Henry Spencer's Regexp Engine Revisited

#ifndef REGEXP_H_
#define REGEXP_H_

#include <stddef.h>

/*
 * Definitions etc. for regexp(3) routines.
 *
 * NOTE: this was completely redone from the old code to have a
 * saner interface (with pretty much the same functionality).
 */
#ifdef REGEXP_UNICODE
#include <wchar.h>
typedef wchar_t CHAR_TYPE;
#else
typedef char CHAR_TYPE;
#endif

typedef int regoffset;
typedef struct regmatch
{
    regoffset begin;
    regoffset end;
} regmatch;

struct tag_regexp;
typedef struct tag_regexp regexp;

/* error codes -- similar to POSIX codes */
#define REGEXP_BADARG  -1         /* bad argument--NULL pointer or such */
#define REGEXP_ESIZE   -2         /* regexp too big */
#define REGEXP_ESPACE  -3         /* out of memory */
#define REGEXP_EPAREN  -4         /* unmatched ) */
#define REGEXP_ERANGE  -5         /* invalid [] range */
#define REGEXP_EBRACK  -6         /* unclosed ] */
#define REGEXP_BADRPT  -7         /* *+? follows nothing */
#define REGEXP_EESCAPE -8         /* trailing backslash */
#define REGEXP_EEND   -99         /* unspecified internal error */

#ifdef __cplusplus
extern "C" 
{
#endif
    
extern void re_error(int errcode, const regexp* re, char *buffer, size_t bufsize);
extern int re_nsubexp(const regexp *rp);
extern void re_free(void* object);

/* Unicode-dependent */
extern int re_comp_w(regexp **rpp, const CHAR_TYPE* regex);
extern int re_exec_w(const regexp *rp, const CHAR_TYPE *s, size_t nmatch, regmatch pmatch[]);
extern int re_sub_w(const regexp *rp, const CHAR_TYPE* s, const CHAR_TYPE *src, CHAR_TYPE** sub);
extern int re_subcount_w(const regexp* rp, const CHAR_TYPE* s, const CHAR_TYPE* src, regmatch matches[10]);
extern int re_dosub_w(const CHAR_TYPE* s, const CHAR_TYPE* src, regmatch matches[10], CHAR_TYPE* dest);
    
#if defined(REGEXP_UNICODE)
extern int re_comp(regexp **rpp, const char *regex);
extern int re_exec(const regexp *rp, const char *s, size_t nmatch, regmatch pmatch[]);
extern int re_sub(const regexp* rp, const char* s, const char* src, char** sub);

#elif defined(__cplusplus)
/* forward inline */
inline int re_comp(regexp** rpp, const char *re)
{ return re_comp_w(rpp, re); }
    
inline int re_exec(const regexp* rp, const char *s, size_t nmatch, regmatch pmatch[])
{ return re_exec_w(rp, s, nmatch, pmatch); }

inline int re_sub(const regexp *rp, const char* s, const char* src, char** sub)
{ return re_sub_w(rp, s, src, sub); }
    
#else
    
#define re_comp re_comp_w
#define re_exec re_exec_w
#define re_sub  re_sub_w

#endif

#ifdef __cplusplus
}
#endif

#endif /* REGEXP_H_ */