kc3-lang/libxml2/buf.c

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• Hash : 776d15d3
  Author :
  Date : 2022-03-02T00:29:17
  

  Don't check for standard C89 headers
  
  Don't check for
  
  - ctype.h
  - errno.h
  - float.h
  - limits.h
  - math.h
  - signal.h
  - stdarg.h
  - stdlib.h
  - string.h
  - time.h
  
  Stop including non-standard headers
  
  - malloc.h
  - strings.h
  

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• buf.c

• /*
   * buf.c: memory buffers for libxml2
   *
   * new buffer structures and entry points to simplify the maintenance
   * of libxml2 and ensure we keep good control over memory allocations
   * and stay 64 bits clean.
   * The new entry point use the xmlBufPtr opaque structure and
   * xmlBuf...() counterparts to the old xmlBuf...() functions
   *
   * See Copyright for the status of this software.
   *
   * daniel@veillard.com
   */
  
  #define IN_LIBXML
  #include "libxml.h"
  
  #include <string.h> /* for memset() only ! */
  #include <limits.h>
  #include <ctype.h>
  #include <stdlib.h>
  
  #include <libxml/tree.h>
  #include <libxml/globals.h>
  #include <libxml/tree.h>
  #include <libxml/parserInternals.h> /* for XML_MAX_TEXT_LENGTH */
  #include "buf.h"
  
  #define WITH_BUFFER_COMPAT
  
  /**
   * xmlBuf:
   *
   * A buffer structure. The base of the structure is somehow compatible
   * with struct _xmlBuffer to limit risks on application which accessed
   * directly the input->buf->buffer structures.
   */
  
  struct _xmlBuf {
      xmlChar *content;		/* The buffer content UTF8 */
      unsigned int compat_use;    /* for binary compatibility */
      unsigned int compat_size;   /* for binary compatibility */
      xmlBufferAllocationScheme alloc; /* The realloc method */
      xmlChar *contentIO;		/* in IO mode we may have a different base */
      size_t use;		        /* The buffer size used */
      size_t size;		/* The buffer size */
      xmlBufferPtr buffer;        /* wrapper for an old buffer */
      int error;                  /* an error code if a failure occurred */
  };
  
  #ifdef WITH_BUFFER_COMPAT
  /*
   * Macro for compatibility with xmlBuffer to be used after an xmlBuf
   * is updated. This makes sure the compat fields are updated too.
   */
  #define UPDATE_COMPAT(buf)				    \
       if (buf->size < INT_MAX) buf->compat_size = buf->size; \
       else buf->compat_size = INT_MAX;			    \
       if (buf->use < INT_MAX) buf->compat_use = buf->use; \
       else buf->compat_use = INT_MAX;
  
  /*
   * Macro for compatibility with xmlBuffer to be used in all the xmlBuf
   * entry points, it checks that the compat fields have not been modified
   * by direct call to xmlBuffer function from code compiled before 2.9.0 .
   */
  #define CHECK_COMPAT(buf)				    \
       if (buf->size != (size_t) buf->compat_size)	    \
           if (buf->compat_size < INT_MAX)		    \
  	     buf->size = buf->compat_size;		    \
       if (buf->use != (size_t) buf->compat_use)		    \
           if (buf->compat_use < INT_MAX)			    \
  	     buf->use = buf->compat_use;
  
  #else /* ! WITH_BUFFER_COMPAT */
  #define UPDATE_COMPAT(buf)
  #define CHECK_COMPAT(buf)
  #endif /* WITH_BUFFER_COMPAT */
  
  /**
   * xmlBufMemoryError:
   * @extra:  extra information
   *
   * Handle an out of memory condition
   * To be improved...
   */
  static void
  xmlBufMemoryError(xmlBufPtr buf, const char *extra)
  {
      __xmlSimpleError(XML_FROM_BUFFER, XML_ERR_NO_MEMORY, NULL, NULL, extra);
      if ((buf) && (buf->error == 0))
          buf->error = XML_ERR_NO_MEMORY;
  }
  
  /**
   * xmlBufOverflowError:
   * @extra:  extra information
   *
   * Handle a buffer overflow error
   * To be improved...
   */
  static void
  xmlBufOverflowError(xmlBufPtr buf, const char *extra)
  {
      __xmlSimpleError(XML_FROM_BUFFER, XML_BUF_OVERFLOW, NULL, NULL, extra);
      if ((buf) && (buf->error == 0))
          buf->error = XML_BUF_OVERFLOW;
  }
  
  
  /**
   * xmlBufCreate:
   *
   * routine to create an XML buffer.
   * returns the new structure.
   */
  xmlBufPtr
  xmlBufCreate(void) {
      xmlBufPtr ret;
  
      ret = (xmlBufPtr) xmlMalloc(sizeof(xmlBuf));
      if (ret == NULL) {
  	xmlBufMemoryError(NULL, "creating buffer");
          return(NULL);
      }
      ret->compat_use = 0;
      ret->use = 0;
      ret->error = 0;
      ret->buffer = NULL;
      ret->size = xmlDefaultBufferSize;
      ret->compat_size = xmlDefaultBufferSize;
      ret->alloc = xmlBufferAllocScheme;
      ret->content = (xmlChar *) xmlMallocAtomic(ret->size * sizeof(xmlChar));
      if (ret->content == NULL) {
  	xmlBufMemoryError(ret, "creating buffer");
  	xmlFree(ret);
          return(NULL);
      }
      ret->content[0] = 0;
      ret->contentIO = NULL;
      return(ret);
  }
  
  /**
   * xmlBufCreateSize:
   * @size: initial size of buffer
   *
   * routine to create an XML buffer.
   * returns the new structure.
   */
  xmlBufPtr
  xmlBufCreateSize(size_t size) {
      xmlBufPtr ret;
  
      ret = (xmlBufPtr) xmlMalloc(sizeof(xmlBuf));
      if (ret == NULL) {
  	xmlBufMemoryError(NULL, "creating buffer");
          return(NULL);
      }
      ret->compat_use = 0;
      ret->use = 0;
      ret->error = 0;
      ret->buffer = NULL;
      ret->alloc = xmlBufferAllocScheme;
      ret->size = (size ? size+2 : 0);         /* +1 for ending null */
      ret->compat_size = (int) ret->size;
      if (ret->size){
          ret->content = (xmlChar *) xmlMallocAtomic(ret->size * sizeof(xmlChar));
          if (ret->content == NULL) {
  	    xmlBufMemoryError(ret, "creating buffer");
              xmlFree(ret);
              return(NULL);
          }
          ret->content[0] = 0;
      } else
  	ret->content = NULL;
      ret->contentIO = NULL;
      return(ret);
  }
  
  /**
   * xmlBufDetach:
   * @buf:  the buffer
   *
   * Remove the string contained in a buffer and give it back to the
   * caller. The buffer is reset to an empty content.
   * This doesn't work with immutable buffers as they can't be reset.
   *
   * Returns the previous string contained by the buffer.
   */
  xmlChar *
  xmlBufDetach(xmlBufPtr buf) {
      xmlChar *ret;
  
      if (buf == NULL)
          return(NULL);
      if (buf->alloc == XML_BUFFER_ALLOC_IMMUTABLE)
          return(NULL);
      if (buf->buffer != NULL)
          return(NULL);
      if (buf->error)
          return(NULL);
  
      ret = buf->content;
      buf->content = NULL;
      buf->size = 0;
      buf->use = 0;
      buf->compat_use = 0;
      buf->compat_size = 0;
  
      return ret;
  }
  
  
  /**
   * xmlBufCreateStatic:
   * @mem: the memory area
   * @size:  the size in byte
   *
   * routine to create an XML buffer from an immutable memory area.
   * The area won't be modified nor copied, and is expected to be
   * present until the end of the buffer lifetime.
   *
   * returns the new structure.
   */
  xmlBufPtr
  xmlBufCreateStatic(void *mem, size_t size) {
      xmlBufPtr ret;
  
      if (mem == NULL)
          return(NULL);
  
      ret = (xmlBufPtr) xmlMalloc(sizeof(xmlBuf));
      if (ret == NULL) {
  	xmlBufMemoryError(NULL, "creating buffer");
          return(NULL);
      }
      if (size < INT_MAX) {
          ret->compat_use = size;
          ret->compat_size = size;
      } else {
          ret->compat_use = INT_MAX;
          ret->compat_size = INT_MAX;
      }
      ret->use = size;
      ret->size = size;
      ret->alloc = XML_BUFFER_ALLOC_IMMUTABLE;
      ret->content = (xmlChar *) mem;
      ret->error = 0;
      ret->buffer = NULL;
      return(ret);
  }
  
  /**
   * xmlBufGetAllocationScheme:
   * @buf:  the buffer
   *
   * Get the buffer allocation scheme
   *
   * Returns the scheme or -1 in case of error
   */
  int
  xmlBufGetAllocationScheme(xmlBufPtr buf) {
      if (buf == NULL) {
  #ifdef DEBUG_BUFFER
          xmlGenericError(xmlGenericErrorContext,
  		"xmlBufGetAllocationScheme: buf == NULL\n");
  #endif
          return(-1);
      }
      return(buf->alloc);
  }
  
  /**
   * xmlBufSetAllocationScheme:
   * @buf:  the buffer to tune
   * @scheme:  allocation scheme to use
   *
   * Sets the allocation scheme for this buffer
   *
   * returns 0 in case of success and -1 in case of failure
   */
  int
  xmlBufSetAllocationScheme(xmlBufPtr buf,
                            xmlBufferAllocationScheme scheme) {
      if ((buf == NULL) || (buf->error != 0)) {
  #ifdef DEBUG_BUFFER
          xmlGenericError(xmlGenericErrorContext,
  		"xmlBufSetAllocationScheme: buf == NULL or in error\n");
  #endif
          return(-1);
      }
      if ((buf->alloc == XML_BUFFER_ALLOC_IMMUTABLE) ||
          (buf->alloc == XML_BUFFER_ALLOC_IO))
          return(-1);
      if ((scheme == XML_BUFFER_ALLOC_DOUBLEIT) ||
          (scheme == XML_BUFFER_ALLOC_EXACT) ||
          (scheme == XML_BUFFER_ALLOC_HYBRID) ||
          (scheme == XML_BUFFER_ALLOC_IMMUTABLE) ||
  	(scheme == XML_BUFFER_ALLOC_BOUNDED)) {
  	buf->alloc = scheme;
          if (buf->buffer)
              buf->buffer->alloc = scheme;
          return(0);
      }
      /*
       * Switching a buffer ALLOC_IO has the side effect of initializing
       * the contentIO field with the current content
       */
      if (scheme == XML_BUFFER_ALLOC_IO) {
          buf->alloc = XML_BUFFER_ALLOC_IO;
          buf->contentIO = buf->content;
      }
      return(-1);
  }
  
  /**
   * xmlBufFree:
   * @buf:  the buffer to free
   *
   * Frees an XML buffer. It frees both the content and the structure which
   * encapsulate it.
   */
  void
  xmlBufFree(xmlBufPtr buf) {
      if (buf == NULL) {
  #ifdef DEBUG_BUFFER
          xmlGenericError(xmlGenericErrorContext,
  		"xmlBufFree: buf == NULL\n");
  #endif
  	return;
      }
  
      if ((buf->alloc == XML_BUFFER_ALLOC_IO) &&
          (buf->contentIO != NULL)) {
          xmlFree(buf->contentIO);
      } else if ((buf->content != NULL) &&
          (buf->alloc != XML_BUFFER_ALLOC_IMMUTABLE)) {
          xmlFree(buf->content);
      }
      xmlFree(buf);
  }
  
  /**
   * xmlBufEmpty:
   * @buf:  the buffer
   *
   * empty a buffer.
   */
  void
  xmlBufEmpty(xmlBufPtr buf) {
      if ((buf == NULL) || (buf->error != 0)) return;
      if (buf->content == NULL) return;
      CHECK_COMPAT(buf)
      buf->use = 0;
      if (buf->alloc == XML_BUFFER_ALLOC_IMMUTABLE) {
          buf->content = BAD_CAST "";
      } else if ((buf->alloc == XML_BUFFER_ALLOC_IO) &&
                 (buf->contentIO != NULL)) {
          size_t start_buf = buf->content - buf->contentIO;
  
  	buf->size += start_buf;
          buf->content = buf->contentIO;
          buf->content[0] = 0;
      } else {
          buf->content[0] = 0;
      }
      UPDATE_COMPAT(buf)
  }
  
  /**
   * xmlBufShrink:
   * @buf:  the buffer to dump
   * @len:  the number of xmlChar to remove
   *
   * Remove the beginning of an XML buffer.
   * NOTE that this routine behaviour differs from xmlBufferShrink()
   * as it will return 0 on error instead of -1 due to size_t being
   * used as the return type.
   *
   * Returns the number of byte removed or 0 in case of failure
   */
  size_t
  xmlBufShrink(xmlBufPtr buf, size_t len) {
      if ((buf == NULL) || (buf->error != 0)) return(0);
      CHECK_COMPAT(buf)
      if (len == 0) return(0);
      if (len > buf->use) return(0);
  
      buf->use -= len;
      if ((buf->alloc == XML_BUFFER_ALLOC_IMMUTABLE) ||
          ((buf->alloc == XML_BUFFER_ALLOC_IO) && (buf->contentIO != NULL))) {
  	/*
  	 * we just move the content pointer, but also make sure
  	 * the perceived buffer size has shrunk accordingly
  	 */
          buf->content += len;
  	buf->size -= len;
  
          /*
  	 * sometimes though it maybe be better to really shrink
  	 * on IO buffers
  	 */
  	if ((buf->alloc == XML_BUFFER_ALLOC_IO) && (buf->contentIO != NULL)) {
  	    size_t start_buf = buf->content - buf->contentIO;
  	    if (start_buf >= buf->size) {
  		memmove(buf->contentIO, &buf->content[0], buf->use);
  		buf->content = buf->contentIO;
  		buf->content[buf->use] = 0;
  		buf->size += start_buf;
  	    }
  	}
      } else {
  	memmove(buf->content, &buf->content[len], buf->use);
  	buf->content[buf->use] = 0;
      }
      UPDATE_COMPAT(buf)
      return(len);
  }
  
  /**
   * xmlBufGrowInternal:
   * @buf:  the buffer
   * @len:  the minimum free size to allocate
   *
   * Grow the available space of an XML buffer, @len is the target value
   * Error checking should be done on buf->error since using the return
   * value doesn't work that well
   *
   * Returns 0 in case of error or the length made available otherwise
   */
  static size_t
  xmlBufGrowInternal(xmlBufPtr buf, size_t len) {
      size_t size;
      xmlChar *newbuf;
  
      if ((buf == NULL) || (buf->error != 0)) return(0);
      CHECK_COMPAT(buf)
  
      if (buf->alloc == XML_BUFFER_ALLOC_IMMUTABLE) return(0);
      if (buf->use + len < buf->size)
          return(buf->size - buf->use);
  
      /*
       * Windows has a BIG problem on realloc timing, so we try to double
       * the buffer size (if that's enough) (bug 146697)
       * Apparently BSD too, and it's probably best for linux too
       * On an embedded system this may be something to change
       */
  #if 1
      if (buf->size > (size_t) len)
          size = buf->size * 2;
      else
          size = buf->use + len + 100;
  #else
      size = buf->use + len + 100;
  #endif
  
      if (buf->alloc == XML_BUFFER_ALLOC_BOUNDED) {
          /*
  	 * Used to provide parsing limits
  	 */
          if ((buf->use + len >= XML_MAX_TEXT_LENGTH) ||
  	    (buf->size >= XML_MAX_TEXT_LENGTH)) {
  	    xmlBufMemoryError(buf, "buffer error: text too long\n");
  	    return(0);
  	}
  	if (size >= XML_MAX_TEXT_LENGTH)
  	    size = XML_MAX_TEXT_LENGTH;
      }
      if ((buf->alloc == XML_BUFFER_ALLOC_IO) && (buf->contentIO != NULL)) {
          size_t start_buf = buf->content - buf->contentIO;
  
  	newbuf = (xmlChar *) xmlRealloc(buf->contentIO, start_buf + size);
  	if (newbuf == NULL) {
  	    xmlBufMemoryError(buf, "growing buffer");
  	    return(0);
  	}
  	buf->contentIO = newbuf;
  	buf->content = newbuf + start_buf;
      } else {
  	newbuf = (xmlChar *) xmlRealloc(buf->content, size);
  	if (newbuf == NULL) {
  	    xmlBufMemoryError(buf, "growing buffer");
  	    return(0);
  	}
  	buf->content = newbuf;
      }
      buf->size = size;
      UPDATE_COMPAT(buf)
      return(buf->size - buf->use);
  }
  
  /**
   * xmlBufGrow:
   * @buf:  the buffer
   * @len:  the minimum free size to allocate
   *
   * Grow the available space of an XML buffer, @len is the target value
   * This is been kept compatible with xmlBufferGrow() as much as possible
   *
   * Returns -1 in case of error or the length made available otherwise
   */
  int
  xmlBufGrow(xmlBufPtr buf, int len) {
      size_t ret;
  
      if ((buf == NULL) || (len < 0)) return(-1);
      if (len == 0)
          return(0);
      ret = xmlBufGrowInternal(buf, len);
      if (buf->error != 0)
          return(-1);
      return((int) ret);
  }
  
  /**
   * xmlBufInflate:
   * @buf:  the buffer
   * @len:  the minimum extra free size to allocate
   *
   * Grow the available space of an XML buffer, adding at least @len bytes
   *
   * Returns 0 if successful or -1 in case of error
   */
  int
  xmlBufInflate(xmlBufPtr buf, size_t len) {
      if (buf == NULL) return(-1);
      xmlBufGrowInternal(buf, len + buf->size);
      if (buf->error)
          return(-1);
      return(0);
  }
  
  /**
   * xmlBufDump:
   * @file:  the file output
   * @buf:  the buffer to dump
   *
   * Dumps an XML buffer to  a FILE *.
   * Returns the number of #xmlChar written
   */
  size_t
  xmlBufDump(FILE *file, xmlBufPtr buf) {
      size_t ret;
  
      if ((buf == NULL) || (buf->error != 0)) {
  #ifdef DEBUG_BUFFER
          xmlGenericError(xmlGenericErrorContext,
  		"xmlBufDump: buf == NULL or in error\n");
  #endif
  	return(0);
      }
      if (buf->content == NULL) {
  #ifdef DEBUG_BUFFER
          xmlGenericError(xmlGenericErrorContext,
  		"xmlBufDump: buf->content == NULL\n");
  #endif
  	return(0);
      }
      CHECK_COMPAT(buf)
      if (file == NULL)
  	file = stdout;
      ret = fwrite(buf->content, sizeof(xmlChar), buf->use, file);
      return(ret);
  }
  
  /**
   * xmlBufContent:
   * @buf:  the buffer
   *
   * Function to extract the content of a buffer
   *
   * Returns the internal content
   */
  
  xmlChar *
  xmlBufContent(const xmlBuf *buf)
  {
      if ((!buf) || (buf->error))
          return NULL;
  
      return(buf->content);
  }
  
  /**
   * xmlBufEnd:
   * @buf:  the buffer
   *
   * Function to extract the end of the content of a buffer
   *
   * Returns the end of the internal content or NULL in case of error
   */
  
  xmlChar *
  xmlBufEnd(xmlBufPtr buf)
  {
      if ((!buf) || (buf->error))
          return NULL;
      CHECK_COMPAT(buf)
  
      return(&buf->content[buf->use]);
  }
  
  /**
   * xmlBufAddLen:
   * @buf:  the buffer
   * @len:  the size which were added at the end
   *
   * Sometime data may be added at the end of the buffer without
   * using the xmlBuf APIs that is used to expand the used space
   * and set the zero terminating at the end of the buffer
   *
   * Returns -1 in case of error and 0 otherwise
   */
  int
  xmlBufAddLen(xmlBufPtr buf, size_t len) {
      if ((buf == NULL) || (buf->error))
          return(-1);
      CHECK_COMPAT(buf)
      if (len > (buf->size - buf->use))
          return(-1);
      buf->use += len;
      UPDATE_COMPAT(buf)
      if (buf->size > buf->use)
          buf->content[buf->use] = 0;
      else
          return(-1);
      return(0);
  }
  
  /**
   * xmlBufErase:
   * @buf:  the buffer
   * @len:  the size to erase at the end
   *
   * Sometime data need to be erased at the end of the buffer
   *
   * Returns -1 in case of error and 0 otherwise
   */
  int
  xmlBufErase(xmlBufPtr buf, size_t len) {
      if ((buf == NULL) || (buf->error))
          return(-1);
      CHECK_COMPAT(buf)
      if (len > buf->use)
          return(-1);
      buf->use -= len;
      buf->content[buf->use] = 0;
      UPDATE_COMPAT(buf)
      return(0);
  }
  
  /**
   * xmlBufLength:
   * @buf:  the buffer
   *
   * Function to get the length of a buffer
   *
   * Returns the length of data in the internal content
   */
  
  size_t
  xmlBufLength(const xmlBufPtr buf)
  {
      if ((!buf) || (buf->error))
          return 0;
      CHECK_COMPAT(buf)
  
      return(buf->use);
  }
  
  /**
   * xmlBufUse:
   * @buf:  the buffer
   *
   * Function to get the length of a buffer
   *
   * Returns the length of data in the internal content
   */
  
  size_t
  xmlBufUse(const xmlBufPtr buf)
  {
      if ((!buf) || (buf->error))
          return 0;
      CHECK_COMPAT(buf)
  
      return(buf->use);
  }
  
  /**
   * xmlBufAvail:
   * @buf:  the buffer
   *
   * Function to find how much free space is allocated but not
   * used in the buffer. It does not account for the terminating zero
   * usually needed
   *
   * Returns the amount or 0 if none or an error occurred
   */
  
  size_t
  xmlBufAvail(const xmlBufPtr buf)
  {
      if ((!buf) || (buf->error))
          return 0;
      CHECK_COMPAT(buf)
  
      return(buf->size - buf->use);
  }
  
  /**
   * xmlBufIsEmpty:
   * @buf:  the buffer
   *
   * Tell if a buffer is empty
   *
   * Returns 0 if no, 1 if yes and -1 in case of error
   */
  int
  xmlBufIsEmpty(const xmlBufPtr buf)
  {
      if ((!buf) || (buf->error))
          return(-1);
      CHECK_COMPAT(buf)
  
      return(buf->use == 0);
  }
  
  /**
   * xmlBufResize:
   * @buf:  the buffer to resize
   * @size:  the desired size
   *
   * Resize a buffer to accommodate minimum size of @size.
   *
   * Returns  0 in case of problems, 1 otherwise
   */
  int
  xmlBufResize(xmlBufPtr buf, size_t size)
  {
      unsigned int newSize;
      xmlChar* rebuf = NULL;
      size_t start_buf;
  
      if ((buf == NULL) || (buf->error))
          return(0);
      CHECK_COMPAT(buf)
  
      if (buf->alloc == XML_BUFFER_ALLOC_IMMUTABLE) return(0);
      if (buf->alloc == XML_BUFFER_ALLOC_BOUNDED) {
          /*
  	 * Used to provide parsing limits
  	 */
          if (size >= XML_MAX_TEXT_LENGTH) {
  	    xmlBufMemoryError(buf, "buffer error: text too long\n");
  	    return(0);
  	}
      }
  
      /* Don't resize if we don't have to */
      if (size < buf->size)
          return 1;
  
      /* figure out new size */
      switch (buf->alloc){
  	case XML_BUFFER_ALLOC_IO:
  	case XML_BUFFER_ALLOC_DOUBLEIT:
  	    /*take care of empty case*/
  	    newSize = (buf->size ? buf->size*2 : size + 10);
  	    while (size > newSize) {
  	        if (newSize > UINT_MAX / 2) {
  	            xmlBufMemoryError(buf, "growing buffer");
  	            return 0;
  	        }
  	        newSize *= 2;
  	    }
  	    break;
  	case XML_BUFFER_ALLOC_EXACT:
  	    newSize = size+10;
  	    break;
          case XML_BUFFER_ALLOC_HYBRID:
              if (buf->use < BASE_BUFFER_SIZE)
                  newSize = size;
              else {
                  newSize = buf->size * 2;
                  while (size > newSize) {
                      if (newSize > UINT_MAX / 2) {
                          xmlBufMemoryError(buf, "growing buffer");
                          return 0;
                      }
                      newSize *= 2;
                  }
              }
              break;
  
  	default:
  	    newSize = size+10;
  	    break;
      }
  
      if ((buf->alloc == XML_BUFFER_ALLOC_IO) && (buf->contentIO != NULL)) {
          start_buf = buf->content - buf->contentIO;
  
          if (start_buf > newSize) {
  	    /* move data back to start */
  	    memmove(buf->contentIO, buf->content, buf->use);
  	    buf->content = buf->contentIO;
  	    buf->content[buf->use] = 0;
  	    buf->size += start_buf;
  	} else {
  	    rebuf = (xmlChar *) xmlRealloc(buf->contentIO, start_buf + newSize);
  	    if (rebuf == NULL) {
  		xmlBufMemoryError(buf, "growing buffer");
  		return 0;
  	    }
  	    buf->contentIO = rebuf;
  	    buf->content = rebuf + start_buf;
  	}
      } else {
  	if (buf->content == NULL) {
  	    rebuf = (xmlChar *) xmlMallocAtomic(newSize);
  	} else if (buf->size - buf->use < 100) {
  	    rebuf = (xmlChar *) xmlRealloc(buf->content, newSize);
          } else {
  	    /*
  	     * if we are reallocating a buffer far from being full, it's
  	     * better to make a new allocation and copy only the used range
  	     * and free the old one.
  	     */
  	    rebuf = (xmlChar *) xmlMallocAtomic(newSize);
  	    if (rebuf != NULL) {
  		memcpy(rebuf, buf->content, buf->use);
  		xmlFree(buf->content);
  		rebuf[buf->use] = 0;
  	    }
  	}
  	if (rebuf == NULL) {
  	    xmlBufMemoryError(buf, "growing buffer");
  	    return 0;
  	}
  	buf->content = rebuf;
      }
      buf->size = newSize;
      UPDATE_COMPAT(buf)
  
      return 1;
  }
  
  /**
   * xmlBufAdd:
   * @buf:  the buffer to dump
   * @str:  the #xmlChar string
   * @len:  the number of #xmlChar to add
   *
   * Add a string range to an XML buffer. if len == -1, the length of
   * str is recomputed.
   *
   * Returns 0 successful, a positive error code number otherwise
   *         and -1 in case of internal or API error.
   */
  int
  xmlBufAdd(xmlBufPtr buf, const xmlChar *str, int len) {
      unsigned int needSize;
  
      if ((str == NULL) || (buf == NULL) || (buf->error))
  	return -1;
      CHECK_COMPAT(buf)
  
      if (buf->alloc == XML_BUFFER_ALLOC_IMMUTABLE) return -1;
      if (len < -1) {
  #ifdef DEBUG_BUFFER
          xmlGenericError(xmlGenericErrorContext,
  		"xmlBufAdd: len < 0\n");
  #endif
  	return -1;
      }
      if (len == 0) return 0;
  
      if (len < 0)
          len = xmlStrlen(str);
  
      if (len < 0) return -1;
      if (len == 0) return 0;
  
      needSize = buf->use + len + 2;
      if (needSize > buf->size){
  	if (buf->alloc == XML_BUFFER_ALLOC_BOUNDED) {
  	    /*
  	     * Used to provide parsing limits
  	     */
  	    if (needSize >= XML_MAX_TEXT_LENGTH) {
  		xmlBufMemoryError(buf, "buffer error: text too long\n");
  		return(-1);
  	    }
  	}
          if (!xmlBufResize(buf, needSize)){
  	    xmlBufMemoryError(buf, "growing buffer");
              return XML_ERR_NO_MEMORY;
          }
      }
  
      memmove(&buf->content[buf->use], str, len*sizeof(xmlChar));
      buf->use += len;
      buf->content[buf->use] = 0;
      UPDATE_COMPAT(buf)
      return 0;
  }
  
  /**
   * xmlBufAddHead:
   * @buf:  the buffer
   * @str:  the #xmlChar string
   * @len:  the number of #xmlChar to add
   *
   * Add a string range to the beginning of an XML buffer.
   * if len == -1, the length of @str is recomputed.
   *
   * Returns 0 successful, a positive error code number otherwise
   *         and -1 in case of internal or API error.
   */
  int
  xmlBufAddHead(xmlBufPtr buf, const xmlChar *str, int len) {
      unsigned int needSize;
  
      if ((buf == NULL) || (buf->error))
          return(-1);
      CHECK_COMPAT(buf)
      if (buf->alloc == XML_BUFFER_ALLOC_IMMUTABLE) return -1;
      if (str == NULL) {
  #ifdef DEBUG_BUFFER
          xmlGenericError(xmlGenericErrorContext,
  		"xmlBufAddHead: str == NULL\n");
  #endif
  	return -1;
      }
      if (len < -1) {
  #ifdef DEBUG_BUFFER
          xmlGenericError(xmlGenericErrorContext,
  		"xmlBufAddHead: len < 0\n");
  #endif
  	return -1;
      }
      if (len == 0) return 0;
  
      if (len < 0)
          len = xmlStrlen(str);
  
      if (len <= 0) return -1;
  
      if ((buf->alloc == XML_BUFFER_ALLOC_IO) && (buf->contentIO != NULL)) {
          size_t start_buf = buf->content - buf->contentIO;
  
  	if (start_buf > (unsigned int) len) {
  	    /*
  	     * We can add it in the space previously shrunk
  	     */
  	    buf->content -= len;
              memmove(&buf->content[0], str, len);
  	    buf->use += len;
  	    buf->size += len;
  	    UPDATE_COMPAT(buf)
  	    return(0);
  	}
      }
      needSize = buf->use + len + 2;
      if (needSize > buf->size){
  	if (buf->alloc == XML_BUFFER_ALLOC_BOUNDED) {
  	    /*
  	     * Used to provide parsing limits
  	     */
  	    if (needSize >= XML_MAX_TEXT_LENGTH) {
  		xmlBufMemoryError(buf, "buffer error: text too long\n");
  		return(-1);
  	    }
  	}
          if (!xmlBufResize(buf, needSize)){
  	    xmlBufMemoryError(buf, "growing buffer");
              return XML_ERR_NO_MEMORY;
          }
      }
  
      memmove(&buf->content[len], &buf->content[0], buf->use);
      memmove(&buf->content[0], str, len);
      buf->use += len;
      buf->content[buf->use] = 0;
      UPDATE_COMPAT(buf)
      return 0;
  }
  
  /**
   * xmlBufCat:
   * @buf:  the buffer to add to
   * @str:  the #xmlChar string
   *
   * Append a zero terminated string to an XML buffer.
   *
   * Returns 0 successful, a positive error code number otherwise
   *         and -1 in case of internal or API error.
   */
  int
  xmlBufCat(xmlBufPtr buf, const xmlChar *str) {
      if ((buf == NULL) || (buf->error))
          return(-1);
      CHECK_COMPAT(buf)
      if (buf->alloc == XML_BUFFER_ALLOC_IMMUTABLE) return -1;
      if (str == NULL) return -1;
      return xmlBufAdd(buf, str, -1);
  }
  
  /**
   * xmlBufCCat:
   * @buf:  the buffer to dump
   * @str:  the C char string
   *
   * Append a zero terminated C string to an XML buffer.
   *
   * Returns 0 successful, a positive error code number otherwise
   *         and -1 in case of internal or API error.
   */
  int
  xmlBufCCat(xmlBufPtr buf, const char *str) {
      const char *cur;
  
      if ((buf == NULL) || (buf->error))
          return(-1);
      CHECK_COMPAT(buf)
      if (buf->alloc == XML_BUFFER_ALLOC_IMMUTABLE) return -1;
      if (str == NULL) {
  #ifdef DEBUG_BUFFER
          xmlGenericError(xmlGenericErrorContext,
  		"xmlBufCCat: str == NULL\n");
  #endif
  	return -1;
      }
      for (cur = str;*cur != 0;cur++) {
          if (buf->use  + 10 >= buf->size) {
              if (!xmlBufResize(buf, buf->use+10)){
  		xmlBufMemoryError(buf, "growing buffer");
                  return XML_ERR_NO_MEMORY;
              }
          }
          buf->content[buf->use++] = *cur;
      }
      buf->content[buf->use] = 0;
      UPDATE_COMPAT(buf)
      return 0;
  }
  
  /**
   * xmlBufWriteCHAR:
   * @buf:  the XML buffer
   * @string:  the string to add
   *
   * routine which manages and grows an output buffer. This one adds
   * xmlChars at the end of the buffer.
   *
   * Returns 0 if successful, a positive error code number otherwise
   *         and -1 in case of internal or API error.
   */
  int
  xmlBufWriteCHAR(xmlBufPtr buf, const xmlChar *string) {
      if ((buf == NULL) || (buf->error))
          return(-1);
      CHECK_COMPAT(buf)
      if (buf->alloc == XML_BUFFER_ALLOC_IMMUTABLE)
          return(-1);
      return(xmlBufCat(buf, string));
  }
  
  /**
   * xmlBufWriteChar:
   * @buf:  the XML buffer output
   * @string:  the string to add
   *
   * routine which manage and grows an output buffer. This one add
   * C chars at the end of the array.
   *
   * Returns 0 if successful, a positive error code number otherwise
   *         and -1 in case of internal or API error.
   */
  int
  xmlBufWriteChar(xmlBufPtr buf, const char *string) {
      if ((buf == NULL) || (buf->error))
          return(-1);
      CHECK_COMPAT(buf)
      if (buf->alloc == XML_BUFFER_ALLOC_IMMUTABLE)
          return(-1);
      return(xmlBufCCat(buf, string));
  }
  
  
  /**
   * xmlBufWriteQuotedString:
   * @buf:  the XML buffer output
   * @string:  the string to add
   *
   * routine which manage and grows an output buffer. This one writes
   * a quoted or double quoted #xmlChar string, checking first if it holds
   * quote or double-quotes internally
   *
   * Returns 0 if successful, a positive error code number otherwise
   *         and -1 in case of internal or API error.
   */
  int
  xmlBufWriteQuotedString(xmlBufPtr buf, const xmlChar *string) {
      const xmlChar *cur, *base;
      if ((buf == NULL) || (buf->error))
          return(-1);
      CHECK_COMPAT(buf)
      if (buf->alloc == XML_BUFFER_ALLOC_IMMUTABLE)
          return(-1);
      if (xmlStrchr(string, '\"')) {
          if (xmlStrchr(string, '\'')) {
  #ifdef DEBUG_BUFFER
  	    xmlGenericError(xmlGenericErrorContext,
   "xmlBufWriteQuotedString: string contains quote and double-quotes !\n");
  #endif
  	    xmlBufCCat(buf, "\"");
              base = cur = string;
              while(*cur != 0){
                  if(*cur == '"'){
                      if (base != cur)
                          xmlBufAdd(buf, base, cur - base);
                      xmlBufAdd(buf, BAD_CAST "&quot;", 6);
                      cur++;
                      base = cur;
                  }
                  else {
                      cur++;
                  }
              }
              if (base != cur)
                  xmlBufAdd(buf, base, cur - base);
  	    xmlBufCCat(buf, "\"");
  	}
          else{
  	    xmlBufCCat(buf, "\'");
              xmlBufCat(buf, string);
  	    xmlBufCCat(buf, "\'");
          }
      } else {
          xmlBufCCat(buf, "\"");
          xmlBufCat(buf, string);
          xmlBufCCat(buf, "\"");
      }
      return(0);
  }
  
  /**
   * xmlBufFromBuffer:
   * @buffer: incoming old buffer to convert to a new one
   *
   * Helper routine to switch from the old buffer structures in use
   * in various APIs. It creates a wrapper xmlBufPtr which will be
   * used for internal processing until the xmlBufBackToBuffer() is
   * issued.
   *
   * Returns a new xmlBufPtr unless the call failed and NULL is returned
   */
  xmlBufPtr
  xmlBufFromBuffer(xmlBufferPtr buffer) {
      xmlBufPtr ret;
  
      if (buffer == NULL)
          return(NULL);
  
      ret = (xmlBufPtr) xmlMalloc(sizeof(xmlBuf));
      if (ret == NULL) {
  	xmlBufMemoryError(NULL, "creating buffer");
          return(NULL);
      }
      ret->use = buffer->use;
      ret->size = buffer->size;
      ret->compat_use = buffer->use;
      ret->compat_size = buffer->size;
      ret->error = 0;
      ret->buffer = buffer;
      ret->alloc = buffer->alloc;
      ret->content = buffer->content;
      ret->contentIO = buffer->contentIO;
  
      return(ret);
  }
  
  /**
   * xmlBufBackToBuffer:
   * @buf: new buffer wrapping the old one
   *
   * Function to be called once internal processing had been done to
   * update back the buffer provided by the user. This can lead to
   * a failure in case the size accumulated in the xmlBuf is larger
   * than what an xmlBuffer can support on 64 bits (INT_MAX)
   * The xmlBufPtr @buf wrapper is deallocated by this call in any case.
   *
   * Returns the old xmlBufferPtr unless the call failed and NULL is returned
   */
  xmlBufferPtr
  xmlBufBackToBuffer(xmlBufPtr buf) {
      xmlBufferPtr ret;
  
      if (buf == NULL)
          return(NULL);
      CHECK_COMPAT(buf)
      if ((buf->error) || (buf->buffer == NULL)) {
          xmlBufFree(buf);
          return(NULL);
      }
  
      ret = buf->buffer;
      /*
       * What to do in case of error in the buffer ???
       */
      if (buf->use > INT_MAX) {
          /*
           * Worse case, we really allocated and used more than the
           * maximum allowed memory for an xmlBuffer on this architecture.
           * Keep the buffer but provide a truncated size value.
           */
          xmlBufOverflowError(buf, "Used size too big for xmlBuffer");
          ret->use = INT_MAX;
          ret->size = INT_MAX;
      } else if (buf->size > INT_MAX) {
          /*
           * milder case, we allocated more than the maximum allowed memory
           * for an xmlBuffer on this architecture, but used less than the
           * limit.
           * Keep the buffer but provide a truncated size value.
           */
          xmlBufOverflowError(buf, "Allocated size too big for xmlBuffer");
          ret->use = (int) buf->use;
          ret->size = INT_MAX;
      } else {
          ret->use = (int) buf->use;
          ret->size = (int) buf->size;
      }
      ret->alloc = buf->alloc;
      ret->content = buf->content;
      ret->contentIO = buf->contentIO;
      xmlFree(buf);
      return(ret);
  }
  
  /**
   * xmlBufMergeBuffer:
   * @buf: an xmlBufPtr
   * @buffer: the buffer to consume into @buf
   *
   * The content of @buffer is appended to @buf and @buffer is freed
   *
   * Returns -1 in case of error, 0 otherwise, in any case @buffer is freed
   */
  int
  xmlBufMergeBuffer(xmlBufPtr buf, xmlBufferPtr buffer) {
      int ret = 0;
  
      if ((buf == NULL) || (buf->error)) {
  	xmlBufferFree(buffer);
          return(-1);
      }
      CHECK_COMPAT(buf)
      if ((buffer != NULL) && (buffer->content != NULL) &&
               (buffer->use > 0)) {
          ret = xmlBufAdd(buf, buffer->content, buffer->use);
      }
      xmlBufferFree(buffer);
      return(ret);
  }
  
  /**
   * xmlBufResetInput:
   * @buf: an xmlBufPtr
   * @input: an xmlParserInputPtr
   *
   * Update the input to use the current set of pointers from the buffer.
   *
   * Returns -1 in case of error, 0 otherwise
   */
  int
  xmlBufResetInput(xmlBufPtr buf, xmlParserInputPtr input) {
      if ((input == NULL) || (buf == NULL) || (buf->error))
          return(-1);
      CHECK_COMPAT(buf)
      input->base = input->cur = buf->content;
      input->end = &buf->content[buf->use];
      return(0);
  }
  
  /**
   * xmlBufGetInputBase:
   * @buf: an xmlBufPtr
   * @input: an xmlParserInputPtr
   *
   * Get the base of the @input relative to the beginning of the buffer
   *
   * Returns the size_t corresponding to the displacement
   */
  size_t
  xmlBufGetInputBase(xmlBufPtr buf, xmlParserInputPtr input) {
      size_t base;
  
      if ((input == NULL) || (buf == NULL) || (buf->error))
          return(-1);
      CHECK_COMPAT(buf)
      base = input->base - buf->content;
      /*
       * We could do some pointer arithmetic checks but that's probably
       * sufficient.
       */
      if (base > buf->size) {
          xmlBufOverflowError(buf, "Input reference outside of the buffer");
          base = 0;
      }
      return(base);
  }
  
  /**
   * xmlBufSetInputBaseCur:
   * @buf: an xmlBufPtr
   * @input: an xmlParserInputPtr
   * @base: the base value relative to the beginning of the buffer
   * @cur: the cur value relative to the beginning of the buffer
   *
   * Update the input to use the base and cur relative to the buffer
   * after a possible reallocation of its content
   *
   * Returns -1 in case of error, 0 otherwise
   */
  int
  xmlBufSetInputBaseCur(xmlBufPtr buf, xmlParserInputPtr input,
                        size_t base, size_t cur) {
      if (input == NULL)
          return(-1);
      if ((buf == NULL) || (buf->error)) {
          input->base = input->cur = input->end = BAD_CAST "";
          return(-1);
      }
      CHECK_COMPAT(buf)
      input->base = &buf->content[base];
      input->cur = input->base + cur;
      input->end = &buf->content[buf->use];
      return(0);
  }
  
  

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