merge(third_party/git): Merge squashed git subtree at v2.23.0 r/373

Merge commit '1b593e1ea4d2af0f6444d9a7788d5d99abd6fde5' as 'third_party/git'

1 files changed, 32 insertions, 0 deletions

diff --git a/third_party/git/compat/memmem.c b/third_party/git/compat/memmem.c
new file mode 100644
index 000000000000..56bcb4277f47
--- /dev/null
+++ b/third_party/git/compat/memmem.c
@@ -0,0 +1,32 @@
+#include "../git-compat-util.h"
+
+void *gitmemmem(const void *haystack, size_t haystack_len,
+                const void *needle, size_t needle_len)
+{
+	const char *begin = haystack;
+	const char *last_possible = begin + haystack_len - needle_len;
+	const char *tail = needle;
+	char point;
+
+	/*
+	 * The first occurrence of the empty string is deemed to occur at
+	 * the beginning of the string.
+	 */
+	if (needle_len == 0)
+		return (void *)begin;
+
+	/*
+	 * Sanity check, otherwise the loop might search through the whole
+	 * memory.
+	 */
+	if (haystack_len < needle_len)
+		return NULL;
+
+	point = *tail++;
+	for (; begin <= last_possible; begin++) {
+		if (*begin == point && !memcmp(begin + 1, tail, needle_len - 1))
+			return (void *)begin;
+	}
+
+	return NULL;
+}