From a2095bb8247067f6ff8dc42fe018ad4829497b2e Mon Sep 17 00:00:00 2001
From: Asheraf <acheraf1998@gmail.com>
Date: Mon, 6 Nov 2023 21:00:15 +0100
Subject: [PATCH] Update grfio to work with big grf's on windows

---
 src/common/grfio.c | 21 ++++++++++-----------
 src/common/utils.c | 18 ++++++++++++++++++
 src/common/utils.h |  2 ++
 3 files changed, 30 insertions(+), 11 deletions(-)

diff --git a/src/common/grfio.c b/src/common/grfio.c
index 12c609ce7f9..42cb65f0374 100644
--- a/src/common/grfio.c
+++ b/src/common/grfio.c
@@ -477,14 +477,14 @@ static void *grfio_reads(const char *fname, int *size)
 		if (in != NULL) {
 			int declen;
 			unsigned char *buf = NULL;
-			fseek(in,0,SEEK_END);
-			declen = (int)ftell(in);
+			hseek(in,0,SEEK_END);
+			declen = (int)htell(in);
 			if (declen == -1) {
 				ShowError("An error occurred in fread grfio_reads, fname=%s \n",fname);
 				fclose(in);
 				return NULL;
 			}
-			fseek(in,0,SEEK_SET);
+			hseek(in,0,SEEK_SET);
 			buf = aMalloc(declen+1); // +1 for resnametable zero-termination
 			buf[declen] = '\0';
 			if (fread(buf, 1, declen, in) != (size_t)declen) {
@@ -517,7 +517,7 @@ static void *grfio_reads(const char *fname, int *size)
 			int fsize = entry->srclen_aligned;
 			unsigned char *buf = aMalloc(fsize);
 			unsigned char *buf2 = NULL;
-			if (fseek(in, entry->srcpos, SEEK_SET) != 0
+			if (hseek(in, entry->srcpos, SEEK_SET) != 0
 			 || fread(buf, 1, fsize, in) != (size_t)fsize) {
 				ShowError("An error occurred in fread in grfio_reads, grfname=%s\n",grfname);
 				aFree(buf);
@@ -609,7 +609,6 @@ static bool grfio_is_full_encrypt(const char *fname)
  */
 static int grfio_entryread(const char *grfname, int gentry)
 {
-	long grf_size;
 	unsigned char grf_header[0x2e] = { 0 };
 	int entry,entrys,ofs,grf_version;
 	unsigned char *grf_filelist;
@@ -623,16 +622,16 @@ static int grfio_entryread(const char *grfname, int gentry)
 	}
 	ShowInfo("GRF data file found: '%s'\n", grfname);
 
-	fseek(fp,0,SEEK_END);
-	grf_size = ftell(fp);
-	fseek(fp,0,SEEK_SET);
+	hseek(fp,0,SEEK_END);
+	int64 grf_size = htell(fp);
+	hseek(fp,0,SEEK_SET);
 
 	if (fread(grf_header,1,0x2e,fp) != 0x2e) {
 		ShowError("Couldn't read all grf_header element of %s \n", grfname);
 		fclose(fp);
 		return 2; // 2:file format error
 	}
-	if (strcmp((const char*)grf_header, "Master of Magic") != 0 || fseek(fp, getlong(grf_header+0x1e), SEEK_CUR) != 0) {
+	if (strcmp((const char*)grf_header, "Master of Magic") != 0 || hseek(fp, getlong(grf_header+0x1e), SEEK_CUR) != 0) {
 		fclose(fp);
 		ShowError("GRF %s read error\n", grfname);
 		return 2; // 2:file format error
@@ -642,7 +641,7 @@ static int grfio_entryread(const char *grfname, int gentry)
 
 	if (grf_version == 0x01) {
 		// ****** Grf version 01xx ******
-		long list_size = grf_size - ftell(fp);
+		int64 list_size = grf_size - htell(fp);
 		grf_filelist = aMalloc(list_size);
 		if (fread(grf_filelist,1,list_size,fp) != (size_t)list_size) {
 			ShowError("Couldn't read all grf_filelist element of %s \n", grfname);
@@ -704,7 +703,7 @@ static int grfio_entryread(const char *grfname, int gentry)
 		rSize = getlong(eheader); // Read Size
 		eSize = getlong(eheader+4); // Extend Size
 
-		if ((long)rSize > grf_size-ftell(fp)) {
+		if ((long)rSize > grf_size-htell(fp)) {
 			fclose(fp);
 			ShowError("Illegal data format: GRF compress entry size\n");
 			return 4;
diff --git a/src/common/utils.c b/src/common/utils.c
index 18adcd0d368..a977481d89a 100644
--- a/src/common/utils.c
+++ b/src/common/utils.c
@@ -584,6 +584,24 @@ size_t hwrite(const void *ptr, size_t size, size_t count, FILE *stream)
 	return fwrite(ptr, size, count, stream);
 }
 
+int64 htell(FILE *stream)
+{
+#ifdef WIN32
+	return _ftelli64(stream);
+#else
+	return ftell(stream);
+#endif
+}
+
+int hseek(FILE *stream, int64 offset, int origin)
+{
+#ifdef WIN32
+	return _fseeki64(stream, offset, origin);
+#else
+	return fseek(stream, offset, origin);
+#endif
+}
+
 void HCache_defaults(void)
 {
 	HCache = &HCache_s;
diff --git a/src/common/utils.h b/src/common/utils.h
index df4ec589717..c4df246d741 100644
--- a/src/common/utils.h
+++ b/src/common/utils.h
@@ -81,6 +81,8 @@ extern float GetFloat(const unsigned char* buf);
 
 size_t hread(void * ptr, size_t size, size_t count, FILE * stream);
 size_t hwrite(const void * ptr, size_t size, size_t count, FILE * stream);
+int64 htell(FILE *stream);
+int hseek(FILE *stream, int64 offset, int origin);
 #endif // HERCULES_CORE
 
 #ifdef WIN32