From 6521c4ebce8a9dcbbc0d137d156a1d9f30be1535 Mon Sep 17 00:00:00 2001
From: Takashi Sawanaka <sdottaka@users.sourceforge.net>
Date: Tue, 12 Sep 2023 08:16:03 +0900
Subject: [PATCH] Add diff_2_buffers_xdiff() function

---
 Src/xdiff_gnudiff_compat.cpp | 94 ++++++++++++++++++++++++--------------------
 Src/xdiff_gnudiff_compat.h   |  2 +
 2 files changed, 54 insertions(+), 42 deletions(-)

diff --git a/Src/xdiff_gnudiff_compat.cpp b/Src/xdiff_gnudiff_compat.cpp
index aa0c6da2e..d1f596906 100644
--- a/Src/xdiff_gnudiff_compat.cpp
+++ b/Src/xdiff_gnudiff_compat.cpp
@@ -54,15 +54,57 @@ static int hunk_func(long start_a, long count_a, long start_b, long count_b, voi
 	return 0;
 }
 
-struct change * diff_2_files_xdiff (struct file_data filevec[], int* bin_status, int bMoved_blocks_flag, int* bin_file, unsigned xdl_flags)
+struct change* diff_2_buffers_xdiff(const char* ptr1, size_t size1, const char* ptr2, size_t size2, unsigned xdl_flags)
 {
-	mmfile_t mmfile1 = { 0 }, mmfile2 = { 0 };
 	change *script = nullptr;
 	xdfenv_t xe;
 	xdchange_t *xscr;
 	xpparam_t xpp = { 0 };
 	xdemitconf_t xecfg = { 0 };
 	xdemitcb_t ecb = { 0 };
+	mmfile_t mmfile1 = { const_cast<char*>(ptr1), static_cast<long>(size1) };
+	mmfile_t mmfile2 = { const_cast<char*>(ptr2), static_cast<long>(size2) };
+
+	xpp.flags = xdl_flags;
+	xecfg.hunk_func = hunk_func;
+
+	if (xdl_diff_modified(&mmfile1, &mmfile2, &xpp, &xecfg, &ecb, &xe, &xscr) == 0)
+	{
+		change *prev = nullptr;
+		for (xdchange_t* xcur = xscr; xcur; xcur = xcur->next)
+		{
+			change* e = static_cast<change*>(malloc(sizeof(change)));
+			if (!e)
+				goto abort;
+			if (!script)
+				script = e;
+			e->line0 = xcur->i1;
+			e->line1 = xcur->i2;
+			e->deleted = xcur->chg1;
+			e->inserted = xcur->chg2;
+			e->match0 = -1;
+			e->match1 = -1;
+			e->trivial = static_cast<char>(xcur->ignore);
+			e->link = nullptr;
+			e->ignore = 0;
+			if (prev)
+				prev->link = e;
+			prev = e;
+		}
+
+		xdl_free_script(xscr);
+		xdl_free_env(&xe);
+	}
+
+	return script;
+
+abort:
+	return nullptr;
+}
+
+struct change * diff_2_files_xdiff (struct file_data filevec[], int* bin_status, int bMoved_blocks_flag, int* bin_file, unsigned xdl_flags)
+{
+	change *script = nullptr;
 
 	if (read_files(filevec, no_details_flag & ~ignore_some_changes, bin_file))
 	{
@@ -138,47 +180,15 @@ struct change * diff_2_files_xdiff (struct file_data filevec[], int* bin_status,
 	}
 	else
 	{
-		mmfile1.ptr = const_cast<char*>(filevec[0].prefix_end);
-		mmfile1.size = static_cast<long>(filevec[0].suffix_begin - filevec[0].prefix_end);
-		mmfile2.ptr = const_cast<char*>(filevec[1].prefix_end);
-		mmfile2.size = static_cast<long>(filevec[1].suffix_begin - filevec[1].prefix_end);
-
-		xpp.flags = xdl_flags;
-		xecfg.hunk_func = hunk_func;
-		if (xdl_diff_modified(&mmfile1, &mmfile2, &xpp, &xecfg, &ecb, &xe, &xscr) == 0)
-		{
-			change *prev = nullptr;
-			for (xdchange_t* xcur = xscr; xcur; xcur = xcur->next)
-			{
-				change* e = static_cast<change*>(malloc(sizeof(change)));
-				if (!e)
-					goto abort;
-				if (!script)
-					script = e;
-				e->line0 = xcur->i1;
-				e->line1 = xcur->i2;
-				e->deleted = xcur->chg1;
-				e->inserted = xcur->chg2;
-				e->match0 = -1;
-				e->match1 = -1;
-				e->trivial = static_cast<char>(xcur->ignore);
-				e->link = nullptr;
-				e->ignore = 0;
-				if (prev)
-					prev->link = e;
-				prev = e;
-			}
-
-			if (bMoved_blocks_flag)
-				moved_block_analysis(&script, filevec);
-
-			xdl_free_script(xscr);
-			xdl_free_env(&xe);
-		}
+		script = diff_2_buffers_xdiff(
+			filevec[0].prefix_end,
+			filevec[0].suffix_begin - filevec[0].prefix_end,
+			filevec[1].prefix_end,
+			filevec[1].suffix_begin - filevec[1].prefix_end,
+			xdl_flags);
+		if (bMoved_blocks_flag)
+			moved_block_analysis(&script, filevec);
 	}
 
 	return script;
-
-abort:
-	return nullptr;
 }
diff --git a/Src/xdiff_gnudiff_compat.h b/Src/xdiff_gnudiff_compat.h
index 5dfa542c0..228640da0 100644
--- a/Src/xdiff_gnudiff_compat.h
+++ b/Src/xdiff_gnudiff_compat.h
@@ -1,5 +1,7 @@
 #pragma once
 
 class DiffutilsOptions;
+
 unsigned long make_xdl_flags(const DiffutilsOptions& options);
+struct change* diff_2_buffers_xdiff(const char* ptr1, size_t size1, const char* ptr2, size_t size2, unsigned xdl_flags);
 struct change * diff_2_files_xdiff(struct file_data filevec[], int* bin_status, int bMoved_blocks_flag, int* bin_file, unsigned xdl_flags);
-- 
2.11.0