retocat gif.cpp

source/gif.h

@@ -1,85 +1,102 @@
 #pragma once
 
-#include <cstdint> // Para uint8_t, uint16_t, uint32_t
-#include <cstring> // Para memcpy
+#include <cstdint>  // for uint8_t, uint16_t, uint32_t
+#include <vector>   // for vector
 
-#define EXTENSION_INTRODUCER 0x21
-#define IMAGE_DESCRIPTOR 0x2C
-#define TRAILER 0x3B
-#define GRAPHIC_CONTROL 0xF9
-#define APPLICATION_EXTENSION 0xFF
-#define COMMENT_EXTENSION 0xFE
-#define PLAINTEXT_EXTENSION 0x01
-
-#define READ(dst, size)        \
-    memcpy(dst, buffer, size); \
-    buffer += size
-
-struct ScreenDescriptor
+namespace GIF
 {
-    uint16_t width;
-    uint16_t height;
-    uint8_t fields;
-    uint8_t background_color_index;
-    uint8_t pixel_aspect_ratio;
-};
 
-struct RGB
-{
-    uint8_t r, g, b;
-};
+    // Constantes definidas con constexpr, en lugar de macros
+    constexpr uint8_t EXTENSION_INTRODUCER = 0x21;
+    constexpr uint8_t IMAGE_DESCRIPTOR = 0x2C;
+    constexpr uint8_t TRAILER = 0x3B;
+    constexpr uint8_t GRAPHIC_CONTROL = 0xF9;
+    constexpr uint8_t APPLICATION_EXTENSION = 0xFF;
+    constexpr uint8_t COMMENT_EXTENSION = 0xFE;
+    constexpr uint8_t PLAINTEXT_EXTENSION = 0x01;
 
-struct ImageDescriptor
-{
-    uint16_t image_left_position;
-    uint16_t image_top_position;
-    uint16_t image_width;
-    uint16_t image_height;
-    uint8_t fields;
-};
+#pragma pack(push, 1)
+    struct ScreenDescriptor
+    {
+        uint16_t width;
+        uint16_t height;
+        uint8_t fields;
+        uint8_t background_color_index;
+        uint8_t pixel_aspect_ratio;
+    };
 
-struct DictionaryEntry
-{
-    uint8_t byte;
-    int prev;
-    int len;
-};
+    struct RGB
+    {
+        uint8_t r, g, b;
+    };
 
-struct Extension
-{
-    uint8_t extension_code;
-    uint8_t block_size;
-};
+    struct ImageDescriptor
+    {
+        uint16_t image_left_position;
+        uint16_t image_top_position;
+        uint16_t image_width;
+        uint16_t image_height;
+        uint8_t fields;
+    };
+#pragma pack(pop)
 
-struct GraphicControlExtension
-{
-    uint8_t fields;
-    uint16_t delay_time;
-    uint8_t transparent_color_index;
-};
+    struct DictionaryEntry
+    {
+        uint8_t byte;
+        int prev;
+        int len;
+    };
 
-struct ApplicationExtension
-{
-    uint8_t application_id[8];
-    uint8_t version[3];
-};
+    struct Extension
+    {
+        uint8_t extension_code;
+        uint8_t block_size;
+    };
 
-struct PlaintextExtension
-{
-    uint16_t left, top, width, height;
-    uint8_t cell_width, cell_height;
-    uint8_t foreground_color, background_color;
-};
+    struct GraphicControlExtension
+    {
+        uint8_t fields;
+        uint16_t delay_time;
+        uint8_t transparent_color_index;
+    };
 
-class Gif
-{
-public:
-    void uncompress(int code_length, const uint8_t *input, int input_length, uint8_t *out);
-    uint32_t *LoadPalette(uint8_t *buffer);
-    uint8_t *LoadGif(uint8_t *buffer, uint16_t *w, uint16_t *h);
+    struct ApplicationExtension
+    {
+        uint8_t application_id[8];
+        uint8_t version[3];
+    };
 
-private:
-    int read_sub_blocks(uint8_t *buffer, uint8_t **data);
-    uint8_t *process_image_descriptor(uint8_t *buffer, RGB *gct, int gct_size, int resolution_bits);
-    uint8_t *process_gif_stream(uint8_t *buffer, uint16_t *w, uint16_t *h);
-};
+    struct PlaintextExtension
+    {
+        uint16_t left, top, width, height;
+        uint8_t cell_width, cell_height;
+        uint8_t foreground_color, background_color;
+    };
+
+    class Gif
+    {
+    public:
+        // Descompone (uncompress) el bloque comprimido usando LZW.
+        // Este método puede lanzar std::runtime_error en caso de error.
+        void decompress(int code_length, const uint8_t *input, int input_length, uint8_t *out);
+
+        // Carga la paleta (global color table) a partir de un buffer,
+        // retornándola en un vector de uint32_t (cada color se compone de R, G, B).
+        std::vector<uint32_t> loadPalette(const uint8_t *buffer);
+
+        // Carga el stream GIF; devuelve un vector con los datos de imagen sin comprimir y
+        // asigna el ancho y alto mediante referencias.
+        std::vector<uint8_t> loadGif(const uint8_t *buffer, uint16_t &w, uint16_t &h);
+
+    private:
+        // Lee los sub-bloques de datos y los acumula en un std::vector<uint8_t>.
+        std::vector<uint8_t> readSubBlocks(const uint8_t *&buffer);
+
+        // Procesa el Image Descriptor y retorna el vector de datos sin comprimir.
+        std::vector<uint8_t> processImageDescriptor(const uint8_t *&buffer, const std::vector<RGB> &gct, int resolution_bits);
+
+        // Procesa el stream completo del GIF y devuelve los datos sin comprimir.
+        std::vector<uint8_t> processGifStream(const uint8_t *buffer, uint16_t &w, uint16_t &h);
+    };
+
+} // namespace GIF