From 2888453617113c1e6e760da0e2b7f14228d5f64c Mon Sep 17 00:00:00 2001
From: Matthew Fernandez <matthew.fernandez@gmail.com>
Date: Thu, 22 Sep 2022 21:19:33 -0700
Subject: [PATCH] add an abstraction for checking string prefixes

---
 lib/cgraph/CMakeLists.txt         |  1 +
 lib/cgraph/Makefile.am            |  3 ++-
 lib/cgraph/cgraph.vcxproj         |  1 +
 lib/cgraph/cgraph.vcxproj.filters |  3 +++
 lib/cgraph/startswith.h           | 14 ++++++++++++++
 5 files changed, 21 insertions(+), 1 deletion(-)
 create mode 100644 lib/cgraph/startswith.h

diff --git a/lib/cgraph/CMakeLists.txt b/lib/cgraph/CMakeLists.txt
index ac14bc490..7255b88a7 100644
--- a/lib/cgraph/CMakeLists.txt
+++ b/lib/cgraph/CMakeLists.txt
@@ -21,6 +21,7 @@ add_library(cgraph SHARED
   likely.h
   prisize_t.h
   stack.h
+  startswith.h
   strcasecmp.h
   strview.h
   tokenize.h
diff --git a/lib/cgraph/Makefile.am b/lib/cgraph/Makefile.am
index 1a58bda7f..ef8b92b91 100644
--- a/lib/cgraph/Makefile.am
+++ b/lib/cgraph/Makefile.am
@@ -10,7 +10,8 @@ endif
 
 pkginclude_HEADERS = cgraph.h
 noinst_HEADERS = agxbuf.h alloc.h bitarray.h cghdr.h exit.h itos.h likely.h \
-	prisize_t.h stack.h strcasecmp.h strview.h tokenize.h unreachable.h unused.h
+	prisize_t.h stack.h startswith.h strcasecmp.h strview.h tokenize.h \
+	unreachable.h unused.h
 noinst_LTLIBRARIES = libcgraph_C.la
 lib_LTLIBRARIES = libcgraph.la
 pkgconfig_DATA = libcgraph.pc
diff --git a/lib/cgraph/cgraph.vcxproj b/lib/cgraph/cgraph.vcxproj
index 4fd19c689..ee95eeb2a 100644
--- a/lib/cgraph/cgraph.vcxproj
+++ b/lib/cgraph/cgraph.vcxproj
@@ -107,6 +107,7 @@ win_flex -oscan.c scan.l</Command>
     <ClInclude Include="likely.h" />
     <ClInclude Include="prisize_t.h" />
     <ClInclude Include="stack.h" />
+    <ClInclude Include="startswith.h" />
     <ClInclude Include="strcasecmp.h" />
     <ClInclude Include="strview.h" />
     <ClInclude Include="tokenize.h" />
diff --git a/lib/cgraph/cgraph.vcxproj.filters b/lib/cgraph/cgraph.vcxproj.filters
index 83633d7db..ee2d35f65 100644
--- a/lib/cgraph/cgraph.vcxproj.filters
+++ b/lib/cgraph/cgraph.vcxproj.filters
@@ -45,6 +45,9 @@
     <ClInclude Include="stack.h">
       <Filter>Header Files</Filter>
     </ClInclude>
+    <ClInclude Include="startswith.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
     <ClInclude Include="strcasecmp.h">
       <Filter>Header Files</Filter>
     </ClInclude>
diff --git a/lib/cgraph/startswith.h b/lib/cgraph/startswith.h
new file mode 100644
index 000000000..e4e66f924
--- /dev/null
+++ b/lib/cgraph/startswith.h
@@ -0,0 +1,14 @@
+#pragma once
+
+#include <assert.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include <string.h>
+
+/// does the string \p s begin with the string \p prefix?
+static inline bool startswith(const char *s, const char *prefix) {
+  assert(s != NULL);
+  assert(prefix != NULL);
+
+  return strncmp(s, prefix, strlen(prefix)) == 0;
+}
-- 
2.40.0