terom@0: #ifndef PNGTILE_CACHE_H
terom@0: #define PNGTILE_CACHE_H
terom@0: 
terom@0: /**
terom@0:  * @file
terom@0:  *
terom@0:  * Internal image cache implementation
terom@0:  */
terom@0: #include "image.h"
terom@56: #include "png.h"
terom@0: 
terom@1: #include <stdint.h>
terom@1: #include <stdbool.h>
terom@1: 
terom@56: /**
terom@56:  * Cache format version
terom@56:  */
terom@56: #define PT_CACHE_VERSION 2
terom@1: 
terom@0: /**
terom@56:  * Size used to store the cache header
terom@56:  */
terom@56: #define PT_CACHE_HEADER_SIZE 4096
terom@56: 
terom@56: /**
terom@56:  * On-disk header
terom@56:  */
terom@56: struct pt_cache_header {
terom@56:     /** Set to PT_CACHE_VERSION */
terom@56:     uint16_t version;
terom@56: 
terom@56:     /** Image format */
terom@56:     enum pt_img_format {
terom@56:         PT_IMG_PNG,     ///< @see pt_png
terom@56:     } format;
terom@56:     
terom@56:     /** Data header by format  */
terom@56:     union {
terom@56:         struct pt_png_header png;
terom@56:     };
terom@56:     
terom@56:     /** Parameters used */
terom@56:     struct pt_image_params params;
terom@56:     
terom@56:     /** Size of the data segment */
terom@56:     size_t data_size;
terom@56: };
terom@56: 
terom@56: /**
terom@72:  * On-disk data format. This struct is always exactly PT_CACHE_HEADER_SIZE long
terom@56:  */
terom@56: struct pt_cache_file {
terom@56:     /** Header */
terom@56:     struct pt_cache_header header;
terom@56: 
terom@56:     /** Padding for data */
terom@56:     uint8_t padding[PT_CACHE_HEADER_SIZE - sizeof(struct pt_cache_header)];
terom@56: 
terom@56:     /** Data follows, header.data_size bytes */
terom@56:     uint8_t data[];
terom@56: };
terom@56: 
terom@56: /**
terom@56:  * Cache state
terom@0:  */
terom@0: struct pt_cache {
terom@1:     /** Filesystem path to cache file */
terom@1:     char *path;
terom@0: 
terom@1:     /** The mode we are operating in, bitmask of PT_IMG_* */
terom@1:     int mode;
terom@1:     
terom@1:     /** Opened file */
terom@1:     int fd;
terom@1: 
terom@7:     /** Size of the data segment in bytes, starting at PT_CACHE_HEADER_SIZE */
terom@56:     size_t data_size;
terom@1: 
terom@56:     /** The mmap'd file */
terom@56:     struct pt_cache_file *file;
terom@0: };
terom@0: 
terom@0: /**
terom@0:  * Construct the image cache info object associated with the given image.
terom@0:  */
terom@9: int pt_cache_new (struct pt_cache **cache_ptr, const char *path, int mode);
terom@0: 
terom@0: /**
terom@8:  * Verify if the cached data eixsts, or has become stale compared to the given original file.
terom@8:  *
terom@8:  * @return one of pt_cache_status; <0 on error, 0 if fresh, >0 otherwise
terom@0:  */
terom@8: int pt_cache_status (struct pt_cache *cache, const char *img_path);
terom@0: 
terom@0: /**
terom@56:  * Get info for the cached image.
terom@56:  *
terom@56:  * Does not open it if not yet opened.
terom@10:  */
terom@56: void pt_cache_info (struct pt_cache *cache, struct pt_image_info *info);
terom@10: 
terom@10: /**
terom@56:  * Update the cache data from the given image data
terom@0:  */
terom@56: int pt_cache_update (struct pt_cache *cache, struct pt_png_img *img, const struct pt_image_params *params);
terom@0: 
terom@1: /**
terom@10:  * Open the existing .cache for use. If already opened, does nothing.
terom@9:  */
terom@9: int pt_cache_open (struct pt_cache *cache);
terom@9: 
terom@9: /**
terom@56:  * Render out the given tile
terom@9:  *
terom@9:  * If the cache is not yet open, this will open it
terom@9:  */
terom@56: int pt_cache_tile (struct pt_cache *cache, struct pt_tile *tile);
terom@9: 
terom@9: /**
terom@59:  * Close the cache, if opened
terom@59:  */
terom@59: int pt_cache_close (struct pt_cache *cache);
terom@59: 
terom@59: /**
terom@1:  * Release all resources associated with the given cache object without any cleanup.
terom@1:  */
terom@1: void pt_cache_destroy (struct pt_cache *cache);
terom@1: 
terom@0: #endif