From c31ae564014c08378563171f22421de08ba83bc2 Mon Sep 17 00:00:00 2001
From: Romain Vimont <rom@rom1v.com>
Date: Tue, 26 Aug 2014 18:42:51 +0200
Subject: [PATCH] Add a flag to use numeric sort

Add an option --numeric-sort (-N) to compare filepaths according to
string numerical value.

Without this option, the files are transferred in that order:
  file1
  file10
  file11
  file100
  file101
  file19
  file2
  file20

With the option enabled:
  file1
  file2
  file10
  file11
  file19
  file20
  file100
  file101
---
 flist.c   | 38 +++++++++++++++++++++++++++++++++++++-
 options.c |  2 ++
 2 files changed, 39 insertions(+), 1 deletion(-)

diff --git a/flist.c b/flist.c
index c24672e..b5b17d6 100644
--- a/flist.c
+++ b/flist.c
@@ -38,6 +38,7 @@ extern int ignore_errors;
 extern int numeric_ids;
 extern int recurse;
 extern int use_qsort;
+extern int numeric_sort;
 extern int xfer_dirs;
 extern int filesfrom_fd;
 extern int one_file_system;
@@ -3011,6 +3012,11 @@ enum fnc_type { t_PATH, t_ITEM };
 
 static int found_prefix;
 
+static inline must_numcompare(const char c1, const char c2)
+{
+	return numeric_sort && isdigit(c1) && isdigit(c2);
+}
+
 /* Compare the names of two file_struct entities, similar to how strcmp()
  * would do if it were operating on the joined strings.
  *
@@ -3030,6 +3036,7 @@ int f_name_cmp(const struct file_struct *f1, const struct file_struct *f2)
 {
 	int dif;
 	const uchar *c1, *c2;
+	int dcmp; /* digits compare result */
 	enum fnc_state state1, state2;
 	enum fnc_type type1, type2;
 	enum fnc_type t_path = protocol_version >= 29 ? t_PATH : t_ITEM;
@@ -3140,7 +3147,36 @@ int f_name_cmp(const struct file_struct *f1, const struct file_struct *f2)
 			if (type1 != type2)
 				return type1 == t_PATH ? 1 : -1;
 		}
-	} while ((dif = (int)*c1++ - (int)*c2++) == 0);
+		if (must_numcompare(*c1, *c2)) {
+			dcmp = 0;
+			do {
+				if (!dcmp) {
+					if (*c1 < *c2)
+						dcmp = -1;
+					else if (*c1 > *c2)
+						dcmp = 1;
+				}
+				c1++;
+				c2++;
+			} while (isdigit(*c1) && isdigit(*c2));
+
+			if (isdigit(*c1))
+				/* more digits in f1 */
+				return 1;
+
+			if (isdigit(*c2))
+				/* more digits in f2 */
+				return -1;
+
+			if (dcmp)
+				/* same number of digits, but different numbers */
+				return dcmp;
+
+		} else {
+			c1++;
+			c2++;
+		}
+	} while (must_numcompare(*c1, *c2) || (dif = (int)*c1 - (int)*c2) == 0);
 
 	return dif;
 }
diff --git a/options.c b/options.c
index 62dfe4f..86681ab 100644
--- a/options.c
+++ b/options.c
@@ -92,6 +92,7 @@ int force_delete = 0;
 int io_timeout = 0;
 int prune_empty_dirs = 0;
 int use_qsort = 0;
+int numeric_sort = 0;
 char *files_from = NULL;
 int filesfrom_fd = -1;
 char *filesfrom_host = NULL;
@@ -1029,6 +1030,7 @@ static struct poptOption long_options[] = {
   {"no-8-bit-output",  0,  POPT_ARG_VAL,    &allow_8bit_chars, 0, 0, 0 },
   {"no-8",             0,  POPT_ARG_VAL,    &allow_8bit_chars, 0, 0, 0 },
   {"qsort",            0,  POPT_ARG_NONE,   &use_qsort, 0, 0, 0 },
+  {"numeric-sort",    'N', POPT_ARG_NONE,   &numeric_sort, 0, 0, 0 },
   {"address",          0,  POPT_ARG_STRING, &bind_address, 0, 0, 0 },
   {"port",             0,  POPT_ARG_INT,    &rsync_port, 0, 0, 0 },
   {"sockopts",         0,  POPT_ARG_STRING, &sockopts, 0, 0, 0 },
-- 
1.9.1