🖼️ Safe overflow-checked buffer size calculations for images and video frames More...

Functions
asciichat_error_t	image_calc_pixel_count (size_t width, size_t height, size_t *out_pixel_count)

asciichat_error_t	image_calc_pixel_buffer_size (size_t pixel_count, size_t bytes_per_pixel, size_t *out_size)

asciichat_error_t	image_calc_rgb_size (size_t width, size_t height, size_t *out_size)

asciichat_error_t	image_calc_total_allocation (size_t width, size_t height, size_t struct_size, size_t bytes_per_pixel, size_t *out_size)

asciichat_error_t	image_validate_dimensions (size_t width, size_t height)

asciichat_error_t	image_validate_buffer_size (size_t requested_size)

Detailed Description

🖼️ Safe overflow-checked buffer size calculations for images and video frames

Definition in file util/image.c.

Function Documentation

◆ image_calc_pixel_buffer_size()

asciichat_error_t image_calc_pixel_buffer_size	(	size_t	pixel_count,
		size_t	bytes_per_pixel,
		size_t *	out_size
	)

Definition at line 31 of file util/image.c.

                                                                                                             {
  if (!out_size) {
    return SET_ERRNO(ERROR_INVALID_PARAM, "out_size is NULL");
  }
 
  if (pixel_count == 0) {
    return SET_ERRNO(ERROR_INVALID_PARAM, "Pixel count must be non-zero");
  }
 
  if (bytes_per_pixel == 0) {
    return SET_ERRNO(ERROR_INVALID_PARAM, "bytes_per_pixel must be non-zero");
  }
 
  // Check overflow before multiplication
  if (pixel_count > SIZE_MAX / bytes_per_pixel) {
    return SET_ERRNO(ERROR_INVALID_PARAM, "Pixel buffer too large (would overflow): %zu pixels * %zu bpp", pixel_count,
                     bytes_per_pixel);
  }
 
  *out_size = pixel_count * bytes_per_pixel;
  return ASCIICHAT_OK;
}

Referenced by image_calc_rgb_size(), and image_calc_total_allocation().

◆ image_calc_pixel_count()

asciichat_error_t image_calc_pixel_count	(	size_t	width,
		size_t	height,
		size_t *	out_pixel_count
	)

Definition at line 12 of file util/image.c.

                                                                                               {
  if (!out_pixel_count) {
    return SET_ERRNO(ERROR_INVALID_PARAM, "out_pixel_count is NULL");
  }
 
  // Check for zero dimensions
  if (width == 0 || height == 0) {
    return SET_ERRNO(ERROR_INVALID_PARAM, "Image dimensions must be non-zero: %zu x %zu", width, height);
  }
 
  // Check overflow before multiplication
  if (height > SIZE_MAX / width) {
    return SET_ERRNO(ERROR_INVALID_PARAM, "Image dimensions too large (would overflow): %zu x %zu", width, height);
  }
 
  *out_pixel_count = width * height;
  return ASCIICHAT_OK;
}

Referenced by image_calc_rgb_size(), and image_calc_total_allocation().

◆ image_calc_rgb_size()

asciichat_error_t image_calc_rgb_size	(	size_t	width,
		size_t	height,
		size_t *	out_size
	)

Definition at line 54 of file util/image.c.

                                                                                     {
  if (!out_size) {
    return SET_ERRNO(ERROR_INVALID_PARAM, "out_size is NULL");
  }
 
  // Calculate pixel count first
  size_t pixel_count;
  asciichat_error_t err = image_calc_pixel_count(width, height, &pixel_count);
  if (err != ASCIICHAT_OK) {
    return err;
  }
 
  // Calculate size with 3 bytes per pixel (RGB)
  return image_calc_pixel_buffer_size(pixel_count, 3, out_size);
}

References image_calc_pixel_buffer_size(), and image_calc_pixel_count().

Referenced by handle_image_frame_packet().

◆ image_calc_total_allocation()

asciichat_error_t image_calc_total_allocation	(	size_t	width,
		size_t	height,
		size_t	struct_size,
		size_t	bytes_per_pixel,
		size_t *	out_size
	)

Definition at line 70 of file util/image.c.

                                                                {
  if (!out_size) {
    return SET_ERRNO(ERROR_INVALID_PARAM, "out_size is NULL");
  }
 
  // Calculate pixel count first with overflow checking
  size_t pixel_count;
  asciichat_error_t err = image_calc_pixel_count(width, height, &pixel_count);
  if (err != ASCIICHAT_OK) {
    return err;
  }
 
  // Calculate pixel buffer size
  size_t pixel_buffer_size;
  err = image_calc_pixel_buffer_size(pixel_count, bytes_per_pixel, &pixel_buffer_size);
  if (err != ASCIICHAT_OK) {
    return err;
  }
 
  // Check overflow when adding struct size
  if (pixel_buffer_size > SIZE_MAX - struct_size) {
    return SET_ERRNO(ERROR_INVALID_PARAM, "Total allocation size would overflow: struct=%zu + pixels=%zu", struct_size,
                     pixel_buffer_size);
  }
 
  *out_size = struct_size + pixel_buffer_size;
  return ASCIICHAT_OK;
}

References image_calc_pixel_buffer_size(), and image_calc_pixel_count().

◆ image_validate_buffer_size()

asciichat_error_t image_validate_buffer_size ( size_t requested_size )

Definition at line 115 of file util/image.c.

                                                                    {
  if (requested_size > IMAGE_MAX_PIXELS_SIZE) {
    return SET_ERRNO(ERROR_INVALID_PARAM, "Image buffer size exceeds maximum: %zu > %zu bytes", requested_size,
                     IMAGE_MAX_PIXELS_SIZE);
  }
 
  return ASCIICHAT_OK;
}