Replace char * with Str8 in cpath dirup

src/os/cpath/cpath.c

@@ -1,5 +1,8 @@
 #include "cpath.h"
 #include "aliases.h"
+#include "mem_allocator.h"
+#include "mem_arena_allocator.h"
+#include "misc_utils.h"
 #include "str8.h"
 #include <stdarg.h>
 #include <stdbool.h>
@@ -59,56 +62,76 @@ u32 wapp_cpath_join_path(Str8 *dst, const Str8List *parts) {
   return CPATH_JOIN_SUCCESS;
 }
 
-void dirup(char *dst, u64 levels, const char *path) {
+Str8 *dirup(const Allocator *allocator, Str8RO *path, u64 levels) {
+  Str8 *output = NULL;
+  if (!allocator || !path) {
+    goto RETURN_DIRUP;
+  }
+
+  bool absolute  = wapp_str8_get(path, 0) == PATH_SEP;
+  Str8 separator = wapp_str8_buf(4);
+  wapp_str8_push_back(&separator, PATH_SEP);
+
+  if (path->size == 0) {
+    output = wapp_str8_alloc_buf(allocator, 16);
+    if (!output) {
+      goto RETURN_DIRUP;
+    }
+
+    wapp_str8_push_back(output, absolute ? PATH_SEP : '.');
+    goto RETURN_DIRUP;
+  }
+
   if (levels < 1) {
-    return;
+    output = wapp_str8_alloc_str8(allocator, path);
+    goto RETURN_DIRUP;
   }
 
-  u64 copy_count = 0;
-  u64 sep_count = 0;
-
-  u64 full_length;
-  u64 length;
-  length = full_length = strlen(path);
-
-  if (length > 1 && path[length - 1] == PATH_SEP) {
-    --length;
+  Allocator tmp_arena = wapp_mem_arena_allocator_init(MB(8));
+  if (wapp_mem_allocator_invalid(&tmp_arena)) {
+    goto RETURN_DIRUP;
   }
 
-  for (i64 i = length - 1; i >= 0; --i) {
-    if (path[i] == PATH_SEP) {
-      ++sep_count;
-      copy_count = i + 1;
+  Str8List *parts = wapp_str8_split(&tmp_arena, path, &separator);
+  if (!parts) {
+    goto RETURN_DIRUP;
+  }
 
-      if (sep_count == levels) {
-        break;
+  if (levels >= parts->node_count) {
+    output = wapp_str8_alloc_buf(allocator, 16);
+    if (!output) {
+      goto LIST_CLEANUP_DIRUP;
+    }
+
+    wapp_str8_push_back(output, absolute ? PATH_SEP : '.');
+  } else {
+    for (u64 i = 0; i < levels; ++i) {
+      wapp_str8_list_pop_back(parts);
+    }
+    
+    u64 alignment  = sizeof(void *) * 2;
+    u64 alloc_size = parts->total_size + parts->node_count * separator.size;
+    u64 modulo     = alloc_size & (alignment - 1);
+    alloc_size    += alignment - modulo;
+
+    output = wapp_str8_alloc_buf(allocator, alloc_size);
+    if (output) {
+      if (absolute) {
+        wapp_str8_push_back(output, PATH_SEP);
+      }
+
+      Str8 *joined = wapp_str8_join(&tmp_arena, parts, &separator);
+      if (joined) {
+        wapp_str8_concat_capped(output, joined);
       }
     }
   }
 
-  char tmp[256];
-  snprintf(tmp, 2, "%c", PATH_SEP);
-  // NOTE (Abdelrahman): Conditions stored in variables to silence MSVC warning C5045
-  bool insufficient_levels = sep_count < levels;
-  bool path_to_copy_is_separator = strncmp(path, tmp, copy_count) != 0;
-  if (insufficient_levels && path_to_copy_is_separator) {
-    copy_count = 0;
-  }
+LIST_CLEANUP_DIRUP:
+  wapp_mem_arena_allocator_destroy(&tmp_arena);
 
-  if (dst == path) {
-    memset(&dst[copy_count], 0, full_length - copy_count);
-  } else {
-    u64 dst_length = strlen(dst);
-    memset(dst, 0, dst_length);
-    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] = '.';
-  }
+RETURN_DIRUP:
+  return output;
 }
 
 void join_root_and_leaf(const char *root, const char *leaf, char *dst) {

src/os/cpath/cpath.h

@@ -2,6 +2,7 @@
 #define CPATH_H
 
 #include "aliases.h"
+#include "mem_allocator.h"
 #include "platform.h"
 #include "str8.h"
 
@@ -17,8 +18,8 @@ BEGIN_C_LINKAGE
 #error "Unrecognised platform"
 #endif
 
-#define wapp_cpath_dirname(DST, PATH) dirup(DST, 1, PATH)
-#define wapp_cpath_dirup(DST, COUNT, PATH) dirup(DST, COUNT, PATH)
+#define wapp_cpath_dirname(ALLOCATOR, PATH) dirup(ALLOCATOR, PATH, 1)
+#define wapp_cpath_dirup(ALLOCATOR, PATH, COUNT) dirup(ALLOCATOR, PATH, COUNT)
 
 enum {
   CPATH_JOIN_SUCCESS = 0,
@@ -28,7 +29,7 @@ enum {
 };
 
 u32  wapp_cpath_join_path(Str8 *dst, const Str8List *parts);
-void dirup(char *dst, u64 levels, const char *path);
+Str8 *dirup(const Allocator *allocator, Str8RO *path, u64 levels);
 
 #ifdef __cplusplus
 END_C_LINKAGE