EXPAT usage

Expat can be intimidating due to the many kinds of handlers and options you can set. But you only need to learn four functions in order to do 80% of what you'll want to do with it:

XML_ParserCreate

Create a new parser object.

XML_SetElementHandler

Set handlers for start and end tags.

XML_SetCharacterDataHandler

Set handler for text.

XML_Parse

Pass a buffer full of document to the parser

/*****************************************************************
 * outline.c
 *
 * Copyright 1999, Clark Cooper
 * All rights reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the license contained in the
 * COPYING file that comes with the expat distribution.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
 * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 * Read an XML document from standard input and print an element
 * outline on standard output.
 * Must be used with Expat compiled for UTF-8 output.
 */


#include 
#include 

#if defined(__amigaos__) && defined(__USE_INLINE__)
#include 
#endif

#ifdef XML_LARGE_SIZE
#if defined(XML_USE_MSC_EXTENSIONS) && _MSC_VER < 1400
#define XML_FMT_INT_MOD "I64"
#else
#define XML_FMT_INT_MOD "ll"
#endif
#else
#define XML_FMT_INT_MOD "l"
#endif

#define BUFFSIZE        8192

char Buff[BUFFSIZE];

int Depth;

static void XMLCALL
start(void *data, const char *el, const char **attr)
{
  int i;

  for (i = 0; i < Depth; i++)
    printf("  ");

  printf("%s", el);

  for (i = 0; attr[i]; i += 2) {
    printf(" %s='%s'", attr[i], attr[i + 1]);
  }

  printf("\n");
  Depth++;
}

static void XMLCALL
end(void *data, const char *el)
{
  Depth--;
}

int
main(int argc, char *argv[])
{
  XML_Parser p = XML_ParserCreate(NULL);
  if (! p) {
    fprintf(stderr, "Couldn't allocate memory for parser\n");
    exit(-1);
  }

  XML_SetElementHandler(p, start, end);

  for (;;) {
    int done;
    int len;

    len = (int)fread(Buff, 1, BUFFSIZE, stdin);
    if (ferror(stdin)) {
      fprintf(stderr, "Read error\n");
      exit(-1);
    }
    done = feof(stdin);

    if (XML_Parse(p, Buff, len, done) == XML_STATUS_ERROR) {
      fprintf(stderr, "Parse error at line %" XML_FMT_INT_MOD "u:\n%s\n",
              XML_GetCurrentLineNumber(p),
              XML_ErrorString(XML_GetErrorCode(p)));
      exit(-1);
    }

    if (done)
      break;
  }
  XML_ParserFree(p);
  return 0;
}