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#include "bech32_util.h"
#include <ccan/tal/str/str.h>
#include <common/bech32.h>
static u8 get_bit(const u8 *src, size_t bitoff)
{
return ((src[bitoff / 8] >> (7 - (bitoff % 8))) & 1);
}
void bech32_push_bits(u5 **data, const void *src, size_t nbits)
{
size_t i, b;
size_t data_len = tal_count(*data);
for (i = 0; i < nbits; i += b) {
tal_resize(data, data_len+1);
(*data)[data_len] = 0;
for (b = 0; b < 5; b++) {
(*data)[data_len] <<= 1;
/* If we need bits we don't have, zero */
if (i+b < nbits)
(*data)[data_len] |= get_bit(src, i+b);
}
data_len++;
}
}
static u8 get_u5_bit(const u5 *src, size_t bitoff)
{
return ((src[bitoff / 5] >> (4 - (bitoff % 5))) & 1);
}
void bech32_pull_bits(u8 **data, const u5 *src, size_t nbits)
{
size_t i;
size_t data_len = tal_count(*data);
/* We discard trailing bits. */
for (i = 0; i + 8 <= nbits; i += 8) {
tal_resize(data, data_len+1);
(*data)[data_len] = 0;
for (size_t b = 0; b < 8; b++) {
(*data)[data_len] <<= 1;
(*data)[data_len] |= get_u5_bit(src, i+b);
}
data_len++;
}
}
/* Returns a char, tracks case. */
static int fixup_char(int c, bool *upper, bool *lower)
{
if (c >= 'A' && c <= 'Z') {
*upper = true;
return c + ('a' - 'A');
} else if (c >= 'a' && c <= 'z') {
*lower = true;
}
return c;
}
bool from_bech32_charset(const tal_t *ctx,
const char *bech32,
size_t bech32_len,
char **hrp, u8 **data)
{
u5 *u5data;
const char *sep;
bool upper = false, lower = false;
size_t datalen;
sep = memchr(bech32, '1', bech32_len);
if (!sep)
return false;
*hrp = tal_strndup(ctx, bech32, sep - bech32);
for (size_t i = 0; i < strlen(*hrp); i++)
(*hrp)[i] = fixup_char((*hrp)[i], &upper, &lower);
datalen = bech32_len - (sep + 1 - bech32);
u5data = tal_arr(NULL, u5, datalen);
for (size_t i = 0; i < datalen; i++) {
int c = sep[1+i];
if (c < 0 || c > 128)
goto fail;
c = fixup_char(c, &upper, &lower);
if (bech32_charset_rev[c] == -1)
goto fail;
u5data[i] = bech32_charset_rev[c];
}
/* Check case consistency */
if (upper && lower)
goto fail;
*data = tal_arr(ctx, u8, 0);
bech32_pull_bits(data, u5data, tal_bytelen(u5data) * 5);
tal_free(u5data);
return true;
fail:
*hrp = tal_free(*hrp);
tal_free(u5data);
return false;
}
char *to_bech32_charset(const tal_t *ctx,
const char *hrp, const u8 *data)
{
u5 *u5data = tal_arr(NULL, u5, 0);
char *ret;
bech32_push_bits(&u5data, data, tal_bytelen(data) * 8);
ret = tal_dup_arr(ctx, char, hrp, strlen(hrp),
1 + tal_bytelen(u5data) + 1);
ret[strlen(hrp)] = '1';
for (size_t i = 0; i < tal_bytelen(u5data); i++)
ret[strlen(hrp) + 1 + i] = bech32_charset[u5data[i]];
ret[strlen(hrp) + 1 + tal_bytelen(u5data)] = '\0';
tal_free(u5data);
return ret;
}