flightgear/utils/xmlgrep/xml.c

/* Copyright (c) 2007,2008 by Adalin B.V.
 * Copyright (c) 2007,2008 by Erik Hofman
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *      * Redistributions of source code must retain the above copyright
 *         notice, this list of conditions and the following disclaimer.
 *      * 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.
 *      * Neither the name of (any of) the copyrightholder(s) nor the
 *         names of its contributors may be used to endorse or promote products
 *         derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED ``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 COPYRIGHT HOLDER BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * 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.
 */

#ifdef WIN32
#define WIN32_LEAN_AND_MEAN
#include <windows.h>

typedef struct
{
   HANDLE m;
   void *p;
} SIMPLE_UNMMAP;

static SIMPLE_UNMMAP un;

/*
 * map 'filename' and return a pointer to it.
 */
void *simple_mmap(int, unsigned int, SIMPLE_UNMMAP *);
void simple_unmmap(SIMPLE_UNMMAP *);

#define mmap(a,b,c,d,e,f)	simple_mmap((e), (b), &un)
#define munmap(a,b)		simple_unmmap(&un)

#else	/* !WIN32 */
# include <sys/mman.h>
# include <fcntl.h>
#endif

#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include <ctype.h>

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

struct _xml_id
{
    char *start;
    size_t len;
    int fd;
};

static char *__xmlCopyNode(char *, size_t, const char *);
static char *__xmlGetNode(char *, size_t, const char *, size_t *);
static char *__xmlFindNextElement(char *, size_t, const char *);
static void *memncasemem(const void *, size_t, const void *, size_t);

void *
xmlOpen(char *fn)
{
    struct _xml_id *id = 0;

    if (fn)
    {
        int fd = open(fn, O_RDONLY);
        if (fd > 0)
        {
            id = malloc(sizeof(struct _xml_id));
            if (id)
            {
                struct stat statbuf;

                fstat(fd, &statbuf);

                id->fd = fd;
                id->len = statbuf.st_size;
                id->start = mmap(0, id->len, PROT_READ, MAP_PRIVATE, fd, 0L);
            }
        }
    }

    return (void*)id;
}

void
xmlClose(void *id)
{
    if (id)
    {
        struct _xml_id *xid = (struct _xml_id *)id;
        munmap(xid->start, xid->len);
        close(xid->fd);
        free(id);
        id = 0;
    }
}

void *
xmlCopyNode(void *id, char *path)
{
    struct _xml_id *xsid = 0;

    if (id && path)
    {
        struct _xml_id *xid = (struct _xml_id *)id;
        char *ptr, *p;
        size_t rlen;

        rlen = strlen(path);
        ptr = __xmlGetNode(xid->start, xid->len, path, &rlen);
        if (ptr)
        {
            xsid = malloc(sizeof(struct _xml_id) + rlen);
            if (xsid)
            {
                p = (char *)xsid + sizeof(struct _xml_id);

                xsid->len = rlen;
                xsid->start = p;
                xsid->fd = 0;

                memcpy(xsid->start, ptr, rlen);
           }
       }
   }

   return (void *)xsid;
}

void *
xmlGetNode(void *id, char *path)
{
   struct _xml_id *xsid = 0;

   if (id && path)
   {
      struct _xml_id *xid = (struct _xml_id *)id;
      size_t rlen;
      char *ptr;

      rlen = strlen(path);
      ptr = __xmlGetNode(xid->start, xid->len, path, &rlen);
      if (ptr)
      {
         xsid = malloc(sizeof(struct _xml_id));
         xsid->len = rlen;
         xsid->start = ptr;
         xsid->fd = 0;
      }
   }

   return (void *)xsid;
}

void *
xmlGetNextElement(const void *pid, void *id, char *path)
{
    struct _xml_id *xpid = (struct _xml_id *)pid;
    struct _xml_id *xsid = 0;

    if (id && path)
    {
        struct _xml_id *xid = (struct _xml_id *)id;
        size_t rlen, nlen;
        char *ptr;

        if (xid->len < xpid->len) xid->start += xid->len;
        nlen = xpid->len - (xid->start - xpid->start);

        rlen = strlen(path);
        ptr = __xmlGetNode(xid->start, nlen, path, &rlen);
        if (ptr)
        {
             xid->len = rlen;
             xid->start = ptr;
             xsid = xid;
        }
    }

    return (void *)xsid;
}

int
xmlCompareString(const void *id, const char *s)
{
    struct _xml_id *xid = (struct _xml_id *)id;
    int ret = -1;

    if (xid && xid->len && s && (strlen(s) > 0))
    {
        ret = strncasecmp(xid->start, s, xid->len);
    }

    return ret;
}

int
xmlCompareNodeString(const void *id, const char *path, const char *s)
{
    struct _xml_id *xid = (struct _xml_id *)id;
    int ret = -1;

    if (xid && xid->len && path && s && (strlen(s) > 0))
    {
        size_t rlen;
        char *str;

        rlen = strlen(path);
        str = __xmlGetNode(xid->start, xid->len, path, &rlen);
        if (str) ret = strncasecmp(str, s, rlen);
    }

    return ret;
}

char *
xmlGetNodeString(void *id, const char *path)
{
    struct _xml_id *xid = (struct _xml_id *)id;
    char *str = 0;

    if (xid && xid->len && path)
    {
        str = __xmlCopyNode(xid->start, xid->len, path);
        if (str)
        {
            char *ps, *pe, *pem;
            int slen;

            slen = strlen(str);
            ps = str;
            pe = pem = ps+slen;

            while ((ps<pe) && isspace(*ps)) ps++;
            while ((pe>ps) && isspace(*pe)) pe--;

            if (pe<pem) *++pe = 0;
            slen = (pe-ps);
            if ((ps>str) && slen) memmove(str, ps, slen+1);
            else if (!slen) *str = 0;
        }
    }

    return str;
}

char *
xmlGetString(void *id)
{
    struct _xml_id *xid = (struct _xml_id *)id;
    char *str = 0;

    if (xid && xid->len)
    {
        str = malloc(xid->len+1);
        if (str)
        {
            char *ps, *pe, *pem;
            int slen;

            slen = xid->len;
            memcpy(str, xid->start, slen);
            *(str+slen) = 0;

            ps = str;
            pe = pem = ps+slen;

            while ((ps<pe) && isspace(*ps)) ps++;
            while ((pe>ps) && isspace(*pe)) pe--;

            if (pe<pem) *++pe = 0;
            slen = (pe-ps);
            if ((ps>str) && slen) memmove(str, ps, slen+1);
            else if (!slen) *str = 0;
        }
    }

    return str;
}

unsigned int
xmlCopyString(void *id, const char *path, char *buffer, unsigned int buflen)
{
    struct _xml_id *xid = (struct _xml_id *)id;
    unsigned int rlen = 0;

    if (xid && xid->len && path && buffer && buflen)
    {
        char *str;

        *buffer = 0;
        rlen = strlen(path);
        str = __xmlGetNode(xid->start, xid->len, path, &rlen);
        if (str)
        {
            char *ps, *pe;

            ps = str;
            pe = ps+rlen-1;

            while ((ps<pe) && isspace(*ps)) ps++;
            while ((pe>ps) && isspace(*pe)) pe--;

            rlen = (pe-ps)+1;
            if (rlen >= buflen) rlen = buflen-1;

            memcpy(buffer, ps, rlen);
            str = buffer + rlen;
            *str = 0;
        }
    }

    return rlen;
}

long int
xmlGetNodeInt(void *id, const char *path)
{
    struct _xml_id *xid = (struct _xml_id *)id;
    long int li = 0;

    if (path && xid && xid->len)
    {
        unsigned int rlen;
        char *str;

        rlen = strlen(path);
        str = __xmlGetNode(xid->start, xid->len, path, &rlen);
        if (str) li = strtol(str, (char **)NULL, 10);
    }

    return li;
}

long int
xmlGetInt(void *id)
{
    struct _xml_id *xid = (struct _xml_id *)id;
    long int li = 0;

    if (xid && xid->len)
        li = strtol(xid->start, (char **)NULL, 10);

    return li;
}

double
xmlGetNodeDouble(void *id, const char *path)
{
   struct _xml_id *xid = (struct _xml_id *)id;
   double d = 0.0;

    if (path && xid && xid->len)
    {
        unsigned int rlen;
        char *str;

        rlen = strlen(path);
        str = __xmlGetNode(xid->start, xid->len, path, &rlen);

        if (str) d = strtod(str, (char **)NULL);
    }

    return d;
}

double
xmlGetDouble(void *id)
{
   struct _xml_id *xid = (struct _xml_id *)id;
   double d = 0.0;

    if (xid && xid->len)
        d = strtod(xid->start, (char **)NULL);

    return d;
}


unsigned int
xmlGetNumElements(void *id, const char *path)
{
    struct _xml_id *xid = (struct _xml_id *)id;
    unsigned ret = 0;

    if (xid && xid->len && path)
    {
        unsigned int clen;
        char *p, *pathname;
        char *pname, *nname;

        pathname = (char *)path;
        if (*path == '/') pathname++;

        nname = strrchr(pathname, '/');
        if (nname)
        {
           clen = nname-pathname;
           p = __xmlGetNode(xid->start, xid->len, pname, &clen);
        }
        else
        {
            nname = (char *)pathname;
            p = (char *)xid->start;
            clen = xid->len;
        }
           
        while ((p = __xmlFindNextElement(p, clen, nname)) != 0)
            ret++;
    }

    return ret;
}

void *
xmlMarkId(void *id)
{
   struct _xml_id *xmid = 0;

   if (id)
   {
      xmid = malloc(sizeof(struct _xml_id));
      if (xmid)
      {
          memcpy(xmid, id, sizeof(struct _xml_id));
          xmid->fd = 0;
      }
   }

   return (void *)xmid;
}

/* -------------------------------------------------------------------------- */

char *
__xmlCopyNode(char *start, size_t len, const char *path)
{
   char *p, *ret = 0;
   size_t rlen;

   rlen = strlen(path);
   p = __xmlGetNode(start, len, path, &rlen);
   if (p && rlen)
   {
      ret = calloc(1, rlen+1);
      memcpy(ret, p, rlen);
   }

   return ret;
}

char *
__xmlGetNode(char *start, size_t len, const char *path, size_t *rlen)
{
    char *ret = 0;

    if (len)
    {
        char last_node = 0;
        char *ptr, *name;
        int plen;

        name = (char *)path;
        if (*name == '/') name++;	/* skip the leading '/' character */

        ptr = strchr(name, '/');
        if (!ptr)
        {
           last_node = 1;
           ptr = name + *rlen;
        }
        plen = ptr - name;
         
        if (plen)
        {
            char *p, *cur;

            cur = start;
            do
            {
                if ((p = memncasemem(cur, len, name, plen)) != 0)
                {
                    len -= (p + plen) - cur;
                    cur = p + plen;
                }
            }
            while (p && (*(p-1) != '<'));

            if (p)
            {
                p = cur;
                while ((*cur++ != '>') && (cur<(p+len)));
                len -= cur - p;

                if (last_node)
                {
                    char *rptr = cur;
                    do
                    {
                        if ((p = memncasemem(cur, len, name, plen)) != 0) 
                        {
                            len -= (p + plen) - cur;
                            cur = p + plen;
                            if (*(p-2) == '<' && *(p-1) == '/'
                                && *(p+plen) == '>') break;
                        }
                    }
                    while (p);

                    if (p)
                    {
                        *rlen = p-rptr-2;
                        ret = rptr;
                    }
                }
                else
                {
                    ret = __xmlGetNode(cur, len, ptr+1, rlen);
                }
            }
        }
    }

    return ret;
}

char *
__xmlFindNextElement(char *start, size_t len, const char *name)
{
    char *ret = 0;

    if (start && len && name)
    {
        unsigned int plen;

        plen = strlen(name);
        if (plen)
        {
            char *p, *cur;

            cur = start;
            do
            {
                if ((p = memncasemem(cur, len, name, plen)) != 0)
                {
                    len -= (p + plen) - cur;
                    cur = p + plen;
                }
            }
            while (p && (*(p-1) != '<'));

            if (p)
            {
                char *rptr = cur;

                p = cur;
                while ((*cur++ != '>') && (cur<(p+len)));
                len -= cur - p;

                do
                {
                    if ((p = memncasemem(cur, len, name, plen)) != 0)
                    {
                        len -= (p + plen) - cur;
                        cur = p + plen;
                        if (*(p-2) == '<' && *(p-1) == '/' && *(p+plen) == '>')
                            break;
                    }
                }
                while (p);

                ret = rptr;
          }
      }
   }

   return ret;
}


#define CASECMP(a,b)	( ((a) & 0xdf) == ((b) & 0xdf) )
#define NOCASECMP(a,b)	( ((a)^(b)) & 0xdf )

void *
memncasemem(const void *haystack, size_t haystacklen,
                         const void *needle, size_t needlelen)
{
    void *rptr = 0;

    if (haystack && needle && (needlelen > 0) && (haystacklen >= needlelen))
    {
        const char *ne = (const char *)needle + needlelen;
        const char *he = (const char *)haystack + haystacklen;
        const char *hne = he - needlelen;
        char *ns, *hs = (char *)haystack;

        do
        {
            rptr = 0;
            ns = (char *)needle;
            while((hs <= hne) && NOCASECMP(*hs,*ns))
               hs++;

            if (hs < hne)
            {
                rptr = hs;
                while((hs < he) && (ns < ne) && !NOCASECMP(*hs,*ns))
                {
                    hs++;
                    ns++;
                }
            }
            else break;
        }
        while (ns < ne);
    }

    return rptr;
}

#if 0
const unsigned char *
boyermoore_horspool_memmem(const unsigned char* haystack, size_t hlen,
                           const unsigned char* needle,   size_t nlen)
{
    size_t scan = 0;
    size_t bad_char_skip[UCHAR_MAX + 1]; /* Officially called:
                                          * bad character shift */
 
    /* Sanity checks on the parameters */
    if (nlen <= 0 || !haystack || !needle)
        return NULL;
 
    /* ---- Preprocess ---- */
    /* Initialize the table to default value */
    /* When a character is encountered that does not occur
     * in the needle, we can safely skip ahead for the whole
     * length of the needle.
     */
    for (scan = 0; scan <= UCHAR_MAX; scan = scan + 1)
        bad_char_skip[scan] = nlen;
 
    /* C arrays have the first byte at [0], therefore:
     * [nlen - 1] is the last byte of the array. */
    size_t last = nlen - 1;
 
    /* Then populate it with the analysis of the needle */
    for (scan = 0; scan < last; scan = scan + 1)
        bad_char_skip[needle[scan]] = last - scan;
 
    /* ---- Do the matching ---- */
 
    /* Search the haystack, while the needle can still be within it. */
    while (hlen >= nlen)
    {
        /* scan from the end of the needle */
        for (scan = last; haystack[scan] == needle[scan]; scan = scan - 1)
            if (scan == 0) /* If the first byte matches, we've found it. */
                return haystack;
 
        /* otherwise, we need to skip some bytes and start again. 
           Note that here we are getting the skip value based on the last byte
           of needle, no matter where we didn't match. So if needle is: "abcd"
           then we are skipping based on 'd' and that value will be 4, and
           for "abcdd" we again skip on 'd' but the value will be only 1.
           The alternative of pretending that the mismatched character was 
           the last character is slower in the normal case (Eg. finding 
           "abcd" in "...azcd..." gives 4 by using 'd' but only 
           4-2==2 using 'z'. */
        hlen     -= bad_char_skip[haystack[last]];
        haystack += bad_char_skip[haystack[last]];
    }
 
    return NULL;
}
#endif

#ifdef WIN32
/* Source:
 * https://mollyrocket.com/forums/viewtopic.php?p=2529
 */

void *
simple_mmap(int fd, unsigned int length, SIMPLE_UNMMAP *un)
{
    HANDLE f;
    HANDLE m;
    void *p;

    f = (HANDLE)_get_osfhandle(fd);
    if (!f) return NULL;

    m = CreateFileMapping(f, NULL, PAGE_READONLY, 0, 0, NULL);
    if (!m) return NULL;

    p = MapViewOfFile(m, FILE_MAP_READ, 0,0,0);
    if (!p)
    {
        CloseHandle(m);
        return NULL;
    }

    if (n) *n = GetFileSize(f, NULL);

    if (un)
    {
        un->m = m;
        un->p = p;
    }

    return p;
}

void
simple_unmmap(SIMPLE_UNMMAP *un)
{
   UnmapViewOfFile(un->p);
   CloseHandle(un->m);
}
#endif