/*
 * Copyright (C) 1984-2024  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.
 */

#define NEWBOT 1

/*
 * Standard include file for "less".
 */

/*
 * Defines for MSDOS_COMPILER.
 */
#define MSOFTC          1   /* Microsoft C */
#define BORLANDC        2   /* Borland C */
#define WIN32C          3   /* Windows (Borland C or Microsoft C) */
#define DJGPPC          4   /* DJGPP C */

/*
 * Include the file of compile-time options.
 * The <> make cc search for it in -I., not srcdir.
 */
#include <defines.h>

#ifdef _SEQUENT_
/*
 * Kludge for Sequent Dynix systems that have sigsetmask, but
 * it's not compatible with the way less calls it.
 * {{ Do other systems need this? }}
 */
#undef HAVE_SIGSETMASK
#endif


/* Library function declarations */

#if HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif
#if HAVE_STDIO_H
#include <stdio.h>
#endif
#if HAVE_FCNTL_H
#include <fcntl.h>
#endif
#if HAVE_UNISTD_H
#include <unistd.h>
#endif
#if HAVE_CTYPE_H
#include <ctype.h>
#endif
#if HAVE_WCTYPE_H
#include <wctype.h>
#endif
#if HAVE_LIMITS_H
#include <limits.h>
#endif
#if HAVE_STDINT_H
#include <stdint.h>
#endif
#if HAVE_STDLIB_H
#include <stdlib.h>
#endif
#if HAVE_STRING_H
#include <string.h>
#endif

#if HAVE_STDCKDINT_H
#include <stdckdint.h>
#else
/*
 * These substitutes for C23 stdckdint macros do not set *R on overflow,
 * and they assume A and B are nonnegative.  That is good enough for us.
 */
#define ckd_add(r, a, b) help_ckd_add(r, (uintmax)(a), (uintmax)(b), sizeof *(r), signed_expr(*(r)))
#define ckd_mul(r, a, b) help_ckd_mul(r, (uintmax)(a), (uintmax)(b), sizeof *(r), signed_expr(*(r)))
/* True if the integer expression E, after promotion, is signed.  */
#define signed_expr(e) ((TRUE ? 0 : e) - 1 < 0)
#endif
#define muldiv(val,num,den) umuldiv((uintmax)(val), (uintmax)(num), (uintmax)(den))

#include "lang.h"

#if defined UINTMAX_MAX
typedef uintmax_t uintmax;
#elif defined ULLONG_MAX
typedef unsigned long long uintmax;
#else
typedef unsigned long uintmax;
#endif

/* OS-specific includes */
#ifdef _OSK
#include <modes.h>
#include <strings.h>
#endif

#ifdef __TANDEM
#include <floss.h>
#endif

#if MSDOS_COMPILER==WIN32C || OS2
#include <io.h>
#endif

#if MSDOS_COMPILER==DJGPPC
#include <io.h>
#include <sys/exceptn.h>
#include <conio.h>
#include <pc.h>
#endif

#if !HAVE_STDLIB_H
char *getenv();
off_t lseek();
void *calloc();
void free();
#endif

/*
 * Simple lowercase test which can be used during option processing
 * (before options are parsed which might tell us what charset to use).
 */
#define ASCII_IS_UPPER(c)       ((c) >= 'A' && (c) <= 'Z')
#define ASCII_IS_LOWER(c)       ((c) >= 'a' && (c) <= 'z')
#define ASCII_TO_UPPER(c)       ((c) - 'a' + 'A')
#define ASCII_TO_LOWER(c)       ((c) - 'A' + 'a')

#undef IS_UPPER
#undef IS_LOWER
#undef TO_UPPER
#undef TO_LOWER
#undef IS_SPACE
#undef IS_DIGIT

#if HAVE_WCTYPE
#define IS_UPPER(c)     iswupper((wint_t) (c))
#define IS_LOWER(c)     iswlower((wint_t) (c))
#define TO_UPPER(c)     towupper((wint_t) (c))
#define TO_LOWER(c)     towlower((wint_t) (c))
#else
#if HAVE_UPPER_LOWER
#define IS_UPPER(c)     (is_ascii_char(c) && isupper((unsigned char) (c)))
#define IS_LOWER(c)     (is_ascii_char(c) && islower((unsigned char) (c)))
#define TO_UPPER(c)     (is_ascii_char(c) ? toupper((unsigned char) (c)) : (c))
#define TO_LOWER(c)     (is_ascii_char(c) ? tolower((unsigned char) (c)) : (c))
#else
#define IS_UPPER(c)     (is_ascii_char(c) && ASCII_IS_UPPER(c))
#define IS_LOWER(c)     (is_ascii_char(c) && ASCII_IS_LOWER(c))
#define TO_UPPER(c)     (is_ascii_char(c) ? ASCII_TO_UPPER(c) : (c))
#define TO_LOWER(c)     (is_ascii_char(c) ? ASCII_TO_LOWER(c) : (c))
#endif
#endif

#ifdef isspace
#define IS_SPACE(c)     isspace((unsigned char)(c))
#else
#define IS_SPACE(c)     ((c) == ' ' || (c) == '\t' || (c) == '\n' || (c) == '\r' || (c) == '\f')
#endif

#ifdef isdigit
#define IS_DIGIT(c)     isdigit((unsigned char)(c))
#else
#define IS_DIGIT(c)     ((c) >= '0' && (c) <= '9')
#endif

#define IS_CSI_START(c) (((LWCHAR)(c)) == ESC || (((LWCHAR)(c)) == CSI))

#define OPT_OFF         0
#define OPT_ON          1
#define OPT_ONPLUS      2

#if !HAVE_MEMCPY
#ifndef memcpy
#define memcpy(to,from,len)     bcopy((from),(to),(len))
#endif
#endif

#if HAVE_SNPRINTF
#define SNPRINTF1(str, size, fmt, v1)             snprintf((str), (size), (fmt), (v1))
#define SNPRINTF2(str, size, fmt, v1, v2)         snprintf((str), (size), (fmt), (v1), (v2))
#define SNPRINTF3(str, size, fmt, v1, v2, v3)     snprintf((str), (size), (fmt), (v1), (v2), (v3))
#define SNPRINTF4(str, size, fmt, v1, v2, v3, v4) snprintf((str), (size), (fmt), (v1), (v2), (v3), (v4))
#else
/* Use unsafe sprintf if we don't have snprintf. */
#define SNPRINTF1(str, size, fmt, v1)             sprintf((str), (fmt), (v1))
#define SNPRINTF2(str, size, fmt, v1, v2)         sprintf((str), (fmt), (v1), (v2))
#define SNPRINTF3(str, size, fmt, v1, v2, v3)     sprintf((str), (fmt), (v1), (v2), (v3))
#define SNPRINTF4(str, size, fmt, v1, v2, v3, v4) sprintf((str), (fmt), (v1), (v2), (v3), (v4))
#endif

#define BAD_LSEEK       ((off_t)-1)

#ifndef SEEK_SET
#define SEEK_SET 0
#endif
#ifndef SEEK_END
#define SEEK_END 2
#endif

#ifndef CHAR_BIT
#define CHAR_BIT 8
#endif

/*
 * Upper bound on the string length of an integer converted to string.
 * 302 / 1000 is ceil (log10 (2.0)).  Subtract 1 for the sign bit;
 * add 1 for integer division truncation; add 1 more for a minus sign.
 */
#define INT_STRLEN_BOUND(t) ((sizeof(t) * CHAR_BIT - 1) * 302 / 1000 + 1 + 1)

/*
 * Special types and constants.
 */
typedef unsigned long LWCHAR;
#if defined(MINGW) || (defined(_MSC_VER) && _MSC_VER >= 1500)
typedef long long less_off_t;  /* __int64 */
typedef struct _stat64 less_stat_t;
#define less_fstat _fstat64
#define less_stat _stat64
#define less_lseek _lseeki64
#else
typedef off_t less_off_t;
typedef struct stat less_stat_t;
#define less_fstat fstat
#define less_stat stat
#define less_lseek lseek
#endif
typedef less_off_t      POSITION;
typedef off_t           LINENUM;
#define MIN_LINENUM_WIDTH   7   /* Default min printing width of a line number */
#define MAX_LINENUM_WIDTH   16  /* Max width of a line number */
#define MAX_STATUSCOL_WIDTH 4   /* Max width of the status column */
#define MAX_UTF_CHAR_LEN    6   /* Max bytes in one UTF-8 char */
#define MAX_PRCHAR_LEN      31  /* Max chars in prchar() result */

#define NULL_POSITION   ((POSITION)(-1))

/*
 * Flags for open()
 */
#if MSDOS_COMPILER || OS2
#define OPEN_READ       (O_RDONLY|O_BINARY)
#else
#ifdef _OSK
#define OPEN_READ       (S_IREAD)
#else
#ifdef O_RDONLY
#define OPEN_READ       (O_RDONLY)
#else
#define OPEN_READ       (0)
#endif
#endif
#endif

#if defined(O_WRONLY) && defined(O_APPEND)
#define OPEN_APPEND     (O_APPEND|O_WRONLY)
#else
#ifdef _OSK
#define OPEN_APPEND     (S_IWRITE)
#else
#define OPEN_APPEND     (1)
#endif
#endif

/*
 * Flags for creat()
 */
#if MSDOS_COMPILER
#define CREAT_RW        (S_IREAD|S_IWRITE)
#else
#define CREAT_RW        0644
#endif

/*
 * Set a file descriptor to binary mode.
 */
#if MSDOS_COMPILER==MSOFTC
#define SET_BINARY(f)   _setmode(f, _O_BINARY);
#else
#if MSDOS_COMPILER || OS2
#define SET_BINARY(f)   setmode(f, O_BINARY)
#else
#define SET_BINARY(f)
#endif
#endif

/*
 * Does the shell treat "?" as a metacharacter?
 */
#if MSDOS_COMPILER || OS2 || _OSK
#define SHELL_META_QUEST 0
#else
#define SHELL_META_QUEST 1
#endif

#define SPACES_IN_FILENAMES 1

/*
 * An IFILE represents an input file.
 */
#define IFILE           void*
#define NULL_IFILE      ((IFILE)NULL)

/*
 * The structure used to represent a "screen position".
 * This consists of a file position, and a screen line number.
 * The meaning is that the line starting at the given file
 * position is displayed on the ln-th line of the screen.
 * (Screen lines before ln are empty.)
 */
struct scrpos
{
        POSITION pos;
        int ln;
};

typedef union parg
{
        constant char *p_string;
        int p_int;
        LINENUM p_linenum;
        char p_char;
} PARG;

#define NULL_PARG       ((PARG *)NULL)

struct textlist
{
        char *string;
        char *endstring;
};

struct wchar_range
{
        LWCHAR first, last;
};

struct wchar_range_table 
{
	struct wchar_range *table;
	unsigned int count;
};

#if HAVE_POLL
typedef short POLL_EVENTS;
#endif

#define EOI             (-1)

#define READ_ERR        (-1)
#define READ_INTR       (-2)
#define READ_AGAIN      (-3)

/*
 * A fraction is represented by a long n; the fraction is n/NUM_FRAC_DENOM.
 * To avoid overflow problems, 0 <= n < NUM_FRAC_DENUM <= LONG_MAX/100.
 */
#define NUM_FRAC_DENOM                  1000000
#define NUM_LOG_FRAC_DENOM              6

/* How quiet should we be? */
#define NOT_QUIET       0       /* Ring bell at eof and for errors */
#define LITTLE_QUIET    1       /* Ring bell only for errors */
#define VERY_QUIET      2       /* Never ring bell */

/* How should we prompt? */
#define PR_SHORT        0       /* Prompt with colon */
#define PR_MEDIUM       1       /* Prompt with message */
#define PR_LONG         2       /* Prompt with longer message */

/* How should we handle backspaces? */
#define BS_SPECIAL      0       /* Do special things for underlining and bold */
#define BS_NORMAL       1       /* \b treated as normal char; actually output */
#define BS_CONTROL      2       /* \b treated as control char; prints as ^H */

/* How should we search? */
#define SRCH_FORW       (1 << 0)  /* Search forward from current position */
#define SRCH_BACK       (1 << 1)  /* Search backward from current position */
#define SRCH_NO_MOVE    (1 << 2)  /* Highlight, but don't move */
#define SRCH_INCR       (1 << 3)  /* Incremental search */
#define SRCH_FIND_ALL   (1 << 4)  /* Find and highlight all matches */
#define SRCH_NO_MATCH   (1 << 8)  /* Search for non-matching lines */
#define SRCH_PAST_EOF   (1 << 9)  /* Search past end-of-file, into next file */
#define SRCH_FIRST_FILE (1 << 10) /* Search starting at the first file */
#define SRCH_NO_REGEX   (1 << 12) /* Don't use regular expressions */
#define SRCH_FILTER     (1 << 13) /* Search is for '&' (filter) command */
#define SRCH_AFTER_TARGET (1 << 14) /* Start search after the target line */
#define SRCH_WRAP       (1 << 15) /* Wrap-around search (continue at BOF/EOF) */
#if OSC8_LINK
#define SRCH_OSC8       (1 << 16) /* */
#endif
#define SRCH_SUBSEARCH(i) (1 << (17+(i))) /* Search for subpattern */
/* {{ Depends on NUM_SEARCH_COLORS==5 }} */
#define SRCH_SUBSEARCH_ALL (SRCH_SUBSEARCH(1)|SRCH_SUBSEARCH(2)|SRCH_SUBSEARCH(3)|SRCH_SUBSEARCH(4)|SRCH_SUBSEARCH(5))

#define SRCH_REVERSE(t) (((t) & SRCH_FORW) ? \
                                (((t) & ~SRCH_FORW) | SRCH_BACK) : \
                                (((t) & ~SRCH_BACK) | SRCH_FORW))
/* Parsing position in an OSC8 link: "\e]8;PARAMS;URI\e\\" (final "\e\\" may be "\7") */
typedef enum osc8_state {
	OSC8_NOT,     /* This is not an OSC8 link */
	OSC8_PREFIX,  /* In the "\e]8;" */
	OSC8_PARAMS,  /* In the parameters */
	OSC8_URI,     /* In the URI */
	OSC8_ST_ESC,  /* After the final \e */
	OSC8_END,     /* At end */
} osc8_state;

/* */
#define NO_MCA          0
#define MCA_DONE        1
#define MCA_MORE        2

#define CC_OK           0       /* Char was accepted & processed */
#define CC_QUIT         1       /* Char was a request to abort current cmd */
#define CC_ERROR        2       /* Char could not be accepted due to error */
#define CC_PASS         3       /* Char was rejected (internal) */

#define CF_QUIT_ON_ERASE 0001   /* Abort cmd if its entirely erased */

/* Special char bit-flags used to tell put_line() to do something special */
#define AT_NORMAL       (0)
#define AT_UNDERLINE    (1 << 0)
#define AT_BOLD         (1 << 1)
#define AT_BLINK        (1 << 2)
#define AT_STANDOUT     (1 << 3)
#define AT_ANSI         (1 << 4)  /* Content-supplied "ANSI" escape sequence */
#define AT_BINARY       (1 << 5)  /* LESS*BINFMT representation */
#define AT_HILITE       (1 << 6)  /* Internal highlights (e.g., for search) */

#define AT_COLOR_SHIFT    8
#define AT_NUM_COLORS     16
#define AT_COLOR          ((AT_NUM_COLORS-1) << AT_COLOR_SHIFT)
#define AT_COLOR_ATTN     (1 << AT_COLOR_SHIFT)
#define AT_COLOR_BIN      (2 << AT_COLOR_SHIFT)
#define AT_COLOR_CTRL     (3 << AT_COLOR_SHIFT)
#define AT_COLOR_ERROR    (4 << AT_COLOR_SHIFT)
#define AT_COLOR_LINENUM  (5 << AT_COLOR_SHIFT)
#define AT_COLOR_MARK     (6 << AT_COLOR_SHIFT)
#define AT_COLOR_PROMPT   (7 << AT_COLOR_SHIFT)
#define AT_COLOR_RSCROLL  (8 << AT_COLOR_SHIFT)
#define AT_COLOR_HEADER   (9 << AT_COLOR_SHIFT)
#define AT_COLOR_SEARCH   (10 << AT_COLOR_SHIFT)
#define AT_COLOR_SUBSEARCH(i) ((10+(i)) << AT_COLOR_SHIFT)
#define NUM_SEARCH_COLORS (AT_NUM_COLORS-10-1)

typedef enum { CT_NULL, CT_4BIT, CT_6BIT } COLOR_TYPE;

typedef enum {
	CV_BLUE     = 1,
	CV_GREEN    = 2,
	CV_RED      = 4,
	CV_BRIGHT   = 8,
	CV_NOCHANGE = -2,
	CV_ERROR    = -1
} COLOR_VALUE;

typedef enum {
	CATTR_NULL       = 0,
	CATTR_STANDOUT   = (1 << 0),
	CATTR_BOLD       = (1 << 1),
	CATTR_UNDERLINE  = (1 << 2),
	CATTR_BLINK      = (1 << 3),
} CHAR_ATTR;

/* ANSI states */
typedef enum {
	ANSI_NULL,
	ANSI_MID,
	ANSI_ERR,
	ANSI_END,
} ansi_state;

#if '0' == 240
#define IS_EBCDIC_HOST 1
#endif

#if IS_EBCDIC_HOST
/*
 * Long definition for EBCDIC.
 * Since the argument is usually a constant, this macro normally compiles
 * into a constant.
 */
#define CONTROL(c) ( \
        (c)=='[' ? '\047' : \
        (c)=='a' ? '\001' : \
        (c)=='b' ? '\002' : \
        (c)=='c' ? '\003' : \
        (c)=='d' ? '\067' : \
        (c)=='e' ? '\055' : \
        (c)=='f' ? '\056' : \
        (c)=='g' ? '\057' : \
        (c)=='h' ? '\026' : \
        (c)=='i' ? '\005' : \
        (c)=='j' ? '\025' : \
        (c)=='k' ? '\013' : \
        (c)=='l' ? '\014' : \
        (c)=='m' ? '\015' : \
        (c)=='n' ? '\016' : \
        (c)=='o' ? '\017' : \
        (c)=='p' ? '\020' : \
        (c)=='q' ? '\021' : \
        (c)=='r' ? '\022' : \
        (c)=='s' ? '\023' : \
        (c)=='t' ? '\074' : \
        (c)=='u' ? '\075' : \
        (c)=='v' ? '\062' : \
        (c)=='w' ? '\046' : \
        (c)=='x' ? '\030' : \
        (c)=='y' ? '\031' : \
        (c)=='z' ? '\077' : \
        (c)=='A' ? '\001' : \
        (c)=='B' ? '\002' : \
        (c)=='C' ? '\003' : \
        (c)=='D' ? '\067' : \
        (c)=='E' ? '\055' : \
        (c)=='F' ? '\056' : \
        (c)=='G' ? '\057' : \
        (c)=='H' ? '\026' : \
        (c)=='I' ? '\005' : \
        (c)=='J' ? '\025' : \
        (c)=='K' ? '\013' : \
        (c)=='L' ? '\014' : \
        (c)=='M' ? '\015' : \
        (c)=='N' ? '\016' : \
        (c)=='O' ? '\017' : \
        (c)=='P' ? '\020' : \
        (c)=='Q' ? '\021' : \
        (c)=='R' ? '\022' : \
        (c)=='S' ? '\023' : \
        (c)=='T' ? '\074' : \
        (c)=='U' ? '\075' : \
        (c)=='V' ? '\062' : \
        (c)=='W' ? '\046' : \
        (c)=='X' ? '\030' : \
        (c)=='Y' ? '\031' : \
        (c)=='Z' ? '\077' : \
        (c)=='|' ? '\031' : \
        (c)=='\\' ? '\034' : \
        (c)=='^' ? '\036' : \
        (c)&077)
#else
#define CONTROL(c)      ((c)&037)
#endif /* IS_EBCDIC_HOST */

#define ESC             CONTROL('[')
#define ESCS            "\33"
#define CSI             ((unsigned char)'\233')

#if _OSK_MWC32
#define LSIGNAL(sig,func)       os9_signal(sig,func)
#else
#define LSIGNAL(sig,func)       signal(sig,func)
#endif

#if HAVE_SIGPROCMASK
#if HAVE_SIGSET_T
#else
#undef HAVE_SIGPROCMASK
#endif
#endif
#if HAVE_SIGPROCMASK
#if HAVE_SIGEMPTYSET
#else
#undef  sigemptyset
#define sigemptyset(mp) *(mp) = 0
#endif
#endif

#define S_INTERRUPT     01
#define S_STOP          02
#define S_WINCH         04
#define ABORT_SIGS()    (sigs & (S_INTERRUPT|S_STOP))

#ifdef EXIT_SUCCESS
#define QUIT_OK         EXIT_SUCCESS
#else
#define QUIT_OK         0
#endif
#ifdef EXIT_FAILURE
#define QUIT_ERROR      EXIT_FAILURE
#define QUIT_INTERRUPT  (EXIT_FAILURE+1)
#else
#define QUIT_ERROR      1
#define QUIT_INTERRUPT  2
#endif
#define QUIT_SAVED_STATUS (-1)

#define FOLLOW_DESC     0
#define FOLLOW_NAME     1

/* filestate flags */
#define CH_CANSEEK      001
#define CH_KEEPOPEN     002
#define CH_POPENED      004
#define CH_HELPFILE     010
#define CH_NODATA       020     /* Special case for zero length files */
#define CH_NOTRUSTSIZE  040     /* For files that claim 0 length size falsely */

#define ch_zero()       ((POSITION)0)

#define FAKE_HELPFILE   "@/\\less/\\help/\\file/\\@"
#define FAKE_EMPTYFILE  "@/\\less/\\empty/\\file/\\@"

/* Flags for cvt_text */
#define CVT_TO_LC       01      /* Convert upper-case to lower-case */
#define CVT_BS          02      /* Do backspace processing */
#define CVT_CRLF        04      /* Remove CR after LF */
#define CVT_ANSI        010     /* Remove ANSI escape sequences */

#if HAVE_TIME_T
#define time_type       time_t
#else
#define time_type       long
#endif

/* X11 mouse reporting definitions */
#define X11MOUSE_BUTTON1    0 /* Left button press */
#define X11MOUSE_BUTTON2    1 /* Middle button press */
#define X11MOUSE_BUTTON3    2 /* Right button press */
#define X11MOUSE_BUTTON_REL 3 /* Button release */
#define X11MOUSE_WHEEL_UP   0x40 /* Wheel scroll up */
#define X11MOUSE_WHEEL_DOWN 0x41 /* Wheel scroll down */
#define X11MOUSE_OFFSET     0x20 /* Added to button & pos bytes to create a char */

/* Security features. */
#define SF_EDIT             (1<<1)  /* Edit file (v) */
#define SF_EXAMINE          (1<<2)  /* Examine file (:e) */
#define SF_GLOB             (1<<3)  /* Expand file pattern */
#define SF_HISTORY          (1<<4)  /* History file */
#define SF_LESSKEY          (1<<5)  /* Lesskey files */
#define SF_LESSOPEN         (1<<6)  /* LESSOPEN */
#define SF_LOGFILE          (1<<7)  /* Log file (s, -o) */
#define SF_PIPE             (1<<8)  /* Pipe (|) */
#define SF_SHELL            (1<<9)  /* Shell command (!) */
#define SF_STOP             (1<<10) /* Stop signal */
#define SF_TAGS             (1<<11) /* Tags */
#define SF_OSC8_OPEN        (1<<12) /* OSC8 open */

#if LESSTEST
#define LESS_DUMP_CHAR CONTROL(']')
#endif

struct mlist;
struct loption;
struct hilite_tree;
struct ansi_state;
#include "pattern.h"
#include "xbuf.h"
#include "funcs.h"

/* Functions not included in funcs.h */
void postoa(POSITION, char*, int);
void linenumtoa(LINENUM, char*, int);
void inttoa(int, char*, int);
int lstrtoi(char*, char**, int);
POSITION lstrtopos(char*, char**, int);
unsigned long lstrtoul(char*, char**, int);
int lstrtoic(constant char*, constant char**, int);
POSITION lstrtoposc(constant char*, constant char**, int);
unsigned long lstrtoulc(constant char*, constant char**, int);
#if MSDOS_COMPILER==WIN32C
int pclose(FILE*);
#endif