Add xy_str_start_with() and xy_str_delete_prefix()

test_xy.c

@@ -2,7 +2,7 @@
 * File          : test_xy.c
 * Authors       : Aoran Zeng <ccmywish@qq.com>
 * Created on    : <2023-08-30>
-* Last modified : <2023-09-04>
+* Last modified : <2023-09-05>
 *
 * test_xy:
 *
@@ -31,11 +31,23 @@ main (int argc, char const *argv[])
   putb(xy_str_end_with("abcdef", "abcdef"));  // true
   putb(xy_str_end_with("abcdef", ""));        // true
 
+  putb(xy_str_start_with("abcdef", "abcdefg")); // false
+  putb(xy_str_start_with("abcdef", "abc"));     // true
+  putb(xy_str_start_with("abcdef", "abcde"));   // true
+  putb(xy_str_start_with("abcdef", "abcdef"));  // true
+  putb(xy_str_start_with("abcdef", ""));        // true
+
   puts(xy_str_delete_suffix("abcdefg", "cdef"));  // 不变
   puts(xy_str_delete_suffix("abcdefg", "cdefgh"));// 不变
   puts(xy_str_delete_suffix("abcdefg", ""));      // 不变
   puts(xy_str_delete_suffix("abcdefg", "efg"));   // abcd
 
+
+  puts(xy_str_delete_prefix("abcdefg", "cdef"));  // 不变
+  puts(xy_str_delete_prefix("abcdefg", "0abcde"));// 不变
+  puts(xy_str_delete_prefix("abcdefg", ""));      // 不变
+  puts(xy_str_delete_prefix("abcdefg", "abc"));   // defg
+
   xy_success("成功：输出成功内容");
   xy_info("信息: 输出信息内容");
   xy_warn("警告：输出警告内容");

xy.h

@@ -301,6 +301,38 @@ xy_str_end_with (const char* str, const char* suffix)
   return true;
 }
 
+bool
+xy_str_start_with (const char* str, const char* prefix)
+{
+  size_t len1 = strlen(str);
+  size_t len2 = strlen(prefix);
+
+  if (0==len2)     return true;  // 空字符串直接返回
+  if (len1 < len2) return false;
+
+  const char* cur1 = str;
+  const char* cur2 = prefix;
+
+  for (int i=0; i<len2; i++)
+  {
+    if (*cur1 != *cur2) return false;
+    cur1++; cur2++;
+  }
+  return true;
+}
+
+char*
+xy_str_delete_prefix (const char* str, const char* prefix)
+{
+  char* new = xy_strdup(str);
+  bool yes = xy_str_start_with(str, prefix);
+  if (!yes) return new;
+
+  size_t len = strlen(prefix);
+  char* cur = new + len;
+  return cur;
+}
+
 
 char*
 xy_str_delete_suffix (const char* str, const char* suffix)