--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/lib/tile.c	Thu Dec 31 14:01:37 2009 +0200
@@ -0,0 +1,135 @@
+#include "tile.h"
+#include "error.h"
+#include "shared/log.h" // only FATAL
+
+#include <stdlib.h>
+
+static void pt_tile_init (struct pt_tile *tile, const struct pt_tile_info *info, enum pt_tile_output out_type)
+{
+    memset(tile, 0, sizeof(*tile));
+    
+    // init
+    tile->info = *info;
+    tile->out_type = out_type;
+}
+
+
+int pt_tile_init_file (struct pt_tile *tile, const struct pt_tile_info *info, FILE *out)
+{
+    pt_tile_init(tile, info, PT_TILE_OUT_FILE);
+
+    tile->out.file = out;
+
+    return 0;
+}
+
+int pt_tile_init_mem (struct pt_tile *tile, const struct pt_tile_info *info)
+{
+    pt_tile_init(tile, info, PT_TILE_OUT_MEM);
+    
+    // init buffer
+    if ((tile->out.mem.base = malloc(PT_TILE_BUF_SIZE)) == NULL)
+        RETURN_ERROR(PT_ERR_MEM);
+
+    tile->out.mem.len = PT_TILE_BUF_SIZE;
+    tile->out.mem.off = 0;
+
+    return 0;
+}
+
+static void pt_tile_mem_write (png_structp png, png_bytep data, png_size_t length)
+{
+    struct pt_tile_mem *buf = png_get_io_ptr(png);
+    size_t buf_len = buf->len;
+
+    // grow?
+    while (buf->off + length > buf_len)
+        buf_len *= 2;
+
+    if (buf_len != buf->len) {
+        char *tmp;
+
+        if ((tmp = realloc(buf->base, buf_len)) == NULL)
+            png_error(png, "pt_tile_buf_write - realloc failed");
+
+        buf->base = tmp;
+        buf->len = buf_len;
+    }
+
+    // copy
+    memcpy(buf->base + buf->off, data, length);
+
+    buf->off += length;
+}
+
+static void pt_tile_mem_flush (png_structp png_ptr)
+{
+    // no-op
+}
+
+
+int pt_tile_render (struct pt_tile *tile, struct pt_cache *cache)
+{
+    png_structp png = NULL;
+    png_infop info = NULL;
+    int err = 0;
+
+    // open PNG writer
+    if ((png = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL)) == NULL)
+        JUMP_SET_ERROR(err, PT_ERR_PNG_CREATE);
+    
+    if ((info = png_create_info_struct(png)) == NULL)
+        JUMP_SET_ERROR(err, PT_ERR_PNG_CREATE);
+
+    // libpng error trap
+    if (setjmp(png_jmpbuf(png)))
+        JUMP_SET_ERROR(err, PT_ERR_PNG);
+ 
+    // setup output I/O
+    switch (tile->out_type) {
+        case PT_TILE_OUT_FILE:
+            // use default FILE* operation
+            png_init_io(png, tile->out.file);
+
+            break;
+
+        case PT_TILE_OUT_MEM:
+            // use pt_tile_mem struct via pt_tile_mem_* callbacks
+            png_set_write_fn(png, &tile->out.mem, pt_tile_mem_write, pt_tile_mem_flush);
+
+            break;
+
+        default:
+            FATAL("tile->out_type: %d", tile->out_type);
+    }
+
+    // render tile
+    if ((err = pt_cache_tile_png(cache, png, info, &tile->info)))
+        JUMP_ERROR(err);
+
+    // done
+    png_write_end(png, info);
+
+error:
+    // cleanup
+    png_destroy_write_struct(&png, &info);
+
+    return err;
+}
+
+void pt_tile_abort (struct pt_tile *tile)
+{
+    // cleanup
+    switch (tile->out_type) {
+        case PT_TILE_OUT_FILE:
+            // no-op
+            break;
+
+        case PT_TILE_OUT_MEM:
+            // drop buffer
+            free(tile->out.mem.base);
+
+            break;
+    }
+}
+