/*

** Routines to represent binary data in ASCII and vice-versa

**

** This module currently supports the following encodings:

** uuencode:

** each line encodes 45 bytes (except possibly the last)

** First char encodes (binary) length, rest data

** each char encodes 6 bits, as follows:

** binary: 01234567 abcdefgh ijklmnop

** ascii: 012345 67abcd efghij klmnop

** ASCII encoding method is "excess-space": 000000 is encoded as ' ', etc.

** short binary data is zero-extended (so the bits are always in the

** right place), this does *not* reflect in the length.

** base64:

** Line breaks are insignificant, but lines are at most 76 chars

** each char encodes 6 bits, in similar order as uucode/hqx. Encoding

** is done via a table.

** Short binary data is filled (in ASCII) with '='.

** hqx:

** File starts with introductory text, real data starts and ends

** with colons.

** Data consists of three similar parts: info, datafork, resourcefork.

** Each part is protected (at the end) with a 16-bit crc

** The binary data is run-length encoded, and then ascii-fied:

** binary: 01234567 abcdefgh ijklmnop

** ascii: 012345 67abcd efghij klmnop

** ASCII encoding is table-driven, see the code.

** Short binary data results in the runt ascii-byte being output with

** the bits in the right place.

**

** While I was reading dozens of programs that encode or decode the formats

** here (documentation? hihi:-) I have formulated Jansen's Observation:

**

** Programs that encode binary data in ASCII are written in

** such a style that they are as unreadable as possible. Devices used

** include unnecessary global variables, burying important tables

** in unrelated sourcefiles, putting functions in include files,

** using seemingly-descriptive variable names for different purposes,

** calls to empty subroutines and a host of others.

**

** I have attempted to break with this tradition, but I guess that that

** does make the performance sub-optimal. Oh well, too bad...

**

** Jack Jansen, CWI, July 1995.

**

** Added support for quoted-printable encoding, based on rfc 1521 et al

** quoted-printable encoding specifies that non printable characters (anything

** below 32 and above 126) be encoded as =XX where XX is the hexadecimal value

** of the character. It also specifies some other behavior to enable 8bit data

** in a mail message with little difficulty (maximum line sizes, protecting

** some cases of whitespace, etc).

**

** Brandon Long, September 2001.

*/

#define PY_SSIZE_T_CLEAN

#include "Python.h"

#include "pystrhex.h"

#ifdef USE_ZLIB_CRC32

#include "zlib.h"

#endif

static PyObject *Error;

static PyObject *Incomplete;

/*

** hqx lookup table, ascii->binary.

*/

#define RUNCHAR 0x90

#define DONE 0x7F

#define SKIP 0x7E

#define FAIL 0x7D

static const unsigned char table_a2b_hqx[256] = {

/* ^@ ^A ^B ^C ^D ^E ^F ^G */

/* 0*/ FAIL, FAIL, FAIL, FAIL, FAIL, FAIL, FAIL, FAIL,

/* \b \t \n ^K ^L \r ^N ^O */

/* 1*/ FAIL, FAIL, SKIP, FAIL, FAIL, SKIP, FAIL, FAIL,

/* ^P ^Q ^R ^S ^T ^U ^V ^W */

/* 2*/ FAIL, FAIL, FAIL, FAIL, FAIL, FAIL, FAIL, FAIL,

/* ^X ^Y ^Z ^[ ^\ ^] ^^ ^_ */

/* 3*/ FAIL, FAIL, FAIL, FAIL, FAIL, FAIL, FAIL, FAIL,

/* ! " # $ % & ' */

/* 4*/ FAIL, 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06,

/* ( ) * + , - . / */

/* 5*/ 0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, FAIL, FAIL,

/* 0 1 2 3 4 5 6 7 */

/* 6*/ 0x0D, 0x0E, 0x0F, 0x10, 0x11, 0x12, 0x13, FAIL,

/* 8 9 : ; < = > ? */

/* 7*/ 0x14, 0x15, DONE, FAIL, FAIL, FAIL, FAIL, FAIL,

/* @ A B C D E F G */

/* 8*/ 0x16, 0x17, 0x18, 0x19, 0x1A, 0x1B, 0x1C, 0x1D,

/* H I J K L M N O */

/* 9*/ 0x1E, 0x1F, 0x20, 0x21, 0x22, 0x23, 0x24, FAIL,

/* P Q R S T U V W */

/*10*/ 0x25, 0x26, 0x27, 0x28, 0x29, 0x2A, 0x2B, FAIL,

/* X Y Z [ \ ] ^ _ */

/*11*/ 0x2C, 0x2D, 0x2E, 0x2F, FAIL, FAIL, FAIL, FAIL,

/* ` a b c d e f g */

/*12*/ 0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, FAIL,

/* h i j k l m n o */

/*13*/ 0x37, 0x38, 0x39, 0x3A, 0x3B, 0x3C, FAIL, FAIL,

/* p q r s t u v w */

/*14*/ 0x3D, 0x3E, 0x3F, FAIL, FAIL, FAIL, FAIL, FAIL,

/* x y z { | } ~ ^? */

/*15*/ FAIL, FAIL, FAIL, FAIL, FAIL, FAIL, FAIL, FAIL,

/*16*/ FAIL, FAIL, FAIL, FAIL, FAIL, FAIL, FAIL, FAIL,

FAIL, FAIL, FAIL, FAIL, FAIL, FAIL, FAIL, FAIL,

FAIL, FAIL, FAIL, FAIL, FAIL, FAIL, FAIL, FAIL,

FAIL, FAIL, FAIL, FAIL, FAIL, FAIL, FAIL, FAIL,

FAIL, FAIL, FAIL, FAIL, FAIL, FAIL, FAIL, FAIL,

FAIL, FAIL, FAIL, FAIL, FAIL, FAIL, FAIL, FAIL,

FAIL, FAIL, FAIL, FAIL, FAIL, FAIL, FAIL, FAIL,

FAIL, FAIL, FAIL, FAIL, FAIL, FAIL, FAIL, FAIL,

FAIL, FAIL, FAIL, FAIL, FAIL, FAIL, FAIL, FAIL,

FAIL, FAIL, FAIL, FAIL, FAIL, FAIL, FAIL, FAIL,

FAIL, FAIL, FAIL, FAIL, FAIL, FAIL, FAIL, FAIL,

FAIL, FAIL, FAIL, FAIL, FAIL, FAIL, FAIL, FAIL,

FAIL, FAIL, FAIL, FAIL, FAIL, FAIL, FAIL, FAIL,

FAIL, FAIL, FAIL, FAIL, FAIL, FAIL, FAIL, FAIL,

FAIL, FAIL, FAIL, FAIL, FAIL, FAIL, FAIL, FAIL,

FAIL, FAIL, FAIL, FAIL, FAIL, FAIL, FAIL, FAIL,

};

static const unsigned char table_b2a_hqx[] =

"!\"#$%&'()*+,-012345689@ABCDEFGHIJKLMNPQRSTUVXYZ[`abcdefhijklmpqr";

static const char table_a2b_base64[] = {

-1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1,

-1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1,

-1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,62, -1,-1,-1,63,

52,53,54,55, 56,57,58,59, 60,61,-1,-1, -1, 0,-1,-1, /* Note PAD->0 */

-1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10, 11,12,13,14,

15,16,17,18, 19,20,21,22, 23,24,25,-1, -1,-1,-1,-1,

-1,26,27,28, 29,30,31,32, 33,34,35,36, 37,38,39,40,

41,42,43,44, 45,46,47,48, 49,50,51,-1, -1,-1,-1,-1

};

#define BASE64_PAD '='

/* Max binary chunk size; limited only by available memory */

#define BASE64_MAXBIN ((PY_SSIZE_T_MAX - 3) / 2)

static const unsigned char table_b2a_base64[] =

"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

static const unsigned short crctab_hqx[256] = {

0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50a5, 0x60c6, 0x70e7,

0x8108, 0x9129, 0xa14a, 0xb16b, 0xc18c, 0xd1ad, 0xe1ce, 0xf1ef,

0x1231, 0x0210, 0x3273, 0x2252, 0x52b5, 0x4294, 0x72f7, 0x62d6,

0x9339, 0x8318, 0xb37b, 0xa35a, 0xd3bd, 0xc39c, 0xf3ff, 0xe3de,

0x2462, 0x3443, 0x0420, 0x1401, 0x64e6, 0x74c7, 0x44a4, 0x5485,

0xa56a, 0xb54b, 0x8528, 0x9509, 0xe5ee, 0xf5cf, 0xc5ac, 0xd58d,

0x3653, 0x2672, 0x1611, 0x0630, 0x76d7, 0x66f6, 0x5695, 0x46b4,

0xb75b, 0xa77a, 0x9719, 0x8738, 0xf7df, 0xe7fe, 0xd79d, 0xc7bc,

0x48c4, 0x58e5, 0x6886, 0x78a7, 0x0840, 0x1861, 0x2802, 0x3823,

0xc9cc, 0xd9ed, 0xe98e, 0xf9af, 0x8948, 0x9969, 0xa90a, 0xb92b,

0x5af5, 0x4ad4, 0x7ab7, 0x6a96, 0x1a71, 0x0a50, 0x3a33, 0x2a12,

0xdbfd, 0xcbdc, 0xfbbf, 0xeb9e, 0x9b79, 0x8b58, 0xbb3b, 0xab1a,

0x6ca6, 0x7c87, 0x4ce4, 0x5cc5, 0x2c22, 0x3c03, 0x0c60, 0x1c41,

0xedae, 0xfd8f, 0xcdec, 0xddcd, 0xad2a, 0xbd0b, 0x8d68, 0x9d49,

0x7e97, 0x6eb6, 0x5ed5, 0x4ef4, 0x3e13, 0x2e32, 0x1e51, 0x0e70,

0xff9f, 0xefbe, 0xdfdd, 0xcffc, 0xbf1b, 0xaf3a, 0x9f59, 0x8f78,

0x9188, 0x81a9, 0xb1ca, 0xa1eb, 0xd10c, 0xc12d, 0xf14e, 0xe16f,

0x1080, 0x00a1, 0x30c2, 0x20e3, 0x5004, 0x4025, 0x7046, 0x6067,

0x83b9, 0x9398, 0xa3fb, 0xb3da, 0xc33d, 0xd31c, 0xe37f, 0xf35e,

0x02b1, 0x1290, 0x22f3, 0x32d2, 0x4235, 0x5214, 0x6277, 0x7256,

0xb5ea, 0xa5cb, 0x95a8, 0x8589, 0xf56e, 0xe54f, 0xd52c, 0xc50d,

0x34e2, 0x24c3, 0x14a0, 0x0481, 0x7466, 0x6447, 0x5424, 0x4405,

0xa7db, 0xb7fa, 0x8799, 0x97b8, 0xe75f, 0xf77e, 0xc71d, 0xd73c,

0x26d3, 0x36f2, 0x0691, 0x16b0, 0x6657, 0x7676, 0x4615, 0x5634,

0xd94c, 0xc96d, 0xf90e, 0xe92f, 0x99c8, 0x89e9, 0xb98a, 0xa9ab,

0x5844, 0x4865, 0x7806, 0x6827, 0x18c0, 0x08e1, 0x3882, 0x28a3,

0xcb7d, 0xdb5c, 0xeb3f, 0xfb1e, 0x8bf9, 0x9bd8, 0xabbb, 0xbb9a,

0x4a75, 0x5a54, 0x6a37, 0x7a16, 0x0af1, 0x1ad0, 0x2ab3, 0x3a92,

0xfd2e, 0xed0f, 0xdd6c, 0xcd4d, 0xbdaa, 0xad8b, 0x9de8, 0x8dc9,

0x7c26, 0x6c07, 0x5c64, 0x4c45, 0x3ca2, 0x2c83, 0x1ce0, 0x0cc1,

0xef1f, 0xff3e, 0xcf5d, 0xdf7c, 0xaf9b, 0xbfba, 0x8fd9, 0x9ff8,

0x6e17, 0x7e36, 0x4e55, 0x5e74, 0x2e93, 0x3eb2, 0x0ed1, 0x1ef0,

};

/*[clinic input]

module binascii

[clinic start generated code]*/

/*[clinic end generated code: output=da39a3ee5e6b4b0d input=de89fb46bcaf3fec]*/

/*[python input]

class ascii_buffer_converter(CConverter):

type = 'Py_buffer'

converter = 'ascii_buffer_converter'

impl_by_reference = True

c_default = "{NULL, NULL}"

def cleanup(self):

name = self.name

return "".join(["if (", name, ".obj)\n PyBuffer_Release(&", name, ");\n"])

[python start generated code]*/

/*[python end generated code: output=da39a3ee5e6b4b0d input=3eb7b63610da92cd]*/

static int

ascii_buffer_converter(PyObject *arg, Py_buffer *buf)

{

if (arg == NULL) {

PyBuffer_Release(buf);

return 1;

}

if (PyUnicode_Check(arg)) {

if (PyUnicode_READY(arg) < 0)

return 0;

if (!PyUnicode_IS_ASCII(arg)) {

PyErr_SetString(PyExc_ValueError,

"string argument should contain only ASCII characters");

return 0;

}

assert(PyUnicode_KIND(arg) == PyUnicode_1BYTE_KIND);

buf->buf = (void *) PyUnicode_1BYTE_DATA(arg);

buf->len = PyUnicode_GET_LENGTH(arg);

buf->obj = NULL;

return 1;

}

if (PyObject_GetBuffer(arg, buf, PyBUF_SIMPLE) != 0) {

PyErr_Format(PyExc_TypeError,

"argument should be bytes, buffer or ASCII string, "

"not '%.100s'", Py_TYPE(arg)->tp_name);

return 0;

}

if (!PyBuffer_IsContiguous(buf, 'C')) {

PyErr_Format(PyExc_TypeError,

"argument should be a contiguous buffer, "

"not '%.100s'", Py_TYPE(arg)->tp_name);

PyBuffer_Release(buf);

return 0;

}

return Py_CLEANUP_SUPPORTED;

}

#include "clinic/binascii.c.h"

/*[clinic input]

binascii.a2b_uu

data: ascii_buffer

/

Decode a line of uuencoded data.

[clinic start generated code]*/

static PyObject *

binascii_a2b_uu_impl(PyObject *module, Py_buffer *data)

/*[clinic end generated code: output=e027f8e0b0598742 input=7cafeaf73df63d1c]*/

{

const unsigned char *ascii_data;

unsigned char *bin_data;

int leftbits = 0;

unsigned char this_ch;

unsigned int leftchar = 0;

PyObject *rv;

Py_ssize_t ascii_len, bin_len;

ascii_data = data->buf;

ascii_len = data->len;

assert(ascii_len >= 0);

/* First byte: binary data length (in bytes) */

bin_len = (*ascii_data++ - ' ') & 077;

ascii_len--;

/* Allocate the buffer */

if ( (rv=PyBytes_FromStringAndSize(NULL, bin_len)) == NULL )

return NULL;

bin_data = (unsigned char *)PyBytes_AS_STRING(rv);

for( ; bin_len > 0 ; ascii_len--, ascii_data++ ) {

/* XXX is it really best to add NULs if there's no more data */

this_ch = (ascii_len > 0) ? *ascii_data : 0;

if ( this_ch == '\n' || this_ch == '\r' || ascii_len <= 0) {

/*

** Whitespace. Assume some spaces got eaten at

** end-of-line. (We check this later)

*/

this_ch = 0;

} else {

/* Check the character for legality

** The 64 in stead of the expected 63 is because

** there are a few uuencodes out there that use

** '`' as zero instead of space.

*/

if ( this_ch < ' ' || this_ch > (' ' + 64)) {

PyErr_SetString(Error, "Illegal char");

Py_DECREF(rv);

return NULL;

}

this_ch = (this_ch - ' ') & 077;

}

/*

** Shift it in on the low end, and see if there's

** a byte ready for output.

*/

leftchar = (leftchar << 6) | (this_ch);

leftbits += 6;

if ( leftbits >= 8 ) {

leftbits -= 8;

*bin_data++ = (leftchar >> leftbits) & 0xff;

leftchar &= ((1 << leftbits) - 1);

bin_len--;

}

}

/*

** Finally, check that if there's anything left on the line

** that it's whitespace only.

*/

while( ascii_len-- > 0 ) {

this_ch = *ascii_data++;

/* Extra '`' may be written as padding in some cases */

if ( this_ch != ' ' && this_ch != ' '+64 &&

this_ch != '\n' && this_ch != '\r' ) {

PyErr_SetString(Error, "Trailing garbage");

Py_DECREF(rv);

return NULL;

}

}

return rv;

}

/*[clinic input]

binascii.b2a_uu

data: Py_buffer

/

*

backtick: bool(accept={int}) = False

Uuencode line of data.

[clinic start generated code]*/

static PyObject *

binascii_b2a_uu_impl(PyObject *module, Py_buffer *data, int backtick)

/*[clinic end generated code: output=b1b99de62d9bbeb8 input=b26bc8d32b6ed2f6]*/

{

unsigned char *ascii_data;

const unsigned char *bin_data;

int leftbits = 0;

unsigned char this_ch;

unsigned int leftchar = 0;

Py_ssize_t bin_len, out_len;

_PyBytesWriter writer;

_PyBytesWriter_Init(&writer);

bin_data = data->buf;

bin_len = data->len;

if ( bin_len > 45 ) {

/* The 45 is a limit that appears in all uuencode's */

PyErr_SetString(Error, "At most 45 bytes at once");

return NULL;

}

/* We're lazy and allocate to much (fixed up later) */

out_len = 2 + (bin_len + 2) / 3 * 4;

ascii_data = _PyBytesWriter_Alloc(&writer, out_len);

if (ascii_data == NULL)

return NULL;

/* Store the length */

if (backtick && !bin_len)

*ascii_data++ = '`';

else

*ascii_data++ = ' ' + (unsigned char)bin_len;

for( ; bin_len > 0 || leftbits != 0 ; bin_len--, bin_data++ ) {

/* Shift the data (or padding) into our buffer */

if ( bin_len > 0 ) /* Data */

leftchar = (leftchar << 8) | *bin_data;

else /* Padding */

leftchar <<= 8;

leftbits += 8;

/* See if there are 6-bit groups ready */

while ( leftbits >= 6 ) {

this_ch = (leftchar >> (leftbits-6)) & 0x3f;

leftbits -= 6;

if (backtick && !this_ch)

*ascii_data++ = '`';

else

*ascii_data++ = this_ch + ' ';

}

}

*ascii_data++ = '\n'; /* Append a courtesy newline */

return _PyBytesWriter_Finish(&writer, ascii_data);

}

static int

binascii_find_valid(const unsigned char *s, Py_ssize_t slen, int num)

{

/* Finds & returns the (num+1)th

** valid character for base64, or -1 if none.

*/

int ret = -1;

unsigned char c, b64val;

while ((slen > 0) && (ret == -1)) {

c = *s;

b64val = table_a2b_base64[c & 0x7f];

if ( ((c <= 0x7f) && (b64val != (unsigned char)-1)) ) {

if (num == 0)

ret = *s;

num--;

}

s++;

slen--;

}

return ret;

}

/*[clinic input]

binascii.a2b_base64

data: ascii_buffer

/

Decode a line of base64 data.

[clinic start generated code]*/

static PyObject *

binascii_a2b_base64_impl(PyObject *module, Py_buffer *data)

/*[clinic end generated code: output=0628223f19fd3f9b input=5872acf6e1cac243]*/

{

const unsigned char *ascii_data;

unsigned char *bin_data;

unsigned char *bin_data_start;

int leftbits = 0;

unsigned char this_ch;

unsigned int leftchar = 0;

Py_ssize_t ascii_len, bin_len;

int quad_pos = 0;

_PyBytesWriter writer;

ascii_data = data->buf;

ascii_len = data->len;

assert(ascii_len >= 0);

if (ascii_len > PY_SSIZE_T_MAX - 3)

return PyErr_NoMemory();

bin_len = ((ascii_len+3)/4)*3; /* Upper bound, corrected later */

_PyBytesWriter_Init(&writer);

/* Allocate the buffer */

bin_data = _PyBytesWriter_Alloc(&writer, bin_len);

if (bin_data == NULL)

return NULL;

bin_data_start = bin_data;

for( ; ascii_len > 0; ascii_len--, ascii_data++) {

this_ch = *ascii_data;

if (this_ch > 0x7f ||

this_ch == '\r' || this_ch == '\n' || this_ch == ' ')

continue;

/* Check for pad sequences and ignore

** the invalid ones.

*/

if (this_ch == BASE64_PAD) {

if ( (quad_pos < 2) ||

((quad_pos == 2) &&

(binascii_find_valid(ascii_data, ascii_len, 1)

!= BASE64_PAD)) )

{

continue;

}

else {

/* A pad sequence means no more input.

** We've already interpreted the data

** from the quad at this point.

*/

leftbits = 0;

break;

}

}

this_ch = table_a2b_base64[*ascii_data];

if ( this_ch == (unsigned char) -1 )

continue;

/*

** Shift it in on the low end, and see if there's

** a byte ready for output.

*/

quad_pos = (quad_pos + 1) & 0x03;

leftchar = (leftchar << 6) | (this_ch);

leftbits += 6;

if ( leftbits >= 8 ) {

leftbits -= 8;

*bin_data++ = (leftchar >> leftbits) & 0xff;

leftchar &= ((1 << leftbits) - 1);

}

}

if (leftbits != 0) {

if (leftbits == 6) {

/*

** There is exactly one extra valid, non-padding, base64 character.

** This is an invalid length, as there is no possible input that

** could encoded into such a base64 string.

*/

PyErr_Format(Error,

"Invalid base64-encoded string: "

"number of data characters (%zd) cannot be 1 more "

"than a multiple of 4",

(bin_data - bin_data_start) / 3 * 4 + 1);

} else {

PyErr_SetString(Error, "Incorrect padding");

}

_PyBytesWriter_Dealloc(&writer);

return NULL;

}

return _PyBytesWriter_Finish(&writer, bin_data);

}

/*[clinic input]

binascii.b2a_base64

data: Py_buffer

/

*

newline: bool(accept={int}) = True

Base64-code line of data.

[clinic start generated code]*/

static PyObject *

binascii_b2a_base64_impl(PyObject *module, Py_buffer *data, int newline)

/*[clinic end generated code: output=4ad62c8e8485d3b3 input=6083dac5777fa45d]*/

{

unsigned char *ascii_data;

const unsigned char *bin_data;

int leftbits = 0;

unsigned char this_ch;

unsigned int leftchar = 0;

Py_ssize_t bin_len, out_len;

_PyBytesWriter writer;

bin_data = data->buf;

bin_len = data->len;

_PyBytesWriter_Init(&writer);

assert(bin_len >= 0);

if ( bin_len > BASE64_MAXBIN ) {

PyErr_SetString(Error, "Too much data for base64 line");

return NULL;

}

/* We're lazy and allocate too much (fixed up later).

"+2" leaves room for up to two pad characters.

Note that 'b' gets encoded as 'Yg==\n' (1 in, 5 out). */

out_len = bin_len*2 + 2;

if (newline)

out_len++;

ascii_data = _PyBytesWriter_Alloc(&writer, out_len);

if (ascii_data == NULL)

return NULL;

for( ; bin_len > 0 ; bin_len--, bin_data++ ) {

/* Shift the data into our buffer */

leftchar = (leftchar << 8) | *bin_data;

leftbits += 8;

/* See if there are 6-bit groups ready */

while ( leftbits >= 6 ) {

this_ch = (leftchar >> (leftbits-6)) & 0x3f;

leftbits -= 6;

*ascii_data++ = table_b2a_base64[this_ch];

}

}

if ( leftbits == 2 ) {

*ascii_data++ = table_b2a_base64[(leftchar&3) << 4];

*ascii_data++ = BASE64_PAD;

*ascii_data++ = BASE64_PAD;

} else if ( leftbits == 4 ) {

*ascii_data++ = table_b2a_base64[(leftchar&0xf) << 2];

*ascii_data++ = BASE64_PAD;

}

if (newline)

*ascii_data++ = '\n'; /* Append a courtesy newline */

return _PyBytesWriter_Finish(&writer, ascii_data);

}

/*[clinic input]

binascii.a2b_hqx

data: ascii_buffer

/

Decode .hqx coding.

[clinic start generated code]*/

static PyObject *

binascii_a2b_hqx_impl(PyObject *module, Py_buffer *data)

/*[clinic end generated code: output=4d6d8c54d54ea1c1 input=0d914c680e0eed55]*/

{

const unsigned char *ascii_data;

unsigned char *bin_data;

int leftbits = 0;

unsigned char this_ch;

unsigned int leftchar = 0;

PyObject *res;

Py_ssize_t len;

int done = 0;

_PyBytesWriter writer;

ascii_data = data->buf;

len = data->len;

_PyBytesWriter_Init(&writer);

assert(len >= 0);

if (len > PY_SSIZE_T_MAX - 2)

return PyErr_NoMemory();

/* Allocate a string that is too big (fixed later)

Add two to the initial length to prevent interning which

would preclude subsequent resizing. */

bin_data = _PyBytesWriter_Alloc(&writer, len + 2);

if (bin_data == NULL)

return NULL;

for( ; len > 0 ; len--, ascii_data++ ) {

/* Get the byte and look it up */

this_ch = table_a2b_hqx[*ascii_data];

if ( this_ch == SKIP )

continue;

if ( this_ch == FAIL ) {

PyErr_SetString(Error, "Illegal char");

_PyBytesWriter_Dealloc(&writer);

return NULL;

}

if ( this_ch == DONE ) {

/* The terminating colon */

done = 1;

break;

}

/* Shift it into the buffer and see if any bytes are ready */

leftchar = (leftchar << 6) | (this_ch);

leftbits += 6;

if ( leftbits >= 8 ) {

leftbits -= 8;

*bin_data++ = (leftchar >> leftbits) & 0xff;

leftchar &= ((1 << leftbits) - 1);

}

}

if ( leftbits && !done ) {

PyErr_SetString(Incomplete,

"String has incomplete number of bytes");

_PyBytesWriter_Dealloc(&writer);

return NULL;

}

res = _PyBytesWriter_Finish(&writer, bin_data);

if (res == NULL)

return NULL;

return Py_BuildValue("Ni", res, done);

}

/*[clinic input]

binascii.rlecode_hqx

data: Py_buffer

/

Binhex RLE-code binary data.

[clinic start generated code]*/

static PyObject *

binascii_rlecode_hqx_impl(PyObject *module, Py_buffer *data)

/*[clinic end generated code: output=393d79338f5f5629 input=e1f1712447a82b09]*/

{

const unsigned char *in_data;

unsigned char *out_data;

unsigned char ch;

Py_ssize_t in, inend, len;

_PyBytesWriter writer;

_PyBytesWriter_Init(&writer);

in_data = data->buf;

len = data->len;

assert(len >= 0);

if (len > PY_SSIZE_T_MAX / 2 - 2)

return PyErr_NoMemory();

/* Worst case: output is twice as big as input (fixed later) */

out_data = _PyBytesWriter_Alloc(&writer, len * 2 + 2);

if (out_data == NULL)

return NULL;

for( in=0; in<len; in++) {

ch = in_data[in];

if ( ch == RUNCHAR ) {

/* RUNCHAR. Escape it. */

*out_data++ = RUNCHAR;

*out_data++ = 0;

} else {

/* Check how many following are the same */

for(inend=in+1;

inend<len && in_data[inend] == ch &&

inend < in+255;

inend++) ;

if ( inend - in > 3 ) {

/* More than 3 in a row. Output RLE. */

*out_data++ = ch;

*out_data++ = RUNCHAR;

*out_data++ = (unsigned char) (inend-in);

in = inend-1;

} else {

/* Less than 3. Output the byte itself */

*out_data++ = ch;

}

}

}

return _PyBytesWriter_Finish(&writer, out_data);

}

/*[clinic input]

binascii.b2a_hqx

data: Py_buffer

/

Encode .hqx data.

[clinic start generated code]*/

static PyObject *

binascii_b2a_hqx_impl(PyObject *module, Py_buffer *data)

/*[clinic end generated code: output=d0aa5a704bc9f7de input=9596ebe019fe12ba]*/

{

unsigned char *ascii_data;

const unsigned char *bin_data;

int leftbits = 0;

unsigned char this_ch;

unsigned int leftchar = 0;

Py_ssize_t len;

_PyBytesWriter writer;

bin_data = data->buf;

len = data->len;

_PyBytesWriter_Init(&writer);

assert(len >= 0);

if (len > PY_SSIZE_T_MAX / 2 - 2)

return PyErr_NoMemory();

/* Allocate a buffer that is at least large enough */

ascii_data = _PyBytesWriter_Alloc(&writer, len * 2 + 2);

if (ascii_data == NULL)

return NULL;

for( ; len > 0 ; len--, bin_data++ ) {

/* Shift into our buffer, and output any 6bits ready */

leftchar = (leftchar << 8) | *bin_data;

leftbits += 8;

while ( leftbits >= 6 ) {

this_ch = (leftchar >> (leftbits-6)) & 0x3f;

leftbits -= 6;

*ascii_data++ = table_b2a_hqx[this_ch];

}

}

/* Output a possible runt byte */

if ( leftbits ) {

leftchar <<= (6-leftbits);

*ascii_data++ = table_b2a_hqx[leftchar & 0x3f];

}

return _PyBytesWriter_Finish(&writer, ascii_data);

}

/*[clinic input]

binascii.rledecode_hqx

data: Py_buffer

/

Decode hexbin RLE-coded string.

[clinic start generated code]*/

static PyObject *

binascii_rledecode_hqx_impl(PyObject *module, Py_buffer *data)

/*[clinic end generated code: output=9826619565de1c6c input=54cdd49fc014402c]*/

{

const unsigned char *in_data;

unsigned char *out_data;

unsigned char in_byte, in_repeat;

Py_ssize_t in_len;

_PyBytesWriter writer;

in_data = data->buf;

in_len = data->len;

_PyBytesWriter_Init(&writer);

assert(in_len >= 0);

/* Empty string is a special case */

if ( in_len == 0 )

return PyBytes_FromStringAndSize("", 0);

else if (in_len > PY_SSIZE_T_MAX / 2)

return PyErr_NoMemory();

/* Allocate a buffer of reasonable size. Resized when needed */

out_data = _PyBytesWriter_Alloc(&writer, in_len);

if (out_data == NULL)

return NULL;

/* Use overallocation */

writer.overallocate = 1;

/*

** We need two macros here to get/put bytes and handle

** end-of-buffer for input and output strings.

*/

#define INBYTE(b) \

do { \

if ( --in_len < 0 ) { \

PyErr_SetString(Incomplete, ""); \

goto error; \

} \

b = *in_data++; \

} while(0)

/*

** Handle first byte separately (since we have to get angry

** in case of an orphaned RLE code).

*/

INBYTE(in_byte);

if (in_byte == RUNCHAR) {

INBYTE(in_repeat);

/* only 1 byte will be written, but 2 bytes were preallocated:

subtract 1 byte to prevent overallocation */

writer.min_size--;

if (in_repeat != 0) {

/* Note Error, not Incomplete (which is at the end

** of the string only). This is a programmer error.

*/

PyErr_SetString(Error, "Orphaned RLE code at start");

goto error;

}

*out_data++ = RUNCHAR;

} else {

*out_data++ = in_byte;

}

while( in_len > 0 ) {

INBYTE(in_byte);

if (in_byte == RUNCHAR) {

INBYTE(in_repeat);

/* only 1 byte will be written, but 2 bytes were preallocated:

subtract 1 byte to prevent overallocation */

writer.min_size--;

if ( in_repeat == 0 ) {

/* Just an escaped RUNCHAR value */

*out_data++ = RUNCHAR;

} else {

/* Pick up value and output a sequence of it */

in_byte = out_data[-1];

/* enlarge the buffer if needed */

if (in_repeat > 1) {

/* -1 because we already preallocated 1 byte */

out_data = _PyBytesWriter_Prepare(&writer, out_data,

in_repeat - 1);

if (out_data == NULL)

goto error;

}

while ( --in_repeat > 0 )

*out_data++ = in_byte;

}

} else {

/* Normal byte */

*out_data++ = in_byte;

}

}

return _PyBytesWriter_Finish(&writer, out_data);

error:

_PyBytesWriter_Dealloc(&writer);

return NULL;

}

/*[clinic input]

binascii.crc_hqx -> unsigned_int

data: Py_buffer

crc: unsigned_int(bitwise=True)

/

Compute CRC-CCITT incrementally.

[clinic start generated code]*/

static unsigned int

binascii_crc_hqx_impl(PyObject *module, Py_buffer *data, unsigned int crc)

/*[clinic end generated code: output=8ec2a78590d19170 input=f18240ff8c705b79]*/

{

const unsigned char *bin_data;

Py_ssize_t len;

crc &= 0xffff;

bin_data = data->buf;

len = data->len;

while(len-- > 0) {

crc = ((crc<<8)&0xff00) ^ crctab_hqx[(crc>>8)^*bin_data++];

}

return crc;

}

#ifndef USE_ZLIB_CRC32

/* Crc - 32 BIT ANSI X3.66 CRC checksum files

Also known as: ISO 3307

**********************************************************************|

* *|

* Demonstration program to compute the 32-bit CRC used as the frame *|

* check sequence in ADCCP (ANSI X3.66, also known as FIPS PUB 71 *|

* and FED-STD-1003, the U.S. versions of CCITT's X.25 link-level *|

* protocol). The 32-bit FCS was added via the Federal Register, *|

* 1 June 1982, p.23798. I presume but don't know for certain that *|

* this polynomial is or will be included in CCITT V.41, which *|

* defines the 16-bit CRC (often called CRC-CCITT) polynomial. FIPS *|

* PUB 78 says that the 32-bit FCS reduces otherwise undetected *|

* errors by a factor of 10^-5 over 16-bit FCS. *|

* *|

**********************************************************************|

Copyright (C) 1986 Gary S. Brown. You may use this program, or

code or tables extracted from it, as desired without restriction.

First, the polynomial itself and its table of feedback terms. The

polynomial is

X^32+X^26+X^23+X^22+X^16+X^12+X^11+X^10+X^8+X^7+X^5+X^4+X^2+X^1+X^0

Note that we take it "backwards" and put the highest-order term in

the lowest-order bit. The X^32 term is "implied"; the LSB is the

X^31 term, etc. The X^0 term (usually shown as "+1") results in

the MSB being 1.

Note that the usual hardware shift register implementation, which

is what we're using (we're merely optimizing it by doing eight-bit

chunks at a time) shifts bits into the lowest-order term. In our

implementation, that means shifting towards the right. Why do we

do it this way? Because the calculated CRC must be transmitted in

order from highest-order term to lowest-order term. UARTs transmit

characters in order from LSB to MSB. By storing the CRC this way,

we hand it to the UART in the order low-byte to high-byte; the UART

sends each low-bit to hight-bit; and the result is transmission bit

by bit from highest- to lowest-order term without requiring any bit

shuffling on our part. Reception works similarly.

The feedback terms table consists of 256, 32-bit entries. Notes:

1. The table can be generated at runtime if desired; code to do so

is shown later. It might not be obvious, but the feedback

terms simply represent the results of eight shift/xor opera-

tions for all combinations of data and CRC register values.

2. The CRC accumulation logic is the same for all CRC polynomials,

be they sixteen or thirty-two bits wide. You simply choose the

appropriate table. Alternatively, because the table can be

generated at runtime, you can start by generating the table for

the polynomial in question and use exactly the same "updcrc",

if your application needn't simultaneously handle two CRC