diff options
Diffstat (limited to 'extmod/modubinascii.c')
| -rw-r--r-- | extmod/modubinascii.c | 100 |
1 files changed, 58 insertions, 42 deletions
diff --git a/extmod/modubinascii.c b/extmod/modubinascii.c index 2ef1a6f21d..25fc8852ac 100644 --- a/extmod/modubinascii.c +++ b/extmod/modubinascii.c @@ -1,5 +1,5 @@ /* - * This file is part of the Micro Python project, http://micropython.org/ + * This file is part of the MicroPython project, http://micropython.org/ * * The MIT License (MIT) * @@ -42,6 +42,12 @@ mp_obj_t mod_binascii_hexlify(size_t n_args, const mp_obj_t *args) { mp_buffer_info_t bufinfo; 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) { @@ -75,7 +81,7 @@ mp_obj_t mod_binascii_unhexlify(mp_obj_t data) { mp_get_buffer_raise(data, &bufinfo, MP_BUFFER_READ); if ((bufinfo.len & 1) != 0) { - nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_ValueError, "odd-length string")); + mp_raise_ValueError("odd-length string"); } vstr_t vstr; vstr_init_len(&vstr, bufinfo.len / 2); @@ -86,7 +92,7 @@ mp_obj_t mod_binascii_unhexlify(mp_obj_t data) { if (unichar_isxdigit(hex_ch)) { hex_byte += unichar_xdigit_value(hex_ch); } else { - nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_ValueError, "non-hex digit found")); + mp_raise_ValueError("non-hex digit found"); } if (i & 1) { hex_byte <<= 4; @@ -99,54 +105,64 @@ mp_obj_t mod_binascii_unhexlify(mp_obj_t data) { } 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); - if (bufinfo.len % 4 != 0) { - nlr_raise(mp_obj_new_exception_msg(&mp_type_ValueError, "incorrect padding")); - } + byte *in = bufinfo.buf; vstr_t vstr; - byte *in = bufinfo.buf; - if (bufinfo.len == 0) { - vstr_init_len(&vstr, 0); - } - else { - vstr_init_len(&vstr, ((bufinfo.len / 4) * 3) - ((in[bufinfo.len-1] == '=') ? ((in[bufinfo.len-2] == '=') ? 2 : 1 ) : 0)); - } - byte *out = (byte*)vstr.buf; - for (mp_uint_t i = bufinfo.len; i; i -= 4) { - char hold[4]; - for (int j = 4; j--;) { - if (in[j] >= 'A' && in[j] <= 'Z') { - hold[j] = in[j] - 'A'; - } else if (in[j] >= 'a' && in[j] <= 'z') { - hold[j] = in[j] - 'a' + 26; - } else if (in[j] >= '0' && in[j] <= '9') { - hold[j] = in[j] - '0' + 52; - } else if (in[j] == '+') { - hold[j] = 62; - } else if (in[j] == '/') { - hold[j] = 63; - } else if (in[j] == '=') { - if (j < 2 || i > 4) { - nlr_raise(mp_obj_new_exception_msg(&mp_type_ValueError, "incorrect padding")); - } - hold[j] = 64; - } else { - nlr_raise(mp_obj_new_exception_msg(&mp_type_ValueError, "invalid character")); + 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; } - in += 4; - *out++ = (hold[0]) << 2 | (hold[1]) >> 4; - if (hold[2] != 64) { - *out++ = (hold[1] & 0x0F) << 4 | hold[2] >> 2; - if (hold[3] != 64) { - *out++ = (hold[2] & 0x03) << 6 | hold[3]; - } + 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("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); @@ -178,7 +194,7 @@ mp_obj_t mod_binascii_b2a_base64(mp_obj_t data) { *out++ = (in[0] & 0x03) << 4; *out++ = 64; } - *out++ = 64; + *out = 64; } // Second pass, we convert number base 64 values to actual base64 ascii encoding |