libxml2 parsing code

libxml2SAX.m

- (BOOL)parse
{
    NSLog(@"Began parsing");
    [inputStream open];
    /* Read 4 bytes initially to create the push parser context and begin parsing */
    NSStreamStatus status = [inputStream streamStatus];
    uint8_t buf[4];
    NSInteger bytesRead;
    while (status != NSStreamStatusAtEnd) {
        if (status == NSStreamStatusError) { 
            [self closeInputStream];
            return NO; 
        }
        if ([inputStream hasBytesAvailable]) {
            bytesRead = [inputStream read:buf maxLength:4];
            break;
        }
    }
    if (!bytesRead) { 
        [self closeInputStream];
        return NO; 
    }
    ctx = xmlCreatePushParserCtxt(&saxHandlerStruct, NULL, (const void*)buf, (int)bytesRead, NULL);
    int options = XML_PARSE_RECOVER|XML_PARSE_NOENT|XML_PARSE_DTDLOAD;
    xmlCtxtUseOptions(ctx, options);
    while ([inputStream streamStatus] != NSStreamStatusAtEnd) {
        if ([inputStream streamStatus] == NSStreamStatusError) { 
            [self closeInputStream];
            return NO; 
        }
        /* If there are bytes available then read a chunk of size PAGE_SIZE (usually 4KB) */
        if ([inputStream hasBytesAvailable]) {
            uint8_t chunk[PAGE_SIZE];
            NSInteger length = [inputStream read:chunk maxLength:PAGE_SIZE];
            /* If the input stream has nothing left to read then terminate after this chunk */
            BOOL terminate = [inputStream streamStatus] == NSStreamStatusAtEnd;
            if (xmlParseChunk(ctx, (const void*)chunk, (int)length, terminate)) {
                /* If an error is encountered then do clean up and return */
                [self closeInputStream];
                return NO;
            }
        }
    }
    NSLog(@"Finished parsing!");
    [self closeInputStream];
    return YES;
}

- (void)closeInputStream
{
    [inputStream close];
    inputStream = nil;
    if (ctx) {
        xmlFreeParserCtxt(ctx);
        xmlCleanupParser();
        ctx = NULL;
    }
}