base64.c

Purpose

Standard and URL-safe Base64 encode/decode helpers.

API Reference

char *XBase64_Encrypt(const uint8_t *pInput, size_t *pLength)

• Arguments:
  • pInput: source bytes.
  • pLength: in/out length pointer; input size on entry, encoded length on success.
• Does:
  • encodes input with standard Base64 alphabet and = padding.
• Returns:
  • newly allocated NUL-terminated string on success.
  • NULL when pInput == NULL, pLength == NULL, *pLength == 0 or allocation fails.

char *XBase64_Decrypt(const uint8_t *pInput, size_t *pLength)

• Arguments:
  • pInput: Base64 text.
  • pLength: in/out length pointer; encoded size on entry, decoded byte count on success.
• Does:
  • accepts both properly padded input and missing-padding input.
  • internally rounds the length to a multiple of 4 when necessary.
• Returns:
  • newly allocated decoded buffer on success.
  • NULL on invalid args or allocation failure.

char *XBase64_UrlEncrypt(const uint8_t *pInput, size_t *pLength)

• Arguments:
  • same shape as XBase64_Encrypt.
• Does:
  • uses URL-safe alphabet - and _.
  • strips trailing = padding from the textual result.
• Returns:
  • newly allocated encoded string or NULL.

char *XBase64_UrlDecrypt(const uint8_t *pInput, size_t *pLength)

• Arguments:
  • same shape as XBase64_Decrypt.
• Does:
  • converts URL-safe alphabet back to standard Base64.
  • then decodes through the standard decoder.
• Returns:
  • newly allocated decoded buffer or NULL.

Notes

• Decoded buffers are convenient for text because the implementation appends a trailing NUL, but the authoritative size is always *pLength.