source: BAORadio/libindi/v1.0.1/libs/lilxml.c@ 674

#if 0
    liblilxml
    Copyright (C) 2003 Elwood C. Downey

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) any later version.

    This library 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
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA

#endif

/* little DOM-style XML parser.
 * only handles elements, attributes and pcdata content.
 * <! ... > and <? ... > are silently ignored.
 * pcdata is collected into one string, sans leading whitespace first line.
 *
 * #define MAIN_TST to create standalone test program
 */

#include <stdlib.h>
#include <string.h>
#include <ctype.h>

#include "lilxml.h"

/* used to efficiently manage growing malloced string space */
typedef struct {
    char *s;                            /* malloced memory for string */
    int sl;                             /* string length, sans trailing \0 */
    int sm;                             /* total malloced bytes */
} String;
#define MINMEM  64                      /* starting string length */

static int oneXMLchar (LilXML *lp, int c, char errmsg[]);
static void initParser(LilXML *lp);
static void pushXMLEle(LilXML *lp);
static void popXMLEle(LilXML *lp);
static void resetEndTag(LilXML *lp);
static XMLAtt *growAtt(XMLEle *e);
static XMLEle *growEle(XMLEle *pe);
static void freeAtt (XMLAtt *a);
static int isTokenChar (int start, int c);
static void growString (String *sp, int c);
static void appendString (String *sp, const char *str);
static void freeString (String *sp);
static void newString (String *sp);
static void *moremem (void *old, int n);

typedef enum  {
    LOOK4START = 0,                     /* looking for first element start */
    LOOK4TAG,                           /* looking for element tag */
    INTAG,                              /* reading tag */
    LOOK4ATTRN,                         /* looking for attr name, > or / */
    INATTRN,                            /* reading attr name */
    LOOK4ATTRV,                         /* looking for attr value */
    SAWSLASH,                           /* saw / in element opening */
    INATTRV,                            /* in attr value */
    ENTINATTRV,                         /* in entity in attr value */
    LOOK4CON,                           /* skipping leading content whitespc */
    INCON,                              /* reading content */
    ENTINCON,                           /* in entity in pcdata */
    SAWLTINCON,                         /* saw < in content */
    LOOK4CLOSETAG,                      /* looking for closing tag after < */
    INCLOSETAG                          /* reading closing tag */
} State;                                /* parsing states */

/* maintain state while parsing */
struct _LilXML {
    State cs;                           /* current state */
    int ln;                             /* line number for diags */
    XMLEle *ce;                         /* current element being built */
    String endtag;                      /* to check for match with opening tag*/
    String entity;                      /* collect entity seq */
    int delim;                          /* attribute value delimiter */
    int lastc;                          /* last char (just used wiht skipping)*/
    int skipping;                       /* in comment or declaration */
};

/* internal representation of a (possibly nested) XML element */
struct _xml_ele {
    String tag;                         /* element tag */
    XMLEle *pe;                         /* parent element, or NULL if root */
    XMLAtt **at;                        /* list of attributes */
    int nat;                            /* number of attributes */
    int ait;                            /* used to iterate over at[] */
    XMLEle **el;                        /* list of child elements */
    int nel;                            /* number of child elements */
    int eit;                            /* used to iterate over el[] */
    String pcdata;                      /* character data in this element */
    int pcdata_hasent;                  /* 1 if pcdata contains an entity char*/
};

/* internal representation of an attribute */
struct _xml_att {
    String name;                        /* name */
    String valu;                        /* value */
    XMLEle *ce;                         /* containing element */
};

/* characters that need escaping as "entities" in attr values and pcdata
 */
static char entities[] = "&<>'\"";

/* default memory managers, override with indi_xmlMalloc() */
static void *(*mymalloc)(size_t size) = malloc;
static void *(*myrealloc)(void *ptr, size_t size) = realloc;
static void (*myfree)(void *ptr) = free;

/* install new version of malloc/realloc/free.
 * N.B. don't call after first use of any other lilxml function
 */
void
indi_xmlMalloc (void *(*newmalloc)(size_t size),
           void *(*newrealloc)(void *ptr, size_t size),
           void (*newfree)(void *ptr))
{
        mymalloc = newmalloc;
        myrealloc = newrealloc;
        myfree = newfree;
}

/* pass back a fresh handle for use with our other functions */
LilXML *
newLilXML ()
{
        LilXML *lp = (LilXML *) moremem (NULL, sizeof(LilXML));
        memset (lp, 0, sizeof(LilXML));
        initParser(lp);
        return (lp);
}

/* discard */
void
delLilXML (LilXML *lp)
{
        delXMLEle (lp->ce);
        freeString (&lp->endtag);
        (*myfree) (lp);
}

/* delete ep and all its children and remove from parent's list if known */
void
delXMLEle (XMLEle *ep)
{
        int i;

        /* benign if NULL */
        if (!ep)
            return;

        /* delete all parts of ep */
        freeString (&ep->tag);
        freeString (&ep->pcdata);
        if (ep->at) {
            for (i = 0; i < ep->nat; i++)
                freeAtt (ep->at[i]);
            (*myfree) (ep->at);
        }
        if (ep->el) {
            for (i = 0; i < ep->nel; i++) {
                /* forget parent so deleting doesn't modify _this_ el[] */
                ep->el[i]->pe = NULL;

                delXMLEle (ep->el[i]);
            }
            (*myfree) (ep->el);
        }

        /* remove from parent's list if known */
        if (ep->pe) {
            XMLEle *pe = ep->pe;
            for (i = 0; i < pe->nel; i++) {
                if (pe->el[i] == ep) {
                    memmove (&pe->el[i], &pe->el[i+1],
                                              (--pe->nel-i)*sizeof(XMLEle*));
                    break;
                }
            }
        }

        /* delete ep itself */
        (*myfree) (ep);
}

/* process one more character of an XML file.
 * when find closure with outter element return root of complete tree.
 * when find error return NULL with reason in errmsg[].
 * when need more return NULL with errmsg[0] = '\0'.
 * N.B. it is up to the caller to delete any tree returned with delXMLEle().
 */
XMLEle *
readXMLEle (LilXML *lp, int newc, char errmsg[])
{
        XMLEle *root;
        int s;

        /* start optimistic */
        errmsg[0] = '\0';

        /* EOF? */
        if (newc == 0) {
            sprintf (errmsg, "Line %d: early XML EOF", lp->ln);
            initParser(lp);
            return (NULL);
        }

        /* new line? */
        if (newc == '\n')
            lp->ln++;

        /* skip comments and declarations. requires 1 char history */
        if (!lp->skipping && lp->lastc == '<' && (newc == '?' || newc == '!')) {
            lp->skipping = 1;
            lp->lastc = newc;
            return (NULL);
        }
        if (lp->skipping) {
            if (newc == '>')
                lp->skipping = 0;
            lp->lastc = newc;
            return (NULL);
        }
        if (newc == '<') {
            lp->lastc = '<';
            return (NULL);
        }

        /* do a pending '<' first then newc */
        if (lp->lastc == '<') {
            if (oneXMLchar (lp, '<', errmsg) < 0) {
                initParser(lp);
                return (NULL);
            }
            /* N.B. we assume '<' will never result in closure */
        }

        /* process newc (at last!) */
        s = oneXMLchar (lp, newc, errmsg);
        if (s == 0) {
            lp->lastc = newc;
            return (NULL);
        }
        if (s < 0) {
            initParser(lp);
            return (NULL);
        }

        /* Ok! return ce and we start over.
         * N.B. up to caller to call delXMLEle with what we return.
         */
        root = lp->ce;
        lp->ce = NULL;
        initParser(lp);
        return (root);
}

/* search ep for an attribute with given name.
 * return NULL if not found.
 */
XMLAtt *
findXMLAtt (XMLEle *ep, const char *name)
{
        int i;

        for (i = 0; i < ep->nat; i++)
            if (!strcmp (ep->at[i]->name.s, name))
                return (ep->at[i]);
        return (NULL);
}

/* search ep for an element with given tag.
 * return NULL if not found.
 */
XMLEle *
findXMLEle (XMLEle *ep, const char *tag)
{
        int tl = strlen (tag);
        int i;

        for (i = 0; i < ep->nel; i++) {
            String *sp = &ep->el[i]->tag;
            if (sp->sl == tl && !strcmp (sp->s, tag))
                return (ep->el[i]);
        }
        return (NULL);
}

/* iterate over each child element of ep.
 * call first time with first set to 1, then 0 from then on.
 * returns NULL when no more or err
 */
XMLEle *
nextXMLEle (XMLEle *ep, int init)
{
        int eit;
        
        if (init)
            ep->eit = 0;

        eit = ep->eit++;
        if (eit < 0 || eit >= ep->nel)
            return (NULL);
        return (ep->el[eit]);
}

/* iterate over each attribute of ep.
 * call first time with first set to 1, then 0 from then on.
 * returns NULL when no more or err
 */
XMLAtt *
nextXMLAtt (XMLEle *ep, int init)
{
        int ait;

        if (init)
            ep->ait = 0;

        ait = ep->ait++;
        if (ait < 0 || ait >= ep->nat)
            return (NULL);
        return (ep->at[ait]);
}

/* return parent of given XMLEle */
XMLEle *
parentXMLEle (XMLEle *ep)
{
        return (ep->pe);
}

/* return parent element of given XMLAtt */
XMLEle *
parentXMLAtt (XMLAtt *ap)
{
        return (ap->ce);
}

/* access functions */

/* return the tag name of the given element */
char *
tagXMLEle (XMLEle *ep)
{
        return (ep->tag.s);
}

/* return the pcdata portion of the given element */
char *
pcdataXMLEle (XMLEle *ep)
{
        return (ep->pcdata.s);
}

/* return the number of characters in the pcdata portion of the given element */
int 
pcdatalenXMLEle (XMLEle *ep)
{
        return (ep->pcdata.sl);
}

/* return the name of the given attribute */
char *
nameXMLAtt (XMLAtt *ap)
{
        return (ap->name.s);
}

/* return the value of the given attribute */
char *
valuXMLAtt (XMLAtt *ap)
{
        return (ap->valu.s);
}

/* return the number of child elements of the given element */
int
nXMLEle (XMLEle *ep)
{
        return (ep->nel);
}

/* return the number of attributes in the given element */
int
nXMLAtt (XMLEle *ep)
{
        return (ep->nat);
}


/* search ep for an attribute with the given name and return its value.
 * return "" if not found.
 */
const char *
findXMLAttValu (XMLEle *ep, const char *name)
{
        XMLAtt *a = findXMLAtt (ep, name);
        return (a ? a->valu.s : "");
}

/* handy wrapper to read one xml file.
 * return root element else NULL with report in errmsg[]
 */
XMLEle *
readXMLFile (FILE *fp, LilXML *lp, char errmsg[])
{
        int c;

        while ((c = fgetc(fp)) != EOF) {
            XMLEle *root = readXMLEle (lp, c, errmsg);
            if (root || errmsg[0])
                return (root);
        }

        return (NULL);
}

/* add an element with the given tag to the given element.
 * parent can be NULL to make a new root.
 */
XMLEle *
addXMLEle (XMLEle *parent, const char *tag)
{
        XMLEle *ep = growEle (parent);
        appendString (&ep->tag, tag);
        return (ep);
}

/* set the pcdata of the given element */
void
editXMLEle (XMLEle *ep, const char *pcdata)
{
        freeString (&ep->pcdata);
        appendString (&ep->pcdata, pcdata);
        ep->pcdata_hasent = (strpbrk (pcdata, entities) != NULL);
}

/* add an attribute to the given XML element */
XMLAtt *
addXMLAtt (XMLEle *ep, const char *name, const char *valu)
{
        XMLAtt *ap = growAtt (ep);
        appendString (&ap->name, name);
        appendString (&ap->valu, valu);
        return (ap);
}

/* remove the named attribute from ep, if any */
void
rmXMLAtt (XMLEle *ep, const char *name)
{
        int i;

        for (i = 0; i < ep->nat; i++) {
            if (strcmp (ep->at[i]->name.s, name) == 0) {
                freeAtt (ep->at[i]);
                memmove (&ep->at[i],&ep->at[i+1],(--ep->nat-i)*sizeof(XMLAtt*));
                return;
            }
        }
}

/* change the value of an attribute to str */
void
editXMLAtt (XMLAtt *ap, const char *str)
{
        freeString (&ap->valu);
        appendString (&ap->valu, str);
}

/* sample print ep to fp
 * N.B. set level = 0 on first call
 */
#define PRINDENT        4               /* sample print indent each level */
void
prXMLEle (FILE *fp, XMLEle *ep, int level)
{
        int indent = level*PRINDENT;
        int i;

        fprintf (fp, "%*s<%s", indent, "", ep->tag.s);
        for (i = 0; i < ep->nat; i++)
            fprintf (fp, " %s=\"%s\"", ep->at[i]->name.s,
                                                entityXML(ep->at[i]->valu.s));
        if (ep->nel > 0) {
            fprintf (fp, ">\n");
            for (i = 0; i < ep->nel; i++)
                prXMLEle (fp, ep->el[i], level+1);
        }
        if (ep->pcdata.sl > 0) {
            if (ep->nel == 0)
                fprintf (fp, ">\n");
            if (ep->pcdata_hasent)
                fprintf (fp, "%s", entityXML(ep->pcdata.s));
            else
                fprintf (fp, "%s", ep->pcdata.s);
            if (ep->pcdata.s[ep->pcdata.sl-1] != '\n')
                fprintf (fp, "\n");
        }
        if (ep->nel > 0 || ep->pcdata.sl > 0)
            fprintf (fp, "%*s</%s>\n", indent, "", ep->tag.s);
        else
            fprintf (fp, "/>\n");
}

/* sample print ep to string s.
 * N.B. s must be at least as large as that reported by sprlXMLEle()+1.
 * N.B. set level = 0 on first call
 * return length of resulting string (sans trailing \0)
 */
int
sprXMLEle (char *s, XMLEle *ep, int level)
{
        int indent = level*PRINDENT;
        int sl = 0;
        int i;

        sl += sprintf (s+sl, "%*s<%s", indent, "", ep->tag.s);
        for (i = 0; i < ep->nat; i++)
            sl += sprintf (s+sl, " %s=\"%s\"", ep->at[i]->name.s,
                                                entityXML(ep->at[i]->valu.s));
        if (ep->nel > 0) {
            sl += sprintf (s+sl, ">\n");
            for (i = 0; i < ep->nel; i++)
                sl += sprXMLEle (s+sl, ep->el[i], level+1);
        }
        if (ep->pcdata.sl > 0) {
            if (ep->nel == 0)
                sl += sprintf (s+sl, ">\n");
            if (ep->pcdata_hasent)
                sl += sprintf (s+sl, "%s", entityXML(ep->pcdata.s));
            else {
                strcpy (s+sl, ep->pcdata.s);
                sl += ep->pcdata.sl;
            }
            if (ep->pcdata.s[ep->pcdata.sl-1] != '\n')
                sl += sprintf (s+sl, "\n");
        }
        if (ep->nel > 0 || ep->pcdata.sl > 0)
            sl += sprintf (s+sl, "%*s</%s>\n", indent, "", ep->tag.s);
        else
            sl += sprintf (s+sl, "/>\n");

        return (sl);
}

/* return number of bytes in a string guaranteed able to hold result of
 * sprXLMEle(ep) (sans trailing \0).
 * N.B. set level = 0 on first call
 */
int
sprlXMLEle (XMLEle *ep, int level)
{
        int indent = level*PRINDENT;
        int l = 0;
        int i;

        l += indent + 1 + ep->tag.sl;
        for (i = 0; i < ep->nat; i++)
            l += ep->at[i]->name.sl + 4 + strlen(entityXML(ep->at[i]->valu.s));

        if (ep->nel > 0) {
            l += 2;
            for (i = 0; i < ep->nel; i++)
                l += sprlXMLEle (ep->el[i], level+1);
        }
        if (ep->pcdata.sl > 0) {
            if (ep->nel == 0)
                l += 2;
            if (ep->pcdata_hasent)
                l += strlen (entityXML(ep->pcdata.s));
            else
                l += ep->pcdata.sl;
            if (ep->pcdata.s[ep->pcdata.sl-1] != '\n')
                l += 1;
        }
        if (ep->nel > 0 || ep->pcdata.sl > 0)
            l += indent + 4 + ep->tag.sl;
        else
            l += 3;

        return (l);
}

/* return a string with all xml-sensitive characters within the passed string s
 * replaced with their entity sequence equivalents.
 * N.B. caller must use the returned string before calling us again.
 */
char *
entityXML (char *s)
{
        static char *malbuf;
        int nmalbuf = 0;
        char *sret;
        char *ep;

        /* scan for each entity, if any */
        for (sret = s; (ep = strpbrk (s, entities)) != NULL; s = ep+1) {

            /* found another entity, copy preceding to malloced buffer */
            int nnew = ep - s;                  /* all but entity itself */
            sret = malbuf = moremem (malbuf, nmalbuf + nnew + 10);
            memcpy (malbuf+nmalbuf, s, nnew);
            nmalbuf += nnew;

            /* replace with entity encoding */
            switch (*ep) {
            case '&':
                nmalbuf += sprintf (malbuf+nmalbuf, "&amp;");
                break;
            case '<':
                nmalbuf += sprintf (malbuf+nmalbuf, "&lt;");
                break;
            case '>':
                nmalbuf += sprintf (malbuf+nmalbuf, "&gt;");
                break;
            case '\'':
                nmalbuf += sprintf (malbuf+nmalbuf, "&apos;");
                break;
            case '"':
                nmalbuf += sprintf (malbuf+nmalbuf, "&quot;");
                break;

            }

        }

        /* return s if no entities, else malloc cleaned-up copy */
        if (sret == s) {
            /* using s, so free any malloced memory from last time */
            if (malbuf) {
                free (malbuf);
                malbuf = NULL;
            }
        } else {
            /* put remaining part of s into malbuf */
            int nleft = strlen (s) + 1;         /* include \0 */
            sret = malbuf = moremem (malbuf, nmalbuf + nleft);
            memcpy (malbuf+nmalbuf, s, nleft);
        }

        return (sret);
}

/* if ent is a recognized xml entity sequence, set *cp to char and return 1
 * else return 0
 */
static int
decodeEntity (char *ent, int *cp)
{
        static struct {
            const char *ent;
            char c;
        } enttable[] = {
            {"&amp;",  '&'},
            {"&apos;", '\''},
            {"&lt;",   '<'},
            {"&gt;",   '>'},
            {"&quot;", '"'},
        };
        unsigned int i;

        for (i = 0; i < sizeof(enttable)/sizeof(enttable[0]); i++) {
            if (strcmp (ent, enttable[i].ent) == 0) {
                *cp = enttable[i].c;
                return (1);
            }
        }
        
        return (0);
}

/* process one more char in XML file.
 * if find final closure, return 1 and tree is in ce.
 * if need more, return 0.
 * if real trouble, return -1 and put reason in errmsg.
 */
static int
oneXMLchar (LilXML *lp, int c, char errmsg[])
{
        switch (lp->cs) {
        case LOOK4START:                /* looking for first element start */
            if (c == '<') {
                pushXMLEle(lp);
                lp->cs = LOOK4TAG;
            }
            /* silently ignore until resync */
            break;

        case LOOK4TAG:                  /* looking for element tag */
            if (isTokenChar (1, c)) {
                growString (&lp->ce->tag, c);
                lp->cs = INTAG;
            } else if (!isspace(c)) {
                sprintf (errmsg, "Line %d: Bogus tag char %c", lp->ln, c);
                return (-1);
            }
            break;
                
        case INTAG:                     /* reading tag */
            if (isTokenChar (0, c))
                growString (&lp->ce->tag, c);
            else if (c == '>')
                lp->cs = LOOK4CON;
            else if (c == '/')
                lp->cs = SAWSLASH;
            else 
                lp->cs = LOOK4ATTRN;
            break;

        case LOOK4ATTRN:                /* looking for attr name, > or / */
            if (c == '>')
                lp->cs = LOOK4CON;
            else if (c == '/')
                lp->cs = SAWSLASH;
            else if (isTokenChar (1, c)) {
                XMLAtt *ap = growAtt(lp->ce);
                growString (&ap->name, c);
                lp->cs = INATTRN;
            } else if (!isspace(c)) {
                sprintf (errmsg, "Line %d: Bogus leading attr name char: %c",
                                                                    lp->ln, c);
                return (-1);
            }
            break;

        case SAWSLASH:                  /* saw / in element opening */
            if (c == '>') {
                if (!lp->ce->pe)
                    return(1);          /* root has no content */
                popXMLEle(lp);
                lp->cs = LOOK4CON;
            } else {
                sprintf (errmsg, "Line %d: Bogus char %c before >", lp->ln, c);
                return (-1);
            }
            break;
                
        case INATTRN:                   /* reading attr name */
            if (isTokenChar (0, c))
                growString (&lp->ce->at[lp->ce->nat-1]->name, c);
            else if (isspace(c) || c == '=')
                lp->cs = LOOK4ATTRV;
            else {
                sprintf (errmsg, "Line %d: Bogus attr name char: %c", lp->ln,c);
                return (-1);
            }
            break;

        case LOOK4ATTRV:                /* looking for attr value */
            if (c == '\'' || c == '"') {
                lp->delim = c;
                lp->cs = INATTRV;
            } else if (!(isspace(c) || c == '=')) {
                sprintf (errmsg, "Line %d: No value for attribute %s", lp->ln,
                                        lp->ce->at[lp->ce->nat-1]->name.s);
                return (-1);
            }
            break;

        case INATTRV:                   /* in attr value */
            if (c == '&') {
                newString (&lp->entity);
                growString (&lp->entity, c);
                lp->cs = ENTINATTRV;
            } else if (c == lp->delim)
                lp->cs = LOOK4ATTRN;
            else if (!iscntrl(c))
                growString (&lp->ce->at[lp->ce->nat-1]->valu, c);
            break;

        case ENTINATTRV:                /* working on entity in attr valu */
            if (c == ';') {
                /* if find a recongized esp seq, add equiv char else raw seq */
                growString (&lp->entity, c);
                if (decodeEntity (lp->entity.s, &c))
                    growString (&lp->ce->at[lp->ce->nat-1]->valu, c);
                else
                    appendString(&lp->ce->at[lp->ce->nat-1]->valu,lp->entity.s);
                freeString (&lp->entity);
                lp->cs = INATTRV;
            } else
                growString (&lp->entity, c);
            break;

        case LOOK4CON:                  /* skipping leading content whitespace*/
            if (c == '<')
                lp->cs = SAWLTINCON;
            else if (!isspace(c)) {
                growString (&lp->ce->pcdata, c);
                lp->cs = INCON;
            }
            break;

        case INCON:                     /* reading content */
            if (c == '&') {
                newString (&lp->entity);
                growString (&lp->entity, c);
                lp->cs = ENTINCON;
            } else if (c == '<') {
                /* chomp trailing whitespace */
                while (lp->ce->pcdata.sl > 0 &&
                            isspace(lp->ce->pcdata.s[lp->ce->pcdata.sl-1]))
                    lp->ce->pcdata.s[--(lp->ce->pcdata.sl)] = '\0';
                lp->cs = SAWLTINCON;
            } else {
                growString (&lp->ce->pcdata, c);
            }
            break;

        case ENTINCON:                  /* working on entity in content */
            if (c == ';') {
                /* if find a recognized esc seq, add equiv char else raw seq */
                growString (&lp->entity, c);
                if (decodeEntity (lp->entity.s, &c))
                    growString (&lp->ce->pcdata, c);
                else {
                    appendString(&lp->ce->pcdata, lp->entity.s);
                    lp->ce->pcdata_hasent = 1;
                }
                freeString (&lp->entity);
                lp->cs = INCON;
            } else
                growString (&lp->entity, c);
            break;

        case SAWLTINCON:                /* saw < in content */
            if (c == '/') {
                resetEndTag(lp);
                lp->cs = LOOK4CLOSETAG;
            } else {
                pushXMLEle(lp);
                if (isTokenChar(1,c)) {
                    growString (&lp->ce->tag, c);
                    lp->cs = INTAG;
                } else
                    lp->cs = LOOK4TAG;
            }
            break;

        case LOOK4CLOSETAG:             /* looking for closing tag after < */
            if (isTokenChar (1, c)) {
                growString (&lp->endtag, c);
                lp->cs = INCLOSETAG;
            } else if (!isspace(c)) {
                sprintf (errmsg, "Line %d: Bogus preend tag char %c", lp->ln,c);
                return (-1);
            }
            break;

        case INCLOSETAG:                /* reading closing tag */
            if (isTokenChar(0, c))
                growString (&lp->endtag, c);
            else if (c == '>') {
                if (strcmp (lp->ce->tag.s, lp->endtag.s)) {
                    sprintf (errmsg,"Line %d: closing tag %s does not match %s",
                                    lp->ln, lp->endtag.s, lp->ce->tag.s);
                    return (-1);
                } else if (lp->ce->pe) {
                    popXMLEle(lp);
                    lp->cs = LOOK4CON;  /* back to content after nested elem */
                } else
                    return (1);         /* yes! */
            } else if (!isspace(c)) {
                sprintf (errmsg, "Line %d: Bogus end tag char %c", lp->ln, c);
                return (-1);
            }
            break;
        }

        return (0);
}

/* set up for a fresh start again */
static void
initParser(LilXML *lp)
{
        delXMLEle (lp->ce);
        freeString (&lp->endtag);
        memset (lp, 0, sizeof(*lp));
        newString (&lp->endtag);
        lp->cs = LOOK4START;
        lp->ln = 1;
}

/* start a new XMLEle.
 * point ce to a new XMLEle.
 * if ce already set up, add to its list of child elements too.
 * endtag no longer valid.
 */
static void
pushXMLEle(LilXML *lp)
{
        lp->ce = growEle (lp->ce);
        resetEndTag(lp);
}

/* point ce to parent of current ce.
 * endtag no longer valid.
 */
static void
popXMLEle(LilXML *lp)
{
        lp->ce = lp->ce->pe;
        resetEndTag(lp);
}

/* return one new XMLEle, added to the given element if given */
static XMLEle *
growEle (XMLEle *pe)
{
        XMLEle *newe = (XMLEle *) moremem (NULL, sizeof(XMLEle));

        memset (newe, 0, sizeof(XMLEle));
        newString (&newe->tag);
        newString (&newe->pcdata);
        newe->pe = pe;

        if (pe) {
            pe->el = (XMLEle **) moremem (pe->el, (pe->nel+1)*sizeof(XMLEle *));
            pe->el[pe->nel++] = newe;
        }

        return (newe);
}

/* add room for and return one new XMLAtt to the given element */
static XMLAtt *
growAtt(XMLEle *ep)
{
        XMLAtt *newa = (XMLAtt *) moremem (NULL, sizeof(XMLAtt));

        memset (newa, 0, sizeof(*newa));
        newString(&newa->name);
        newString(&newa->valu);
        newa->ce = ep;

        ep->at = (XMLAtt **) moremem (ep->at, (ep->nat+1)*sizeof(XMLAtt *));
        ep->at[ep->nat++] = newa;

        return (newa);
}

/* free a and all it holds */
static void
freeAtt (XMLAtt *a)
{
        if (!a)
            return;
        freeString (&a->name);
        freeString (&a->valu);
        (*myfree)(a);
}

/* reset endtag */
static void
resetEndTag(LilXML *lp)
{
        freeString (&lp->endtag);
        newString (&lp->endtag);
}

/* 1 if c is a valid token character, else 0.
 * it can be alpha or '_' or numeric unless start.
 */
static int
isTokenChar (int start, int c)
{
        return (isalpha(c) || c == '_' || (!start && isdigit(c)));
}

/* grow the String storage at *sp to append c */
static void
growString (String *sp, int c)
{
        int l = sp->sl + 2;             /* need room for '\0' plus c */

        if (l > sp->sm) {
            if (!sp->s)
                newString (sp);
            else
                sp->s = (char *) moremem (sp->s, sp->sm *= 2);
        }
        sp->s[--l] = '\0';
        sp->s[--l] = (char)c;
        sp->sl++;
}

/* append str to the String storage at *sp */
static void
appendString (String *sp, const char *str)
{
        int strl = strlen (str);
        int l = sp->sl + strl + 1;      /* need room for '\0' */

        if (l > sp->sm) {
            if (!sp->s)
                newString (sp);
            if (l > sp->sm)
                sp->s = (char *) moremem (sp->s, (sp->sm = l));
        }
        strcpy (&sp->s[sp->sl], str);
        sp->sl += strl;         
}

/* init a String with a malloced string containing just \0 */
static void
newString(String *sp)
{
        sp->s = (char *)moremem(NULL, MINMEM);
        sp->sm = MINMEM;
        *sp->s = '\0';
        sp->sl = 0;
}

/* free memory used by the given String */
static void
freeString (String *sp)
{
        if (sp->s)
            (*myfree) (sp->s);
        sp->s = NULL;
        sp->sl = 0;
        sp->sm = 0;
}

/* like malloc but knows to use realloc if already started */
static void *
moremem (void *old, int n)
{
        return (old ? (*myrealloc)(old, n) : (*mymalloc)(n));
}

#if defined(MAIN_TST)
int
main (int ac, char *av[])
{
        LilXML *lp = newLilXML();
        char errmsg[1024];
        XMLEle *root;

        root = readXMLFile (stdin, lp, errmsg);
        if (root) {
            char *str;
            int l;

            if (ac > 1) {
                XMLEle *theend = addXMLEle (root, "theend");
                editXMLEle (theend, "Added to test editing");
                addXMLAtt (theend, "hello", "world");
            }

            fprintf (stderr, "::::::::::::: %s\n", tagXMLEle(root));
            prXMLEle (stdout, root, 0);

            l = sprlXMLEle (root, 0);
            str = malloc (l+1);
            fprintf (stderr, "::::::::::::: %s : %d : %d",
                                tagXMLEle(root), l, sprXMLEle (str, root, 0));
            fprintf (stderr, ": %d\n", printf ("%s", str));

            delXMLEle (root);
        } else if (errmsg[0]) {
            fprintf (stderr, "Error: %s\n", errmsg);
        }

        delLilXML (lp);

        return (0);
}
#endif