Move path utils to os, fix bugs with it and write tests

src/core/cpath/cpath.c

@@ -1,18 +1,9 @@
 #include "cpath.h"
 #include "aliases.h"
-#include "platform.h"
 #include <stdarg.h>
 #include <stdio.h>
 #include <string.h>
 
-#ifdef WAPP_PLATFORM_POSIX
-internal char path_sep = '/';
-#elif defined(WAPP_PLATFORM_WINDOWS)
-internal char path_sep = '\\';
-#else
-#error "Unrecognised platform"
-#endif
-
 void join_root_and_leaf(const char *root, const char *leaf, char *dst);
 
 void join_path(char *dst, u64 count, ...) {
@@ -32,21 +23,21 @@ void dirup(char *dst, u64 levels, const char *path) {
     return;
   }
 
-  u64 end_index = 0;
+  u64 copy_count = 0;
   u64 sep_count = 0;
 
   u64 full_length;
   u64 length;
   length = full_length = strlen(path);
 
-  if (path[length - 1] == path_sep) {
+  if (length > 1 && path[length - 1] == PATH_SEP) {
     --length;
   }
 
   for (i64 i = length - 1; i >= 0; --i) {
-    if (path[i] == path_sep) {
+    if (path[i] == PATH_SEP) {
       ++sep_count;
-      end_index = i;
+      copy_count = i + 1;
 
       if (sep_count == levels) {
         break;
@@ -54,37 +45,44 @@ void dirup(char *dst, u64 levels, const char *path) {
     }
   }
 
-  if (sep_count < levels) {
-    end_index = 0;
+  char tmp[256];
+  sprintf(tmp, "%c", PATH_SEP);
+  if (sep_count < levels && strncmp(path, tmp, copy_count) != 0) {
+    copy_count = 0;
   }
 
   if (dst == path) {
-    memset(&dst[end_index], 0, full_length - end_index);
+    memset(&dst[copy_count], 0, full_length - copy_count);
   } else {
     u64 dst_length = strlen(dst);
     memset(dst, 0, dst_length);
-    strncpy(dst, path, end_index);
+    strncpy(dst, path, copy_count);
+  }
+
+  u64 final_length = strlen(dst);
+  if (final_length > 1) {
+    dst[final_length - 1] = '\0';
+  } else if (final_length == 0) {
+    dst[0] = '.';
   }
 }
 
 void join_root_and_leaf(const char *root, const char *leaf, char *dst) {
   u64 root_length = strlen(root);
-  u64 root_end = root_length - 1;
-
   u64 leaf_length = strlen(leaf);
-  u64 leaf_start = 0;
 
-  if (root[root_end] == path_sep) {
-    --root_end;
+  memcpy(dst, root, root_length);
+
+  if (leaf_length == 0) {
+    return;
   }
 
-  if (leaf[leaf_start] == path_sep) {
-    ++leaf_start;
+  u64 copy_start = root_length;
+
+  if (root_length > 0 && root[root_length - 1] != PATH_SEP && leaf[0] != PATH_SEP) {
+    dst[root_length] = PATH_SEP;
+    ++copy_start;
   }
 
-  memcpy(dst, root, ++root_end);
-
-  dst[root_end] = path_sep;
-
-  memcpy(&(dst[++root_end]), &(leaf[leaf_start]), leaf_length - leaf_start);
+  memcpy(&(dst[copy_start]), leaf, leaf_length);
 }

src/core/cpath/cpath.h

@@ -1,12 +1,21 @@
-#ifndef PATH_UTILS_H
-#define PATH_UTILS_H
+#ifndef CPATH_H
+#define CPATH_H
 
 #include "aliases.h"
+#include "platform.h"
 
 #ifdef __cplusplus
 BEGIN_C_LINKAGE
 #endif // __cplusplus
 
+#ifdef WAPP_PLATFORM_POSIX
+#define PATH_SEP '/'
+#elif defined(WAPP_PLATFORM_WINDOWS)
+#define PATH_SEP '\\'
+#else
+#error "Unrecognised platform"
+#endif
+
 #define NUMPARTS(...) (sizeof((const char *[]){"", __VA_ARGS__}) / sizeof(const char *) - 1)
 
 #define wapp_cpath_join_path(DST, ...) join_path(DST, NUMPARTS(__VA_ARGS__), __VA_ARGS__)