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minix3/commands/mined/mined2.c

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/*
* Part 2 of the mined editor.
*/
/* ======================================================================== *
* Move Commands *
* ======================================================================== */
#include "mined.h"
#include <string.h>
/*
* Move one line up.
*/
void UP(void)
{
if (y == 0) { /* Top line of screen. Scroll one line */
(void) reverse_scroll();
move_to(x, y);
}
else /* Move to previous line */
move_to(x, y - 1);
}
/*
* Move one line down.
*/
void DN(void)
{
if (y == last_y) { /* Last line of screen. Scroll one line */
if (bot_line->next == tail && bot_line->text[0] != '\n') {
dummy_line(); /* Create new empty line */
DN();
return;
}
else {
(void) forward_scroll();
move_to(x, y);
}
}
else /* Move to next line */
move_to(x, y + 1);
}
/*
* Move left one position.
*/
void LF(void)
{
if (x == 0 && get_shift(cur_line->shift_count) == 0) {/* Begin of line */
if (cur_line->prev != header) {
UP(); /* Move one line up */
move_to(LINE_END, y);
}
}
else
move_to(x - 1, y);
}
/*
* Move right one position.
*/
void RT(void)
{
if (*cur_text == '\n') {
if (cur_line->next != tail) { /* Last char of file */
DN(); /* Move one line down */
move_to(LINE_START, y);
}
}
else
move_to(x + 1, y);
}
/*
* Move to coordinates [0, 0] on screen.
*/
void HIGH(void)
{
move_to(0, 0);
}
/*
* Move to coordinates [0, YMAX] on screen.
*/
void LOW(void)
{
move_to(0, last_y);
}
/*
* Move to begin of line.
*/
void BL(void)
{
move_to(LINE_START, y);
}
/*
* Move to end of line.
*/
void EL(void)
{
move_to(LINE_END, y);
}
/*
* GOTO() prompts for a linenumber and moves to that line.
*/
void GOTO(void)
{
int number;
LINE *line;
if (get_number("Please enter line number.", &number) == ERRORS)
return;
if (number <= 0 || (line = proceed(header->next, number - 1)) == tail)
error("Illegal line number: ", num_out((long) number));
else
move_to(x, find_y(line));
}
/*
* Scroll forward one page or to eof, whatever comes first. (Bot_line becomes
* top_line of display.) Try to leave the cursor on the same line. If this is
* not possible, leave cursor on the line halfway the page.
*/
void PD(void)
{
register int i;
for (i = 0; i < screenmax; i++)
if (forward_scroll() == ERRORS)
break; /* EOF reached */
if (y - i < 0) /* Line no longer on screen */
move_to(0, screenmax >> 1);
else
move_to(0, y - i);
}
/*
* Scroll backwards one page or to top of file, whatever comes first. (Top_line
* becomes bot_line of display). The very bottom line (YMAX) is always blank.
* Try to leave the cursor on the same line. If this is not possible, leave
* cursor on the line halfway the page.
*/
void PU(void)
{
register int i;
for (i = 0; i < screenmax; i++)
if (reverse_scroll() == ERRORS)
break; /* Top of file reached */
set_cursor(0, ymax); /* Erase very bottom line */
#ifdef UNIX
tputs(CE, 0, _putchar);
#else
string_print(blank_line);
#endif /* UNIX */
if (y + i > screenmax) /* line no longer on screen */
move_to(0, screenmax >> 1);
else
move_to(0, y + i);
}
/*
* Go to top of file, scrolling if possible, else redrawing screen.
*/
void HO(void)
{
if (proceed(top_line, -screenmax) == header)
PU(); /* It fits. Let PU do it */
else {
reset(header->next, 0);/* Reset top_line, etc. */
RD(); /* Display full page */
}
move_to(LINE_START, 0);
}
/*
* Go to last line of file, scrolling if possible, else redrawing screen
*/
void EF(void)
{
if (tail->prev->text[0] != '\n')
dummy_line();
if (proceed(bot_line, screenmax) == tail)
PD(); /* It fits. Let PD do it */
else {
reset(proceed(tail->prev, -screenmax), screenmax);
RD(); /* Display full page */
}
move_to(LINE_START, last_y);
}
/*
* Scroll one line up. Leave the cursor on the same line (if possible).
*/
void SU(void)
{
if (top_line->prev == header) /* Top of file. Can't scroll */
return;
(void) reverse_scroll();
set_cursor(0, ymax); /* Erase very bottom line */
#ifdef UNIX
tputs(CE, 0, _putchar);
#else
string_print(blank_line);
#endif /* UNIX */
move_to(x, (y == screenmax) ? screenmax : y + 1);
}
/*
* Scroll one line down. Leave the cursor on the same line (if possible).
*/
void SD(void)
{
if (forward_scroll() != ERRORS)
move_to(x, (y == 0) ? 0 : y - 1);
else
set_cursor(x, y);
}
/*
* Perform a forward scroll. It returns ERRORS if we're at the last line of the
* file.
*/
int forward_scroll(void)
{
if (bot_line->next == tail) /* Last line of file. No dice */
return ERRORS;
top_line = top_line->next;
bot_line = bot_line->next;
cur_line = cur_line->next;
set_cursor(0, ymax);
line_print(bot_line);
return FINE;
}
/*
* Perform a backwards scroll. It returns ERRORS if we're at the first line
* of the file.
*/
int reverse_scroll(void)
{
if (top_line->prev == header)
return ERRORS; /* Top of file. Can't scroll */
if (last_y != screenmax) /* Reset last_y if necessary */
last_y++;
else
bot_line = bot_line->prev; /* Else adjust bot_line */
top_line = top_line->prev;
cur_line = cur_line->prev;
/* Perform the scroll */
set_cursor(0, 0);
#ifdef UNIX
tputs(AL, 0, _putchar);
#else
string_print(rev_scroll);
#endif /* UNIX */
set_cursor(0, 0);
line_print(top_line);
return FINE;
}
/*
* A word is defined as a number of non-blank characters separated by tabs
* spaces or linefeeds.
*/
/*
* MP() moves to the start of the previous word. A word is defined as a
* number of non-blank characters separated by tabs spaces or linefeeds.
*/
void MP(void)
{
move_previous_word(NO_DELETE);
}
void move_previous_word(FLAG remove)
{
register char *begin_line;
register char *textp;
char start_char = *cur_text;
char *start_pos = cur_text;
/* Fist check if we're at the beginning of line. */
if (cur_text == cur_line->text) {
if (cur_line->prev == header)
return;
start_char = '\0';
}
LF();
begin_line = cur_line->text;
textp = cur_text;
/* Check if we're in the middle of a word. */
if (!alpha(*textp) || !alpha(start_char)) {
while (textp != begin_line && (white_space(*textp) || *textp == '\n'))
textp--;
}
/* Now we're at the end of previous word. Skip non-blanks until a blank comes */
while (textp != begin_line && alpha(*textp))
textp--;
/* Go to the next char if we're not at the beginning of the line */
if (textp != begin_line && *textp != '\n')
textp++;
/* Find the x-coordinate of this address, and move to it */
move_address(textp);
if (remove == DELETE)
delete(cur_line, textp, cur_line, start_pos);
}
/*
* MN() moves to the start of the next word. A word is defined as a number of
* non-blank characters separated by tabs spaces or linefeeds. Always keep in
* mind that the pointer shouldn't pass the '\n'.
*/
void MN(void)
{
move_next_word(NO_DELETE);
}
void move_next_word(FLAG remove)
{
register char *textp = cur_text;
/* Move to the end of the current word. */
while (*textp != '\n' && alpha(*textp))
textp++;
/* Skip all white spaces */
while (*textp != '\n' && white_space(*textp))
textp++;
/* If we're deleting. delete the text in between */
if (remove == DELETE) {
delete(cur_line, cur_text, cur_line, textp);
return;
}
/* If we're at end of line. move to the first word on the next line. */
if (*textp == '\n' && cur_line->next != tail) {
DN();
move_to(LINE_START, y);
textp = cur_text;
while (*textp != '\n' && white_space(*textp))
textp++;
}
move_address(textp);
}
/* ======================================================================== *
* Modify Commands *
* ======================================================================== */
/*
* DCC deletes the character under the cursor. If this character is a '\n' the
* current line is joined with the next one.
* If this character is the only character of the line, the current line will
* be deleted.
*/
void DCC(void)
{
if (*cur_text == '\n')
delete(cur_line,cur_text, cur_line->next,cur_line->next->text);
else
delete(cur_line, cur_text, cur_line, cur_text + 1);
}
/*
* DPC deletes the character on the left side of the cursor. If the cursor is
* at the beginning of the line, the last character if the previous line is
* deleted.
*/
void DPC(void)
{
if (x == 0 && cur_line->prev == header)
return; /* Top of file */
LF(); /* Move one left */
DCC(); /* Delete character under cursor */
}
/*
* DLN deletes all characters until the end of the line. If the current
* character is a '\n', then delete that char.
*/
void DLN(void)
{
if (*cur_text == '\n')
DCC();
else
delete(cur_line, cur_text, cur_line, cur_text + length_of(cur_text) -1);
}
/*
* DNW() deletes the next word (as described in MN())
*/
void DNW(void)
{
if (*cur_text == '\n')
DCC();
else
move_next_word(DELETE);
}
/*
* DPW() deletes the next word (as described in MP())
*/
void DPW(void)
{
if (cur_text == cur_line->text)
DPC();
else
move_previous_word(DELETE);
}
/*
* Insert character `character' at current location.
*/
void S(int character)
{
static char buffer[2];
buffer[0] = character;
/* Insert the character */
if (insert(cur_line, cur_text, buffer) == ERRORS)
return;
/* Fix screen */
if (character == '\n') {
set_cursor(0, y);
if (y == screenmax) { /* Can't use display */
line_print(cur_line);
(void) forward_scroll();
}
else {
reset(top_line, y); /* Reset pointers */
display(0, y, cur_line, last_y - y);
}
move_to(0, (y == screenmax) ? y : y + 1);
}
else if (x + 1 == XBREAK)/* If line must be shifted, just call move_to*/
move_to(x + 1, y);
else { /* else display rest of line */
put_line(cur_line, x, FALSE);
move_to(x + 1, y);
}
}
/*
* CTL inserts a control-char at the current location. A message that this
* function is called is displayed at the status line.
*/
void CTL(void)
{
register char ctrl;
status_line("Enter control character.", NULL);
if ((ctrl = getchar()) >= '\01' && ctrl <= '\037') {
S(ctrl); /* Insert the char */
clear_status();
}
else
error ("Unknown control character", NULL);
}
/*
* LIB insert a line at the current position and moves back to the end of
* the previous line.
*/
void LIB(void)
{
S('\n'); /* Insert the line */
UP(); /* Move one line up */
move_to(LINE_END, y); /* Move to end of this line */
}
/*
* Line_insert() inserts a new line with text pointed to by `string'.
* It returns the address of the new line.
*/
LINE *line_insert(register LINE *line, char *string, int len)
{
register LINE *new_line;
/* Allocate space for LINE structure and text */
new_line = install_line(string, len);
/* Install the line into the double linked list */
new_line->prev = line;
new_line->next = line->next;
line->next = new_line;
new_line->next->prev = new_line;
/* Increment nlines */
nlines++;
return new_line;
}
/*
* Insert() insert the string `string' at the given line and location.
*/
int insert(register LINE *line, char *location, char *string)
{
register char *bufp = text_buffer; /* Buffer for building line */
register char *textp = line->text;
if (length_of(textp) + length_of(string) >= MAX_CHARS) {
error("Line too long", NULL);
return ERRORS;
}
modified = TRUE; /* File has been modified */
/* Copy part of line until `location' has been reached */
while (textp != location)
*bufp++ = *textp++;
/* Insert string at this location */
while (*string != '\0')
*bufp++ = *string++;
*bufp = '\0';
if (*(string - 1) == '\n') /* Insert a new line */
(void) line_insert(line, location, length_of(location));
else /* Append last part of line */
copy_string(bufp, location);
/* Install the new text in this line */
free_space(line->text);
line->text = alloc(length_of(text_buffer) + 1);
copy_string(line->text, text_buffer);
return FINE;
}
/*
* Line_delete() deletes the argument line out of the line list. The pointer to
* the next line is returned.
*/
LINE *line_delete(register LINE *line)
{
register LINE *next_line = line->next;
/* Delete the line */
line->prev->next = line->next;
line->next->prev = line->prev;
/* Free allocated space */
free_space(line->text);
free_space((char*)line);
/* Decrement nlines */
nlines--;
return next_line;
}
/*
* Delete() deletes all the characters (including newlines) between the
* startposition and endposition and fixes the screen accordingly. It
* returns the number of lines deleted.
*/
void delete(register LINE *start_line, char *start_textp, LINE *end_line,
char *end_textp)
{
register char *textp = start_line->text;
register char *bufp = text_buffer; /* Storage for new line->text */
LINE *line, *stop;
int line_cnt = 0; /* Nr of lines deleted */
int count = 0;
int shift = 0; /* Used in shift calculation */
int nx = x;
modified = TRUE; /* File has been modified */
/* Set up new line. Copy first part of start line until start_position. */
while (textp < start_textp) {
*bufp++ = *textp++;
count++;
}
/* Check if line doesn't exceed MAX_CHARS */
if (count + length_of(end_textp) >= MAX_CHARS) {
error("Line too long", NULL);
return;
}
/* Copy last part of end_line if end_line is not tail */
copy_string(bufp, (end_textp != NULL) ? end_textp : "\n");
/* Delete all lines between start and end_position (including end_line) */
line = start_line->next;
stop = end_line->next;
while (line != stop && line != tail) {
line = line_delete(line);
line_cnt++;
}
/* Check if last line of file should be deleted */
if (end_textp == NULL && length_of(start_line->text) == 1 && nlines > 1) {
start_line = start_line->prev;
(void) line_delete(start_line->next);
line_cnt++;
}
else { /* Install new text */
free_space(start_line->text);
start_line->text = alloc(length_of(text_buffer) + 1);
copy_string(start_line->text, text_buffer);
}
/* Fix screen. First check if line is shifted. Perhaps we should shift it back*/
if (get_shift(start_line->shift_count)) {
shift = (XBREAK - count_chars(start_line)) / SHIFT_SIZE;
if (shift > 0) { /* Shift line `shift' back */
if (shift >= get_shift(start_line->shift_count))
start_line->shift_count = 0;
else
start_line->shift_count -= shift;
nx += shift * SHIFT_SIZE;/* Reset x value */
}
}
if (line_cnt == 0) { /* Check if only one line changed */
if (shift > 0) { /* Reprint whole line */
set_cursor(0, y);
line_print(start_line);
}
else { /* Just display last part of line */
set_cursor(x, y);
put_line(start_line, x, TRUE);
}
move_to(nx, y); /* Reset cur_text */
return;
}
shift = last_y; /* Save value */
reset(top_line, y);
display(0, y, start_line, shift - y);
move_to((line_cnt == 1) ? nx : 0, y);
}
/* ======================================================================== *
* Yank Commands *
* ======================================================================== */
LINE *mark_line; /* For marking position. */
char *mark_text;
int lines_saved; /* Nr of lines in buffer */
/*
* PT() inserts the buffer at the current location.
*/
void PT(void)
{
register int fd; /* File descriptor for buffer */
if ((fd = scratch_file(READ)) == ERRORS)
error("Buffer is empty.", NULL);
else {
file_insert(fd, FALSE);/* Insert the buffer */
(void) close(fd);
}
}
/*
* IF() prompt for a filename and inserts the file at the current location
* in the file.
*/
void IF(void)
{
register int fd; /* File descriptor of file */
char name[LINE_LEN]; /* Buffer for file name */
/* Get the file name */
if (get_file("Get and insert file:", name) != FINE)
return;
if ((fd = open(name, 0)) < 0)
error("Cannot open ", name);
else {
file_insert(fd, TRUE); /* Insert the file */
(void) close(fd);
}
}
/*
* File_insert() inserts a an opened file (as given by filedescriptor fd)
* at the current location.
*/
void file_insert(int fd, FLAG old_pos)
{
char line_buffer[MAX_CHARS]; /* Buffer for next line */
register LINE *line = cur_line;
register int line_count = nlines; /* Nr of lines inserted */
LINE *page = cur_line;
int ret = ERRORS;
/* Get the first piece of text (might be ended with a '\n') from fd */
if (get_line(fd, line_buffer) == ERRORS)
return; /* Empty file */
/* Insert this text at the current location. */
if (insert(line, cur_text, line_buffer) == ERRORS)
return;
/* Repeat getting lines (and inserting lines) until EOF is reached */
while ((ret = get_line(fd, line_buffer)) != ERRORS && ret != NO_LINE)
line = line_insert(line, line_buffer, ret);
if (ret == NO_LINE) { /* Last line read not ended by a '\n' */
line = line->next;
(void) insert(line, line->text, line_buffer);
}
/* Calculate nr of lines added */
line_count = nlines - line_count;
/* Fix the screen */
if (line_count == 0) { /* Only one line changed */
set_cursor(0, y);
line_print(line);
move_to((old_pos == TRUE) ? x : x + length_of(line_buffer), y);
}
else { /* Several lines changed */
reset(top_line, y); /* Reset pointers */
while (page != line && page != bot_line->next)
page = page->next;
if (page != bot_line->next || old_pos == TRUE)
display(0, y, cur_line, screenmax - y);
if (old_pos == TRUE)
move_to(x, y);
else if (ret == NO_LINE)
move_to(length_of(line_buffer), find_y(line));
else
move_to(0, find_y(line->next));
}
/* If nr of added line >= REPORT, print the count */
if (line_count >= REPORT)
status_line(num_out((long) line_count), " lines added.");
}
/*
* WB() writes the buffer (yank_file) into another file, which
* is prompted for.
*/
void WB(void)
{
register int new_fd; /* Filedescriptor to copy file */
int yank_fd; /* Filedescriptor to buffer */
register int cnt; /* Count check for read/write */
int ret = 0; /* Error check for write */
char file[LINE_LEN]; /* Output file */
/* Checkout the buffer */
if ((yank_fd = scratch_file(READ)) == ERRORS) {
error("Buffer is empty.", NULL);
return;
}
/* Get file name */
if (get_file("Write buffer to file:", file) != FINE)
return;
/* Creat the new file */
if ((new_fd = creat(file, 0644)) < 0) {
error("Cannot create ", file);
return;
}
status_line("Writing ", file);
/* Copy buffer into file */
while ((cnt = read(yank_fd, text_buffer, sizeof(text_buffer))) > 0)
if (write(new_fd, text_buffer, cnt) != cnt) {
bad_write(new_fd);
ret = ERRORS;
break;
}
/* Clean up open files and status_line */
(void) close(new_fd);
(void) close(yank_fd);
if (ret != ERRORS) /* Bad write */
file_status("Wrote", chars_saved, file, lines_saved, TRUE, FALSE);
}
/*
* MA sets mark_line (mark_text) to the current line (text pointer).
*/
void MA(void)
{
mark_line = cur_line;
mark_text = cur_text;
status_line("Mark set", NULL);
}
/*
* YA() puts the text between the marked position and the current
* in the buffer.
*/
void YA(void)
{
set_up(NO_DELETE);
}
/*
* DT() is essentially the same as YA(), but in DT() the text is deleted.
*/
void DT(void)
{
set_up(DELETE);
}
/*
* Set_up is an interface to the actual yank. It calls checkmark () to check
* if the marked position is still valid. If it is, yank is called with the
* arguments in the right order.
*/
void set_up(FLAG remove)
{
switch (checkmark()) {
case NOT_VALID :
error("Mark not set.", NULL);
return;
case SMALLER :
yank(mark_line, mark_text, cur_line, cur_text, remove);
break;
case BIGGER :
yank(cur_line, cur_text, mark_line, mark_text, remove);
break;
case SAME : /* Ignore stupid behaviour */
yank_status = EMPTY;
chars_saved = 0L;
status_line("0 characters saved in buffer.", NULL);
break;
}
}
/*
* Check_mark() checks if mark_line and mark_text are still valid pointers. If
* they are it returns SMALLER if the marked position is before the current,
* BIGGER if it isn't or SAME if somebody didn't get the point.
* NOT_VALID is returned when mark_line and/or mark_text are no longer valid.
* Legal() checks if mark_text is valid on the mark_line.
*/
FLAG checkmark(void)
{
register LINE *line;
FLAG cur_seen = FALSE;
/* Special case: check is mark_line and cur_line are the same. */
if (mark_line == cur_line) {
if (mark_text == cur_text) /* Even same place */
return SAME;
if (legal() == ERRORS) /* mark_text out of range */
return NOT_VALID;
return (mark_text < cur_text) ? SMALLER : BIGGER;
}
/* Start looking for mark_line in the line structure */
for (line = header->next; line != tail; line = line->next) {
if (line == cur_line)
cur_seen = TRUE;
else if (line == mark_line)
break;
}
/* If we found mark_line (line != tail) check for legality of mark_text */
if (line == tail || legal() == ERRORS)
return NOT_VALID;
/* cur_seen is TRUE if cur_line is before mark_line */
return (cur_seen == TRUE) ? BIGGER : SMALLER;
}
/*
* Legal() checks if mark_text is still a valid pointer.
*/
int legal(void)
{
register char *textp = mark_line->text;
/* Locate mark_text on mark_line */
while (textp != mark_text && *textp++ != '\0')
;
return (*textp == '\0') ? ERRORS : FINE;
}
/*
* Yank puts all the text between start_position and end_position into
* the buffer.
* The caller must check that the arguments to yank() are valid. (E.g. in
* the right order)
*/
void yank(LINE *start_line, char *start_textp, LINE *end_line, char *end_textp,
FLAG remove)
{
register LINE *line = start_line;
register char *textp = start_textp;
int fd;
/* Creat file to hold buffer */
if ((fd = scratch_file(WRITE)) == ERRORS)
return;
chars_saved = 0L;
lines_saved = 0;
status_line("Saving text.", NULL);
/* Keep writing chars until the end_location is reached. */
while (textp != end_textp) {
if (write_char(fd, *textp) == ERRORS) {
(void) close(fd);
return;
}
if (*textp++ == '\n') { /* Move to the next line */
line = line->next;
textp = line->text;
lines_saved++;
}
chars_saved++;
}
/* Flush the I/O buffer and close file */
if (flush_buffer(fd) == ERRORS) {
(void) close(fd);
return;
}
(void) close(fd);
yank_status = VALID;
/*
* Check if the text should be deleted as well. If it should, the following
* hack is used to save a lot of code. First move back to the start_position.
* (This might be the location we're on now!) and them delete the text.
* It might be a bit confusing the first time somebody uses it.
* Delete() will fix the screen.
*/
if (remove == DELETE) {
move_to(find_x(start_line, start_textp), find_y(start_line));
delete(start_line, start_textp, end_line, end_textp);
}
status_line(num_out(chars_saved), " characters saved in buffer.");
}
/*
* Scratch_file() creates a uniq file in /usr/tmp. If the file couldn't
* be created other combinations of files are tried until a maximum
* of MAXTRAILS times. After MAXTRAILS times, an error message is given
* and ERRORS is returned.
*/
#define MAXTRAILS 26
int scratch_file(FLAG mode)
{
static int trials = 0; /* Keep track of trails */
register char *y_ptr, *n_ptr;
int fd; /* Filedescriptor to buffer */
/* If yank_status == NOT_VALID, scratch_file is called for the first time */
if (yank_status == NOT_VALID && mode == WRITE) { /* Create new file */
/* Generate file name. */
y_ptr = &yank_file[11];
n_ptr = num_out((long) getpid());
while ((*y_ptr = *n_ptr++) != '\0')
y_ptr++;
*y_ptr++ = 'a' + trials;
*y_ptr = '\0';
/* Check file existence */
if (access(yank_file, 0) == 0 || (fd = creat(yank_file, 0644)) < 0) {
if (trials++ >= MAXTRAILS) {
error("Unable to creat scratchfile.", NULL);
return ERRORS;
}
else
return scratch_file(mode);/* Have another go */
}
}
else if ((mode == READ && (fd = open(yank_file, 0)) < 0) ||
(mode == WRITE && (fd = creat(yank_file, 0644)) < 0)) {
yank_status = NOT_VALID;
return ERRORS;
}
clear_buffer();
return fd;
}
/* ======================================================================== *
* Search Routines *
* ======================================================================== */
/*
* A regular expression consists of a sequence of:
* 1. A normal character matching that character.
* 2. A . matching any character.
* 3. A ^ matching the begin of a line.
* 4. A $ (as last character of the pattern) mathing the end of a line.
* 5. A \<character> matching <character>.
* 6. A number of characters enclosed in [] pairs matching any of these
* characters. A list of characters can be indicated by a '-'. So
* [a-z] matches any letter of the alphabet. If the first character
* after the '[' is a '^' then the set is negated (matching none of
* the characters).
* A ']', '^' or '-' can be escaped by putting a '\' in front of it.
* 7. If one of the expressions as described in 1-6 is followed by a
* '*' than that expressions matches a sequence of 0 or more of
* that expression.
*/
char typed_expression[LINE_LEN]; /* Holds previous expr. */
/*
* SF searches forward for an expression.
*/
void SF(void)
{
search("Search forward:", FORWARD);
}
/*
* SF searches backwards for an expression.
*/
void SR(void)
{
search("Search reverse:", REVERSE);
}
/*
* Get_expression() prompts for an expression. If just a return is typed, the
* old expression is used. If the expression changed, compile() is called and
* the returning REGEX structure is returned. It returns NULL upon error.
* The save flag indicates whether the expression should be appended at the
* message pointer.
*/
REGEX *get_expression(char *message)
{
static REGEX program; /* Program of expression */
char exp_buf[LINE_LEN]; /* Buffer for new expr. */
if (get_string(message, exp_buf, FALSE) == ERRORS)
return NULL;
if (exp_buf[0] == '\0' && typed_expression[0] == '\0') {
error("No previous expression.", NULL);
return NULL;
}
if (exp_buf[0] != '\0') { /* A new expr. is typed */
copy_string(typed_expression, exp_buf);/* Save expr. */
compile(exp_buf, &program); /* Compile new expression */
}
if (program.status == REG_ERROR) { /* Error during compiling */
error(program.result.err_mess, NULL);
return NULL;
}
return &program;
}
/*
* GR() a replaces all matches from the current position until the end
* of the file.
*/
void GR(void)
{
change("Global replace:", VALID);
}
/*
* LR() replaces all matches on the current line.
*/
void LR(void)
{
change("Line replace:", NOT_VALID);
}
/*
* Change() prompts for an expression and a substitution pattern and changes
* all matches of the expression into the substitution. change() start looking
* for expressions at the current line and continues until the end of the file
* if the FLAG file is VALID.
*/
void change(char *message, FLAG file)
{
char mess_buf[LINE_LEN]; /* Buffer to hold message */
char replacement[LINE_LEN]; /* Buffer to hold subst. pattern */
REGEX *program; /* Program resulting from compilation */
register LINE *line = cur_line;
register char *textp;
long lines = 0L; /* Nr of lines on which subs occurred */
long subs = 0L; /* Nr of subs made */
int page = y; /* Index to check if line is on screen*/
/* Save message and get expression */
copy_string(mess_buf, message);
if ((program = get_expression(mess_buf)) == NULL)
return;
/* Get substitution pattern */
build_string(mess_buf, "%s %s by:", mess_buf, typed_expression);
if (get_string(mess_buf, replacement, FALSE) == ERRORS)
return;
set_cursor(0, ymax);
flush();
/* Substitute until end of file */
do {
if (line_check(program, line->text, FORWARD)) {
lines++;
/* Repeat sub. on this line as long as we find a match*/
do {
subs++; /* Increment subs */
if ((textp = substitute(line, program,replacement))
== NULL)
return; /* Line too long */
} while ((program->status & BEGIN_LINE) != BEGIN_LINE &&
(program->status & END_LINE) != END_LINE &&
line_check(program, textp, FORWARD));
/* Check to see if we can print the result */
if (page <= screenmax) {
set_cursor(0, page);
line_print(line);
}
}
if (page <= screenmax)
page++;
line = line->next;
} while (line != tail && file == VALID && quit == FALSE);
copy_string(mess_buf, (quit == TRUE) ? "(Aborted) " : "");
/* Fix the status line */
if (subs == 0L && quit == FALSE)
error("Pattern not found.", NULL);
else if (lines >= REPORT || quit == TRUE) {
build_string(mess_buf, "%s %D substitutions on %D lines.", mess_buf,
subs, lines);
status_line(mess_buf, NULL);
}
else if (file == NOT_VALID && subs >= REPORT)
status_line(num_out(subs), " substitutions.");
else
clear_status();
move_to (x, y);
}
/*
* Substitute() replaces the match on this line by the substitute pattern
* as indicated by the program. Every '&' in the replacement is replaced by
* the original match. A \ in the replacement escapes the next character.
*/
char *substitute(LINE *line, REGEX *program, char *replacement)
{
register char *textp = text_buffer;
register char *subp = replacement;
char *linep = line->text;
char *amp;
modified = TRUE;
/* Copy part of line until the beginning of the match */
while (linep != program->start_ptr)
*textp++ = *linep++;
/*
* Replace the match by the substitution pattern. Each occurrence of '&' is
* replaced by the original match. A \ escapes the next character.
*/
while (*subp != '\0' && textp < &text_buffer[MAX_CHARS]) {
if (*subp == '&') { /* Replace the original match */
amp = program->start_ptr;
while (amp < program->end_ptr && textp<&text_buffer[MAX_CHARS])
*textp++ = *amp++;
subp++;
}
else {
if (*subp == '\\' && *(subp + 1) != '\0')
subp++;
*textp++ = *subp++;
}
}
/* Check for line length not exceeding MAX_CHARS */
if (length_of(text_buffer) + length_of(program->end_ptr) >= MAX_CHARS) {
error("Substitution result: line too big", NULL);
return NULL;
}
/* Append last part of line to the new build line */
copy_string(textp, program->end_ptr);
/* Free old line and install new one */
free_space(line->text);
line->text = alloc(length_of(text_buffer) + 1);
copy_string(line->text, text_buffer);
return(line->text + (textp - text_buffer));
}
/*
* Search() calls get_expression to fetch the expression. If this went well,
* the function match() is called which returns the line with the next match.
* If this line is the NULL, it means that a match could not be found.
* Find_x() and find_y() display the right page on the screen, and return
* the right coordinates for x and y. These coordinates are passed to move_to()
*/
void search(char *message, FLAG method)
{
register REGEX *program;
register LINE *match_line;
/* Get the expression */
if ((program = get_expression(message)) == NULL)
return;
set_cursor(0, ymax);
flush();
/* Find the match */
if ((match_line = match(program, cur_text, method)) == NULL) {
if (quit == TRUE)
status_line("Aborted", NULL);
else
status_line("Pattern not found.", NULL);
return;
}
move(0, program->start_ptr, find_y(match_line));
clear_status();
}
/*
* find_y() checks if the matched line is on the current page. If it is, it
* returns the new y coordinate, else it displays the correct page with the
* matched line in the middle and returns the new y value;
*/
int find_y(LINE *match_line)
{
register LINE *line;
register int count = 0;
/* Check if match_line is on the same page as currently displayed. */
for (line = top_line; line != match_line && line != bot_line->next;
line = line->next)
count++;
if (line != bot_line->next)
return count;
/* Display new page, with match_line in center. */
if ((line = proceed(match_line, -(screenmax >> 1))) == header) {
/* Can't display in the middle. Make first line of file top_line */
count = 0;
for (line = header->next; line != match_line; line = line->next)
count++;
line = header->next;
}
else /* New page is displayed. Set cursor to middle of page */
count = screenmax >> 1;
/* Reset pointers and redraw the screen */
reset(line, 0);
RD();
return count;
}
/* Opcodes for characters */
#define NORMAL 0x0200
#define DOT 0x0400
#define EOLN 0x0800
#define STAR 0x1000
#define BRACKET 0x2000
#define NEGATE 0x0100
#define DONE 0x4000
/* Mask for opcodes and characters */
#define LOW_BYTE 0x00FF
#define HIGH_BYTE 0xFF00
/* Previous is the contents of the previous address (ptr) points to */
#define previous(ptr) (*((ptr) - 1))
/* Buffer to store outcome of compilation */
int exp_buffer[BLOCK_SIZE];
/* Errors often used */
char *too_long = "Regular expression too long";
/*
* Reg_error() is called by compile() is something went wrong. It set the
* status of the structure to error, and assigns the error field of the union.
*/
#define reg_error(str) program->status = REG_ERROR, \
program->result.err_mess = (str)
/*
* Finished() is called when everything went right during compilation. It
* allocates space for the expression, and copies the expression buffer into
* this field.
*/
void finished(register REGEX *program, int *last_exp)
{
register int length = (last_exp - exp_buffer) * sizeof(int);
/* Allocate space */
program->result.expression = (int *) alloc(length);
/* Copy expression. (expression consists of ints!) */
bcopy(exp_buffer, program->result.expression, length);
}
/*
* Compile compiles the pattern into a more comprehensible form and returns a
* REGEX structure. If something went wrong, the status field of the structure
* is set to REG_ERROR and an error message is set into the err_mess field of
* the union. If all went well the expression is saved and the expression
* pointer is set to the saved (and compiled) expression.
*/
void compile(register char *pattern, REGEX *program)
{
register int *expression = exp_buffer;
int *prev_char; /* Pointer to previous compiled atom */
int *acct_field; /* Pointer to last BRACKET start */
FLAG negate; /* Negate flag for BRACKET */
char low_char; /* Index for chars in BRACKET */
char c;
/* Check for begin of line */
if (*pattern == '^') {
program->status = BEGIN_LINE;
pattern++;
}
else {
program->status = 0;
/* If the first character is a '*' we have to assign it here. */
if (*pattern == '*') {
*expression++ = '*' + NORMAL;
pattern++;
}
}
for (; ;) {
switch (c = *pattern++) {
case '.' :
*expression++ = DOT;
break;
case '$' :
/*
* Only means EOLN if it is the last char of the pattern
*/
if (*pattern == '\0') {
*expression++ = EOLN | DONE;
program->status |= END_LINE;
finished(program, expression);
return;
}
else
*expression++ = NORMAL + '$';
break;
case '\0' :
*expression++ = DONE;
finished(program, expression);
return;
case '\\' :
/* If last char, it must! mean a normal '\' */
if (*pattern == '\0')
*expression++ = NORMAL + '\\';
else
*expression++ = NORMAL + *pattern++;
break;
case '*' :
/*
* If the previous expression was a [] find out the
* begin of the list, and adjust the opcode.
*/
prev_char = expression - 1;
if (*prev_char & BRACKET)
*(expression - (*acct_field & LOW_BYTE))|= STAR;
else
*prev_char |= STAR;
break;
case '[' :
/*
* First field in expression gives information about
* the list.
* The opcode consists of BRACKET and if necessary
* NEGATE to indicate that the list should be negated
* and/or STAR to indicate a number of sequence of this
* list.
* The lower byte contains the length of the list.
*/
acct_field = expression++;
if (*pattern == '^') { /* List must be negated */
pattern++;
negate = TRUE;
}
else
negate = FALSE;
while (*pattern != ']') {
if (*pattern == '\0') {
reg_error("Missing ]");
return;
}
if (*pattern == '\\')
pattern++;
*expression++ = *pattern++;
if (*pattern == '-') {
/* Make list of chars */
low_char = previous(pattern);
pattern++; /* Skip '-' */
if (low_char++ > *pattern) {
reg_error("Bad range in [a-z]");
return;
}
/* Build list */
while (low_char <= *pattern)
*expression++ = low_char++;
pattern++;
}
if (expression >= &exp_buffer[BLOCK_SIZE]) {
reg_error(too_long);
return;
}
}
pattern++; /* Skip ']' */
/* Assign length of list in acct field */
if ((*acct_field = (expression - acct_field)) == 1) {
reg_error("Empty []");
return;
}
/* Assign negate and bracket field */
*acct_field |= BRACKET;
if (negate == TRUE)
*acct_field |= NEGATE;
/*
* Add BRACKET to opcode of last char in field because
* a '*' may be following the list.
*/
previous(expression) |= BRACKET;
break;
default :
*expression++ = c + NORMAL;
}
if (expression == &exp_buffer[BLOCK_SIZE]) {
reg_error(too_long);
return;
}
}
/* NOTREACHED */
}
/*
* Match gets as argument the program, pointer to place in current line to
* start from and the method to search for (either FORWARD or REVERSE).
* Match() will look through the whole file until a match is found.
* NULL is returned if no match could be found.
*/
LINE *match(REGEX *program, char *string, register FLAG method)
{
register LINE *line = cur_line;
char old_char; /* For saving chars */
/* Corrupted program */
if (program->status == REG_ERROR)
return NULL;
/* Check part of text first */
if (!(program->status & BEGIN_LINE)) {
if (method == FORWARD) {
if (line_check(program, string + 1, method) == MATCH)
return cur_line; /* Match found */
}
else if (!(program->status & END_LINE)) {
old_char = *string; /* Save char and */
*string = '\n'; /* Assign '\n' for line_check */
if (line_check(program, line->text, method) == MATCH) {
*string = old_char; /* Restore char */
return cur_line; /* Found match */
}
*string = old_char; /* No match, but restore char */
}
}
/* No match in last (or first) part of line. Check out rest of file */
do {
line = (method == FORWARD) ? line->next : line->prev;
if (line->text == NULL) /* Header/tail */
continue;
if (line_check(program, line->text, method) == MATCH)
return line;
} while (line != cur_line && quit == FALSE);
/* No match found. */
return NULL;
}
/*
* Line_check() checks the line (or rather string) for a match. Method
* indicates FORWARD or REVERSE search. It scans through the whole string
* until a match is found, or the end of the string is reached.
*/
int line_check(register REGEX *program, char *string, FLAG method)
{
register char *textp = string;
/* Assign start_ptr field. We might find a match right away! */
program->start_ptr = textp;
/* If the match must be anchored, just check the string. */
if (program->status & BEGIN_LINE)
return check_string(program, string, NULL);
if (method == REVERSE) {
/* First move to the end of the string */
for (textp = string; *textp != '\n'; textp++)
;
/* Start checking string until the begin of the string is met */
while (textp >= string) {
program->start_ptr = textp;
if (check_string(program, textp--, NULL))
return MATCH;
}
}
else {
/* Move through the string until the end of is found */
while (quit == FALSE && *textp != '\0') {
program->start_ptr = textp;
if (check_string(program, textp, NULL))
return MATCH;
if (*textp == '\n')
break;
textp++;
}
}
return NO_MATCH;
}
/*
* Check() checks of a match can be found in the given string. Whenever a STAR
* is found during matching, then the begin position of the string is marked
* and the maximum number of matches is performed. Then the function star()
* is called which starts to finish the match from this position of the string
* (and expression). Check() return MATCH for a match, NO_MATCH is the string
* couldn't be matched or REG_ERROR for an illegal opcode in expression.
*/
int check_string(REGEX *program, register char *string, int *expression)
{
register int opcode; /* Holds opcode of next expr. atom */
char c; /* Char that must be matched */
char *mark; /* For marking position */
int star_fl; /* A star has been born */
if (expression == NULL)
expression = program->result.expression;
/* Loop until end of string or end of expression */
while (quit == FALSE && !(*expression & DONE) &&
*string != '\0' && *string != '\n') {
c = *expression & LOW_BYTE; /* Extract match char */
opcode = *expression & HIGH_BYTE; /* Extract opcode */
if ((star_fl = (opcode & STAR))) { /* Check star occurrence */
opcode &= ~STAR; /* Strip opcode */
mark = string; /* Mark current position */
}
expression++; /* Increment expr. */
switch (opcode) {
case NORMAL :
if (star_fl)
while (*string++ == c) /* Skip all matches */
;
else if (*string++ != c)
return NO_MATCH;
break;
case DOT :
string++;
if (star_fl) /* Skip to eoln */
while (*string != '\0' && *string++ != '\n')
;
break;
case NEGATE | BRACKET:
case BRACKET :
if (star_fl)
while (in_list(expression, *string++, c, opcode)
== MATCH)
;
else if (in_list(expression, *string++, c, opcode) == NO_MATCH)
return NO_MATCH;
expression += c - 1; /* Add length of list */
break;
default :
panic("Corrupted program in check_string()");
}
if (star_fl)
return star(program, mark, string, expression);
}
if (*expression & DONE) {
program->end_ptr = string; /* Match ends here */
/*
* We might have found a match. The last thing to do is check
* whether a '$' was given at the end of the expression, or
* the match was found on a null string. (E.g. [a-z]* always
* matches) unless a ^ or $ was included in the pattern.
*/
if ((*expression & EOLN) && *string != '\n' && *string != '\0')
return NO_MATCH;
if (string == program->start_ptr && !(program->status & BEGIN_LINE)
&& !(*expression & EOLN))
return NO_MATCH;
return MATCH;
}
return NO_MATCH;
}
/*
* Star() calls check_string() to find out the longest match possible.
* It searches backwards until the (in check_string()) marked position
* is reached, or a match is found.
*/
int star(REGEX *program, register char *end_position, register char *string,
int *expression)
{
do {
string--;
if (check_string(program, string, expression))
return MATCH;
} while (string != end_position);
return NO_MATCH;
}
/*
* In_list() checks if the given character is in the list of []. If it is
* it returns MATCH. if it isn't it returns NO_MATCH. These returns values
* are reversed when the NEGATE field in the opcode is present.
*/
int in_list(int *list, int c, register int list_length, int opcode)
{
if (c == '\0' || c == '\n') /* End of string, never matches */
return NO_MATCH;
while (list_length-- > 1) { /* > 1, don't check acct_field */
if ((*list & LOW_BYTE) == c)
return (opcode & NEGATE) ? NO_MATCH : MATCH;
list++;
}
return (opcode & NEGATE) ? MATCH : NO_MATCH;
}
/*
* Dummy_line() adds an empty line at the end of the file. This is sometimes
* useful in combination with the EF and DN command in combination with the
* Yank command set.
*/
void dummy_line(void)
{
(void) line_insert(tail->prev, "\n", 1);
tail->prev->shift_count = DUMMY;
if (last_y != screenmax) {
last_y++;
bot_line = bot_line->next;
}
}
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