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# std/encodings

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Routines for converting between different character encodings. On UNIX, this uses the iconv library, on Windows the Windows API.

The following example shows how to change character encodings.

Example:

    import std/encodings
    when defined(windows):
      let
        orig = "öäüß"
        # convert `orig` from "UTF-8" to "CP1252"
        cp1252 = convert(orig, "CP1252", "UTF-8")
        # convert `cp1252` from "CP1252" to "ibm850"
        ibm850 = convert(cp1252, "ibm850", "CP1252")
        current = getCurrentEncoding()
      assert orig == "\195\182\195\164\195\188\195\159"
      assert ibm850 == "\148\132\129\225"
      assert convert(ibm850, current, "ibm850") == orig

The example below uses a reuseable `EncodingConverter` object which is created by `open` with `destEncoding` and `srcEncoding` specified. You can use `convert` on this object multiple times.

Example:

    import std/encodings
    when defined(windows):
      var fromGB2312 = open("utf-8", "gb2312")
      let first = "\203\173\197\194\163\191\210\187" &
          "\203\242\209\204\211\234\200\206\198\189\201\250"
      assert fromGB2312.convert(first) == "谁怕？一蓑烟雨任平生"

      let second = "\211\208\176\215\205\183\200\231" &
          "\208\194\163\172\199\227\184\199\200\231\185\202"
      assert fromGB2312.convert(second) == "有白头如新，倾盖如故"

# Imports

os, assertions

# Types

    EncodingConverter = ptr ConverterObj

  Can convert between two character sets. Source Edit

    EncodingError = object of ValueError

  Exception that is raised for encoding errors. Source Edit

# Procs

    proc close(c: EncodingConverter) {....raises: [], tags: [], forbids: [].}

  Frees the resources the converter `c` holds. Source Edit

    proc convert(c: EncodingConverter; s: string): string {....raises: [OSError],
        tags: [], forbids: [].}

  Converts `s` to `destEncoding` that was given to the converter `c`. It assumes that `s` is in `srcEncoding`.
  Warning: UTF-16BE and UTF-32 conversions are not supported on Windows.
  Source Edit

    proc convert(s: string; destEncoding = "UTF-8"; srcEncoding = "CP1252"): string {.
        ...raises: [EncodingError, OSError], tags: [], forbids: [].}

  Converts `s` to `destEncoding`. It assumed that `s` is in `srcEncoding`. This opens a converter, uses it and closes it again and is thus more convenient but also likely less efficient than re-using a converter.
  Warning: UTF-16BE and UTF-32 conversions are not supported on Windows.
  Source Edit

    proc getCurrentEncoding(uiApp = false): string {....raises: [], tags: [],
        forbids: [].}

  Retrieves the current encoding. On Unix, "UTF-8" is always returned. The `uiApp` parameter is Windows specific. If true, the UI's code-page is returned, if false, the Console's code-page is returned. Source Edit

    proc open(destEncoding = "UTF-8"; srcEncoding = "CP1252"): EncodingConverter {.
        ...raises: [EncodingError], tags: [], forbids: [].}

  Opens a converter that can convert from `srcEncoding` to `destEncoding`. Raises `EncodingError` if it cannot fulfill the request. Source Edit