[acquire/acquire_net_common.h] Experimentally improve header file ; [acquire/acquire_string_extras.h] clang-format ; [README.md] Improve formatting

Author: SamuelMarks

README.md

@@ -27,7 +27,7 @@ Supports:
 
   - Extremely portable C code (ANSI C: C89)
   - link with different libraries, including those built in to your OS
-  - very small executable size (thanks to above)
+  - _very_ small executable size (thanks to above)
   - fast
   - simple API, easy to integrate in your C project (or really any language, they all have nice FFI back to C or a C intermediary language)
   - default cipher selection >= TLS 1.2
@@ -82,9 +82,10 @@ Note that most checksum libraries are crypto libraries so working with these API
 ## Docker
 
 `Dockerfile`s are provided for convenience, try them out, e.g., by running:
-
-    docker build . -f Dockerfile.alpine --tag libacquire
-    docker run libacquire
+```sh
+docker build . -f Dockerfile.alpine --tag libacquire
+docker run libacquire
+```
 
 ## Shell script equivalent (UNIX with `grep`, `curl`, and `tar`)
 

acquire/acquire_net_common.h

@@ -1,6 +1,8 @@
 /*
- * API that is common between all network libraries… however requires network
- * libs included first
+ * Networking helper API
+ *
+ * Provides minimal networking-related helpers used throughout libacquire.
+ * Does NOT implement fileutils functions (moved to acquire_fileutils.h).
  * */
 
 #ifndef LIBACQUIRE_ACQUIRE_NET_COMMON_H
@@ -10,11 +12,18 @@
 extern "C" {
 #endif /* __cplusplus */
 
-#include "acquire_download.h"
-#include "acquire_string_extras.h"
 #include "acquire_common_defs.h"
 
-bool LIBACQUIRE_LIB_EXPORT is_downloaded(const char *url,
+/**
+ * Check if a file represented by URL is already downloaded locally and matches the checksum.
+ *
+ * @param url URL or filename
+ * @param checksum checksum enum type, e.g., LIBACQUIRE_SHA256
+ * @param hash expected hash string to verify
+ * @param target_location directory to check in (if NULL, defaults to ".downloads")
+ * @return true if already downloaded and checksum verifies, else false
+ */
+extern LIBACQUIRE_LIB_EXPORT bool is_downloaded(const char *url,
                                          enum Checksum checksum,
                                          const char *hash,
                                          const char *target_location);
@@ -26,34 +35,43 @@ bool LIBACQUIRE_LIB_EXPORT is_downloaded(const char *url,
 const char *get_download_dir() { return ".downloads"; }
 #endif /* !DOWNLOAD_DIR_IMPL */
 
+/**
+ * Implementation of is_downloaded.
+ * Uses fileutils functions for existence checks and checksum functions for verification.
+ */
 bool is_downloaded(const char *url, enum Checksum checksum, const char *hash,
                    const char *target_location) {
   char full_local_fname[NAME_MAX + 1];
   const char *filename = is_url(url) ? get_path_from_url(url) : url;
 
-  if (target_location == NULL)
+  if (target_location == NULL) {
     target_location = get_download_dir();
+  }
 
   if (filename == NULL || strlen(filename) == 0 ||
-      !is_directory(target_location))
+      !is_directory(target_location)) {
     return false;
+  }
 
   snprintf(full_local_fname, NAME_MAX + 1, "%s" PATH_SEP "%s", target_location,
            filename);
 
-  if (!is_file(full_local_fname))
+  if (!is_file(full_local_fname)) {
     return false;
+  }
 
   switch (checksum) {
   case LIBACQUIRE_SHA256:
     return sha256(full_local_fname, hash);
   case LIBACQUIRE_SHA512:
-    /* return sha512(full_local_fname, hash); */
+    // TODO: can add sha512 once implemented and enabled
+    return false;
   case LIBACQUIRE_UNSUPPORTED_CHECKSUM:
   default:
     return false;
   }
 }
+
 #endif /* LIBACQUIRE_IMPLEMENTATION */
 
 #ifdef __cplusplus

acquire/acquire_string_extras.h

@@ -10,9 +10,9 @@
 extern "C" {
 #endif /* __cplusplus */
 
+#include <ctype.h>
 #include <stdarg.h>
 #include <stdio.h>
-#include <ctype.h>
 #ifdef HAVE_LIBBSD
 #include <bsd/string.h>
 #else
@@ -162,13 +162,15 @@ extern LIBACQUIRE_LIB_EXPORT int strcasecmp(const char *, const char *);
 #define strcasecmp _stricmp
 #else
 /* from MIT licensed musl @ e0ef93c20de1a9e0a6b8f4a4a951a8e61a1a2973 */
-  int strncasecmp(const char *_l, const char *_r, size_t n)
-  {
-    const unsigned char *l=(void *)_l, *r=(void *)_r;
-    if (!n--) return 0;
-    for (; *l && *r && n && (*l == *r || tolower(*l) == tolower(*r)); l++, r++, n--);
-    return tolower(*l) - tolower(*r);
-  }
+int strncasecmp(const char *_l, const char *_r, size_t n) {
+  const unsigned char *l = (void *)_l, *r = (void *)_r;
+  if (!n--)
+    return 0;
+  for (; *l && *r && n && (*l == *r || tolower(*l) == tolower(*r));
+       l++, r++, n--)
+    ;
+  return tolower(*l) - tolower(*r);
+}
 #endif /* defined(_MSC_VER) && !defined(__INTEL_COMPILER) */
 
 #endif /* LIBACQUIRE_IMPLEMENTATION */