text: #ifndef AWS_IO_URI_H
  #define AWS_IO_URI_H
  /**
   * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
   * SPDX-License-Identifier: Apache-2.0.
   */
  #include <aws/io/io.h>
  
  #include <aws/common/byte_buf.h>
  
  /**
   * Data representing a URI. uri_str is always allocated and filled in.
   * The other portions are merely storing offsets into uri_str.
   */
  struct aws_uri {
      size_t self_size;
      struct aws_allocator *allocator;
      struct aws_byte_buf uri_str;
      struct aws_byte_cursor scheme;
      struct aws_byte_cursor authority;
      struct aws_byte_cursor host_name;
      uint16_t port;
      struct aws_byte_cursor path;
      struct aws_byte_cursor query_string;
      struct aws_byte_cursor path_and_query;
  };
  
  /**
   * key/value pairs for a query string. If the query fragment was not in format key=value, the fragment value
   * will be stored in key
   */
  struct aws_uri_param {
      struct aws_byte_cursor key;
      struct aws_byte_cursor value;
  };
  
  /**
   * Arguments for building a URI instance. All members must
   * be initialized before passing them to aws_uri_init().
   *
   * query_string and query_params are exclusive to each other. If you set
   * query_string, do not prepend it with '?'
   */
  struct aws_uri_builder_options {
      struct aws_byte_cursor scheme;
      struct aws_byte_cursor path;
      struct aws_byte_cursor host_name;
      uint16_t port;
      struct aws_array_list *query_params;
      struct aws_byte_cursor query_string;
  };
  
  AWS_EXTERN_C_BEGIN
  
  /**
   * Parses 'uri_str' and initializes uri. Returns AWS_OP_SUCCESS, on success, AWS_OP_ERR on failure.
   * After calling this function, the parts can be accessed.
   */
  AWS_IO_API int aws_uri_init_parse(
      struct aws_uri *uri,
      struct aws_allocator *allocator,
      const struct aws_byte_cursor *uri_str);
  
  /**
   * Initializes uri to values specified in options. Returns AWS_OP_SUCCESS, on success, AWS_OP_ERR on failure.
   * After calling this function, the parts can be accessed.
   */
  AWS_IO_API int aws_uri_init_from_builder_options(
      struct aws_uri *uri,
      struct aws_allocator *allocator,
      struct aws_uri_builder_options *options);
  AWS_IO_API void aws_uri_clean_up(struct aws_uri *uri);
  
  /**
   * Returns the scheme portion of the uri (e.g. http, https, ftp, ftps, etc...). If the scheme was not present
   * in the uri, the returned value will be empty. It is the users job to determine the appropriate defaults
   * if this field is empty, based on protocol, port, etc...
   */
  AWS_IO_API const struct aws_byte_cursor *aws_uri_scheme(const struct aws_uri *uri);
  
  /**
   * Returns the authority portion of the uri (host[:port]). If it was not present, this was a request uri. In that
   * case, the value will be empty.
   */
  AWS_IO_API const struct aws_byte_cursor *aws_uri_authority(const struct aws_uri *uri);
  
  /**
   * Returns the path portion of the uri. If the original value was empty, this value will be "/".
   */
  AWS_IO_API const struct aws_byte_cursor *aws_uri_path(const struct aws_uri *uri);
  
  /**
   * Returns the query string portion of the uri, minus the '?'. If not present, this value will be empty.
   */
  AWS_IO_API const struct aws_byte_cursor *aws_uri_query_string(const struct aws_uri *uri);
  
  /**
   * Returns the 'host_name' portion of the authority. If no authority was present, this value will be empty.
   */
  AWS_IO_API const struct aws_byte_cursor *aws_uri_host_name(const struct aws_uri *uri);
  
  /**
   * Returns the port portion of the authority if it was present, otherwise, returns 0.
   * If this is 0, it is the users job to determine the correct port based on scheme and protocol.
   */
  AWS_IO_API uint16_t aws_uri_port(const struct aws_uri *uri);
  
  /**
   * Returns the path and query portion of the uri (i.e., the thing you send accross the wire).
   */
  AWS_IO_API const struct aws_byte_cursor *aws_uri_path_and_query(const struct aws_uri *uri);
  
  /**
   * For iterating over the params in the uri query string.
   * `param` is an in/out argument used to track progress, it MUST be zeroed out to start.
   * If true is returned, `param` contains the value of the next param.
   * If false is returned, there are no further params.
   *
   * Edge cases:
   * 1) Entries without '=' sign are treated as having a key and no value.
   *    Example: First param in query string "a&b=c" has key="a" value=""
   *
   * 2) Blank entries are skipped.
   *    Example: The only param in query string "&&a=b" is key="a" value="b"
   */
  AWS_IO_API bool aws_uri_query_string_next_param(const struct aws_uri *uri, struct aws_uri_param *param);
  
  /**
   * Parses query string and stores the parameters in 'out_params'. Returns AWS_OP_SUCCESS on success and
   * AWS_OP_ERR on failure. The user is responsible for initializing out_params with item size of struct aws_query_param.
   * The user is also responsible for cleaning up out_params when finished.
   */
  AWS_IO_API int aws_uri_query_string_params(const struct aws_uri *uri, struct aws_array_list *out_params);
  
  /**
   * Writes the uri path encoding of a cursor to a buffer.  This is the modified version of rfc3986 used by
   * sigv4 signing.
   */
  AWS_IO_API int aws_byte_buf_append_encoding_uri_path(struct aws_byte_buf *buffer, const struct aws_byte_cursor *cursor);
  
  /**
   * Writes the uri query param encoding (passthrough alnum + '-' '_' '~' '.') of a UTF-8 cursor to a buffer
   * For example, reading "a b_c" would write "a%20b_c".
   */
  AWS_IO_API int aws_byte_buf_append_encoding_uri_param(
      struct aws_byte_buf *buffer,
      const struct aws_byte_cursor *cursor);
  
  /**
   * Writes the uri decoding of a UTF-8 cursor to a buffer,
   * replacing %xx escapes by their single byte equivalent.
   * For example, reading "a%20b_c" would write "a b_c".
   */
  AWS_IO_API int aws_byte_buf_append_decoding_uri(struct aws_byte_buf *buffer, const struct aws_byte_cursor *cursor);
  
  AWS_EXTERN_C_END
  
  #endif /* AWS_IO_URI_H */
  