建档

Library/SDL2_image-2.5.2/IMG_qoi.c

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+/*
+  SDL_image:  An example image loading library for use with SDL
+  Copyright (C) 1997-2022 Sam Lantinga <slouken@libsdl.org>
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+
+/* This file use QOI library:
+ * https://github.com/phoboslab/qoi
+ */
+
+#include "SDL_image.h"
+#include <limits.h> /* for INT_MAX */
+
+#ifdef LOAD_QOI
+
+/* SDL < 2.0.12 compatibility */
+#ifndef SDL_zeroa
+#define SDL_zeroa(x) SDL_memset((x), 0, sizeof((x)))
+#endif
+
+#define QOI_MALLOC(sz) SDL_malloc(sz)
+#define QOI_FREE(p)    SDL_free(p)
+#define QOI_ZEROARR(a) SDL_zeroa(a)
+
+#define QOI_NO_STDIO
+#define QOI_IMPLEMENTATION
+#include "qoi.h"
+
+/* See if an image is contained in a data source */
+int IMG_isQOI(SDL_RWops *src)
+{
+    Sint64 start;
+    int is_QOI;
+    char magic[4];
+
+    if ( !src )
+        return 0;
+    start = SDL_RWtell(src);
+    is_QOI = 0;
+    if ( SDL_RWread(src, magic, sizeof(magic), 1) ) {
+        if ( SDL_strncmp(magic, "qoif", 4) == 0 ) {
+            is_QOI = 1;
+        }
+    }
+    SDL_RWseek(src, start, RW_SEEK_SET);
+    return(is_QOI);
+}
+
+/* Load a QOI type image from an SDL datasource */
+SDL_Surface *IMG_LoadQOI_RW(SDL_RWops *src)
+{
+    void *data;
+    size_t size;
+    void *pixel_data;
+    qoi_desc image_info;
+    SDL_Surface *surface = NULL;
+
+    data = (void *)SDL_LoadFile_RW(src, &size, SDL_FALSE);
+    if ( !data ) {
+        return NULL;
+    }
+    if ( size > INT_MAX ) {
+        SDL_free(data);
+        IMG_SetError("QOI image is too big.");
+        return NULL;
+    }
+
+    pixel_data = qoi_decode(data, (int)size, &image_info, 4);
+    /* pixel_data is in R,G,B,A order regardless of endianness */
+    SDL_free(data);
+    if ( !pixel_data ) {
+        IMG_SetError("Couldn't parse QOI image");
+        return NULL;
+    }
+
+    surface = SDL_CreateRGBSurfaceWithFormatFrom(pixel_data,
+                                                 image_info.width,
+                                                 image_info.height,
+                                                 32,
+					         (image_info.width * 4),
+                                                 SDL_PIXELFORMAT_RGBA32);
+    if ( !surface ) {
+        SDL_free(pixel_data);
+        IMG_SetError("Couldn't create SDL_Surface");
+        return NULL;
+    }
+
+    /* Let SDL manage the memory now */
+    surface->flags &= ~SDL_PREALLOC;
+
+    return surface;
+}
+
+#else
+#if _MSC_VER >= 1300
+#pragma warning(disable : 4100) /* warning C4100: 'op' : unreferenced formal parameter */
+#endif
+
+/* See if an image is contained in a data source */
+int IMG_isQOI(SDL_RWops *src)
+{
+    return(0);
+}
+
+/* Load a QOI type image from an SDL datasource */
+SDL_Surface *IMG_LoadQOI_RW(SDL_RWops *src)
+{
+    return(NULL);
+}
+
+#endif /* LOAD_QOI */