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Description
Base64 is an encoding that allows a sequence of arbitrary bytes to be encoded as a sequence of printable ASCII characters. For the definition of Base64, see RFC 1421 or RFC 2045. Base64 is most commonly used as a MIME transfer encoding for email.
GLib supports incremental encoding using g_base64_encode_step() and
g_base64_encode_close(). Incremental decoding can be done with
g_base64_decode_step(). To encode or decode data in one go, use
g_base64_encode() or g_base64_decode(). To avoid memory allocation when
decoding, you can use g_base64_decode_inplace().
Support for Base64 encoding has been added in GLib 2.12.
Functions
g_base64_encode_step ()
gsize g_base64_encode_step (const guchar *in,gsize len,gboolean break_lines,gchar *out,gint *state,gint *save);
Incrementally encode a sequence of binary data into its Base-64 stringified representation. By calling this function multiple times you can convert data in chunks to avoid having to have the full encoded data in memory.
When all of the data has been converted you must call
g_base64_encode_close() to flush the saved state.
The output buffer must be large enough to fit all the data that will
be written to it. Due to the way base64 encodes you will need
at least: (len
/ 3 + 1) * 4 + 4 bytes (+ 4 may be needed in case of
non-zero state). If you enable line-breaking you will need at least:
((len
/ 3 + 1) * 4 + 4) / 72 + 1 bytes of extra space.
break_lines
is typically used when putting base64-encoded data in emails.
It breaks the lines at 72 columns instead of putting all of the text on
the same line. This avoids problems with long lines in the email system.
Note however that it breaks the lines with LF characters, not
CR LF sequences, so the result cannot be passed directly to SMTP
or certain other protocols.
Parameters
in |
the binary data to encode. |
[array length=len][element-type guint8] |
len |
the length of |
|
break_lines |
whether to break long lines |
|
out |
pointer to destination buffer. |
[out][array][element-type guint8] |
state |
Saved state between steps, initialize to 0. |
[inout] |
save |
Saved state between steps, initialize to 0. |
[inout] |
Since 2.12
g_base64_encode_close ()
gsize g_base64_encode_close (gboolean break_lines,gchar *out,gint *state,gint *save);
Flush the status from a sequence of calls to g_base64_encode_step().
The output buffer must be large enough to fit all the data that will be written to it. It will need up to 4 bytes, or up to 5 bytes if line-breaking is enabled.
Parameters
break_lines |
whether to break long lines |
|
out |
pointer to destination buffer. |
[out][array][element-type guint8] |
state |
Saved state from |
[inout] |
save |
Saved state from |
[inout] |
Since 2.12
g_base64_encode ()
gchar * g_base64_encode (const guchar *data,gsize len);
Encode a sequence of binary data into its Base-64 stringified representation.
Parameters
data |
the binary data to encode. |
[array length=len][element-type guint8] |
len |
the length of |
Returns
a newly allocated, zero-terminated Base-64
encoded string representing data
. The returned string must
be freed with g_free().
[transfer full]
Since 2.12
g_base64_decode_step ()
gsize g_base64_decode_step (const gchar *in,gsize len,guchar *out,gint *state,guint *save);
Incrementally decode a sequence of binary data from its Base-64 stringified representation. By calling this function multiple times you can convert data in chunks to avoid having to have the full encoded data in memory.
The output buffer must be large enough to fit all the data that will
be written to it. Since base64 encodes 3 bytes in 4 chars you need
at least: (len
/ 4) * 3 + 3 bytes (+ 3 may be needed in case of non-zero
state).
Parameters
in |
binary input data. |
[array length=len][element-type guint8] |
len |
max length of |
|
out |
output buffer. |
[out][array][element-type guint8] |
state |
Saved state between steps, initialize to 0. |
[inout] |
save |
Saved state between steps, initialize to 0. |
[inout] |
Since 2.12
g_base64_decode ()
guchar * g_base64_decode (const gchar *text,gsize *out_len);
Decode a sequence of Base-64 encoded text into binary data. Note that the returned binary data is not necessarily zero-terminated, so it should not be used as a character string.
Parameters
text |
zero-terminated string with base64 text to decode |
|
out_len |
The length of the decoded data is written here. |
[out] |
Returns
newly allocated buffer containing the binary data
that text
represents. The returned buffer must
be freed with g_free().
[transfer full][array length=out_len][element-type guint8]
Since 2.12
g_base64_decode_inplace ()
guchar * g_base64_decode_inplace (gchar *text,gsize *out_len);
Decode a sequence of Base-64 encoded text into binary data by overwriting the input data.
Parameters
text |
zero-terminated string with base64 text to decode. |
[inout][array length=out_len][element-type guint8] |
out_len |
The length of the decoded data is written here. |
[inout] |
Returns
The binary data that text
responds. This pointer
is the same as the input text
.
[transfer none]
Since 2.20