From 53ba9c800a5853eb2ff027685657cdf85b17109a Mon Sep 17 00:00:00 2001
From: Chloe Kudryavtsev <code@toast.bunkerlabs.net>
Date: Sat, 6 May 2023 22:13:53 -0400
Subject: [PATCH] Add get/opt cbytes

Like getcstring, but operates on a byteview.
When writing bindings (i.e what capi.c is primarily used for), it's
common to want to accept a buffer *or* a string rather than just
a string.
For this, a byteview is perfect (and why not accept keywords while
you're at it?).
However, there's no built-in function for getting a cstring out of
a byteview, this adds one.
This also reformulates getcstring to be an edge-case of getcbytes
(simply adding an explicit check for stringness).
---
 src/core/capi.c     | 22 ++++++++++++++++++----
 src/include/janet.h |  2 ++
 2 files changed, 20 insertions(+), 4 deletions(-)

diff --git a/src/core/capi.c b/src/core/capi.c
index 0b918e0e..4972d8fb 100644
--- a/src/core/capi.c
+++ b/src/core/capi.c
@@ -209,14 +209,28 @@ const char *janet_optcstring(const Janet *argv, int32_t argc, int32_t n, const c
 #undef DEFINE_OPTLEN
 
 const char *janet_getcstring(const Janet *argv, int32_t n) {
-    const uint8_t *jstr = janet_getstring(argv, n);
-    const char *cstr = (const char *)jstr;
-    if (strlen(cstr) != (size_t) janet_string_length(jstr)) {
-        janet_panic("string contains embedded 0s");
+    if (!janet_checktype(argv[n], JANET_STRING)) {
+        janet_panic_type(argv[n], n, JANET_TFLAG_STRING);
+    }
+    return janet_getcbytes(argv, n);
+}
+
+const char* janet_getcbytes(const Janet *argv, int32_t n) {
+    JanetByteView view = janet_getbytes(argv, n);
+    const char *cstr = (const char *)view.bytes;
+    if (strlen(cstr) != (size_t) view.len) {
+        janet_panic("bytes contain embedded 0s");
     }
     return cstr;
 }
 
+const char *janet_optcbytes(const Janet *argv, int32_t argc, int32_t n, const char *dflt) {
+    if (n >= argc || janet_checktype(argv[n], JANET_NIL)) {
+        return dflt;
+    }
+    return janet_getcbytes(argv, n);
+}
+
 int32_t janet_getnat(const Janet *argv, int32_t n) {
     Janet x = argv[n];
     if (!janet_checkint(x)) goto bad;
diff --git a/src/include/janet.h b/src/include/janet.h
index a6d0d901..88cda071 100644
--- a/src/include/janet.h
+++ b/src/include/janet.h
@@ -1968,6 +1968,7 @@ JANET_API JanetTable *janet_gettable(const Janet *argv, int32_t n);
 JANET_API JanetStruct janet_getstruct(const Janet *argv, int32_t n);
 JANET_API JanetString janet_getstring(const Janet *argv, int32_t n);
 JANET_API const char *janet_getcstring(const Janet *argv, int32_t n);
+JANET_API const char *janet_getcbytes(const Janet *argv, int32_t n);
 JANET_API JanetSymbol janet_getsymbol(const Janet *argv, int32_t n);
 JANET_API JanetKeyword janet_getkeyword(const Janet *argv, int32_t n);
 JANET_API JanetBuffer *janet_getbuffer(const Janet *argv, int32_t n);
@@ -1997,6 +1998,7 @@ JANET_API JanetTuple janet_opttuple(const Janet *argv, int32_t argc, int32_t n,
 JANET_API JanetStruct janet_optstruct(const Janet *argv, int32_t argc, int32_t n, JanetStruct dflt);
 JANET_API JanetString janet_optstring(const Janet *argv, int32_t argc, int32_t n, JanetString dflt);
 JANET_API const char *janet_optcstring(const Janet *argv, int32_t argc, int32_t n, const char *dflt);
+JANET_API const char *janet_optcbytes(const Janet *argv, int32_t argc, int32_t n, const char *dflt);
 JANET_API JanetSymbol janet_optsymbol(const Janet *argv, int32_t argc, int32_t n, JanetString dflt);
 JANET_API JanetKeyword janet_optkeyword(const Janet *argv, int32_t argc, int32_t n, JanetString dflt);
 JANET_API JanetFiber *janet_optfiber(const Janet *argv, int32_t argc, int32_t n, JanetFiber *dflt);