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search.c
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/*
* Copyright (C) 1984-2025 Mark Nudelman
*
* You may distribute under the terms of either the GNU General Public
* License or the Less License, as specified in the README file.
*
* For more information, see the README file.
*/
/*
* Routines to search a file for a pattern.
*/
#include "less.h"
#include "position.h"
#include "charset.h"
#define MINPOS(a,b) (((a) < (b)) ? (a) : (b))
#define MAXPOS(a,b) (((a) > (b)) ? (a) : (b))
extern int sigs;
extern int how_search;
extern int caseless;
extern int linenums;
extern int jump_sline;
extern int bs_mode;
extern int proc_backspace;
extern int proc_return;
extern int ctldisp;
extern int status_col;
extern void *ml_search;
extern POSITION start_attnpos;
extern POSITION end_attnpos;
extern int utf_mode;
extern int sc_width;
extern int sc_height;
extern int hshift;
extern int match_shift;
extern int nosearch_header_lines;
extern int nosearch_header_cols;
extern int header_lines;
extern int header_cols;
extern LWCHAR rscroll_char;
#if HILITE_SEARCH
extern int hilite_search;
extern lbool squished;
extern int can_goto_line;
extern lbool no_eof_bell;
static lbool hide_hilite;
static POSITION prep_startpos;
static POSITION prep_endpos;
public POSITION header_start_pos = NULL_POSITION;
static POSITION header_end_pos;
public lbool search_wrapped = FALSE;
#if OSC8_LINK
public POSITION osc8_linepos = NULL_POSITION;
public POSITION osc8_match_start = NULL_POSITION;
public POSITION osc8_match_end = NULL_POSITION;
public POSITION osc8_params_start = NULL_POSITION;
public POSITION osc8_params_end = NULL_POSITION;
public POSITION osc8_uri_start = NULL_POSITION;
public POSITION osc8_uri_end = NULL_POSITION;
public POSITION osc8_text_start = NULL_POSITION;
public POSITION osc8_text_end = NULL_POSITION;
char *osc8_path = NULL;
char *osc8_uri = NULL;
constant char *osc8_search_param = NULL;
#endif
/*
* Structures for maintaining a set of ranges for hilites and filtered-out
* lines. Each range is stored as a node within a red-black tree, and we
* try to extend existing ranges (without creating overlaps) rather than
* create new nodes if possible. We remember the last node found by a
* search for constant-time lookup if the next search is near enough to
* the previous. To aid that, we overlay a secondary doubly-linked list
* on top of the red-black tree so we can find the preceding/succeeding
* nodes also in constant time.
*
* Each node is allocated from a series of pools, each pool double the size
* of the previous (for amortised constant time allocation). Since our only
* tree operations are clear and node insertion, not node removal, we don't
* need to maintain a usage bitmap or freelist and can just return nodes
* from the pool in-order until capacity is reached.
*/
struct hilite
{
POSITION hl_startpos;
POSITION hl_endpos;
int hl_attr;
};
struct hilite_node
{
struct hilite_node *parent;
struct hilite_node *left;
struct hilite_node *right;
struct hilite_node *prev;
struct hilite_node *next;
int red;
struct hilite r;
};
struct hilite_storage
{
size_t capacity;
size_t used;
struct hilite_storage *next;
struct hilite_node *nodes;
};
struct hilite_tree
{
struct hilite_storage *first;
struct hilite_storage *current;
struct hilite_node *root;
struct hilite_node *lookaside;
};
#define HILITE_INITIALIZER() { NULL, NULL, NULL, NULL }
#define HILITE_LOOKASIDE_STEPS 2
static struct hilite_tree hilite_anchor = HILITE_INITIALIZER();
static struct hilite_tree filter_anchor = HILITE_INITIALIZER();
static struct pattern_info *filter_infos = NULL;
#endif
/*
* These are the static variables that represent the "remembered"
* search pattern and filter pattern.
*/
struct pattern_info {
PATTERN_TYPE compiled;
char* text;
int search_type;
lbool is_ucase_pattern;
struct pattern_info *next;
};
#if NO_REGEX
#define info_compiled(info) ((void*)0)
#else
#define info_compiled(info) ((info)->compiled)
#endif
static struct pattern_info search_info;
public int is_caseless;
/*
* Are there any uppercase letters in this string?
*/
static lbool is_ucase(constant char *str)
{
constant char *str_end = str + strlen(str);
LWCHAR ch;
while (str < str_end)
{
ch = step_charc(&str, +1, str_end);
if (IS_UPPER(ch))
return (TRUE);
}
return (FALSE);
}
/*
* Discard a saved pattern.
*/
static void clear_pattern(struct pattern_info *info)
{
if (info->text != NULL)
free(info->text);
info->text = NULL;
#if !NO_REGEX
uncompile_pattern(&info->compiled);
#endif
}
/*
* Compile and save a search pattern.
*/
static int set_pattern(struct pattern_info *info, constant char *pattern, int search_type, int show_error)
{
/*
* Ignore case if -I is set OR
* -i is set AND the pattern is all lowercase.
*/
info->is_ucase_pattern = (pattern == NULL) ? FALSE : is_ucase(pattern);
is_caseless = (info->is_ucase_pattern && caseless != OPT_ONPLUS) ? 0 : caseless;
#if !NO_REGEX
if (pattern == NULL)
SET_NULL_PATTERN(info->compiled);
else if (compile_pattern(pattern, search_type, show_error, &info->compiled) < 0)
return -1;
#endif
/* Pattern compiled successfully; save the text too. */
if (info->text != NULL)
free(info->text);
info->text = NULL;
if (pattern != NULL)
{
info->text = (char *) ecalloc(1, strlen(pattern)+1);
strcpy(info->text, pattern);
}
info->search_type = search_type;
return 0;
}
/*
* Initialize saved pattern to nothing.
*/
static void init_pattern(struct pattern_info *info)
{
SET_NULL_PATTERN(info->compiled);
info->text = NULL;
info->search_type = 0;
info->next = NULL;
}
/*
* Initialize search variables.
*/
public void init_search(void)
{
init_pattern(&search_info);
}
/*
* Determine which text conversions to perform before pattern matching.
*/
public int get_cvt_ops(int search_type)
{
int ops = 0;
if (is_caseless && (!re_handles_caseless || (search_type & SRCH_NO_REGEX)))
ops |= CVT_TO_LC;
if (proc_backspace == OPT_ON || (bs_mode == BS_SPECIAL && proc_backspace == OPT_OFF))
ops |= CVT_BS;
if (proc_return == OPT_ON || (bs_mode != BS_CONTROL && proc_backspace == OPT_OFF))
ops |= CVT_CRLF;
if (ctldisp == OPT_ONPLUS)
ops |= CVT_ANSI;
return (ops);
}
/*
* Is there a previous (remembered) search pattern?
*/
static lbool prev_pattern(struct pattern_info *info)
{
#if !NO_REGEX
if ((info->search_type & SRCH_NO_REGEX) == 0)
return (!is_null_pattern(info->compiled));
#endif
return (info->text != NULL);
}
#if HILITE_SEARCH
/*
* Repaint the hilites currently displayed on the screen.
* Repaint each line which contains highlighted text.
* If on==0, force all hilites off.
*/
public void repaint_hilite(lbool on)
{
int sindex;
POSITION pos;
lbool save_hide_hilite;
if (squished)
repaint();
save_hide_hilite = hide_hilite;
if (!on)
{
if (hide_hilite)
return;
hide_hilite = TRUE;
}
if (!can_goto_line)
{
repaint();
hide_hilite = save_hide_hilite;
return;
}
for (sindex = TOP; sindex < TOP + sc_height-1; sindex++)
{
pos = position(sindex);
if (pos == NULL_POSITION)
continue;
(void) forw_line(pos, NULL, NULL);
goto_line(sindex);
clear_eol();
put_line(FALSE);
}
overlay_header();
lower_left();
hide_hilite = save_hide_hilite;
}
#endif
/*
* Clear the attn hilite.
*/
public void clear_attn(void)
{
#if HILITE_SEARCH
int sindex;
POSITION old_start_attnpos;
POSITION old_end_attnpos;
POSITION pos;
POSITION epos;
int moved = 0;
if (start_attnpos == NULL_POSITION)
return;
old_start_attnpos = start_attnpos;
old_end_attnpos = end_attnpos;
start_attnpos = end_attnpos = NULL_POSITION;
if (!can_goto_line)
{
repaint();
return;
}
if (squished)
repaint();
for (sindex = TOP; sindex < TOP + sc_height-1; sindex++)
{
pos = position(sindex);
if (pos == NULL_POSITION)
continue;
epos = position(sindex+1);
if (pos <= old_end_attnpos &&
(epos == NULL_POSITION || epos > old_start_attnpos))
{
(void) forw_line(pos, NULL, NULL);
goto_line(sindex);
clear_eol();
put_line(FALSE);
moved = 1;
}
}
if (overlay_header())
moved = 1;
if (moved)
lower_left();
#endif
}
/*
* Toggle or clear search string highlighting.
*/
public void undo_search(lbool clear)
{
clear_pattern(&search_info);
#if OSC8_LINK
osc8_linepos = NULL_POSITION;
#endif
#if HILITE_SEARCH
if (clear)
{
clr_hilite();
} else
{
if (hilite_anchor.first == NULL)
{
error("No previous regular expression", NULL_PARG);
return;
}
hide_hilite = !hide_hilite;
}
repaint_hilite(TRUE);
#endif
}
#if HILITE_SEARCH
/*
* Clear the hilite list.
*/
public void clr_hlist(struct hilite_tree *anchor)
{
struct hilite_storage *hls;
struct hilite_storage *nexthls;
for (hls = anchor->first; hls != NULL; hls = nexthls)
{
nexthls = hls->next;
free((void*)hls->nodes);
free((void*)hls);
}
anchor->first = NULL;
anchor->current = NULL;
anchor->root = NULL;
anchor->lookaside = NULL;
prep_startpos = prep_endpos = NULL_POSITION;
}
public void clr_hilite(void)
{
clr_hlist(&hilite_anchor);
}
public void clr_filter(void)
{
clr_hlist(&filter_anchor);
}
/*
* Find the node covering pos, or the node after it if no node covers it,
* or return NULL if pos is after the last range. Remember the found node,
* to speed up subsequent searches for the same or similar positions (if
* we return NULL, remember the last node.)
*/
static struct hilite_node* hlist_find(struct hilite_tree *anchor, POSITION pos)
{
struct hilite_node *n, *m;
if (anchor->lookaside)
{
int steps = 0;
int hit = 0;
n = anchor->lookaside;
for (;;)
{
if (pos < n->r.hl_endpos)
{
if (n->prev == NULL || pos >= n->prev->r.hl_endpos)
{
hit = 1;
break;
}
} else if (n->next == NULL)
{
n = NULL;
hit = 1;
break;
}
/*
* If we don't find the right node within a small
* distance, don't keep doing a linear search!
*/
if (steps >= HILITE_LOOKASIDE_STEPS)
break;
steps++;
if (pos < n->r.hl_endpos)
anchor->lookaside = n = n->prev;
else
anchor->lookaside = n = n->next;
}
if (hit)
return n;
}
n = anchor->root;
m = NULL;
while (n != NULL)
{
if (pos < n->r.hl_startpos)
{
if (n->left != NULL)
{
m = n;
n = n->left;
continue;
}
break;
}
if (pos >= n->r.hl_endpos)
{
if (n->right != NULL)
{
n = n->right;
continue;
}
if (m != NULL)
{
n = m;
} else
{
m = n;
n = NULL;
}
}
break;
}
if (n != NULL)
anchor->lookaside = n;
else if (m != NULL)
anchor->lookaside = m;
return n;
}
/*
* Should any characters in a specified range be highlighted?
*/
static int hilited_range_attr(POSITION pos, POSITION epos)
{
struct hilite_node *n = hlist_find(&hilite_anchor, pos);
if (n == NULL)
return 0;
if (epos != NULL_POSITION && epos <= n->r.hl_startpos)
return 0;
return n->r.hl_attr;
}
/*
* Set header parameters.
*/
public void set_header(POSITION pos)
{
header_start_pos = (header_lines == 0) ? NULL_POSITION : pos;
if (header_start_pos != NULL_POSITION)
{
int ln;
for (ln = 0; ln < header_lines; ++ln)
{
pos = forw_raw_line(pos, NULL, NULL);
if (pos == NULL_POSITION) break;
}
header_end_pos = pos;
}
}
/*
* Is a position within the header lines?
*/
static lbool pos_in_header(POSITION pos)
{
return (header_start_pos != NULL_POSITION &&
pos >= header_start_pos && pos < header_end_pos);
}
/*
* Is a line "filtered" -- that is, should it be hidden?
*/
public lbool is_filtered(POSITION pos)
{
struct hilite_node *n;
if (!is_filtering())
return (FALSE);
if (pos_in_header(pos))
return (FALSE);
n = hlist_find(&filter_anchor, pos);
return (n != NULL && pos >= n->r.hl_startpos);
}
/*
* If pos is hidden, return the next position which isn't, otherwise
* just return pos.
*/
public POSITION next_unfiltered(POSITION pos)
{
if (!is_filtering())
return (pos);
if (pos_in_header(pos))
return (pos);
flush();
while (pos != NULL_POSITION)
{
prep_hilite(pos, NULL_POSITION, 1);
if (!is_filtered(pos))
break;
pos = forw_raw_line(pos, NULL, NULL);
}
return pos;
}
/*
* Set the hshift for the line starting at line_pos so that the string
* between start_off and end_off is visible on the screen.
*/
static void shift_visible(POSITION line_pos, size_t start_off, size_t end_off)
{
POSITION start_pos = line_pos + start_off;
POSITION end_pos = line_pos + end_off;
int start_col = col_from_pos(line_pos, start_pos, NULL_POSITION, -1);
int end_col = col_from_pos(line_pos, end_pos, start_pos, start_col);
int swidth = sc_width - line_pfx_width() - (rscroll_char ? 1 : 0);
int new_hshift;
if (start_col < 0 || end_col < 0)
return;
if (end_col < swidth) /* whole string is in first screen */
new_hshift = 0;
else if (start_col > hshift && end_col < hshift + swidth)
new_hshift = hshift; /* already visible; leave hshift unchanged */
else
{
int eol_col = col_from_pos(line_pos, NULL_POSITION, end_pos, end_col) - swidth;
if (start_col >= eol_col) /* whole string is in last screen */
new_hshift = eol_col;
else /* shift it to column match_shift */
new_hshift = (start_col < match_shift) ? 0 : start_col - match_shift;
}
if (new_hshift != hshift)
{
hshift = new_hshift;
screen_trashed();
}
}
/*
* Should any characters in a specified range be highlighted?
* If nohide is nonzero, don't consider hide_hilite.
*/
public int is_hilited_attr(POSITION pos, POSITION epos, int nohide, int *p_matches)
{
int attr;
if (p_matches != NULL)
*p_matches = 0;
if (!status_col &&
start_attnpos != NULL_POSITION &&
pos <= end_attnpos &&
(epos == NULL_POSITION || epos > start_attnpos))
/*
* The attn line overlaps this range.
*/
return (AT_HILITE|AT_COLOR_ATTN);
#if OSC8_LINK
if (osc8_linepos != NULL_POSITION &&
pos <= osc8_text_end && (epos == NULL_POSITION || epos > osc8_text_start))
return (AT_HILITE|AT_COLOR_SEARCH);
#endif
attr = hilited_range_attr(pos, epos);
if (attr == 0)
return (0);
if (p_matches == NULL)
/*
* Kinda kludgy way to recognize that caller is checking for
* hilite in status column. In this case we want to return
* hilite status even if hiliting is disabled or hidden.
*/
return (attr);
/*
* Report matches, even if we're hiding highlights.
*/
*p_matches = 1;
if (hilite_search == 0)
/*
* Not doing highlighting.
*/
return (0);
if (!nohide && hide_hilite)
/*
* Highlighting is hidden.
*/
return (0);
return (attr);
}
/*
* Tree node storage: get the current block of nodes if it has spare
* capacity, or create a new one if not.
*/
static struct hilite_storage * hlist_getstorage(struct hilite_tree *anchor)
{
size_t capacity = 1;
struct hilite_storage *s;
if (anchor->current)
{
if (anchor->current->used < anchor->current->capacity)
return anchor->current;
capacity = anchor->current->capacity * 2;
}
s = (struct hilite_storage *) ecalloc(1, sizeof(struct hilite_storage));
s->nodes = (struct hilite_node *) ecalloc(capacity, sizeof(struct hilite_node));
s->capacity = capacity;
s->used = 0;
s->next = NULL;
if (anchor->current)
anchor->current->next = s;
else
anchor->first = s;
anchor->current = s;
return s;
}
/*
* Tree node storage: retrieve a new empty node to be inserted into the
* tree.
*/
static struct hilite_node * hlist_getnode(struct hilite_tree *anchor)
{
struct hilite_storage *s = hlist_getstorage(anchor);
return &s->nodes[s->used++];
}
/*
* Rotate the tree left around a pivot node.
*/
static void hlist_rotate_left(struct hilite_tree *anchor, struct hilite_node *n)
{
struct hilite_node *np = n->parent;
struct hilite_node *nr = n->right;
struct hilite_node *nrl = n->right->left;
if (np != NULL)
{
if (n == np->left)
np->left = nr;
else
np->right = nr;
} else
{
anchor->root = nr;
}
nr->left = n;
n->right = nrl;
nr->parent = np;
n->parent = nr;
if (nrl != NULL)
nrl->parent = n;
}
/*
* Rotate the tree right around a pivot node.
*/
static void hlist_rotate_right(struct hilite_tree *anchor, struct hilite_node *n)
{
struct hilite_node *np = n->parent;
struct hilite_node *nl = n->left;
struct hilite_node *nlr = n->left->right;
if (np != NULL)
{
if (n == np->right)
np->right = nl;
else
np->left = nl;
} else
{
anchor->root = nl;
}
nl->right = n;
n->left = nlr;
nl->parent = np;
n->parent = nl;
if (nlr != NULL)
nlr->parent = n;
}
/*
* Add a new hilite to a hilite list.
*/
static void add_hilite(struct hilite_tree *anchor, struct hilite *hl)
{
struct hilite_node *p, *n, *u;
/* Ignore empty ranges. */
if (hl->hl_startpos >= hl->hl_endpos)
return;
p = anchor->root;
/* Inserting the very first node is trivial. */
if (p == NULL)
{
n = hlist_getnode(anchor);
n->r = *hl;
anchor->root = n;
anchor->lookaside = n;
return;
}
/*
* Find our insertion point. If we come across any overlapping
* or adjoining existing ranges, shrink our range and discard
* if it become empty.
*/
for (;;)
{
if (hl->hl_startpos < p->r.hl_startpos)
{
if (hl->hl_endpos > p->r.hl_startpos && hl->hl_attr == p->r.hl_attr)
hl->hl_endpos = p->r.hl_startpos;
if (p->left != NULL)
{
p = p->left;
continue;
}
break;
}
if (hl->hl_startpos < p->r.hl_endpos && hl->hl_attr == p->r.hl_attr) {
hl->hl_startpos = p->r.hl_endpos;
if (hl->hl_startpos >= hl->hl_endpos)
return;
}
if (p->right != NULL)
{
p = p->right;
continue;
}
break;
}
/*
* Now we're at the right leaf, again check for contiguous ranges
* and extend the existing node if possible to avoid the
* insertion. Otherwise insert a new node at the leaf.
*/
if (hl->hl_startpos < p->r.hl_startpos) {
if (hl->hl_attr == p->r.hl_attr)
{
if (hl->hl_endpos == p->r.hl_startpos)
{
p->r.hl_startpos = hl->hl_startpos;
return;
}
if (p->prev != NULL && p->prev->r.hl_endpos == hl->hl_startpos)
{
p->prev->r.hl_endpos = hl->hl_endpos;
return;
}
}
p->left = n = hlist_getnode(anchor);
n->next = p;
if (p->prev != NULL)
{
n->prev = p->prev;
p->prev->next = n;
}
p->prev = n;
} else {
if (hl->hl_attr == p->r.hl_attr)
{
if (p->r.hl_endpos == hl->hl_startpos)
{
p->r.hl_endpos = hl->hl_endpos;
return;
}
if (p->next != NULL && hl->hl_endpos == p->next->r.hl_startpos) {
p->next->r.hl_startpos = hl->hl_startpos;
return;
}
}
p->right = n = hlist_getnode(anchor);
n->prev = p;
if (p->next != NULL)
{
n->next = p->next;
p->next->prev = n;
}
p->next = n;
}
n->parent = p;
n->red = 1;
n->r = *hl;
/*
* The tree is in the correct order and covers the right ranges
* now, but may have become unbalanced. Rebalance it using the
* standard red-black tree constraints and operations.
*/
for (;;)
{
/* case 1 - current is root, root is always black */
if (n->parent == NULL)
{
n->red = 0;
break;
}
/* case 2 - parent is black, we can always be red */
if (!n->parent->red)
break;
/*
* constraint: because the root must be black, if our
* parent is red it cannot be the root therefore we must
* have a grandparent
*/
/*
* case 3 - parent and uncle are red, repaint them black,
* the grandparent red, and start again at the grandparent.
*/
u = n->parent->parent->left;
if (n->parent == u)
u = n->parent->parent->right;
if (u != NULL && u->red)
{
n->parent->red = 0;
u->red = 0;
n = n->parent->parent;
n->red = 1;
continue;
}
/*
* case 4 - parent is red but uncle is black, parent and
* grandparent on opposite sides. We need to start
* changing the structure now. This and case 5 will shorten
* our branch and lengthen the sibling, between them
* restoring balance.
*/
if (n == n->parent->right &&
n->parent == n->parent->parent->left)
{
hlist_rotate_left(anchor, n->parent);
n = n->left;
} else if (n == n->parent->left &&
n->parent == n->parent->parent->right)
{
hlist_rotate_right(anchor, n->parent);
n = n->right;
}
/*
* case 5 - parent is red but uncle is black, parent and
* grandparent on same side
*/
n->parent->red = 0;
n->parent->parent->red = 1;
if (n == n->parent->left)
hlist_rotate_right(anchor, n->parent->parent);
else
hlist_rotate_left(anchor, n->parent->parent);
break;
}
}
/*
* Highlight every character in a range of displayed characters.
*/
static void create_hilites(POSITION linepos, constant char *line, constant char *sp, constant char *ep, int attr, int *chpos)
{
size_t start_index = ptr_diff(sp, line); /*{{type-issue}}*/
size_t end_index = ptr_diff(ep, line);
struct hilite hl;
size_t i;
/* Start the first hilite. */
hl.hl_startpos = linepos + chpos[start_index];
hl.hl_attr = attr;
/*
* Step through the displayed chars.
* If the source position (before cvt) of the char is one more
* than the source pos of the previous char (the usual case),
* just increase the size of the current hilite by one.
* Otherwise (there are backspaces or something involved),
* finish the current hilite and start a new one.
*/
for (i = start_index+1; i <= end_index; i++)
{
if (chpos[i] != chpos[i-1] + 1 || i == end_index)
{
hl.hl_endpos = linepos + chpos[i-1] + 1;
add_hilite(&hilite_anchor, &hl);
/* Start new hilite unless this is the last char. */
if (i < end_index)
{
hl.hl_startpos = linepos + chpos[i];
}
}
}
}
/*
* Make a hilite for each string in a physical line which matches
* the current pattern.
* sp,ep delimit the first match already found.
*/
static void hilite_line(POSITION linepos, constant char *line, size_t line_len, int *chpos, constant char **sp, constant char **ep, int nsp)
{
size_t line_off = 0;
/*
* sp[0] and ep[0] delimit the first match in the line.
* Mark the corresponding file positions, then
* look for further matches and mark them.
* {{ This technique, of calling match_pattern on subsequent
* substrings of the line, may mark more than is correct
* if the pattern starts with "^". This bug is fixed