/*-
 * Copyright (c) 2010, 2013 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by David A. Holland.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "union.h"
#include "array.h"
#include "mode.h"
#include "place.h"
#include "macro.h"
#include "output.h"

struct expansionitem {
        enum { EI_STRING, EI_PARAM, EI_FILE, EI_LINE } itemtype;
        union {
                char *ei_string;                /* for EI_STRING */
                unsigned ei_param;              /* for EI_PARAM */
        } UN;
};
DECLARRAY(expansionitem, static UNUSED);
DEFARRAY(expansionitem, static);

#ifdef NEED_UNION_ACCESSORS
#define ei_string un.ei_string
#define ei_param un.ei_param
#endif


struct macro {
        struct place defplace;
        struct place expansionplace;
        unsigned hash;
        char *name;
        bool hasparams;
        struct stringarray params;
        struct expansionitemarray expansion;
        bool inuse;
};
DECLARRAY(macro, static UNUSED);
DEFARRAY(macro, static);
DECLARRAY(macroarray, static UNUSED);
DEFARRAY(macroarray, static);

static struct macroarrayarray macros;
static unsigned total_macros;
static unsigned hashmask;

////////////////////////////////////////////////////////////
// macro structure ops

static
struct expansionitem *
expansionitem_create_string(const char *string)
{
        struct expansionitem *ei;

        ei = domalloc(sizeof(*ei));
        ei->itemtype = EI_STRING;
        ei->ei_string = dostrdup(string);
        return ei;
}

static
struct expansionitem *
expansionitem_create_stringlen(const char *string, size_t len)
{
        struct expansionitem *ei;

        ei = domalloc(sizeof(*ei));
        ei->itemtype = EI_STRING;
        ei->ei_string = dostrndup(string, len);
        return ei;
}

static
struct expansionitem *
expansionitem_create_param(unsigned param)
{
        struct expansionitem *ei;

        ei = domalloc(sizeof(*ei));
        ei->itemtype = EI_PARAM;
        ei->ei_param = param;
        return ei;
}

static
struct expansionitem *
expansionitem_create_file(void)
{
        struct expansionitem *ei;

        ei = domalloc(sizeof(*ei));
        ei->itemtype = EI_FILE;
        return ei;
}

static
struct expansionitem *
expansionitem_create_line(void)
{
        struct expansionitem *ei;

        ei = domalloc(sizeof(*ei));
        ei->itemtype = EI_LINE;
        return ei;
}

static
void
expansionitem_destroy(struct expansionitem *ei)
{
        switch (ei->itemtype) {
            case EI_STRING:
                dostrfree(ei->ei_string);
                break;
            case EI_PARAM:
            case EI_FILE:
            case EI_LINE:
                break;
        }
        dofree(ei, sizeof(*ei));
}

static
bool
expansionitem_eq(const struct expansionitem *ei1,
                 const struct expansionitem *ei2)
{
        if (ei1->itemtype != ei2->itemtype) {
                return false;
        }
        switch (ei1->itemtype) {
            case EI_STRING:
                if (strcmp(ei1->ei_string, ei2->ei_string) != 0) {
                        return false;
                }
                break;
            case EI_PARAM:
                if (ei1->ei_param != ei2->ei_param) {
                        return false;
                }
                break;
            case EI_FILE:
            case EI_LINE:
                break;
        }
        return true;
}

static
struct macro *
macro_create(struct place *p1, const char *name, unsigned hash,
             struct place *p2)
{
        struct macro *m;

        m = domalloc(sizeof(*m));
        m->defplace = *p1;
        m->expansionplace = *p2;
        m->hash = hash;
        m->name = dostrdup(name);
        m->hasparams = false;
        stringarray_init(&m->params);
        expansionitemarray_init(&m->expansion);
        m->inuse = false;
        return m;
}

DESTROYALL_ARRAY(expansionitem, );

static
void
macro_destroy(struct macro *m)
{
        expansionitemarray_destroyall(&m->expansion);
        expansionitemarray_cleanup(&m->expansion);
        dostrfree(m->name);
        dofree(m, sizeof(*m));
}

static
bool
macro_eq(const struct macro *m1, const struct macro *m2)
{
        unsigned num1, num2, i;
        struct expansionitem *ei1, *ei2;
        const char *p1, *p2;

        if (strcmp(m1->name, m2->name) != 0) {
                return false;
        }

        if (m1->hasparams != m2->hasparams) {
                return false;
        }

        num1 = expansionitemarray_num(&m1->expansion);
        num2 = expansionitemarray_num(&m2->expansion);
        if (num1 != num2) {
                return false;
        }

        for (i=0; i<num1; i++) {
                ei1 = expansionitemarray_get(&m1->expansion, i);
                ei2 = expansionitemarray_get(&m2->expansion, i);
                if (!expansionitem_eq(ei1, ei2)) {
                        return false;
                }
        }

        num1 = stringarray_num(&m1->params);
        num2 = stringarray_num(&m2->params);
        if (num1 != num2) {
                return false;
        }

        for (i=0; i<num1; i++) {
                p1 = stringarray_get(&m1->params, i);
                p2 = stringarray_get(&m2->params, i);
                if (strcmp(p1, p2) != 0) {
                        return false;
                }
        }
        return true;
}

////////////////////////////////////////////////////////////
// macro table

/*
 * Unless I've screwed up, this is something called Fletcher's Checksum
 * that showed up in Dr. Dobbs in, according to my notes, May 1992. The
 * implementation is new.
 */
static
unsigned
hashfunc(const char *s, size_t len)
{
        uint16_t x1, x2, a;
        size_t i;

        x1 = (uint16_t) (len >> 16);
        x2 = (uint16_t) (len);
        if (x1==0) {
                x1++;
        }
        if (x2==0) {
                x2++;
        }

        for (i=0; i<len; i+=2) {
                if (i==len-1) {
                        a = (unsigned char)s[i];
                        /* don't run off the end of the array */
                }
                else {
                        a = (unsigned char)s[i] +
                                ((uint16_t)(unsigned char)s[i+1] << 8);
                }
                x1 += a;
                if (x1 < a) {
                        x1++;
                }
                x2 += x1;
                if (x2 < x1) {
                        x2++;
                }
        }

        x1 ^= 0xffff;
        x2 ^= 0xffff;
        return ((uint32_t)x2)*65535U + x1;
}

static
void
macrotable_init(void)
{
        unsigned i;

        macroarrayarray_init(&macros);
        macroarrayarray_setsize(&macros, 4);
        for (i=0; i<4; i++) {
                macroarrayarray_set(&macros, i, NULL);
        }
        total_macros = 0;
        hashmask = 0x3;
}

DESTROYALL_ARRAY(macro, );

static
void
macrotable_cleanup(void)
{
        struct macroarray *bucket;
        unsigned numbuckets, i;

        numbuckets = macroarrayarray_num(&macros);
        for (i=0; i<numbuckets; i++) {
                bucket = macroarrayarray_get(&macros, i);
                if (bucket != NULL) {
                        macroarray_destroyall(bucket);
                        macroarray_destroy(bucket);
                }
        }
        macroarrayarray_setsize(&macros, 0);
        macroarrayarray_cleanup(&macros);
}

static
struct macro *
macrotable_findlen(const char *name, size_t len, bool remove_it)
{
        unsigned hash;
        struct macroarray *bucket;
        struct macro *m, *m2;
        unsigned i, num;
        size_t mlen;

        hash = hashfunc(name, len);
        bucket = macroarrayarray_get(&macros, hash & hashmask);
        if (bucket == NULL) {
                return NULL;
        }
        num = macroarray_num(bucket);
        for (i=0; i<num; i++) {
                m = macroarray_get(bucket, i);
                if (hash != m->hash) {
                        continue;
                }
                mlen = strlen(m->name);
                if (len == mlen && !memcmp(name, m->name, len)) {
                        if (remove_it) {
                                if (i < num-1) {
                                        m2 = macroarray_get(bucket, num-1);
                                        macroarray_set(bucket, i, m2);
                                }
                                macroarray_setsize(bucket, num-1);
                                total_macros--;
                        }
                        return m;
                }
        }
        return NULL;
}

static
struct macro *
macrotable_find(const char *name, bool remove_it)
{
        return macrotable_findlen(name, strlen(name), remove_it);
}

static
void
macrotable_rehash(void)
{
        struct macroarray *newbucket, *oldbucket;
        struct macro *m;
        unsigned newmask, tossbit;
        unsigned numbuckets, i;
        unsigned oldnum, j, k;

        numbuckets = macroarrayarray_num(&macros);
        macroarrayarray_setsize(&macros, numbuckets*2);

        assert(hashmask == numbuckets - 1);
        newmask = (hashmask << 1) | 1U;
        tossbit = newmask & ~hashmask;
        hashmask = newmask;

        for (i=0; i<numbuckets; i++) {
                newbucket = NULL;
                oldbucket = macroarrayarray_get(&macros, i);
                if (oldbucket == NULL) {
                        macroarrayarray_set(&macros, numbuckets + i, NULL);
                        continue;
                }
                oldnum = macroarray_num(oldbucket);
                for (j=0; j<oldnum; j++) {
                        m = macroarray_get(oldbucket, j);
                        if (m->hash & tossbit) {
                                if (newbucket == NULL) {
                                        newbucket = macroarray_create();
                                }
                                macroarray_set(oldbucket, j, NULL);
                                macroarray_add(newbucket, m, NULL);
                        }
                }
                for (j=k=0; j<oldnum; j++) {
                        m = macroarray_get(oldbucket, j);
                        if (m != NULL) {
                                if (k < j) {
                                        macroarray_set(oldbucket, k, m);
                                }
                                k++;
                        }
                }
                macroarray_setsize(oldbucket, k);
                macroarrayarray_set(&macros, numbuckets + i, newbucket);
        }
}

static
void
macrotable_add(struct macro *m)
{
        unsigned hash;
        struct macroarray *bucket;
        unsigned numbuckets;

        numbuckets = macroarrayarray_num(&macros);
        if (total_macros > 0 && total_macros / numbuckets > 9) {
                macrotable_rehash();
        }

        hash = hashfunc(m->name, strlen(m->name));
        bucket = macroarrayarray_get(&macros, hash & hashmask);
        if (bucket == NULL) {
                bucket = macroarray_create();
                macroarrayarray_set(&macros, hash & hashmask, bucket);
        }
        macroarray_add(bucket, m, NULL);
        total_macros++;
}

////////////////////////////////////////////////////////////
// external macro definition interface

static
struct macro *
macro_define_common_start(struct place *p1, const char *macro,
                          struct place *p2)
{
        struct macro *m;
        unsigned hash;

        if (!is_identifier(macro)) {
                complain(p1, "Invalid macro name %s", macro);
                complain_fail();
        }

        hash = hashfunc(macro, strlen(macro));
        m = macro_create(p1, macro, hash, p2);
        return m;
}

static
void
macro_define_common_end(struct macro *m)
{
        struct macro *oldm;
        bool ok;

        oldm = macrotable_find(m->name, false);
        if (oldm != NULL) {
                ok = macro_eq(m, oldm);
                if (ok) {
                        /* in traditional cpp this is silent */
                        //complain(&m->defplace,
                        //       "Warning: redefinition of %s", m->name);
                        //complain(&oldm->defplace,
                        //       "Previous definition was here");
                        //if (mode.werror) {
                        //      complain_fail();
                        //}
                } else {
                        complain(&m->defplace,
                                 "Warning: non-identical redefinition of %s",
                                 m->name);
                        complain(&oldm->defplace,
                                 "Previous definition was here");
                        /* in traditional cpp this is not fatal */
                        if (mode.werror) {
                                complain_fail();
                        }
                }
                macro_destroy(m);
                return;
        }
        macrotable_add(m);
}

static
void
macro_parse_parameters(struct macro *m, struct place *p, const char *params)
{
        size_t len;
        const char *s;
        char *param;

        while (params != NULL) {
                len = strspn(params, ws);
                params += len;
                place_addcolumns(p, len);
                s = strchr(params, ',');
                if (s) {
                        len = s-params;
                        param = dostrndup(params, len);
                        s++;
                } else {
                        len = strlen(params);
                        param = dostrndup(params, len);
                }
                notrailingws(param, strlen(param));
                if (!is_identifier(param)) {
                        complain(p, "Invalid macro parameter name %s", param);
                        complain_fail();
                } else {
                        stringarray_add(&m->params, param, NULL);
                }
                params = s;
                place_addcolumns(p, len);
        }
}

static
bool
isparam(struct macro *m, const char *name, size_t len, unsigned *num_ret)
{
        unsigned num, i;
        const char *param;

        num = stringarray_num(&m->params);
        for (i=0; i<num; i++) {
                param = stringarray_get(&m->params, i);
                if (strlen(param) == len && !memcmp(name, param, len)) {
                        *num_ret = i;
                        return true;
                }
        }
        return false;
}

static
void
macro_parse_expansion(struct macro *m, const char *buf)
{
        size_t blockstart, wordstart, pos;
        struct expansionitem *ei;
        unsigned param;

        pos = blockstart = 0;
        while (buf[pos] != '\0') {
                pos += strspn(buf+pos, ws);
                if (strchr(alnum, buf[pos])) {
                        wordstart = pos;
                        pos += strspn(buf+pos, alnum);
                        if (isparam(m, buf+wordstart, pos-wordstart, &param)) {
                                if (wordstart > blockstart) {
                                        ei = expansionitem_create_stringlen(
                                                buf + blockstart,
                                                wordstart - blockstart);
                                        expansionitemarray_add(&m->expansion,
                                                               ei, NULL);
                                }
                                ei = expansionitem_create_param(param);
                                expansionitemarray_add(&m->expansion, ei,NULL);
                                blockstart = pos;
                                continue;
                        }
                        continue;
                }
                pos++;
        }
        if (pos > blockstart) {
                ei = expansionitem_create_stringlen(buf + blockstart,
                                                    pos - blockstart);
                expansionitemarray_add(&m->expansion, ei, NULL);
        }
}

void
macro_define_plain(struct place *p1, const char *macro,
                   struct place *p2, const char *expansion)
{
        struct macro *m;
        struct expansionitem *ei;

        m = macro_define_common_start(p1, macro, p2);
        ei = expansionitem_create_string(expansion);
        expansionitemarray_add(&m->expansion, ei, NULL);
        macro_define_common_end(m);
}

void
macro_define_params(struct place *p1, const char *macro,
                    struct place *p2, const char *params,
                    struct place *p3, const char *expansion)
{
        struct macro *m;

        m = macro_define_common_start(p1, macro, p3);
        m->hasparams = true;
        macro_parse_parameters(m, p2, params);
        macro_parse_expansion(m, expansion);
        macro_define_common_end(m);
}

void
macro_define_magic(struct place *p, const char *macro)
{
        struct macro *m;
        struct expansionitem *ei;

        m = macro_define_common_start(p, macro, p);
        if (!strcmp(macro, "__FILE__")) {
                ei = expansionitem_create_file();
        }
        else {
                assert(!strcmp(macro, "__LINE__"));
                ei = expansionitem_create_line();
        }
        expansionitemarray_add(&m->expansion, ei, NULL);
        macro_define_common_end(m);
}

void
macro_undef(const char *macro)
{
        struct macro *m;

        m = macrotable_find(macro, true);
        if (m) {
                macro_destroy(m);
        }
}

bool
macro_isdefined(const char *macro)
{
        struct macro *m;

        m = macrotable_find(macro, false);
        return m != NULL;
}

////////////////////////////////////////////////////////////
// macro expansion

struct expstate {
        bool honordefined;
        enum { ES_NORMAL, ES_WANTLPAREN, ES_NOARG, ES_HAVEARG } state;
        struct macro *curmacro;
        struct stringarray args;
        unsigned argparens;

        bool tobuf;
        char *buf;
        size_t bufpos, bufmax;
};

static struct expstate mainstate;

static void doexpand(struct expstate *es, struct place *p,
                     const char *buf, size_t len);

static
void
expstate_init(struct expstate *es, bool tobuf, bool honordefined)
{
        es->honordefined = honordefined;
        es->state = ES_NORMAL;
        es->curmacro = NULL;
        stringarray_init(&es->args);
        es->argparens = 0;
        es->tobuf = tobuf;
        es->buf = NULL;
        es->bufpos = 0;
        es->bufmax = 0;
}

static
void
expstate_cleanup(struct expstate *es)
{
        assert(es->state == ES_NORMAL);
        stringarray_cleanup(&es->args);
        if (es->buf) {
                dofree(es->buf, es->bufmax);
        }
}

static
void
expstate_destroyargs(struct expstate *es)
{
        unsigned i, num;

        num = stringarray_num(&es->args);
        for (i=0; i<num; i++) {
                dostrfree(stringarray_get(&es->args, i));
        }
        stringarray_setsize(&es->args, 0);
}

static
void
expand_send(struct expstate *es, struct place *p, const char *buf, size_t len)
{
        size_t oldmax;

        if (es->tobuf) {
                assert(es->bufpos <= es->bufmax);
                if (es->bufpos + len > es->bufmax) {
                        oldmax = es->bufmax;
                        if (es->bufmax == 0) {
                                es->bufmax = 64;
                        }
                        while (es->bufpos + len > es->bufmax) {
                                es->bufmax *= 2;
                        }
                        es->buf = dorealloc(es->buf, oldmax, es->bufmax);
                }
                memcpy(es->buf + es->bufpos, buf, len);
                es->bufpos += len;
                assert(es->bufpos <= es->bufmax);
        } else {
                output(p, buf, len);
        }
}

static
void
expand_send_eof(struct expstate *es, struct place *p)
{
        if (es->tobuf) {
                expand_send(es, p, "", 1);
                es->bufpos--;
        } else {
                output_eof();
        }
}

static
void
expand_newarg(struct expstate *es, const char *buf, size_t len)
{
        char *text;

        text = dostrndup(buf, len);
        stringarray_add(&es->args, text, NULL);
}

static
void
expand_appendarg(struct expstate *es, const char *buf, size_t len)
{
        unsigned num;
        char *text;
        size_t oldlen;

        num = stringarray_num(&es->args);
        assert(num > 0);

        text = stringarray_get(&es->args, num - 1);
        oldlen = strlen(text);
        text = dorealloc(text, oldlen + 1, oldlen + len + 1);
        memcpy(text + oldlen, buf, len);
        text[oldlen+len] = '\0';
        stringarray_set(&es->args, num - 1, text);
}

static
char *
expand_substitute(struct place *p, struct expstate *es)
{
        struct expansionitem *ei;
        unsigned i, num;
        size_t len;
        char *arg;
        char *ret;
        unsigned numargs, numparams;
        char numbuf[64];

        numargs = stringarray_num(&es->args);
        numparams = stringarray_num(&es->curmacro->params);

        if (numargs == 0 && numparams == 1) {
                /* no arguments <=> one empty argument */
                stringarray_add(&es->args, dostrdup(""), NULL);
                numargs++;
        }
        if (numargs != numparams) {
                complain(p, "Wrong number of arguments for macro %s; "
                         "found %u, expected %u",
                         es->curmacro->name, numargs, numparams);
                complain_fail();
                while (numargs < numparams) {
                        stringarray_add(&es->args, dostrdup(""), NULL);
                        numargs++;
                }
        }

        len = 0;
        num = expansionitemarray_num(&es->curmacro->expansion);
        for (i=0; i<num; i++) {
                ei = expansionitemarray_get(&es->curmacro->expansion, i);
                switch (ei->itemtype) {
                    case EI_STRING:
                        len += strlen(ei->ei_string);
                        break;
                    case EI_PARAM:
                        arg = stringarray_get(&es->args, ei->ei_param);
                        len += strlen(arg);
                        break;
                    case EI_FILE:
                        len += strlen(place_getname(p)) + 2;
                        break;
                    case EI_LINE:
                        len += snprintf(numbuf, sizeof(numbuf), "%u", p->line);
                        break;
                }
        }

        ret = domalloc(len+1);
        *ret = '\0';
        for (i=0; i<num; i++) {
                ei = expansionitemarray_get(&es->curmacro->expansion, i);
                switch (ei->itemtype) {
                    case EI_STRING:
                        strlcat(ret, ei->ei_string, len + 1);
                        break;
                    case EI_PARAM:
                        arg = stringarray_get(&es->args, ei->ei_param);
                        strlcat(ret, arg, len + 1);
                        break;
                    case EI_FILE:
                        strlcat(ret, "\"", len + 1);
                        strlcat(ret, place_getname(p), len + 1);
                        strlcat(ret, "\"", len + 1);
                        break;
                    case EI_LINE:
                        snprintf(numbuf, sizeof(numbuf), "%u", p->line);
                        strlcat(ret, numbuf, len + 1);
                        break;
                }
        }

        return ret;
}

static
void
expand_domacro(struct expstate *es, struct place *p)
{
        struct macro *m;
        const char *name, *val;
        char *newbuf, *newbuf2;

        if (es->curmacro == NULL) {
                /* defined() */
                if (stringarray_num(&es->args) != 1) {
                        complain(p, "Too many arguments for defined()");
                        complain_fail();
                        expand_send(es, p, "0", 1);
                        return;
                }
                name = stringarray_get(&es->args, 0);
                m = macrotable_find(name, false);
                val = (m != NULL) ? "1" : "0";
                debuglog(p, "defined(%s): %s", name, val); 
                expand_send(es, p, val, 1);
                expstate_destroyargs(es);
                return;
        }

        m = es->curmacro;
        assert(m->inuse == false);
        m->inuse = true;

        debuglog(p, "Expanding macro %s", m->name);
        newbuf = expand_substitute(p, es);
        debuglog(p, "Substituting for %s: %s", m->name, newbuf);

        newbuf2 = macroexpand(p, newbuf, strlen(newbuf), false);
        dostrfree(newbuf);
        expstate_destroyargs(es);
        debuglog(p, "Complete expansion for %s: %s", m->name, newbuf2);

        doexpand(es, p, newbuf2, strlen(newbuf2));
        dostrfree(newbuf2);

        m->inuse = false;
}

/*
 * The traditional behavior if a function-like macro appears without
 * arguments is to pretend it isn't a macro; that is, just emit its
 * name.
 */
static
void
expand_missingargs(struct expstate *es, struct place *p, bool needspace)
{
        if (es->curmacro == NULL) {
                /* defined */
                expand_send(es, p, "defined", 7);
                return;
        }
        expand_send(es, p, es->curmacro->name, strlen(es->curmacro->name));
        /* send a space in case we ate whitespace after the macro name */
        if (needspace) {
                expand_send(es, p, " ", 1);
        }
}

static
void
expand_got_ws(struct expstate *es, struct place *p,
              const char *buf, size_t len)
{
        switch (es->state) {
            case ES_NORMAL:
                expand_send(es, p, buf, len);
                break;
            case ES_WANTLPAREN:
                /* XXX notyet */
                //expand_send(es, p, buf, len);
                break;
            case ES_NOARG:
                expand_newarg(es, buf, len);
                es->state = ES_HAVEARG;
                break;
            case ES_HAVEARG:
                expand_appendarg(es, buf, len);
                break;
        }
}

static
void
expand_got_word(struct expstate *es, struct place *p,
                const char *buf, size_t len)
{
        struct macro *m;

        switch (es->state) {
            case ES_NORMAL:
                if (es->honordefined &&
                    len == 7 && !memcmp(buf, "defined", 7)) {
                        es->curmacro = NULL;
                        es->state = ES_WANTLPAREN;
                        break;
                }
                m = macrotable_findlen(buf, len, false);
                if (m == NULL || m->inuse) {
                        expand_send(es, p, buf, len);
                } else if (!m->hasparams) {
                        es->curmacro = m;
                        expand_domacro(es, p);
                } else {
                        es->curmacro = m;
                        es->state = ES_WANTLPAREN;
                }
                break;
            case ES_WANTLPAREN:
                if (es->curmacro != NULL) {
                        expand_missingargs(es, p, true);
                        es->state = ES_NORMAL;
                        /* try again */
                        expand_got_word(es, p, buf, len);
                } else {
                        /* "defined foo" means "defined(foo)" */
                        expand_newarg(es, buf, len);
                        es->state = ES_NORMAL;
                        expand_domacro(es, p);
                }
                break;
            case ES_NOARG:
                expand_newarg(es, buf, len);
                es->state = ES_HAVEARG;
                break;
            case ES_HAVEARG:
                expand_appendarg(es, buf, len);
                break;
        }
}

static
void
expand_got_lparen(struct expstate *es, struct place *p,
                  const char *buf, size_t len)
{
        switch (es->state) {
            case ES_NORMAL:
                expand_send(es, p, buf, len);
                break;
            case ES_WANTLPAREN:
                es->state = ES_NOARG;
                break;
            case ES_NOARG:
                expand_newarg(es, buf, len);
                es->state = ES_HAVEARG;
                es->argparens++;
                break;
            case ES_HAVEARG:
                expand_appendarg(es, buf, len);
                es->argparens++;
                break;
        }
}

static
void
expand_got_rparen(struct expstate *es, struct place *p,
                  const char *buf, size_t len)
{
        switch (es->state) {
            case ES_NORMAL:
                expand_send(es, p, buf, len);
                break;
            case ES_WANTLPAREN:
                expand_missingargs(es, p, false);
                es->state = ES_NORMAL;
                /* try again */
                expand_got_rparen(es, p, buf, len);
                break;
            case ES_NOARG:
                assert(es->argparens == 0);
                if (stringarray_num(&es->args) > 0) {
                        /* we are after a comma; enter an empty argument */
                        expand_newarg(es, buf, 0);
                }
                es->state = ES_NORMAL;
                expand_domacro(es, p);
                break;
            case ES_HAVEARG:
                if (es->argparens > 0) {
                        es->argparens--;
                        expand_appendarg(es, buf, len);
                } else {
                        es->state = ES_NORMAL;
                        expand_domacro(es, p);
                }
                break;
        }
}

static
void
expand_got_comma(struct expstate *es, struct place *p,
                 const char *buf, size_t len)
{
        switch (es->state) {
            case ES_NORMAL:
                expand_send(es, p, buf, len);
                break;
            case ES_WANTLPAREN:
                expand_missingargs(es, p, false);
                es->state = ES_NORMAL;
                /* try again */
                expand_got_comma(es, p, buf, len);
                break;
            case ES_NOARG:
                assert(es->argparens == 0);
                expand_newarg(es, buf, 0);
                break;
            case ES_HAVEARG:
                if (es->argparens > 0) {
                        expand_appendarg(es, buf, len);
                } else {
                        es->state = ES_NOARG;
                }
                break;
        }
}

static
void
expand_got_other(struct expstate *es, struct place *p,
                 const char *buf, size_t len)
{
        switch (es->state) {
            case ES_NORMAL:
                expand_send(es, p, buf, len);
                break;
            case ES_WANTLPAREN:
                expand_missingargs(es, p, false);
                es->state = ES_NORMAL;
                /* try again */
                expand_got_other(es, p, buf, len);
                break;
            case ES_NOARG:
                expand_newarg(es, buf, len);
                es->state = ES_HAVEARG;
                break;
            case ES_HAVEARG:
                expand_appendarg(es, buf, len);
                break;
        }
}

static
void
expand_got_eof(struct expstate *es, struct place *p)
{
        switch (es->state) {
            case ES_NORMAL:
                break;
            case ES_WANTLPAREN:
                expand_missingargs(es, p, false);
                break;
            case ES_NOARG:
            case ES_HAVEARG:
                if (es->curmacro) {
                        complain(p, "Unclosed argument list for macro %s",
                                 es->curmacro->name);
                } else {
                        complain(p, "Unclosed argument list for defined()");
                }
                complain_fail();
                expstate_destroyargs(es);
                break;
        }
        expand_send_eof(es, p);
        es->state = ES_NORMAL;
        es->curmacro = NULL;
        es->argparens = 0;
}

static
void
doexpand(struct expstate *es, struct place *p, const char *buf, size_t len)
{
        char *s;
        size_t x;
        bool inquote = false;
        char quote = '\0';

        while (len > 0) {
                x = strspn(buf, ws);
                if (x > len) {
                        /* XXX gross, need strnspn */
                        x = len;
                }

                if (x > 0) {
                        expand_got_ws(es, p, buf, x);
                        buf += x;
                        len -= x;
                        continue;
                }

                x = strspn(buf, alnum);
                if (x > len) {
                        /* XXX gross, need strnspn */
                        x = len;
                }

                if (!inquote && x > 0) {
                        expand_got_word(es, p, buf, x);
                        buf += x;
                        len -= x;
                        continue;
                }

                if (!inquote && len > 1 && buf[0] == '/' && buf[1] == '*') {
                        s = strstr(buf, "*/");
                        if (s) {
                                x = s - buf;
                        } else {
                                x = len;
                        }
                        expand_got_ws(es, p, buf, x);
                        buf += x;
                        len -= x;
                        continue;
                }

                if (!inquote && buf[0] == '(') {
                        expand_got_lparen(es, p, buf, 1);
                        buf++;
                        len--;
                        continue;
                }

                if (!inquote && buf[0] == ')') {
                        expand_got_rparen(es, p, buf, 1);
                        buf++;
                        len--;
                        continue;
                }

                if (!inquote && buf[0] == ',') {
                        expand_got_comma(es, p, buf, 1);
                        buf++;
                        len--;
                        continue;
                }

                if (len > 1 && buf[0] == '\\' &&
                    (buf[1] == '"' || buf[1] == '\'')) {
                        expand_got_other(es, p, buf, 2);
                        buf += 2;
                        len -= 2;
                        continue;
                }
                if (!inquote && (buf[0] == '"' || buf[0] == '\'')) {
                        inquote = true;
                        quote = buf[0];
                } else if (inquote && buf[0] == quote) {
                        inquote = false;
                }

                expand_got_other(es, p, buf, 1);
                buf++;
                len--;
        }
}

char *
macroexpand(struct place *p, const char *buf, size_t len, bool honordefined)
{
        struct expstate es;
        char *ret;

        expstate_init(&es, true, honordefined);
        doexpand(&es, p, buf, len);
        expand_got_eof(&es, p);

        /* trim to fit, so the malloc debugging won't complain */
        es.buf = dorealloc(es.buf, es.bufmax, strlen(es.buf) + 1);

        ret = es.buf;
        es.buf = NULL;
        es.bufpos = es.bufmax = 0;

        expstate_cleanup(&es);

        return ret;
}

void
macro_sendline(struct place *p, const char *buf, size_t len)
{
        doexpand(&mainstate, p, buf, len);
        switch (mainstate.state) {
            case ES_NORMAL:
                /*
                 * If we were sent a blank line, don't emit a newline
                 * for it. This matches the prior behavior of tradcpp.
                 */
                if (len > 0) {
                        output(p, "\n", 1);
                }
                break;
            case ES_WANTLPAREN:
            case ES_NOARG:
            case ES_HAVEARG:
                /*
                 * Apparently to match gcc's -traditional behavior we
                 * need to emit a space for each newline that appears
                 * while processing macro args.
                 */
                expand_got_ws(&mainstate, p, " ", 1);
                break;
        }
}

void
macro_sendeof(struct place *p)
{
        expand_got_eof(&mainstate, p);
}

////////////////////////////////////////////////////////////
// module initialization

void
macros_init(void)
{
        macrotable_init();
        expstate_init(&mainstate, false, false);
}

void
macros_cleanup(void)
{
        expstate_cleanup(&mainstate);
        macrotable_cleanup();
}