int first_row, int cursor_col, int footer_cursor_col, int fix_rows_offset);
+extern void window_fill(int window_identifier, int srcy, int srcx, int cursor_row, DataDesc *desc, ScrDesc *scrdesc, Options *opts);
+extern void draw_data(Options *opts, ScrDesc *scrdesc, DataDesc *desc, int first_data_row, int first_row, int cursor_col, int footer_cursor_col, int fix_rows_offset);
 
 /* from pspg.c */
-bool is_expanded_header(Options *opts, char *str, int *ei_minx, int *ei_maxx);
-int min_int(int a, int b);
+extern bool is_expanded_header(Options *opts, char *str, int *ei_minx, int *ei_maxx);
+extern int min_int(int a, int b);
+extern const char *nstrstr(const char *haystack, const char *needle);
+extern const char *nstrstr_ignore_lower_case(const char *haystack, const char *needle);
 
 #endif
\ No newline at end of file
diff --git a/src/themes.h b/src/themes.h
index 94a71a5..61acc1b 100644
--- a/src/themes.h
+++ b/src/themes.h
@@ -45,7 +45,7 @@ typedef struct
 #define		WINDOW_TOP_BAR			5
 #define		WINDOW_BOTTOM_BAR		6
 
-void initialize_color_pairs(int theme);
-void initialize_theme(int theme, int window_identifier, bool is_tabular_fmt, bool no_highlight_lines, Theme *t);
+extern void initialize_color_pairs(int theme);
+extern void initialize_theme(int theme, int window_identifier, bool is_tabular_fmt, bool no_highlight_lines, Theme *t);
 
 #endif
\ No newline at end of file