Add a base64 codec, due to popular request
I still think that base64 is awful, but users have spoken.
This commit is contained in:
Frank Denis
parent
308684790f
commit
3f272cbbfc
@ -61,6 +61,22 @@ int sodium_hex2bin(unsigned char * const bin, const size_t bin_maxlen,
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const char * const ignore, size_t * const bin_len,
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const char ** const hex_end);
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#define sodium_bin2b64_VARIANT_ORIGINAL 1
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#define sodium_bin2b64_VARIANT_ORIGINAL_NO_PADDING 3
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#define sodium_bin2b64_VARIANT_URLSAFE 5
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#define sodium_bin2b64_VARIANT_URLSAFE_NO_PADDING 7
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SODIUM_EXPORT
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char *sodium_bin2base64(char * const b64, const size_t b64_maxlen,
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const unsigned char * const bin, const size_t bin_len,
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const int variant);
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SODIUM_EXPORT
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int sodium_base642bin(unsigned char * const bin, const size_t bin_maxlen,
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const char * const b64, const size_t b64_len,
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const char * const ignore, size_t * const bin_len,
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const char ** const b64_end, const int variant);
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SODIUM_EXPORT
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int sodium_mlock(void * const addr, const size_t len);
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@ -3,6 +3,7 @@
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#include <limits.h>
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#include <stddef.h>
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#include <stdlib.h>
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#include <string.h>
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#include "core.h"
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#include "utils.h"
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@ -89,3 +90,218 @@ sodium_hex2bin(unsigned char *const bin, const size_t bin_maxlen,
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}
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return ret;
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}
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/*
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* Some macros for constant-time comparisons. These work over values in
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* the 0..255 range. Returned value is 0x00 on "false", 0xFF on "true".
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*
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* Original code by Thomas Pornin.
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*/
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#define EQ(x, y) \
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((((0U - ((unsigned int) (x) ^ (unsigned int) (y))) >> 8) & 0xFF) ^ 0xFF)
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#define GT(x, y) ((((unsigned int) (y) - (unsigned int) (x)) >> 8) & 0xFF)
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#define GE(x, y) (GT(y, x) ^ 0xFF)
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#define LT(x, y) GT(y, x)
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#define LE(x, y) GE(y, x)
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static int
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b64_byte_to_char(unsigned int x)
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{
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return (LT(x, 26) & (x + 'A')) |
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(GE(x, 26) & LT(x, 52) & (x + ('a' - 26))) |
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(GE(x, 52) & LT(x, 62) & (x + ('0' - 52))) | (EQ(x, 62) & '+') |
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(EQ(x, 63) & '/');
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}
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static unsigned int
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b64_char_to_byte(int c)
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{
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const unsigned int x =
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(GE(c, 'A') & LE(c, 'Z') & (c - 'A')) |
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(GE(c, 'a') & LE(c, 'z') & (c - ('a' - 26))) |
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(GE(c, '0') & LE(c, '9') & (c - ('0' - 52))) | (EQ(c, '+') & 62) |
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(EQ(c, '/') & 63);
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return x | (EQ(x, 0) & (EQ(c, 'A') ^ 0xFF));
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}
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static int
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b64_byte_to_urlsafe_char(unsigned int x)
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{
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return (LT(x, 26) & (x + 'A')) |
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(GE(x, 26) & LT(x, 52) & (x + ('a' - 26))) |
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(GE(x, 52) & LT(x, 62) & (x + ('0' - 52))) | (EQ(x, 62) & '-') |
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(EQ(x, 63) & '_');
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}
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static unsigned int
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b64_urlsafe_char_to_byte(int c)
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{
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const unsigned x =
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(GE(c, 'A') & LE(c, 'Z') & (c - 'A')) |
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(GE(c, 'a') & LE(c, 'z') & (c - ('a' - 26))) |
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(GE(c, '0') & LE(c, '9') & (c - ('0' - 52))) | (EQ(c, '-') & 62) |
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(EQ(c, '_') & 63);
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return x | (EQ(x, 0) & (EQ(c, 'A') ^ 0xFF));
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}
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#define VARIANT_NO_PADDING_MASK 0x2U
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#define VARIANT_URLSAFE_MASK 0x4U
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char *
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sodium_bin2base64(char * const b64, const size_t b64_maxlen,
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const unsigned char * const bin, const size_t bin_len,
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const int variant)
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{
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size_t acc_len = (size_t) 0;
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size_t b64_len;
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size_t b64_pos = (size_t) 0;
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size_t bin_pos = (size_t) 0;
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size_t nibbles;
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size_t remainder;
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unsigned int acc = 0U;
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if ((((unsigned int) variant) & ~ 0x6U) != 0x1U) {
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sodium_misuse();
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}
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nibbles = bin_len / 3;
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remainder = bin_len - 3 * nibbles;
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b64_len = nibbles * 4;
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if (remainder != 0) {
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if ((((unsigned int) variant) & VARIANT_NO_PADDING_MASK) == 0U) {
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b64_len += 4;
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} else {
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b64_len += 2;
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if (remainder == 2) {
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b64_len++;
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}
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}
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}
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if (b64_maxlen <= b64_len) {
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sodium_misuse();
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}
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if ((((unsigned int) variant) & VARIANT_URLSAFE_MASK) != 0U) {
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while (bin_pos < bin_len) {
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acc = (acc << 8) + bin[bin_pos++];
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acc_len += 8;
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while (acc_len >= 6) {
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acc_len -= 6;
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b64[b64_pos++] = (char) b64_byte_to_urlsafe_char((acc >> acc_len) & 0x3F);
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}
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}
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if (acc_len > 0) {
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b64[b64_pos++] = (char) b64_byte_to_urlsafe_char((acc << (6 - acc_len)) & 0x3F);
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}
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} else {
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while (bin_pos < bin_len) {
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acc = (acc << 8) + bin[bin_pos++];
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acc_len += 8;
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while (acc_len >= 6) {
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acc_len -= 6;
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b64[b64_pos++] = (char) b64_byte_to_char((acc >> acc_len) & 0x3F);
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}
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}
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if (acc_len > 0) {
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b64[b64_pos++] = (char) b64_byte_to_char((acc << (6 - acc_len)) & 0x3F);
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}
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}
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while (b64_pos < b64_len) {
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b64[b64_pos++] = '=';
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}
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b64[b64_pos++] = 0;
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return b64;
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}
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static int
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_sodium_base642bin_skip_padding(const char * const b64, const size_t b64_len,
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size_t * const b64_pos_p,
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const char * const ignore, int padding_len)
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{
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int c;
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while (padding_len > 0) {
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if (*b64_pos_p >= b64_len) {
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errno = ERANGE;
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return -1;
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}
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c = b64[*b64_pos_p];
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if (c == '=') {
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padding_len--;
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} else if (ignore == NULL || strchr(ignore, c) == NULL) {
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errno = EINVAL;
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return -1;
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}
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(*b64_pos_p)++;
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}
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return 0;
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}
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int
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sodium_base642bin(unsigned char * const bin, const size_t bin_maxlen,
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const char * const b64, const size_t b64_len,
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const char * const ignore, size_t * const bin_len,
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const char ** const b64_end, const int variant)
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{
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size_t acc_len = (size_t) 0;
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size_t b64_pos = (size_t) 0;
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size_t bin_pos = (size_t) 0;
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int is_urlsafe;
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int ret = 0;
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unsigned int acc = 0U;
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unsigned int d;
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char c;
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if ((((unsigned int) variant) & ~ 0x6U) != 0x1U) {
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sodium_misuse();
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}
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is_urlsafe = ((unsigned int) variant) & VARIANT_URLSAFE_MASK;
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while (b64_pos < b64_len) {
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c = b64[b64_pos];
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if (is_urlsafe) {
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d = b64_urlsafe_char_to_byte(c);
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} else {
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d = b64_char_to_byte(c);
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}
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if (d == 0xFF) {
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if (ignore != NULL && strchr(ignore, c) != NULL) {
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if (b64_pos >= b64_len) {
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errno = ERANGE;
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ret = -1;
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break;
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}
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b64_pos++;
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continue;
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}
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break;
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}
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acc = (acc << 6) + d;
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acc_len += 6;
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if (acc_len >= 8) {
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acc_len -= 8;
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if (bin_pos >= bin_maxlen) {
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errno = ERANGE;
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ret = -1;
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break;
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}
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bin[bin_pos++] = (acc >> acc_len) & 0xFF;
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}
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b64_pos++;
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}
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if (acc_len > 4U || (acc & ((1U << acc_len) - 1U)) != 0U) {
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ret = -1;
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} else if (ret == 0 &&
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(((unsigned int) variant) & VARIANT_NO_PADDING_MASK) == 0U) {
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ret = _sodium_base642bin_skip_padding(b64, b64_len, &b64_pos, ignore,
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acc_len / 2);
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}
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if (bin_len != NULL) {
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*bin_len = bin_pos;
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}
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if (b64_end != NULL) {
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*b64_end = &b64[b64_pos];
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}
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return ret;
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}
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