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-rw-r--r--miscutils/less.c484
1 files changed, 236 insertions, 248 deletions
diff --git a/miscutils/less.c b/miscutils/less.c
index 73500671d..6843dddcb 100644
--- a/miscutils/less.c
+++ b/miscutils/less.c
@@ -8,30 +8,20 @@
*/
/*
- * This program needs a lot of development, so consider it in a beta stage
- * at best.
+ * TODO:
+ * - Add more regular expression support - search modifiers, certain matches, etc.
+ * - Add more complex bracket searching - currently, nested brackets are
+ * not considered.
+ * - Add support for "F" as an input. This causes less to act in
+ * a similar way to tail -f.
+ * - Allow horizontal scrolling.
*
- * TODO:
- * - Add more regular expression support - search modifiers, certain matches, etc.
- * - Add more complex bracket searching - currently, nested brackets are
- * not considered.
- * - Add support for "F" as an input. This causes less to act in
- * a similar way to tail -f.
- * - Check for binary files, and prompt the user if a binary file
- * is detected.
- * - Allow horizontal scrolling. Currently, lines simply continue onto
- * the next line, per the terminal's discretion
- *
- * Notes:
- * - filename is an array and not a pointer because that avoids all sorts
- * of complications involving the fact that something that is pointed to
- * will be changed if the pointer is changed.
- * - the inp file pointer is used so that keyboard input works after
- * redirected input has been read from stdin
-*/
+ * Notes:
+ * - the inp file pointer is used so that keyboard input works after
+ * redirected input has been read from stdin
+ */
#include "busybox.h"
-
#if ENABLE_FEATURE_LESS_REGEXP
#include "xregex.h"
#endif
@@ -70,12 +60,13 @@ static int height;
static int width;
static char **files;
static char *filename;
-static char **buffer;
+static const char **buffer;
static char **flines;
static int current_file = 1;
static int line_pos;
static int num_flines;
static int num_files = 1;
+static const char *empty_line_marker = "~";
/* Command line options */
#define FLAG_E 1
@@ -84,7 +75,6 @@ static int num_files = 1;
#define FLAG_N (1<<3)
#define FLAG_TILDE (1<<4)
/* hijack command line options variable for internal state vars */
-#define LESS_STATE_PAST_EOF (1<<5)
#define LESS_STATE_MATCH_BACKWARDS (1<<6)
#if ENABLE_FEATURE_LESS_MARKS
@@ -93,11 +83,11 @@ static int num_marks;
#endif
#if ENABLE_FEATURE_LESS_REGEXP
-static int match_found;
static int *match_lines;
static int match_pos;
static int num_matches;
-static regex_t old_pattern;
+static regex_t pattern;
+static int pattern_valid;
#endif
/* Needed termios structures */
@@ -174,52 +164,57 @@ static void data_readlines(void)
unsigned i;
unsigned n = 1;
int w = width;
- char *last_nl = (char*)1; /* "not NULL" */
- char *current_line;
+ /* "remained unused space" in a line (0 if line fills entire width) */
+ int rem, last_rem = 1; /* "not 0" */
+ char *current_line, *p;
FILE *fp;
fp = filename ? xfopen(filename, "r") : stdin;
flines = NULL;
if (option_mask32 & FLAG_N) {
w -= 6;
- if (w < 1) w = 1; /* paranoia */
}
for (i = 0; !feof(fp) && i <= MAXLINES; i++) {
flines = xrealloc(flines, (i+1) * sizeof(char *));
-
current_line = xmalloc(w);
again:
- current_line[0] = '\0';
- fgets(current_line, w, fp);
+ p = current_line;
+ rem = w - 1;
+ do {
+ int c = getc(fp);
+ if (c == EOF) break;
+ if (c == '\n') break;
+ /* NUL is substituted by '\n'! */
+ if (c == '\0') c = '\n';
+ *p++ = c;
+ } while (--rem);
+ *p = '\0';
if (fp != stdin)
die_if_ferror(fp, filename);
- /* Corner case: linewrap with only '\n' wrapping */
- /* Looks ugly on screen, so we handle it specially */
- if (!last_nl && current_line[0] == '\n') {
- last_nl = (char*)1; /* "not NULL" */
+ /* Corner case: linewrap with only "" wrapping to next line */
+ /* Looks ugly on screen, so we do not store this empty line */
+ if (!last_rem && !current_line[0]) {
+ last_rem = 1; /* "not 0" */
n++;
goto again;
}
- last_nl = last_char_is(current_line, '\n');
- if (last_nl)
- *last_nl = '\0';
+ last_rem = rem;
if (option_mask32 & FLAG_N) {
flines[i] = xasprintf((n <= 99999) ? "%5u %s" : "%05u %s",
n % 100000, current_line);
free(current_line);
- if (last_nl)
+ if (rem)
n++;
} else {
flines[i] = xrealloc(current_line, strlen(current_line)+1);
}
}
- num_flines = i - 2;
+ num_flines = i - 1; /* buggie: 'num_flines' must be 'max_fline' */
/* Reset variables for a new file */
line_pos = 0;
- option_mask32 &= ~LESS_STATE_PAST_EOF;
fclose(fp);
}
@@ -238,36 +233,28 @@ static void m_status_print(void)
{
int percentage;
- if (!(option_mask32 & LESS_STATE_PAST_EOF)) {
- if (!line_pos) {
- if (num_files > 1) {
- printf("%s%s %s%i%s%i%s%i-%i/%i ", HIGHLIGHT,
- filename, "(file ", current_file, " of ", num_files, ") lines ",
- line_pos + 1, line_pos + height - 1, num_flines + 1);
- } else {
- printf("%s%s lines %i-%i/%i ", HIGHLIGHT,
- filename, line_pos + 1, line_pos + height - 1,
- num_flines + 1);
- }
- } else {
- printf("%s %s lines %i-%i/%i ", HIGHLIGHT, filename,
+ if (!line_pos) {
+ if (num_files > 1) {
+ printf("%s%s %s%i%s%i%s%i-%i/%i ", HIGHLIGHT,
+ filename, "(file ", current_file, " of ", num_files, ") lines ",
line_pos + 1, line_pos + height - 1, num_flines + 1);
- }
-
- if (line_pos == num_flines - height + 2) {
- printf("(END) %s", NORMAL);
- if ((num_files > 1) && (current_file != num_files))
- printf("%s- Next: %s%s", HIGHLIGHT, files[current_file], NORMAL);
} else {
- percentage = calc_percent();
- printf("%i%% %s", percentage, NORMAL);
+ printf("%s%s lines %i-%i/%i ", HIGHLIGHT,
+ filename, line_pos + 1, line_pos + height - 1,
+ num_flines + 1);
}
} else {
- printf("%s%s lines %i-%i/%i (END) ", HIGHLIGHT, filename,
- line_pos + 1, num_flines + 1, num_flines + 1);
+ printf("%s %s lines %i-%i/%i ", HIGHLIGHT, filename,
+ line_pos + 1, line_pos + height - 1, num_flines + 1);
+ }
+
+ if (line_pos >= num_flines - height + 2) {
+ printf("(END) %s", NORMAL);
if ((num_files > 1) && (current_file != num_files))
- printf("- Next: %s", files[current_file]);
- printf("%s", NORMAL);
+ printf("%s- Next: %s%s", HIGHLIGHT, files[current_file], NORMAL);
+ } else {
+ percentage = calc_percent();
+ printf("%i%% %s", percentage, NORMAL);
}
}
@@ -315,22 +302,123 @@ static void status_print(void)
#endif
}
+static char controls[] =
+ /**/"\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f"
+ "\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f"
+ "\x7f\x9b"; /* DEL and infamous Meta-ESC :( */
+static char ctrlconv[] =
+ /* Note that on input NUL is converted to '\n' ('\x0a') */
+ /* Therefore we subst '\n' with '@', not 'J' */
+ "\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 print_found(const char *line)
+{
+ int match_status;
+ int eflags;
+ char *growline;
+ regmatch_t match_structs;
+
+ char buf[width];
+ const char *str = line;
+ char *p = buf;
+ size_t n;
+
+ while (*str) {
+ n = strcspn(str, controls);
+ if (n) {
+ if (!str[n]) break;
+ memcpy(p, str, n);
+ p += n;
+ str += n;
+ }
+ n = strspn(str, controls);
+ memset(p, '.', n);
+ p += n;
+ str += n;
+ /*
+ do {
+ if (*str == '\x7f') { *p++ = '?'; str++; }
+ else if (*str == '\x9b') { *p++ = '{'; str++; }
+ else *p++ = ctrlconv[(unsigned char)*str++];
+ } while (--n);
+ */
+ }
+ strcpy(p, str);
+
+ /* buf[] holds quarantined version of str */
+
+ /* Each part of the line that matches has the HIGHLIGHT
+ and NORMAL escape sequences placed around it.
+ NB: we regex against line, but insert text
+ from quarantined copy (buf[]) */
+ str = buf;
+ growline = NULL;
+ eflags = 0;
+ goto start;
+
+ while (match_status == 0) {
+ char *new = xasprintf("%s" "%.*s" "%s" "%.*s" "%s",
+ growline ? : "",
+ match_structs.rm_so, str,
+ HIGHLIGHT,
+ match_structs.rm_eo - match_structs.rm_so,
+ str + match_structs.rm_so,
+ NORMAL);
+ free(growline); growline = new;
+ str += match_structs.rm_eo;
+ line += match_structs.rm_eo;
+ eflags = REG_NOTBOL;
+ start:
+ /* Most of the time doesn't find the regex, optimize for that */
+ match_status = regexec(&pattern, line, 1, &match_structs, eflags);
+ }
+
+ if (!growline) {
+ puts(str);
+ return;
+ }
+ printf("%s%s\n", growline, str);
+ free(growline);
+}
+
+static void print_ascii(const char *str)
+{
+ char buf[width];
+ char *p;
+ size_t n;
+
+ while (*str) {
+ n = strcspn(str, controls);
+ if (n) {
+ if (!str[n]) break;
+ printf("%.*s", n, str);
+ str += n;
+ }
+ n = strspn(str, controls);
+ p = buf;
+ do {
+ if (*str == '\x7f') { *p++ = '?'; str++; }
+ else if (*str == '\x9b') { *p++ = '{'; str++; }
+ else *p++ = ctrlconv[(unsigned char)*str++];
+ } while (--n);
+ *p = '\0';
+ printf("%s%s%s", HIGHLIGHT, buf, NORMAL);
+ }
+ puts(str);
+}
+
/* Print the buffer */
static void buffer_print(void)
{
int i;
printf("%s", CLEAR);
- if (num_flines >= height - 2) {
- for (i = 0; i < height - 1; i++)
- printf("%.*s\n", width, buffer[i]);
- } else {
- for (i = 1; i < (height - 1 - num_flines); i++)
- putchar('\n');
- for (i = 0; i < height - 1; i++)
- printf("%.*s\n", width, buffer[i]);
- }
-
+ for (i = 0; i < height - 1; i++)
+ if (pattern_valid)
+ print_found(buffer[i]);
+ else
+ print_ascii(buffer[i]);
status_print();
}
@@ -339,20 +427,20 @@ static void buffer_init(void)
{
int i;
- if (buffer == NULL) {
+ if (!buffer) {
/* malloc the number of lines needed for the buffer */
buffer = xmalloc(height * sizeof(char *));
}
/* Fill the buffer until the end of the file or the
end of the buffer is reached */
- for (i = 0; (i < (height - 1)) && (i <= num_flines); i++) {
+ for (i = 0; i < height - 1 && i <= num_flines; i++) {
buffer[i] = flines[i];
}
/* If the buffer still isn't full, fill it with blank lines */
- for (; i < (height - 1); i++) {
- buffer[i] = "";
+ for (; i < height - 1; i++) {
+ buffer[i] = empty_line_marker;
}
}
@@ -361,72 +449,38 @@ static void buffer_down(int nlines)
{
int i;
- if (!(option_mask32 & LESS_STATE_PAST_EOF)) {
- if (line_pos + (height - 3) + nlines < num_flines) {
- line_pos += nlines;
+ if (line_pos + (height - 3) + nlines < num_flines) {
+ line_pos += nlines;
+ for (i = 0; i < (height - 1); i++) {
+ buffer[i] = flines[line_pos + i];
+ }
+ } else {
+ /* As the number of lines requested was too large, we just move
+ to the end of the file */
+ while (line_pos + (height - 3) + 1 < num_flines) {
+ line_pos += 1;
for (i = 0; i < (height - 1); i++) {
buffer[i] = flines[line_pos + i];
}
- } else {
- /* As the number of lines requested was too large, we just move
- to the end of the file */
- while (line_pos + (height - 3) + 1 < num_flines) {
- line_pos += 1;
- for (i = 0; i < (height - 1); i++) {
- buffer[i] = flines[line_pos + i];
- }
- }
}
-
- /* We exit if the -E flag has been set */
- if ((option_mask32 & FLAG_E) && (line_pos + (height - 2) == num_flines))
- tless_exit(0);
}
+
+ /* We exit if the -E flag has been set */
+ if ((option_mask32 & FLAG_E) && (line_pos + (height - 2) == num_flines))
+ tless_exit(0);
}
static void buffer_up(int nlines)
{
int i;
- int tilde_line;
- if (!(option_mask32 & LESS_STATE_PAST_EOF)) {
- if (line_pos - nlines >= 0) {
- line_pos -= nlines;
- for (i = 0; i < (height - 1); i++) {
- buffer[i] = flines[line_pos + i];
- }
- } else {
- /* As the requested number of lines to move was too large, we
- move one line up at a time until we can't. */
- while (line_pos != 0) {
- line_pos -= 1;
- for (i = 0; i < (height - 1); i++) {
- buffer[i] = flines[line_pos + i];
- }
- }
- }
- }
- else {
- /* Work out where the tildes start */
- tilde_line = num_flines - line_pos + 3;
-
- line_pos -= nlines;
- /* Going backwards nlines lines has taken us to a point where
- nothing is past the EOF, so we revert to normal. */
- if (line_pos < num_flines - height + 3) {
- option_mask32 &= ~LESS_STATE_PAST_EOF;
- buffer_up(nlines);
+ line_pos -= nlines;
+ if (line_pos < 0) line_pos = 0;
+ for (i = 0; i < height - 1; i++) {
+ if (line_pos + i <= num_flines) {
+ buffer[i] = flines[line_pos + i];
} else {
- /* We only move part of the buffer, as the rest
- is past the EOF */
- for (i = 0; i < (height - 1); i++) {
- if (i < tilde_line - nlines + 1) {
- buffer[i] = flines[line_pos + i];
- } else {
- if (line_pos >= num_flines - height + 2)
- buffer[i] = "~";
- }
- }
+ buffer[i] = empty_line_marker;
}
}
}
@@ -434,28 +488,19 @@ static void buffer_up(int nlines)
static void buffer_line(int linenum)
{
int i;
- option_mask32 &= ~LESS_STATE_PAST_EOF;
if (linenum < 0 || linenum > num_flines) {
clear_line();
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++) {
- buffer[i] = flines[linenum + i];
- }
- line_pos = linenum;
- buffer_print();
} else {
- for (i = 0; i < (height - 1); i++) {
- if (linenum + i < num_flines + 2)
+ for (i = 0; i < height - 1; i++) {
+ if (linenum + i <= num_flines)
buffer[i] = flines[linenum + i];
- else
- buffer[i] = (option_mask32 & FLAG_TILDE) ? "" : "~";
+ else {
+ buffer[i] = empty_line_marker;
+ }
}
line_pos = linenum;
- /* Set past_eof so buffer_down and buffer_up act differently */
- option_mask32 |= LESS_STATE_PAST_EOF;
buffer_print();
}
}
@@ -563,76 +608,37 @@ static void colon_process(void)
}
}
-#if ENABLE_FEATURE_LESS_REGEXP
-/* The below two regular expression handler functions NEED development. */
-
-/* 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 *process_regex_on_line(char *line, regex_t *pattern, int action)
+static int normalize_match_pos(int match)
{
-/* UNTESTED. LOOKED BUGGY AND LEAKY AS HELL. */
-/* FIXED. NEED TESTING. */
- /* 'line' should be either returned or free()ed */
-
- /* 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 if action = 1, or has the escape sequences
- removed if action = 0, and then the line is returned. */
- int match_status;
- char *line2 = line;
- char *growline = xstrdup("");
- char *ng;
- regmatch_t match_structs;
-
- match_found = 0;
- match_status = regexec(pattern, line2, 1, &match_structs, 0);
-
- while (match_status == 0) {
- match_found = 1;
- if (action) {
- ng = 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 {
- ng = xasprintf("%s%.*s%.*s", growline,
- match_structs.rm_so - 4, line2,
- match_structs.rm_eo - match_structs.rm_so,
- line2 + match_structs.rm_so);
- }
- free(growline); growline = ng;
- line2 += match_structs.rm_eo;
- match_status = regexec(pattern, line2, 1, &match_structs, REG_NOTBOL);
- }
-
- if (match_found) {
- ng = xasprintf("%s%s", growline, line2);
- free(line);
- } else {
- ng = line;
- }
- free(growline);
- return ng;
+ match_pos = match;
+ if (match < 0)
+ return (match_pos = 0);
+ if (match >= num_matches)
+{
+ match_pos = num_matches - 1;
+}
+ return match_pos;
}
+#if ENABLE_FEATURE_LESS_REGEXP
static void goto_match(int match)
{
- /* This goes to a specific match - all line positions of matches are
- stored within the match_lines[] array. */
- if ((match < num_matches) && (match >= 0)) {
- buffer_line(match_lines[match]);
- match_pos = match;
- }
+ buffer_line(match_lines[normalize_match_pos(match)]);
}
static void regex_process(void)
{
char *uncomp_regex;
- int i;
- int j = 0;
- regex_t pattern;
+
+ /* Reset variables */
+ match_lines = xrealloc(match_lines, sizeof(int));
+ match_lines[0] = -1;
+ match_pos = 0;
+ num_matches = 0;
+ if (pattern_valid) {
+ regfree(&pattern);
+ pattern_valid = 0;
+ }
/* Get the uncompiled regular expression from the user */
clear_line();
@@ -640,56 +646,33 @@ static void regex_process(void)
uncomp_regex = xmalloc_getline(inp);
if (!uncomp_regex || !uncomp_regex[0]) {
free(uncomp_regex);
- if (num_matches)
- goto_match((option_mask32 & LESS_STATE_MATCH_BACKWARDS)
- ? match_pos - 1 : match_pos + 1);
- else
- buffer_print();
+ buffer_print();
return;
}
/* Compile the regex and check for errors */
xregcomp(&pattern, uncomp_regex, 0);
free(uncomp_regex);
+ pattern_valid = 1;
- if (num_matches) {
- /* Get rid of all the highlights we added previously */
- for (i = 0; i <= num_flines; i++) {
- flines[i] = process_regex_on_line(flines[i], &old_pattern, 0);
+ /* Run the regex on each line of the current file */
+ for (match_pos = 0; match_pos <= num_flines; match_pos++) {
+ if (regexec(&pattern, flines[match_pos], 0, NULL, 0) == 0) {
+ match_lines = xrealloc(match_lines, (num_matches+1) * sizeof(int));
+ match_lines[num_matches++] = match_pos;
}
}
- 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++) {
- flines[i] = process_regex_on_line(flines[i], &pattern, 1);
- if (match_found) {
- match_lines = xrealloc(match_lines, (j + 1) * sizeof(int));
- match_lines[j] = i;
- j++;
- }
+ if (num_matches == 0 || num_flines <= height - 2) {
+ buffer_print();
+ return;
}
-
- num_matches = j;
- if ((match_lines[0] != -1) && (num_flines > height - 2)) {
- if (option_mask32 & LESS_STATE_MATCH_BACKWARDS) {
- for (i = 0; i < num_matches; i++) {
- if (match_lines[i] > line_pos) {
- match_pos = i - 1;
- buffer_line(match_lines[match_pos]);
- break;
- }
- }
- } else
- buffer_line(match_lines[0]);
- } else
- buffer_init();
+ for (match_pos = 0; match_pos < num_matches; match_pos++) {
+ if (match_lines[match_pos] > line_pos)
+ break;
+ }
+ if (option_mask32 & LESS_STATE_MATCH_BACKWARDS) match_pos--;
+ buffer_line(match_lines[normalize_match_pos(match_pos)]);
}
#endif
@@ -1111,11 +1094,16 @@ int less_main(int argc, char **argv)
inp = xfopen(CURRENT_TTY, "r");
get_terminal_width_height(fileno(inp), &width, &height);
+ if (width < 10 || height < 3)
+ bb_error_msg_and_die("too narrow here");
+
+ if (option_mask32 & FLAG_TILDE) empty_line_marker = "";
+
data_readlines();
+ tcgetattr(fileno(inp), &term_orig);
signal(SIGTERM, sig_catcher);
signal(SIGINT, sig_catcher);
- tcgetattr(fileno(inp), &term_orig);
term_vi = term_orig;
term_vi.c_lflag &= (~ICANON & ~ECHO);
generated by cgit v1.2.3 (git 2.39.1) at 2024-06-30 12:58:05 +0000