less: more sane way of line numbering. Prepares for

 wrap/unwrap and line numbers to be toggleable.

1 files changed, 53 insertions, 22 deletions

diff --git a/miscutils/less.c b/miscutils/less.c
index cd47590ee..049814319 100644
--- a/miscutils/less.c
+++ b/miscutils/less.c
@@ -166,6 +166,14 @@ struct globals {
         USE_FEATURE_LESS_REGEXP(wanted_match = -1;) \
 } while (0)
 
+/* flines[] are lines read from stdin, each in malloc'ed buffer.
+ * Line numbers are stored as uint32_t prepended to each line.
+ * Pointer is adjusted so that flines[i] points directly past
+ * line number. Accesor: */
+#define MEMPTR(p) ((char*)(p) - 4)
+#define LINENO(p) (*(uint32_t*)((p) - 4))
+
+
 /* Reset terminal input to normal */
 static void set_tty_cooked(void)
 {
@@ -252,15 +260,13 @@ static void read_lines(void)
 
  USE_FEATURE_LESS_REGEXP(again0:)
 
-        p = current_line = xmalloc(w);
+        p = current_line = ((char*)xmalloc(w + 4)) + 4;
         max_fline += last_terminated;
         if (!last_terminated) {
                 const char *cp = flines[max_fline];
-                if (option_mask32 & FLAG_N)
-                        cp += 8;
-                strcpy(current_line, cp);
+                strcpy(p, cp);
                 p += strlen(current_line);
-                free((char*)flines[max_fline]);
+                free(MEMPTR(flines[max_fline]));
                 /* linepos is still valid from previous read_lines() */
         } else {
                 linepos = 0;
@@ -324,17 +330,12 @@ static void read_lines(void)
  reached_eof:
                 last_terminated = terminated;
                 flines = xrealloc_vector(flines, 8, max_fline);
-                if (option_mask32 & FLAG_N) {
-                        /* Width of 7 preserves tab spacing in the text */
-                        flines[max_fline] = xasprintf(
-                                (max_lineno <= 9999999) ? "%7u %s" : "%07u %s",
-                                max_lineno % 10000000, current_line);
-                        free(current_line);
-                        if (terminated)
-                                max_lineno++;
-                } else {
-                        flines[max_fline] = xrealloc(current_line, strlen(current_line) + 1);
-                }
+
+                flines[max_fline] = (char*)xrealloc(MEMPTR(current_line), strlen(current_line) + 1 + 4) + 4;
+                LINENO(flines[max_fline]) = max_lineno;
+                if (terminated)
+                        max_lineno++;
+
                 if (max_fline >= MAXLINES) {
                         eof_error = 0; /* Pretend we saw EOF */
                         break;
@@ -380,7 +381,7 @@ static void read_lines(void)
 #endif
                 }
                 max_fline++;
-                current_line = xmalloc(w);
+                current_line = ((char*)xmalloc(w + 4)) + 4;
                 p = current_line;
                 linepos = 0;
         } /* end of "read lines until we reach cur_fline" loop */
@@ -487,6 +488,30 @@ static const char ctrlconv[] ALIGN1 =
         "\x40\x41\x42\x43\x44\x45\x46\x47\x48\x49\x40\x4b\x4c\x4d\x4e\x4f"
         "\x50\x51\x52\x53\x54\x55\x56\x57\x58\x59\x5a\x5b\x5c\x5d\x5e\x5f";
 
+static void lineno_str(char *nbuf9, const char *line)
+{
+        nbuf9[0] = '\0';
+        if (option_mask32 & FLAG_N) {
+                const char *fmt;
+                unsigned n;
+
+                if (line == empty_line_marker) {
+                        memset(nbuf9, ' ', 8);
+                        nbuf9[8] = '\0';
+                        return;
+                }
+                /* Width of 7 preserves tab spacing in the text */
+                fmt = "%7u ";
+                n = LINENO(line);
+                if (n > 9999999) {
+                        n %= 10000000;
+                        fmt = "%07u ";
+                }
+                sprintf(nbuf9, fmt, n);
+        }
+}
+
+
 #if ENABLE_FEATURE_LESS_REGEXP
 static void print_found(const char *line)
 {
@@ -496,6 +521,7 @@ static void print_found(const char *line)
         regmatch_t match_structs;
 
         char buf[width];
+        char nbuf9[9];
         const char *str = line;
         char *p = buf;
         size_t n;
@@ -532,7 +558,8 @@ static void print_found(const char *line)
                                 match_structs.rm_so, str,
                                 match_structs.rm_eo - match_structs.rm_so,
                                                 str + match_structs.rm_so);
-                free(growline); growline = new;
+                free(growline);
+                growline = new;
                 str += match_structs.rm_eo;
                 line += match_structs.rm_eo;
                 eflags = REG_NOTBOL;
@@ -544,11 +571,12 @@ static void print_found(const char *line)
                         match_status = 1;
         }
 
+        lineno_str(nbuf9, line);
         if (!growline) {
-                printf(CLEAR_2_EOL"%s\n", str);
+                printf(CLEAR_2_EOL"%s%s\n", nbuf9, str);
                 return;
         }
-        printf(CLEAR_2_EOL"%s%s\n", growline, str);
+        printf(CLEAR_2_EOL"%s%s%s\n", nbuf9, growline, str);
         free(growline);
 }
 #else
@@ -558,10 +586,13 @@ void print_found(const char *line);
 static void print_ascii(const char *str)
 {
         char buf[width];
+        char nbuf9[9];
         char *p;
         size_t n;
 
-        printf(CLEAR_2_EOL);
+        lineno_str(nbuf9, str);
+        printf(CLEAR_2_EOL"%s", nbuf9);
+
         while (*str) {
                 n = strcspn(str, controls);
                 if (n) {
@@ -670,7 +701,7 @@ static void reinitialize(void)
 
         if (flines) {
                 for (i = 0; i <= max_fline; i++)
-                        free((void*)(flines[i]));
+                        free(MEMPTR(flines[i]));
                 free(flines);
                 flines = NULL;
         }