Rob Sullivan writes: rewrite the regex handling to improve stability

1 files changed, 51 insertions, 58 deletions

diff --git a/miscutils/less.c b/miscutils/less.c
index eee960821..84e4b612d 100644
--- a/miscutils/less.c
+++ b/miscutils/less.c
@@ -104,10 +104,11 @@ static int num_marks;
 
 #ifdef CONFIG_FEATURE_LESS_REGEXP
 static int match_found;
-static int match_lines[100];
+static int *match_lines;
 static int match_pos;
 static int num_matches;
 static int match_backwards;
+static regex_t old_pattern;
 #endif
 
 /* Needed termios structures */
@@ -235,14 +236,6 @@ static void data_readlines(void)
                 add_linenumbers();
 }
 
-/* Turn a percentage into a line number */
-static int reverse_percent(int percentage)
-{
-        double linenum = percentage;
-        linenum = ((linenum / 100) * num_flines) - 1;
-        return(linenum);
-}
-
 #ifdef CONFIG_FEATURE_LESS_FLAGS
 
 /* Interestingly, writing calc_percent as a function and not a prototype saves around 32 bytes
@@ -463,12 +456,11 @@ static void buffer_up(int nlines)
 static void buffer_line(int linenum)
 {
         int i;
-
         past_eof = 0;
 
-        if (linenum < 1 || linenum > num_flines) {
+        if (linenum < 0 || linenum > num_flines) {
                 clear_line();
-                printf("%s%s%i%s", HIGHLIGHT, "Cannot seek to line number ", linenum, NORMAL);
+                printf("%s%s%i%s", HIGHLIGHT, "Cannot seek to line number ", linenum + 1, NORMAL);
         }
         else if (linenum < (num_flines - height - 2)) {
                 for (i = 0; i < (height - 1); i++) {
@@ -476,6 +468,7 @@ static void buffer_line(int linenum)
                         buffer[i] = bb_xstrdup(flines[linenum + i]);
                 }
                 line_pos = linenum;
+                buffer_print();
         }
         else {
                 for (i = 0; i < (height - 1); i++) {
@@ -488,6 +481,7 @@ static void buffer_line(int linenum)
                 line_pos = linenum;
                 /* Set past_eof so buffer_down and buffer_up act differently */
                 past_eof = 1;
+                buffer_print();
         }
 }
 
@@ -610,46 +604,44 @@ static void colon_process(void)
 /* Get a regular expression from the user, and then go through the current
    file line by line, running a processing regex function on each one. */
 
-static char *insert_highlights(char *line, int start, int end)
-{
-        return bb_xasprintf("%.*s%s%.*s%s%s", start, line, HIGHLIGHT,
-                        end - start, line + start, NORMAL, line + end);
-}
-
-static char *process_regex_on_line(char *line, regex_t *pattern)
+static char *process_regex_on_line(char *line, regex_t *pattern, int action)
 {
         /* This function takes the regex and applies it to the line.
            Each part of the line that matches has the HIGHLIGHT
            and NORMAL escape sequences placed around it by
-           insert_highlights, and then the line is returned. */
-
+           insert_highlights if action = 1, or has the escape sequences
+           removed if action = 0, and then the line is returned. */
         int match_status;
         char *line2 = (char *) xmalloc((sizeof(char) * (strlen(line) + 1)) + 64);
-        char sub_line[256];
-        int prev_eo = 0;
+        char *growline = "";
         regmatch_t match_structs;
 
-        strcpy(line2, line);
+        line2 = bb_xstrdup(line);
 
         match_found = 0;
         match_status = regexec(pattern, line2, 1, &match_structs, 0);
-
+        
         while (match_status == 0) {
-
-                memset(sub_line, 0, sizeof(sub_line));
-
                 if (match_found == 0)
                         match_found = 1;
-
-                line2 = insert_highlights(line2, match_structs.rm_so + prev_eo, match_structs.rm_eo + prev_eo);
-                if ((size_t)match_structs.rm_eo + 11 + prev_eo < strlen(line2))
-                        strcat(sub_line, line2 + match_structs.rm_eo + 11 + prev_eo);
-
-                prev_eo += match_structs.rm_eo + 11;
-                match_status = regexec(pattern, sub_line, 1, &match_structs, REG_NOTBOL);
+                
+                if (action) {
+                        growline = bb_xasprintf("%s%.*s%s%.*s%s", growline, match_structs.rm_so, line2, HIGHLIGHT, match_structs.rm_eo - match_structs.rm_so, line2 + match_structs.rm_so, NORMAL); 
+                }
+                else {
+                        growline = bb_xasprintf("%s%.*s%.*s", growline, match_structs.rm_so - 4, line2, match_structs.rm_eo - match_structs.rm_so, line2 + match_structs.rm_so);
+                }
+                
+                line2 += match_structs.rm_eo;
+                match_status = regexec(pattern, line2, 1, &match_structs, REG_NOTBOL);
         }
-
-        return line2;
+        
+        growline = bb_xasprintf("%s%s", growline, line2);
+        
+        return (match_found ? growline : line);
+        
+        free(growline);
+        free(line2);
 }
 
 static void goto_match(int match)
@@ -665,11 +657,10 @@ static void goto_match(int match)
 static void regex_process(void)
 {
         char uncomp_regex[100];
-        char current_line[256];
+        char *current_line;
         int i;
         int j = 0;
         regex_t pattern;
-
         /* Get the uncompiled regular expression from the user */
         clear_line();
         putchar((match_backwards) ? '?' : '/');
@@ -677,32 +668,43 @@ static void regex_process(void)
         fgets(uncomp_regex, sizeof(uncomp_regex), inp);
         
         if (strlen(uncomp_regex) == 1) {
-                goto_match(match_backwards ? match_pos - 1 : match_pos + 1);
-                buffer_print();
+                if (num_matches)
+                        goto_match(match_backwards ? match_pos - 1 : match_pos + 1);
+                else
+                        buffer_print();
                 return;
         }
-        
         uncomp_regex[strlen(uncomp_regex) - 1] = '\0';
         
         /* Compile the regex and check for errors */
         xregcomp(&pattern, uncomp_regex, 0);
 
+        if (num_matches) {
+                /* Get rid of all the highlights we added previously */
+                for (i = 0; i <= num_flines; i++) {
+                        current_line = process_regex_on_line(flines[i], &old_pattern, 0);
+                        flines[i] = bb_xstrdup(current_line);
+                }
+        }
+        old_pattern = pattern;
+        
         /* Reset variables */
+        match_lines = xrealloc(match_lines, sizeof(int));
         match_lines[0] = -1;
         match_pos = 0;
         num_matches = 0;
         match_found = 0;
-
         /* Run the regex on each line of the current file here */
         for (i = 0; i <= num_flines; i++) {
-                strcpy(current_line, process_regex_on_line(flines[i], &pattern));
+                current_line = process_regex_on_line(flines[i], &pattern, 1);
                 flines[i] = bb_xstrdup(current_line);
                 if (match_found) {
+                        match_lines = xrealloc(match_lines, (j + 1) * sizeof(int));
                         match_lines[j] = i;
                         j++;
                 }
         }
-
+        
         num_matches = j;
         if ((match_lines[0] != -1) && (num_flines > height - 2)) {
                 if (match_backwards) {
@@ -764,7 +766,7 @@ static void number_process(int first_digit)
                                 buffer_line(num - 1);
                         break;
                 case 'p': case '%':
-                        buffer_line(reverse_percent(num));
+                        buffer_line(((num / 100) * num_flines) - 1);
                         break;
 #ifdef CONFIG_FEATURE_LESS_REGEXP
                 case 'n':
@@ -852,7 +854,6 @@ static void full_repaint(void)
         data_readlines();
         buffer_init();
         buffer_line(temp_line_pos);
-        buffer_print();
 }
 
 
@@ -866,7 +867,7 @@ static void save_input_to_file(void)
         printf("Log file: ");
         fgets(current_line, 256, inp);
         current_line[strlen(current_line) - 1] = '\0';
-        if (strlen(current_line)) {
+        if (strlen(current_line) > 1) {
                 fp = bb_xfopen(current_line, "w");
                 for (i = 0; i < num_flines; i++)
                         fprintf(fp, "%s", flines[i]);
@@ -973,7 +974,6 @@ static void match_right_bracket(char bracket)
                         printf("%s%s%s", HIGHLIGHT, "No matching bracket found", NORMAL);
 
                 buffer_line(bracket_line - height + 2);
-                buffer_print();
         }
 }
 
@@ -1001,7 +1001,6 @@ static void match_left_bracket(char bracket)
                         printf("%s%s%s", HIGHLIGHT, "No matching bracket found", NORMAL);
 
                 buffer_line(bracket_line);
-                buffer_print();
         }
 }
 
@@ -1035,12 +1034,10 @@ static void keypress_process(int keypress)
                         buffer_print();
                         break;
                 case 'g': case 'p': case '<': case '%':
-                        buffer_up(num_flines + 1);
-                        buffer_print();
+                        buffer_line(0);
                         break;
                 case 'G': case '>':
-                        buffer_down(num_flines + 1);
-                        buffer_print();
+                        buffer_line(num_flines - height + 2);
                         break;
                 case 'q': case 'Q':
                         tless_exit(0);
@@ -1078,20 +1075,16 @@ static void keypress_process(int keypress)
                 case '/':
                         match_backwards = 0;
                         regex_process();
-                        buffer_print();
                         break;
                 case 'n':
                         goto_match(match_pos + 1);
-                        buffer_print();
                         break;
                 case 'N':
                         goto_match(match_pos - 1);
-                        buffer_print();
                         break;
                 case '?':
                         match_backwards = 1;
                         regex_process();
-                        buffer_print();
                         break;
 #endif
 #ifdef CONFIG_FEATURE_LESS_FLAGCS