initial support for Exif writer

Is not much powerful right now - nothing interesting so far but it will
allow eventually adding some metadata not available in other formats
(SPIFF is effectively dead, JFIF and Adobe contains almost nothing).

Author: MartinPulec

libgpujpeg/gpujpeg_encoder.h

@@ -195,6 +195,7 @@ enum gpujpeg_header_type {
         GPUJPEG_HEADER_JFIF    = 1<<0,
         GPUJPEG_HEADER_SPIFF   = 1<<1,
         GPUJPEG_HEADER_ADOBE   = 1<<2, ///< Adobe APP8 header
+        GPUJPEG_HEADER_EXIF    = 1<<3,
 };
 
 /**
@@ -227,6 +228,7 @@ gpujpeg_encoder_suggest_restart_interval(const struct gpujpeg_image_parameters*
 /// @defgroup enc_hdr_types
 /// @{
 #define GPUJPEG_ENC_HDR_VAL_JFIF     "JFIF"
+#define GPUJPEG_ENC_HDR_VAL_EXIF     "Exif"
 #define GPUJPEG_ENC_HDR_VAL_ADOBE    "Adobe"
 #define GPUJPEG_ENC_HDR_VAL_SPIFF    "SPIFF"
 /// @}

src/compat/endian.h

@@ -0,0 +1,106 @@
+/**
+ * @file   compat/endian.h
+ * @author Martin Pulec     <[email protected]>
+ *
+ * endian.h compat macro for macOS, Windows
+ *
+ * It will be likely possible to remove later, at least for macOS, because it is
+ * required by POSIX 2024.
+ */
+/*
+ * Copyright (c) 2025 CESNET, zájmové sdružení právnických osob
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, is permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * 3. Neither the name of CESNET nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software without
+ *    specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING,
+ * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
+ * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
+ * EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
+ * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+ * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
+ * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef COMPAT_ENDIAN_H_A5D7C443_895D_465E_A46D_BF5E6DAA833F
+#define COMPAT_ENDIAN_H_A5D7C443_895D_465E_A46D_BF5E6DAA833F
+
+#ifdef __APPLE__
+        // https://github.com/zeromq/zmqpp/issues/164#issuecomment-246346344
+        #include <libkern/OSByteOrder.h>
+        #ifndef be16toh
+                #define be16toh(x) OSSwapBigToHostInt16(x)
+                #define be32toh(x) OSSwapBigToHostInt32(x)
+                #define be64toh(x) OSSwapBigToHostInt64(x)
+
+                #define htobe16(x) OSSwapHostToBigInt16(x)
+                #define htobe32(x) OSSwapHostToBigInt32(x)
+                #define htobe64(x) OSSwapHostToBigInt64(x)
+
+                #define htole16(x) OSSwapHostToLittleInt16(x)
+                #define htole32(x) OSSwapHostToLittleInt32(x)
+                #define htole64(x) OSSwapHostToLittleInt64(x)
+
+                #define le16toh(x) OSSwapLittleToHostInt16(x)
+                #define le32toh(x) OSSwapLittleToHostInt32(x)
+                #define le64toh(x) OSSwapLittleToHostInt64(x)
+        #endif
+        // BYTE_ORDER, LITTLE_ENDIAN, BIG_ENDIAN
+        #include <machine/endian.h>
+
+#elif defined _WIN32
+        // little endian archs
+        #if defined(_M_AMD64) || defined(_M_IX86) || defined(_M_ARM) || \
+            defined(_M_ARM64) || \
+            (defined(__BYTE_ORDER__) && \
+             __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__)
+                #include <stdlib.h>
+                #ifndef be16toh
+                        #define be16toh(x) _byteswap_ushort(x)
+                        #define be32toh(x) _byteswap_ulong(x)
+                        #define be64toh(x) _byteswap_uint64(x)
+
+                        #define htobe16(x) _byteswap_ushort(x)
+                        #define htobe32(x) _byteswap_ulong(x)
+                        #define htobe64(x) _byteswap_uint64(x)
+
+                        #define htole16(x) (x)
+                        #define htole32(x) (x)
+                        #define htole64(x) (x)
+
+                        #define le16toh(x) (x)
+                        #define le32toh(x) (x)
+                        #define le64toh(x) (x)
+                #endif
+                #ifndef BYTE_ORDER
+                        #define LITTLE_ENDIAN 1234
+                        #define BIG_ENDIAN    4321
+                        #define BYTE_ORDER    LITTLE_ENDIAN
+                #endif
+        #else
+                #error "Unrecognized Win32 configuration (big-endian or unhandled)"
+        #endif
+
+#else
+        #include <endian.h>
+#endif
+
+#endif // defined COMPAT_ENDIAN_H_A5D7C443_895D_465E_A46D_BF5E6DAA833F

src/gpujpeg_encoder.c

@@ -723,6 +723,8 @@ gpujpeg_encoder_set_option(struct gpujpeg_encoder* encoder, const char *opt, con
     if ( strcmp(opt, GPUJPEG_ENC_OPT_HDR) == 0 ) {
         if (strcasecmp(val, GPUJPEG_ENC_HDR_VAL_JFIF) == 0) {
             encoder->header_type = GPUJPEG_HEADER_JFIF;
+        } else if (strcasecmp(val, GPUJPEG_ENC_HDR_VAL_EXIF) == 0) {
+            encoder->header_type = GPUJPEG_HEADER_EXIF;
         } else if (strcasecmp(val, GPUJPEG_ENC_HDR_VAL_ADOBE) == 0) {
             encoder->header_type = GPUJPEG_HEADER_ADOBE;
         } else if (strcasecmp(val, GPUJPEG_ENC_HDR_VAL_SPIFF) == 0) {
@@ -746,8 +748,8 @@ GPUJPEG_API void
 gpujpeg_encoder_print_options() {
     printf("\t" GPUJPEG_ENC_OPT_OUT "=[" GPUJPEG_ENC_OUT_VAL_PAGEABLE "|" GPUJPEG_ENC_OUT_VAL_PINNED
            "] - compressed data buffer allocation property\n");
-    printf("\t" GPUJPEG_ENC_OPT_HDR "=[" GPUJPEG_ENC_HDR_VAL_JFIF "|" GPUJPEG_ENC_HDR_VAL_ADOBE "|" GPUJPEG_ENC_HDR_VAL_SPIFF
-           "] - output JPEG header\n");
+    printf("\t" GPUJPEG_ENC_OPT_HDR "=[" GPUJPEG_ENC_HDR_VAL_JFIF "|" GPUJPEG_ENC_HDR_VAL_ADOBE
+           "|" GPUJPEG_ENC_HDR_VAL_EXIF "|" GPUJPEG_ENC_HDR_VAL_SPIFF "] - output JPEG header\n");
     printf("\t" GPUJPEG_ENC_OPT_FLIPPED_BOOL "=[" GPUJPEG_VAL_FALSE "|" GPUJPEG_VAL_TRUE
            "] - whether is the input image should be vertically flipped (prior encode)\n");
     printf("\t" GPUJPEG_ENC_OPT_CHANNEL_REMAP "=XYZ[W] - input channel mapping, eg. '210F' for GBRX,\n"