/* Definitions for data structures and routines for the regular
 * expression library, version 0.12.
 * 
 * Copyright (C) 1985, 1989, 1990, 1991, 1992, 1993 Free Software Foundation, Inc.
 * 
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */

#ifndef __REGEXP_LIBRARY_H__
#define __REGEXP_LIBRARY_H__

/* POSIX says that <sys/types.h> must be included (by the caller) before
 * <regex.h>.  */

#ifdef VMS
/* VMS doesn't have `size_t' in <sys/types.h>, even though POSIX says it
 * should be there.  */
#include <stddef.h>
#endif


/* The following bits are used to determine the regexp syntax we
 * recognize.  The set/not-set meanings are chosen so that Emacs syntax
 * remains the value 0.  The bits are given in alphabetical order, and
 * the definitions shifted by one from the previous bit; thus, when we
 * add or remove a bit, only one other definition need change.  */
typedef unsigned reg_syntax_t;

/* If this bit is not set, then \ inside a bracket expression is literal.
 * If set, then such a \ quotes the following character.  */
#define RE_BACKSLASH_ESCAPE_IN_LISTS (1)

/* If this bit is not set, then + and ? are operators, and \+ and \? are
 * literals. 
 * If set, then \+ and \? are operators and + and ? are literals.  */
#define RE_BK_PLUS_QM (RE_BACKSLASH_ESCAPE_IN_LISTS << 1)

/* If this bit is set, then character classes are supported.  They are:
 * [:alpha:], [:upper:], [:lower:],  [:digit:], [:alnum:], [:xdigit:],
 * [:space:], [:print:], [:punct:], [:graph:], and [:cntrl:].
 * If not set, then character classes are not supported.  */
#define RE_CHAR_CLASSES (RE_BK_PLUS_QM << 1)

/* If this bit is set, then ^ and $ are always anchors (outside bracket
 * expressions, of course).
 * If this bit is not set, then it depends:
 * ^  is an anchor if it is at the beginning of a regular
 * expression or after an open-group or an alternation operator;
 * $  is an anchor if it is at the end of a regular expression, or
 * before a close-group or an alternation operator.  
 * 
 * This bit could be (re)combined with RE_CONTEXT_INDEP_OPS, because
 * POSIX draft 11.2 says that * etc. in leading positions is undefined.
 * We already implemented a previous draft which made those constructs
 * invalid, though, so we haven't changed the code back.  */
#define RE_CONTEXT_INDEP_ANCHORS (RE_CHAR_CLASSES << 1)

/* If this bit is set, then special characters are always special
 * regardless of where they are in the pattern.
 * If this bit is not set, then special characters are special only in
 * some contexts; otherwise they are ordinary.  Specifically, 
 * * + ? and intervals are only special when not after the beginning,
 * open-group, or alternation operator.  */
#define RE_CONTEXT_INDEP_OPS (RE_CONTEXT_INDEP_ANCHORS << 1)

/* If this bit is set, then *, +, ?, and { cannot be first in an re or
 * immediately after an alternation or begin-group operator.  */
#define RE_CONTEXT_INVALID_OPS (RE_CONTEXT_INDEP_OPS << 1)

/* If this bit is set, then . matches newline.
 * If not set, then it doesn't.  */
#define RE_DOT_NEWLINE (RE_CONTEXT_INVALID_OPS << 1)

/* If this bit is set, then . doesn't match NUL.
 * If not set, then it does.  */
#define RE_DOT_NOT_NULL (RE_DOT_NEWLINE << 1)

/* If this bit is set, nonmatching lists [^...] do not match newline.
 * If not set, they do.  */
#define RE_HAT_LISTS_NOT_NEWLINE (RE_DOT_NOT_NULL << 1)

/* If this bit is set, either \{...\} or {...} defines an
 * interval, depending on RE_NO_BK_BRACES. 
 * If not set, \{, \}, {, and } are literals.  */
#define RE_INTERVALS (RE_HAT_LISTS_NOT_NEWLINE << 1)

/* If this bit is set, +, ? and | aren't recognized as operators.
 * If not set, they are.  */
#define RE_LIMITED_OPS (RE_INTERVALS << 1)

/* If this bit is set, newline is an alternation operator.
 * If not set, newline is literal.  */
#define RE_NEWLINE_ALT (RE_LIMITED_OPS << 1)

/* If this bit is set, then `{...}' defines an interval, and \{ and \}
 * are literals.
 * If not set, then `\{...\}' defines an interval.  */
#define RE_NO_BK_BRACES (RE_NEWLINE_ALT << 1)

/* If this bit is set, (...) defines a group, and \( and \) are literals.
 * If not set, \(...\) defines a group, and ( and ) are literals.  */
#define RE_NO_BK_PARENS (RE_NO_BK_BRACES << 1)

/* If this bit is set, then \<digit> matches <digit>.
 * If not set, then \<digit> is a back-reference.  */
#define RE_NO_BK_REFS (RE_NO_BK_PARENS << 1)

/* If this bit is set, then | is an alternation operator, and \| is literal. 
 * If not set, then \| is an alternation operator, and | is literal.  */
#define RE_NO_BK_VBAR (RE_NO_BK_REFS << 1)

/* If this bit is set, then an ending range point collating higher
 * than the starting range point, as in [z-a], is invalid.
 * If not set, then when ending range point collates higher than the
 * starting range point, the range is ignored.  */
#define RE_NO_EMPTY_RANGES (RE_NO_BK_VBAR << 1)

/* If this bit is set, then an unmatched ) is ordinary.
 * If not set, then an unmatched ) is invalid.  */
#define RE_UNMATCHED_RIGHT_PAREN_ORD (RE_NO_EMPTY_RANGES << 1)

/* This global variable defines the particular regexp syntax to use (for
 * some interfaces).  When a regexp is compiled, the syntax used is
 * stored in the pattern buffer, so changing this does not affect
 * already-compiled regexps.  */
extern reg_syntax_t re_syntax_options;

/* Define combinations of the above bits for the standard possibilities.
 * (The [[[ comments delimit what gets put into the Texinfo file, so
 * don't delete them!)  */
/* [[[begin syntaxes]]] */
#define RE_SYNTAX_EMACS 0

#define RE_SYNTAX_AWK							\
  (RE_BACKSLASH_ESCAPE_IN_LISTS | RE_DOT_NOT_NULL			\
   | RE_NO_BK_PARENS            | RE_NO_BK_REFS				\
   | RE_NO_BK_VBAR               | RE_NO_EMPTY_RANGES			\
   | RE_UNMATCHED_RIGHT_PAREN_ORD)

#define RE_SYNTAX_POSIX_AWK 						\
  (RE_SYNTAX_POSIX_EXTENDED | RE_BACKSLASH_ESCAPE_IN_LISTS)

#define RE_SYNTAX_GREP							\
  (RE_BK_PLUS_QM              | RE_CHAR_CLASSES				\
   | RE_HAT_LISTS_NOT_NEWLINE | RE_INTERVALS				\
   | RE_NEWLINE_ALT)

#define RE_SYNTAX_EGREP							\
  (RE_CHAR_CLASSES        | RE_CONTEXT_INDEP_ANCHORS			\
   | RE_CONTEXT_INDEP_OPS | RE_HAT_LISTS_NOT_NEWLINE			\
   | RE_NEWLINE_ALT       | RE_NO_BK_PARENS				\
   | RE_NO_BK_VBAR)

#define RE_SYNTAX_POSIX_EGREP						\
  (RE_SYNTAX_EGREP | RE_INTERVALS | RE_NO_BK_BRACES)

/* P1003.2/D11.2, section 4.20.7.1, lines 5078ff.  */
#define RE_SYNTAX_ED RE_SYNTAX_POSIX_BASIC

#define RE_SYNTAX_SED RE_SYNTAX_POSIX_BASIC

/* Syntax bits common to both basic and extended POSIX regex syntax.  */
#define _RE_SYNTAX_POSIX_COMMON						\
  (RE_CHAR_CLASSES | RE_DOT_NEWLINE      | RE_DOT_NOT_NULL		\
   | RE_INTERVALS  | RE_NO_EMPTY_RANGES)

#define RE_SYNTAX_POSIX_BASIC						\
  (_RE_SYNTAX_POSIX_COMMON | RE_BK_PLUS_QM)

/* Differs from ..._POSIX_BASIC only in that RE_BK_PLUS_QM becomes
 * RE_LIMITED_OPS, i.e., \? \+ \| are not recognized.  Actually, this
 * isn't minimal, since other operators, such as \`, aren't disabled.  */
#define RE_SYNTAX_POSIX_MINIMAL_BASIC					\
  (_RE_SYNTAX_POSIX_COMMON | RE_LIMITED_OPS)

#define RE_SYNTAX_POSIX_EXTENDED					\
  (_RE_SYNTAX_POSIX_COMMON | RE_CONTEXT_INDEP_ANCHORS			\
   | RE_CONTEXT_INDEP_OPS  | RE_NO_BK_BRACES				\
   | RE_NO_BK_PARENS       | RE_NO_BK_VBAR				\
   | RE_UNMATCHED_RIGHT_PAREN_ORD)

/* Differs from ..._POSIX_EXTENDED in that RE_CONTEXT_INVALID_OPS
 * replaces RE_CONTEXT_INDEP_OPS and RE_NO_BK_REFS is added.  */
#define RE_SYNTAX_POSIX_MINIMAL_EXTENDED				\
  (_RE_SYNTAX_POSIX_COMMON  | RE_CONTEXT_INDEP_ANCHORS			\
   | RE_CONTEXT_INVALID_OPS | RE_NO_BK_BRACES				\
   | RE_NO_BK_PARENS        | RE_NO_BK_REFS				\
   | RE_NO_BK_VBAR	    | RE_UNMATCHED_RIGHT_PAREN_ORD)
/* [[[end syntaxes]]] */

/* Maximum number of duplicates an interval can allow.  Some systems
 * (erroneously) define this in other header files, but we want our
 * value, so remove any previous define.  */
#ifdef RE_DUP_MAX
#undef RE_DUP_MAX
#endif
#define RE_DUP_MAX ((1 << 15) - 1)


/* POSIX `cflags' bits (i.e., information for `regcomp').  */

/* If this bit is set, then use extended regular expression syntax.
 * If not set, then use basic regular expression syntax.  */
#define REG_EXTENDED 1

/* If this bit is set, then ignore case when matching.
 * If not set, then case is significant.  */
#define REG_ICASE (REG_EXTENDED << 1)

/* If this bit is set, then anchors do not match at newline
 * characters in the string.
 * If not set, then anchors do match at newlines.  */
#define REG_NEWLINE (REG_ICASE << 1)

/* If this bit is set, then report only success or fail in regexec.
 * If not set, then returns differ between not matching and errors.  */
#define REG_NOSUB (REG_NEWLINE << 1)


/* POSIX `eflags' bits (i.e., information for regexec).  */

/* If this bit is set, then the beginning-of-line operator doesn't match
 * the beginning of the string (presumably because it's not the
 * beginning of a line).
 * If not set, then the beginning-of-line operator does match the
 * beginning of the string.  */
#define REG_NOTBOL 1

/* Like REG_NOTBOL, except for the end-of-line.  */
#define REG_NOTEOL (1 << 1)


/* If any error codes are removed, changed, or added, update the
 * `re_error_msg' table in regex.c.  */
typedef enum {
    REG_NOERROR = 0,		/* Success.  */
    REG_NOMATCH,		/* Didn't find a match (for regexec).  */

    /* POSIX regcomp return error codes.  (In the order listed in the
     * standard.)  */
    REG_BADPAT,			/* Invalid pattern.  */
    REG_ECOLLATE,		/* Not implemented.  */
    REG_ECTYPE,			/* Invalid character class name.  */
    REG_EESCAPE,		/* Trailing backslash.  */
    REG_ESUBREG,		/* Invalid back reference.  */
    REG_EBRACK,			/* Unmatched left bracket.  */
    REG_EPAREN,			/* Parenthesis imbalance.  */
    REG_EBRACE,			/* Unmatched \{.  */
    REG_BADBR,			/* Invalid contents of \{\}.  */
    REG_ERANGE,			/* Invalid range end.  */
    REG_ESPACE,			/* Ran out of memory.  */
    REG_BADRPT,			/* No preceding re for repetition op.  */

    /* Error codes we've added.  */
    REG_EEND,			/* Premature end.  */
    REG_ESIZE,			/* Compiled pattern bigger than 2^16 bytes.  */
    REG_ERPAREN			/* Unmatched ) or \); not returned from regcomp.  */
} reg_errcode_t;

/* This data structure represents a compiled pattern.  Before calling
 * the pattern compiler, the fields `buffer', `allocated', `fastmap',
 * `translate', and `no_sub' can be set.  After the pattern has been
 * compiled, the `re_nsub' field is available.  All other fields are
 * private to the regex routines.  */

struct re_pattern_buffer {
/* [[[begin pattern_buffer]]] */
    /* Space that holds the compiled pattern.  It is declared as
     * `unsigned char *' because its elements are
     * sometimes used as array indexes.  */
    unsigned char *buffer;

    /* Number of bytes to which `buffer' points.  */
    unsigned long allocated;

    /* Number of bytes actually used in `buffer'.  */
    unsigned long used;

    /* Syntax setting with which the pattern was compiled.  */
    reg_syntax_t syntax;

    /* Pointer to a fastmap, if any, otherwise zero.  re_search uses
     * the fastmap, if there is one, to skip over impossible
     * starting points for matches.  */
    char *fastmap;

    /* Either a translate table to apply to all characters before
     * comparing them, or zero for no translation.  The translation
     * is applied to a pattern when it is compiled and to a string
     * when it is matched.  */
    char *translate;

    /* Number of subexpressions found by the compiler.  */
    size_t re_nsub;

    /* Zero if this pattern cannot match the empty string, one else.
     * Well, in truth it's used only in `re_search_2', to see
     * whether or not we should use the fastmap, so we don't set
     * this absolutely perfectly; see `re_compile_fastmap' (the
     * `duplicate' case).  */
    unsigned can_be_null:1;

    /* If REGS_UNALLOCATED, allocate space in the `regs' structure
     * for `max (RE_NREGS, re_nsub + 1)' groups.
     * If REGS_REALLOCATE, reallocate space if necessary.
     * If REGS_FIXED, use what's there.  */
#define REGS_UNALLOCATED 0
#define REGS_REALLOCATE 1
#define REGS_FIXED 2
    unsigned regs_allocated:2;

    /* Set to zero when `regex_compile' compiles a pattern; set to one
     * by `re_compile_fastmap' if it updates the fastmap.  */
    unsigned fastmap_accurate:1;

    /* If set, `re_match_2' does not return information about
     * subexpressions.  */
    unsigned no_sub:1;

    /* If set, a beginning-of-line anchor doesn't match at the
     * beginning of the string.  */
    unsigned not_bol:1;

    /* Similarly for an end-of-line anchor.  */
    unsigned not_eol:1;

    /* If true, an anchor at a newline matches.  */
    unsigned newline_anchor:1;

/* [[[end pattern_buffer]]] */
};

typedef struct re_pattern_buffer regex_t;


/* search.c (search_buffer) in Emacs needs this one opcode value.  It is
 * defined both in `regex.c' and here.  */
#define RE_EXACTN_VALUE 1

/* Type for byte offsets within the string.  POSIX mandates this.  */
typedef int regoff_t;


/* This is the structure we store register match data in.  See
 * regex.texinfo for a full description of what registers match.  */
struct re_registers {
    unsigned num_regs;
    regoff_t *start;
    regoff_t *end;
};


/* If `regs_allocated' is REGS_UNALLOCATED in the pattern buffer,
 * `re_match_2' returns information about at least this many registers
 * the first time a `regs' structure is passed.  */
#ifndef RE_NREGS
#define RE_NREGS 30
#endif


/* POSIX specification for registers.  Aside from the different names than
 * `re_registers', POSIX uses an array of structures, instead of a
 * structure of arrays.  */
typedef struct {
    regoff_t rm_so;		/* Byte offset from string's start to substring's start.  */
    regoff_t rm_eo;		/* Byte offset from string's start to substring's end.  */
} regmatch_t;

/* Declarations for routines.  */

/* To avoid duplicating every routine declaration -- once with a
 * prototype (if we are ANSI), and once without (if we aren't) -- we
 * use the following macro to declare argument types.  This
 * unfortunately clutters up the declarations a bit, but I think it's
 * worth it.  */

#ifdef __STDC__

#define _RE_ARGS(args) args

#else /* not __STDC__ */

#define _RE_ARGS(args) ()

#endif /* not __STDC__ */

/* Sets the current default syntax to SYNTAX, and return the old syntax.
 * You can also simply assign to the `re_syntax_options' variable.  */
extern reg_syntax_t re_set_syntax _RE_ARGS((reg_syntax_t syntax));

/* Compile the regular expression PATTERN, with length LENGTH
 * and syntax given by the global `re_syntax_options', into the buffer
 * BUFFER.  Return NULL if successful, and an error string if not.  */
extern const char *re_compile_pattern
     _RE_ARGS((const char *pattern, int length,
	struct re_pattern_buffer * buffer));


/* Compile a fastmap for the compiled pattern in BUFFER; used to
 * accelerate searches.  Return 0 if successful and -2 if was an
 * internal error.  */
extern int re_compile_fastmap _RE_ARGS((struct re_pattern_buffer * buffer));


/* Search in the string STRING (with length LENGTH) for the pattern
 * compiled into BUFFER.  Start searching at position START, for RANGE
 * characters.  Return the starting position of the match, -1 for no
 * match, or -2 for an internal error.  Also return register
 * information in REGS (if REGS and BUFFER->no_sub are nonzero).  */
extern int re_search
    _RE_ARGS((struct re_pattern_buffer * buffer, const char *string,
	int length, int start, int range, struct re_registers * regs));


/* Like `re_search', but search in the concatenation of STRING1 and
 * STRING2.  Also, stop searching at index START + STOP.  */
extern int re_search_2
    _RE_ARGS((struct re_pattern_buffer * buffer, const char *string1,
	int length1, const char *string2, int length2,
	int start, int range, struct re_registers * regs, int stop));


/* Like `re_search', but return how many characters in STRING the regexp
 * in BUFFER matched, starting at position START.  */
extern int re_match
    _RE_ARGS((struct re_pattern_buffer * buffer, const char *string,
	int length, int start, struct re_registers * regs));


/* Relates to `re_match' as `re_search_2' relates to `re_search'.  */
extern int re_match_2
    _RE_ARGS((struct re_pattern_buffer * buffer, const char *string1,
	int length1, const char *string2, int length2,
	int start, struct re_registers * regs, int stop));


/* Set REGS to hold NUM_REGS registers, storing them in STARTS and
 * ENDS.  Subsequent matches using BUFFER and REGS will use this memory
 * for recording register information.  STARTS and ENDS must be
 * allocated with malloc, and must each be at least `NUM_REGS * sizeof
 * (regoff_t)' bytes long.
 * 
 * If NUM_REGS == 0, then subsequent matches should allocate their own
 * register data.
 * 
 * Unless this function is called, the first search or match using
 * PATTERN_BUFFER will allocate its own register data, without
 * freeing the old data.  */
extern void re_set_registers
     _RE_ARGS((struct re_pattern_buffer * buffer, struct re_registers * regs,
	unsigned num_regs, regoff_t * starts, regoff_t * ends));

/* 4.2 bsd compatibility.  */
extern char *re_comp _RE_ARGS((const char *));
extern int re_exec _RE_ARGS((const char *));

/* POSIX compatibility.  */
extern int regcomp _RE_ARGS((regex_t * preg, const char *pattern, int cflags));
extern int regexec
    _RE_ARGS((const regex_t * preg, const char *string, size_t nmatch,
	regmatch_t pmatch[], int eflags));
extern size_t regerror
       _RE_ARGS((int errcode, const regex_t * preg, char *errbuf,
	size_t errbuf_size));
extern void regfree _RE_ARGS((regex_t * preg));

#endif /* not __REGEXP_LIBRARY_H__ */

/*
 * Local variables:
 * make-backup-files: t
 * version-control: t
 * trim-versions-without-asking: nil
 * End:
 */
