Bump minor version

CMakeLists.txt

@@ -1,6 +1,6 @@
 cmake_minimum_required (VERSION 3.0)
 cmake_policy(VERSION 3.0)
-project (mazemaker VERSION 1.1)
+project (mazemaker VERSION 1.2)
 
 SET(EXEC_INSTALL_PREFIX ${CMAKE_INSTALL_PREFIX} CACHE PATH "Installation prefix for executables and object code libraries" FORCE)
 SET(INCLUDE_INSTALL_DIR ${CMAKE_INSTALL_PREFIX}/include CACHE PATH "Installation prefix for C header files" FORCE)

include/mazemaker.h

@@ -25,5 +25,6 @@ typedef enum {
 void mazemaker_generate_maze(int width, int height, mazegrid_t* result);
 void mazemaker_free_maze(mazegrid_t* maze);
 int mazemaker_maze_to_png(mazegrid_t const* maze, char const* filename);
+int mazemaker_maze_to_png_mem(mazegrid_t const* maze, size_t* len, uint8_t** buf);
 
 #endif // !def(_MAZEMAKER_H)

lib/image.c

@@ -16,6 +16,11 @@ typedef struct {
     int w, h;
 } img_data_t;
 
+struct mem_encode {
+    uint8_t *buffer;
+    size_t size;
+};
+
 static void setPixel(img_data_t* img, int x, int y, char v) {
     //fprintf(stderr, "setPixel(img, %d, %d, %d)\n", x, y, v);
     assert((x < img->w) && (y < img->h));
@@ -150,3 +155,76 @@ exit:
     if (img != NULL) freeImageData(img);
     return code;
 }
+
+static void append_png_data(png_structp png_ptr, png_bytep data, png_size_t length) {
+    struct mem_encode* p = (struct mem_encode*)png_get_io_ptr(png_ptr);
+    size_t nsize = p->size + length;
+    if (p->buffer) 
+        p->buffer = realloc(p->buffer, nsize);
+    else
+        p->buffer = malloc(nsize);
+    if (!p->buffer)
+        png_error(png_ptr, "Write error");
+    memcpy(p->buffer + p->size, data, length);
+    p->size += length;
+}
+
+static void png_no_flush(png_structp png_ptr) {
+    /* noop */
+}
+
+int mazemaker_maze_to_png_mem(mazegrid_t const* g, size_t* len, uint8_t** buf) {
+    int code = 1;
+    img_data_t* img = gridToImageData(g);
+    png_structp png_ptr = NULL;
+    png_infop info_ptr  = NULL;
+    struct mem_encode menc = { .buffer = NULL, .size = 0 };
+    
+    png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
+    if (png_ptr == NULL) {
+        fprintf(stderr, "Could not allocate PNG write struct.\n");
+        code = 0;
+        goto exit;
+    }
+
+    info_ptr = png_create_info_struct(png_ptr);
+    if (info_ptr == NULL) {
+        fprintf(stderr, "Could not allocate PNG info struct.\n");
+        code = 0;
+        goto exit;
+    }
+
+    if (setjmp(png_jmpbuf(png_ptr))) {
+        fprintf(stderr, "Error during PNG creation.\n");
+        code = 0;
+        goto exit;
+    }
+
+    png_set_write_fn(png_ptr, &menc, append_png_data, png_no_flush);
+
+    // Write header (8 bit color depth)
+    png_set_IHDR(png_ptr, info_ptr, img->w, img->h,
+                 8, PNG_COLOR_TYPE_RGB, PNG_INTERLACE_NONE,
+                 PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
+
+    png_write_info(png_ptr, info_ptr);
+
+    writeImageData(img, png_ptr);
+
+    png_write_end(png_ptr, NULL);
+
+    *len = menc.size;
+    *buf = menc.buffer;
+
+exit:
+    if (!code && menc.buffer) {
+        free(menc.buffer);
+    }
+	if (info_ptr != NULL) {
+        png_free_data(png_ptr, info_ptr, PNG_FREE_ALL, -1);
+        png_destroy_info_struct(png_ptr, &info_ptr);
+    }
+    if (png_ptr != NULL) png_destroy_write_struct(&png_ptr, (png_infopp)NULL);
+    if (img != NULL) freeImageData(img);
+    return code;
+}