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circuitpython/extmod/modubinascii.c

264 lines
8.5 KiB

/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2014 Paul Sokolovsky
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include <stdio.h>
#include <assert.h>
#include <string.h>
#include "py/runtime.h"
#include "py/binary.h"
#include "extmod/modubinascii.h"
static void check_not_unicode(const mp_obj_t arg) {
#if MICROPY_CPYTHON_COMPAT
if (MP_OBJ_IS_STR(arg)) {
mp_raise_TypeError(translate("a bytes-like object is required"));
}
#endif
}
mp_obj_t mod_binascii_hexlify(size_t n_args, const mp_obj_t *args) {
// Second argument is for an extension to allow a separator to be used
// between values.
const char *sep = NULL;
mp_buffer_info_t bufinfo;
check_not_unicode(args[0]);
mp_get_buffer_raise(args[0], &bufinfo, MP_BUFFER_READ);
// Code below assumes non-zero buffer length when computing size with
// separator, so handle the zero-length case here.
if (bufinfo.len == 0) {
return mp_const_empty_bytes;
}
vstr_t vstr;
size_t out_len = bufinfo.len * 2;
if (n_args > 1) {
// 1-char separator between hex numbers
out_len += bufinfo.len - 1;
sep = mp_obj_str_get_str(args[1]);
}
vstr_init_len(&vstr, out_len);
byte *in = bufinfo.buf, *out = (byte*)vstr.buf;
for (mp_uint_t i = bufinfo.len; i--;) {
byte d = (*in >> 4);
if (d > 9) {
d += 'a' - '9' - 1;
}
*out++ = d + '0';
d = (*in++ & 0xf);
if (d > 9) {
d += 'a' - '9' - 1;
}
*out++ = d + '0';
if (sep != NULL && i != 0) {
*out++ = *sep;
}
}
return mp_obj_new_str_from_vstr(&mp_type_bytes, &vstr);
}
MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(mod_binascii_hexlify_obj, 1, 2, mod_binascii_hexlify);
mp_obj_t mod_binascii_unhexlify(mp_obj_t data) {
mp_buffer_info_t bufinfo;
mp_get_buffer_raise(data, &bufinfo, MP_BUFFER_READ);
if ((bufinfo.len & 1) != 0) {
mp_raise_ValueError(translate("odd-length string"));
}
vstr_t vstr;
vstr_init_len(&vstr, bufinfo.len / 2);
byte *in = bufinfo.buf, *out = (byte*)vstr.buf;
byte hex_byte = 0;
for (mp_uint_t i = bufinfo.len; i--;) {
byte hex_ch = *in++;
if (unichar_isxdigit(hex_ch)) {
hex_byte += unichar_xdigit_value(hex_ch);
} else {
mp_raise_ValueError(translate("non-hex digit found"));
}
if (i & 1) {
hex_byte <<= 4;
} else {
*out++ = hex_byte;
hex_byte = 0;
}
}
return mp_obj_new_str_from_vstr(&mp_type_bytes, &vstr);
}
MP_DEFINE_CONST_FUN_OBJ_1(mod_binascii_unhexlify_obj, mod_binascii_unhexlify);
// If ch is a character in the base64 alphabet, and is not a pad character, then
// the corresponding integer between 0 and 63, inclusively, is returned.
// Otherwise, -1 is returned.
static int mod_binascii_sextet(byte ch) {
if (ch >= 'A' && ch <= 'Z') {
return ch - 'A';
} else if (ch >= 'a' && ch <= 'z') {
return ch - 'a' + 26;
} else if (ch >= '0' && ch <= '9') {
return ch - '0' + 52;
} else if (ch == '+') {
return 62;
} else if (ch == '/') {
return 63;
} else {
return -1;
}
}
mp_obj_t mod_binascii_a2b_base64(mp_obj_t data) {
mp_buffer_info_t bufinfo;
mp_get_buffer_raise(data, &bufinfo, MP_BUFFER_READ);
byte *in = bufinfo.buf;
vstr_t vstr;
vstr_init(&vstr, (bufinfo.len / 4) * 3 + 1); // Potentially over-allocate
byte *out = (byte *)vstr.buf;
uint shift = 0;
int nbits = 0; // Number of meaningful bits in shift
bool hadpad = false; // Had a pad character since last valid character
for (size_t i = 0; i < bufinfo.len; i++) {
if (in[i] == '=') {
if ((nbits == 2) || ((nbits == 4) && hadpad)) {
nbits = 0;
break;
}
hadpad = true;
}
int sextet = mod_binascii_sextet(in[i]);
if (sextet == -1) {
continue;
}
hadpad = false;
shift = (shift << 6) | sextet;
nbits += 6;
if (nbits >= 8) {
nbits -= 8;
out[vstr.len++] = (shift >> nbits) & 0xFF;
}
}
if (nbits) {
mp_raise_ValueError(translate("incorrect padding"));
}
return mp_obj_new_str_from_vstr(&mp_type_bytes, &vstr);
}
MP_DEFINE_CONST_FUN_OBJ_1(mod_binascii_a2b_base64_obj, mod_binascii_a2b_base64);
mp_obj_t mod_binascii_b2a_base64(mp_obj_t data) {
check_not_unicode(data);
mp_buffer_info_t bufinfo;
mp_get_buffer_raise(data, &bufinfo, MP_BUFFER_READ);
vstr_t vstr;
vstr_init_len(&vstr, ((bufinfo.len != 0) ? (((bufinfo.len - 1) / 3) + 1) * 4 : 0) + 1);
// First pass, we convert input buffer to numeric base 64 values
byte *in = bufinfo.buf, *out = (byte*)vstr.buf;
mp_uint_t i;
for (i = bufinfo.len; i >= 3; i -= 3) {
*out++ = (in[0] & 0xFC) >> 2;
*out++ = (in[0] & 0x03) << 4 | (in[1] & 0xF0) >> 4;
*out++ = (in[1] & 0x0F) << 2 | (in[2] & 0xC0) >> 6;
*out++ = in[2] & 0x3F;
in += 3;
}
if (i != 0) {
*out++ = (in[0] & 0xFC) >> 2;
if (i == 2) {
*out++ = (in[0] & 0x03) << 4 | (in[1] & 0xF0) >> 4;
*out++ = (in[1] & 0x0F) << 2;
}
else {
*out++ = (in[0] & 0x03) << 4;
*out++ = 64;
}
*out = 64;
}
// Second pass, we convert number base 64 values to actual base64 ascii encoding
out = (byte*)vstr.buf;
for (mp_uint_t j = vstr.len - 1; j--;) {
if (*out < 26) {
*out += 'A';
} else if (*out < 52) {
*out += 'a' - 26;
} else if (*out < 62) {
*out += '0' - 52;
} else if (*out == 62) {
*out ='+';
} else if (*out == 63) {
*out = '/';
} else {
*out = '=';
}
out++;
}
*out = '\n';
return mp_obj_new_str_from_vstr(&mp_type_bytes, &vstr);
}
MP_DEFINE_CONST_FUN_OBJ_1(mod_binascii_b2a_base64_obj, mod_binascii_b2a_base64);
#if MICROPY_PY_UBINASCII_CRC32
#include "../../lib/uzlib/src/tinf.h"
mp_obj_t mod_binascii_crc32(size_t n_args, const mp_obj_t *args) {
mp_buffer_info_t bufinfo;
check_not_unicode(args[0]);
mp_get_buffer_raise(args[0], &bufinfo, MP_BUFFER_READ);
uint32_t crc = (n_args > 1) ? mp_obj_get_int_truncated(args[1]) : 0;
crc = uzlib_crc32(bufinfo.buf, bufinfo.len, crc ^ 0xffffffff);
return mp_obj_new_int_from_uint(crc ^ 0xffffffff);
}
MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(mod_binascii_crc32_obj, 1, 2, mod_binascii_crc32);
#endif
#if MICROPY_PY_UBINASCII
STATIC const mp_rom_map_elem_t mp_module_binascii_globals_table[] = {
{ MP_ROM_QSTR(MP_QSTR___name__), MP_ROM_QSTR(MP_QSTR_binascii) },
{ MP_ROM_QSTR(MP_QSTR_hexlify), MP_ROM_PTR(&mod_binascii_hexlify_obj) },
{ MP_ROM_QSTR(MP_QSTR_unhexlify), MP_ROM_PTR(&mod_binascii_unhexlify_obj) },
{ MP_ROM_QSTR(MP_QSTR_a2b_base64), MP_ROM_PTR(&mod_binascii_a2b_base64_obj) },
{ MP_ROM_QSTR(MP_QSTR_b2a_base64), MP_ROM_PTR(&mod_binascii_b2a_base64_obj) },
#if MICROPY_PY_UBINASCII_CRC32
{ MP_ROM_QSTR(MP_QSTR_crc32), MP_ROM_PTR(&mod_binascii_crc32_obj) },
#endif
};
STATIC MP_DEFINE_CONST_DICT(mp_module_binascii_globals, mp_module_binascii_globals_table);
const mp_obj_module_t mp_module_ubinascii = {
.base = { &mp_type_module },
.globals = (mp_obj_dict_t*)&mp_module_binascii_globals,
};
#endif //MICROPY_PY_UBINASCII