Move os layer to be part of the core

src/core/os/cpath/cpath.c

@@ -0,0 +1,133 @@
+#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>
+#include <stdio.h>
+#include <string.h>
+
+u32 wapp_cpath_join_path(Str8 *dst, const Str8List *parts) {
+  if (!dst || !parts) {
+    return CPATH_JOIN_INVALID_ARGS;
+  }
+
+  if (parts->node_count == 0) {
+    return CPATH_JOIN_EMPTY_PARTS;
+  }
+
+  Str8 separator = wapp_str8_buf(4);
+  wapp_str8_push_back(&separator, PATH_SEP);
+
+  u64 required_capacity = parts->node_count * separator.size + parts->total_size;
+  if (dst->capacity < required_capacity) {
+    return CPATH_JOIN_INSUFFICIENT_DST_CAPACITY;
+  }
+
+  // Handle first node
+  const Str8Node *first_node = wapp_str8_list_get(parts, 0);
+  wapp_str8_copy_str8_capped(dst, first_node->string);
+
+  // NOTE (Abdelrahman): Uses a while loop instead of a for loop to get rid of
+  // MSVC Spectre mitigation warnings
+  const Str8Node *node = first_node;
+  u64 node_index       = 1;
+  bool running         = true;
+  while (running && node->next) {
+    node = node->next;
+    if (node->string->size == 0) {
+      continue;
+    }
+
+    if (dst->size > 0) {
+      char dst_last = wapp_str8_get(dst, dst->size - 1);
+      char node_start = wapp_str8_get(node->string, 0);
+      bool add_path_sep = dst_last != PATH_SEP && node_start != PATH_SEP;
+
+      if (add_path_sep) {
+        wapp_str8_concat_capped(dst, &separator);
+      }
+    }
+
+    wapp_str8_concat_capped(dst, node->string);
+
+    ++node_index;
+    running = node_index < parts->node_count;
+  }
+
+  return CPATH_JOIN_SUCCESS;
+}
+
+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) {
+    output = wapp_str8_alloc_str8(allocator, path);
+    goto RETURN_DIRUP;
+  }
+
+  Allocator tmp_arena = wapp_mem_arena_allocator_init(MB(8));
+  if (wapp_mem_allocator_invalid(&tmp_arena)) {
+    goto RETURN_DIRUP;
+  }
+
+  Str8List *parts = wapp_str8_split(&tmp_arena, path, &separator);
+  if (!parts) {
+    goto RETURN_DIRUP;
+  }
+
+  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);
+      }
+    }
+  }
+
+LIST_CLEANUP_DIRUP:
+  wapp_mem_arena_allocator_destroy(&tmp_arena);
+
+RETURN_DIRUP:
+  return output;
+}