C++ png_memset函数代码示例

/* Allocate memory for a png_struct or a png_info.  The malloc and
 * memset can be replaced by a single call to calloc() if this is thought
 * to improve performance noticably.
 */
png_voidp
png_create_struct(uInt type)
{
   size_t size;
   png_voidp struct_ptr;

   if (type == PNG_STRUCT_INFO)
     size = sizeof(png_info);
   else if (type == PNG_STRUCT_PNG)
     size = sizeof(png_struct);
   else
     return (png_voidp)NULL;

#if defined(__TURBOC__) && !defined(__FLAT__)
   if ((struct_ptr = (png_voidp)farmalloc(size)) != NULL)
#else
# if defined(_MSC_VER) && defined(MAXSEG_64K)
   if ((struct_ptr = (png_voidp)halloc(size,1)) != NULL)
# else
   if ((struct_ptr = (png_voidp)malloc(size)) != NULL)
# endif
#endif
   {
      png_memset(struct_ptr, 0, size);
   }

   return (struct_ptr);
}

/* Initialize the info structure.  This is now an internal function (0.89)
 * and applications using it are urged to use png_create_info_struct()
 * instead.
 */
void
png_info_init(png_infop info_ptr)
{
   png_debug(1, "in png_info_init\n");
   /* set everything to 0 */
   png_memset(info_ptr, 0, sizeof (png_info));
}

/* Initialize png_ptr structure, and allocate any memory needed */
void
png_write_init(png_structp png_ptr)
{
	jmp_buf tmp_jmp; /* to save current jump buffer */

	png_debug(1, "in png_write_init\n");
	/* save jump buffer and error functions */
	png_memcpy(tmp_jmp, png_ptr->jmpbuf, sizeof (jmp_buf));

	/* reset all variables to 0 */
	png_memset(png_ptr, 0, sizeof (png_struct));

	/* restore jump buffer */
	png_memcpy(png_ptr->jmpbuf, tmp_jmp, sizeof (jmp_buf));

	/* initialize zbuf - compression buffer */
	png_ptr->zbuf_size = PNG_ZBUF_SIZE;
	png_ptr->zbuf = (png_bytep)png_malloc(png_ptr,
		(png_uint_32)png_ptr->zbuf_size);
	png_set_write_fn(png_ptr, NULL, NULL, NULL);

#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
	png_set_filter_heuristics(png_ptr, PNG_FILTER_HEURISTIC_DEFAULT,
		1, NULL, NULL);
#endif
}

/* Alternate version of png_create_struct, for use with user-defined malloc. */
png_voidp /* PRIVATE */
png_create_struct_2(int type, png_malloc_ptr malloc_fn, png_voidp mem_ptr)
{
#endif /* PNG_USER_MEM_SUPPORTED */
    png_size_t size;
    png_voidp struct_ptr;

    if (type == PNG_STRUCT_INFO)
        size = png_sizeof(png_info);
    else if (type == PNG_STRUCT_PNG)
        size = png_sizeof(png_struct);
    else
        return (png_get_copyright(NULL));

#ifdef PNG_USER_MEM_SUPPORTED
    if (malloc_fn != NULL)
    {
        png_struct dummy_struct;
        png_structp png_ptr = &dummy_struct;
        png_ptr->mem_ptr=mem_ptr;
        struct_ptr = (*(malloc_fn))(png_ptr, (png_uint_32)size);
    }
    else
#endif /* PNG_USER_MEM_SUPPORTED */
        struct_ptr = (png_voidp)farmalloc(size);
    if (struct_ptr != NULL)
        png_memset(struct_ptr, 0, size);
    return (struct_ptr);
}

png_voidp
png_debug_malloc(png_structp png_ptr, png_uint_32 size)
{

   /* png_malloc has already tested for NULL; png_create_struct calls
      png_debug_malloc directly, with png_ptr == NULL which is OK */

   if (size == 0)
      return (NULL);

   /* This calls the library allocator twice, once to get the requested
      buffer and once to get a new free list entry. */
   {
      memory_infop pinfo = (memory_infop)png_malloc_default(png_ptr,
         (png_uint_32)sizeof *pinfo);
      pinfo->size = size;
      current_allocation += size;
      total_allocation += size;
      num_allocations ++;
      if (current_allocation > maximum_allocation)
         maximum_allocation = current_allocation;
      pinfo->pointer = (png_voidp)png_malloc_default(png_ptr, size);
      pinfo->next = pinformation;
      pinformation = pinfo;
      /* Make sure the caller isn't assuming zeroed memory. */
      png_memset(pinfo->pointer, 0xdd, pinfo->size);
#if PNG_DEBUG
      if(verbose)
         printf("png_malloc %lu bytes at %x\n",size,pinfo->pointer);
#endif
      assert(pinfo->size != 12345678);
      return (png_voidp)(pinfo->pointer);
   }
}

voidpf PNGAPI
#else
voidpf /* PRIVATE */
#endif
png_zalloc(voidpf png_ptr, uInt items, uInt size)
{
   png_voidp ptr;
   png_structp p;
   png_uint_32 save_flags;
   png_uint_32 num_bytes;

   if (png_ptr == NULL)
      return (NULL);

   p=(png_structp)png_ptr;
   save_flags=p->flags;

   if (items > PNG_UINT_32_MAX/size)
   {
     png_warning (p, "Potential overflow in png_zalloc()");
     return (NULL);
   }
   num_bytes = (png_uint_32)items * size;

   p->flags|=PNG_FLAG_MALLOC_NULL_MEM_OK;
   ptr = (png_voidp)png_malloc((png_structp)png_ptr, num_bytes);
   p->flags=save_flags;

#if defined(PNG_1_0_X) && !defined(PNG_NO_ZALLOC_ZERO)
   if (ptr == NULL)
       return ((voidpf)ptr);

   if (num_bytes > (png_uint_32)0x8000L)
   {
      png_memset(ptr, 0, (png_size_t)0x8000L);
      png_memset((png_bytep)ptr + (png_size_t)0x8000L, 0,
         (png_size_t)(num_bytes - (png_uint_32)0x8000L));
   }
   else
   {
      png_memset(ptr, 0, (png_size_t)num_bytes);
   }
#endif
   return ((voidpf)ptr);
}

/* Function to allocate memory for zlib. */
voidpf
png_zalloc(voidpf png_ptr, uInt items, uInt size)
{
   png_uint_32 num_bytes = (png_uint_32)items * size;
   png_voidp ptr = (png_voidp)png_malloc((png_structp)png_ptr, num_bytes);

   if (num_bytes > (png_uint_32)0x8000L)
   {
      png_memset(ptr, 0, (png_size_t)0x8000L);
      png_memset((png_bytep)ptr + (png_size_t)0x8000L, 0,
         (png_size_t)(num_bytes - (png_uint_32)0x8000L));
   }
   else
   {
      png_memset(ptr, 0, (png_size_t)num_bytes);
   }
   return ((voidpf)ptr);
}

png_voidp PNGAPI
png_calloc(png_structp png_ptr, png_alloc_size_t size)
{
   png_voidp ret;

   ret = (png_malloc(png_ptr, size));
   if (ret != NULL)
      png_memset(ret,0,(png_size_t)size);
   return (ret);
}

png_voidp /* PRIVATE */
png_calloc(png_structp png_ptr, png_uint_32 size)
{
   png_voidp ret;

   ret = (png_malloc(png_ptr, size));
   if (ret != NULL)
      png_memset(ret,0,(png_size_t)size);
   return (ret);
}

/* Free any memory used in png_ptr struct (old method) */
void
png_write_destroy(png_structp png_ptr)
{
   jmp_buf tmp_jmp; /* save jump buffer */
   png_error_ptr error_fn;
   png_error_ptr warning_fn;
   png_voidp error_ptr;
#ifdef PNG_USER_MEM_SUPPORTED
   png_free_ptr free_fn;
#endif

   png_debug(1, "in png_write_destroy\n");
   /* free any memory zlib uses */
   deflateEnd(&png_ptr->zstream);

   /* free our memory.  png_free checks NULL for us. */
   png_free(png_ptr, png_ptr->zbuf);
   png_free(png_ptr, png_ptr->row_buf);
   png_free(png_ptr, png_ptr->prev_row);
   png_free(png_ptr, png_ptr->sub_row);
   png_free(png_ptr, png_ptr->up_row);
   png_free(png_ptr, png_ptr->avg_row);
   png_free(png_ptr, png_ptr->paeth_row);
#if defined(PNG_TIME_RFC1123_SUPPORTED)
   png_free(png_ptr, png_ptr->time_buffer);
#endif /* PNG_TIME_RFC1123_SUPPORTED */
#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
   png_free(png_ptr, png_ptr->prev_filters);
   png_free(png_ptr, png_ptr->filter_weights);
   png_free(png_ptr, png_ptr->inv_filter_weights);
   png_free(png_ptr, png_ptr->filter_costs);
   png_free(png_ptr, png_ptr->inv_filter_costs);
#endif /* PNG_WRITE_WEIGHTED_FILTER_SUPPORTED */

   /* reset structure */
   png_memcpy(tmp_jmp, png_ptr->jmpbuf, sizeof (jmp_buf));

   error_fn = png_ptr->error_fn;
   warning_fn = png_ptr->warning_fn;
   error_ptr = png_ptr->error_ptr;
#ifdef PNG_USER_MEM_SUPPORTED
   free_fn = png_ptr->free_fn;
#endif

   png_memset(png_ptr, 0, sizeof (png_struct));

   png_ptr->error_fn = error_fn;
   png_ptr->warning_fn = warning_fn;
   png_ptr->error_ptr = error_ptr;
#ifdef PNG_USER_MEM_SUPPORTED
   png_ptr->free_fn = free_fn;
#endif

   png_memcpy(png_ptr->jmpbuf, tmp_jmp, sizeof (jmp_buf));
}

/* Allocate memory for a png_struct or a png_info.  The malloc and
   memset can be replaced by a single call to calloc() if this is thought
   to improve performance noticably. */
png_voidp /* PRIVATE */
png_create_struct_2(int type, png_malloc_ptr malloc_fn, png_voidp mem_ptr) {
#endif /* PNG_USER_MEM_SUPPORTED */
    png_size_t size;
    png_voidp struct_ptr;

    if (type == PNG_STRUCT_INFO) {
        size = png_sizeof(png_info);
    } else if (type == PNG_STRUCT_PNG) {
        size = png_sizeof(png_struct);
    } else {
        return (NULL);
    }

#ifdef PNG_USER_MEM_SUPPORTED
    if (malloc_fn != NULL) {
        png_struct dummy_struct;
        png_structp png_ptr = &dummy_struct;
        png_ptr->mem_ptr = mem_ptr;
        struct_ptr = (*(malloc_fn))(png_ptr, size);
        if (struct_ptr != NULL) {
            png_memset(struct_ptr, 0, size);
        }
        return (struct_ptr);
    }
#endif /* PNG_USER_MEM_SUPPORTED */

#if defined(__TURBOC__) && !defined(__FLAT__)
    struct_ptr = (png_voidp)farmalloc(size);
#else
# if defined(_MSC_VER) && defined(MAXSEG_64K)
struct_ptr = (png_voidp)halloc(size, 1);
# else
struct_ptr = (png_voidp)malloc(size);
# endif
#endif
    if (struct_ptr != NULL) {
        png_memset(struct_ptr, 0, size);
    }

    return (struct_ptr);
}

/* Function to allocate memory for zlib and clear it to 0. */
voidpf /* PRIVATE */
png_zalloc(voidpf png_ptr, uInt items, uInt size)
{
   png_uint_32 num_bytes = (png_uint_32)items * size;
   png_voidp ptr = (png_voidp)png_malloc((png_structp)png_ptr, num_bytes);

#ifndef PNG_NO_ZALLOC_ZERO
   if (num_bytes > (png_uint_32)0x8000L)
   {
      png_memset(ptr, 0, (png_size_t)0x8000L);
      png_memset((png_bytep)ptr + (png_size_t)0x8000L, 0,
         (png_size_t)(num_bytes - (png_uint_32)0x8000L));
   }
   else
   {
      png_memset(ptr, 0, (png_size_t)num_bytes);
   }
#endif
   return ((voidpf)ptr);
}

png_bytepp PNGAPI
pngx_malloc_rows_extended(png_structp png_ptr, png_infop info_ptr,
   pngx_alloc_size_t min_row_size, int filler)
{
   pngx_alloc_size_t row_size;
   png_bytep row;
   png_bytepp rows;
   png_uint_32 height, i;

   /* Calculate the row size. */
   row_size = png_get_rowbytes(png_ptr, info_ptr);
   if (row_size == 0)
      return NULL;
   if (row_size < min_row_size)
      row_size = min_row_size;

   /* Deallocate the currently-existing rows. */
   png_free_data(png_ptr, info_ptr, PNG_FREE_ROWS, 0);

   /* Allocate memory for the row index. */
   height = png_get_image_height(png_ptr, info_ptr);
   if (height > (pngx_alloc_size_t)(-1) / sizeof(png_bytep))
   {
      png_warning(png_ptr, "Image height is too large");
      return NULL;
   }
   rows = (png_bytepp)png_malloc(png_ptr,
      (pngx_alloc_size_t)(height * sizeof(png_bytep)));
   if (rows == NULL)
      return NULL;

   /* Allocate memory for each row. */
   for (i = 0; i < height; ++i)
   {
      row = (png_bytep)png_malloc(png_ptr, row_size);
      if (row == NULL)  /* out of memory? */
      {
         /* Release the memory allocated up to the point of failure. */
         while (i > 0)
            png_free(png_ptr, rows[--i]);
         png_free(png_ptr, rows);
         return NULL;
      }
      if (filler >= 0)
         png_memset(row, filler, row_size);
      rows[i] = row;
   }

   /* Set the row pointers. */
   png_set_rows(png_ptr, info_ptr, rows);
   return rows;
}

png_voidp PNGAPI
png_memset_check (png_structp png_ptr, png_voidp s1, int value,
   png_uint_32 length)
{
   png_size_t size;

   size = (png_size_t)length;
   if ((png_uint_32)size != length)
      png_error(png_ptr, "Overflow in png_memset_check.");

   return (png_memset (s1, value, size));

}

/* Allocate memory for a png_struct or a png_info.  The malloc and
   memset can be replaced by a single call to calloc() if this is thought
   to improve performance noticably.*/
png_voidp
png_create_struct_2(int type, png_malloc_ptr malloc_fn)
{
#endif /* PNG_USER_MEM_SUPPORTED */
   png_size_t size;
   png_voidp struct_ptr;

   if (type == PNG_STRUCT_INFO)
      size = sizeof(png_info);
   else if (type == PNG_STRUCT_PNG)
      size = sizeof(png_struct);
   else
      return ((png_voidp)NULL);

#ifdef PNG_USER_MEM_SUPPORTED
   if(malloc_fn != NULL)
   {
      if ((struct_ptr = (*(malloc_fn))(NULL, size)) != NULL)
         png_memset(struct_ptr, 0, size);
      return (struct_ptr);
   }
#endif /* PNG_USER_MEM_SUPPORTED */

#if defined(__TURBOC__) && !defined(__FLAT__)
   if ((struct_ptr = (png_voidp)farmalloc(size)) != NULL)
#else
# if defined(_MSC_VER) && defined(MAXSEG_64K)
   if ((struct_ptr = (png_voidp)halloc(size,1)) != NULL)
# else
   if ((struct_ptr = (png_voidp)malloc(size)) != NULL)
# endif
#endif
   {
      png_memset(struct_ptr, 0, size);
   }

   return (struct_ptr);
}