Implemented CIFF parser

CMakeLists.txt

@@ -3,4 +3,4 @@ project(caff_previewer C)
 
 set(CMAKE_C_STANDARD 11)
 
-add_executable(caff_previewer src/main.c src/magic_memory.c src/magic_memory.h src/libtarga.c src/libtarga.h)
+add_executable(caff_previewer src/main.c src/magic_memory.c src/magic_memory.h src/ciff_tools.h src/ciff_tools.c src/libtarga.c src/libtarga.h)

src/ciff_tools.c

@@ -0,0 +1,83 @@
+//
+// Created by marcsello on 03/11/2020.
+//
+
+#include "ciff_tools.h"
+#include "stdbool.h"
+
+uint8_t contains(const uint8_t* data, uint64_t data_len, uint8_t what) {
+    for (uint64_t i = 0; i < data_len; i++) {
+        if (data[i] == what) {
+            return true;
+        }
+    }
+    return false;
+}
+
+
+uint8_t parse_ciff_from_mem(const uint8_t* data, uint64_t data_len, uint64_t* width, uint64_t* height, uint64_t* pixel_data_starts) {
+    /**
+     * Igazából, ezek többnyire csak változatos ellenőrzések
+     * A függvény validálja a CIFF fájl tartalmát, majd ha ez sikeres volt, akkor megmondja
+     * - A kép dimenzióit
+     * - Hogy hol kezdődik a pixel információ a képben
+     * Az, hogy a kép információt kimásolja-e, az a programozóra van bízva.
+     */
+
+    // Read out the static part of the header (If we have at least header bytes)
+    if (data_len < sizeof(ciff_static_header_t)) {
+        return CIFF_PARSE_HEADER_TOO_SHORT;
+    }
+    ciff_static_header_t* header_info = (struct ciff_static_header_t*)data;
+
+    // Do some preflight checks
+    // Check if the magic is valid...
+    if (header_info->magic != 0x43494646) {
+        return CIFF_PARSE_HEADER_BAD_MAGIC;
+    }
+
+    // Check if the fields in the header seems valid (none of the size fields larger than the whole file)
+    if ((header_info->header_size > data_len) || (header_info->content_size > data_len)) {
+        return CIFF_PARSE_HEADER_LENGTHS_INCORRECT;
+    }
+
+    if ((header_info->header_size+header_info->content_size) > data_len) {
+        return CIFF_PARSE_HEADER_LENGTHS_INCORRECT;
+    }
+
+    // Pre-Calculate some variables and check against those as well
+    uint64_t calculated_pixeldata_length_by_header = header_info->width * header_info->height * 3;
+    if (data_len < calculated_pixeldata_length_by_header) {
+        // The number of pixels defined in the header is larger than the while file
+        return CIFF_PARSE_HEADER_DIMENSIONS_INCORRECT;
+    }
+
+    if (calculated_pixeldata_length_by_header != header_info->content_size) {
+        return CIFF_PARSE_HEADER_DIMENSIONS_INCORRECT;
+    }
+
+    uint64_t calculated_total_length_by_header = calculated_pixeldata_length_by_header + header_info->header_size;
+    if (calculated_total_length_by_header != data_len) {
+        // The header + pixel data is not equals the length of the file
+        return CIFF_PARSE_HEADER_LENGTHS_INCORRECT;
+    }
+
+    // Do some other checks to validate the header
+
+    // According the specifications, the header must contain a newline character after the static fields
+    if (!contains(data+sizeof(struct ciff_static_header_t),header_info->header_size,'\n')) {
+        return CIFF_PARSE_UNKNOWN_ERROR;
+    }
+
+    // According to specifications, the last byte of the header must be a \0
+    if (data[header_info->header_size-1] != 0) {
+        return CIFF_PARSE_UNKNOWN_ERROR;
+    }
+
+    // Set return data
+    *width = header_info->width;
+    *height = header_info->height;
+    *pixel_data_starts = header_info->header_size;
+    return CIFF_PARSE_SUCCESS;
+
+}

src/ciff_tools.h

@@ -0,0 +1,29 @@
+//
+// Created by marcsello on 03/11/2020.
+//
+
+#ifndef CAFF_PREVIEWER_CIFF_TOOLS_H
+#define CAFF_PREVIEWER_CIFF_TOOLS_H
+
+#include <stdint.h>
+#include "magic_memory.h"
+
+#define CIFF_PARSE_UNKNOWN_ERROR 1
+#define CIFF_PARSE_HEADER_LENGTHS_INCORRECT 2
+#define CIFF_PARSE_HEADER_DIMENSIONS_INCORRECT 3
+#define CIFF_PARSE_HEADER_TOO_SHORT 4
+#define CIFF_PARSE_HEADER_BAD_MAGIC 5
+#define CIFF_PARSE_SUCCESS 0
+
+typedef struct __attribute__ ((packed)) ciff_static_header_t {
+    uint32_t magic; // should be equal to 0x43494646
+    uint64_t header_size;
+    uint64_t content_size;
+    uint64_t width;
+    uint64_t height;
+} ciff_static_header_t;
+
+
+uint8_t parse_ciff_from_mem(const uint8_t* data, uint64_t data_len, uint64_t* width, uint64_t* height, uint64_t* pixel_data_starts);
+
+#endif //CAFF_PREVIEWER_CIFF_TOOLS_H