1 #include "image.h"

     2 

     3 static int pt_image_new (struct pt_image **img_ptr, struct pt_ctx *ctx, const char *png_path)

     4 {

     5     struct pt_image *img;

     6 

     7     // alloc

     8     if ((img = calloc(1, sizeof(*img))) == NULL)

     9         return -1;

    10 

    11     if ((img->png_path = strdup(png_path)) == NULL)

    12         goto error;

    13 

    14     // init

    15     img->ctx = ctx;

    16     

    17     // ok

    18     *img_ptr = img;

    19 

    20     return 0;

    21 

    22 error:

    23     pt_image_destroy(img);

    24 

    25     return -1;

    26 }

    27 

    28 /**

    29  * Open the image's FILE

    30  */

    31 static int pt_image_open_file (struct pt_image *img, FILE **file_ptr)

    32 {

    33     FILE *fp;

    34     

    35     // open

    36     if (fopen(img->png_path, "rb") < 0)

    37         return -1;

    38 

    39     // ok

    40     *file_ptr = fp;

    41 

    42     return 0;

    43 }

    44 

    45 /**

    46  * Open the PNG image, setting up the I/O and returning the png_structp and png_infop

    47  */

    48 static int pt_image_open_png (struct pt_image *img, png_structp *png_ptr, png_infop *info_ptr)

    49 {

    50     FILE *fp = NULL;

    51     png_structp png = NULL;

    52     png_infop info = NULL;

    53     

    54     // open I/O

    55     if (pt_image_open_file(img, &fp))

    56         goto error;

    57 

    58     // create the struct

    59     if ((png = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL)) == NULL)

    60         goto error;

    61 

    62     // create the info

    63     if ((info = png_create_info_struct(png)) == NULL)

    64         goto error;

    65 

    66     // setup error trap for the I/O

    67     if (setjmp(png_jmpbuf(png)))

    68         goto error;

    69     

    70     // setup I/O to FILE

    71     png_init_io(png, fp);

    72 

    73     // ok

    74     *png_ptr = png;

    75     *info_ptr = info;

    76 

    77     return 0;

    78 

    79 error:

    80     // cleanup file

    81     if (fp) fclose(fp);

    82 

    83     // cleanup PNG state

    84     png_destroy_read_struct(&png, &info, NULL);

    85 

    86     return -1;

    87 }

    88 

    89 /**

    90  * Open the PNG image, and write out to the cache

    91  */

    92 static int pt_image_update_cache (struct pt_image *img)

    93 {

    94     png_structp png;

    95     png_infop info;

    96 

    97     // open .png

    98     if (pt_image_open_png(img, &png, &info))

    99         return -1;

   100     

   101     // setup error trap

   102     if (setjmp(png_jmpbuf(png)))

   103         goto error;

   104 

   105     // read meta-info

   106     png_read_info(png, info);

   107 

   108     // pass to cache object

   109     if (pt_cache_update_png(img->cache, png, info))

   110         goto error;

   111 

   112     // finish off, ignore trailing data

   113     png_read_end(png, NULL);

   114 

   115     // clean up

   116     png_destroy_read_struct(&png, &info);

   117 

   118     return 0;

   119 

   120 error:

   121     // clean up

   122     png_destroy_read_struct(&png, &info);

   123 

   124     return -1;

   125 }

   126 

   127 int pt_image_open (struct pt_image **img_ptr, struct pt_ctx *ctx, const char *png_path, int cache_mode)

   128 {

   129     struct pt_image *img;

   130 

   131     // XXX: verify that the png_path exists and looks like a PNG file

   132 

   133     // alloc

   134     if (pt_image_new(&img, ctx, png_path))

   135         return -1;

   136 

   137     // open the cache object for this image

   138     if (pt_cache_open(&img->cache, img, mode))

   139         goto error;

   140     

   141     // update if not fresh

   142     if (!pt_cache_fresh(img->cache))

   143         pt_image_update_cache(img);

   144     

   145     // ok, ready for access

   146     *img_ptr = img;

   147 

   148     return 0;

   149 

   150 error:

   151     pt_image_destroy(img);

   152 }