Rob Sullivan writes: rewrite the regex handling to improve stability

diff --git a/miscutils/less.c b/miscutils/less.c
index eee9608..84e4b61 100644 (file)
--- 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