#include "error.h"
#include "stralloc.h"
#include "base32.h"


static const unsigned char base32values[256] = {
    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
    0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
    0x08, 0x09, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
    0xff, 0xff, 0x0a, 0x0b, 0x0c, 0xff, 0x0d, 0x0e,
    0x0f, 0xff, 0x10, 0x11, 0x12, 0x13, 0x14, 0xff,
    0x15, 0x16, 0x17, 0x18, 0x19, 0x1a, 0x1b, 0x1c,
    0x1d, 0x1e, 0x1f, 0xff, 0xff, 0xff, 0xff, 0xff,

    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff
};


int base32_decode(stralloc *out, const unsigned char *in, unsigned int inlen){

    unsigned int i,v=0, vbits=0;
    unsigned char uch;
    char ch;

    if (!stralloc_copys(out,"")) return -1;

    for(i = 0; i < inlen; ++i){
        uch = base32values[in[i]];
        if (uch > 0x1f) {errno = error_proto; out->len = 0; return 0;}
        v |= uch << vbits;
        vbits += 5;

        if (vbits >= 8){
            ch = v;
            if (!stralloc_append(out, &ch)) {out->len = 0; return -1;}
            vbits -= 8; v >>= 8;
        }
    }
    if (vbits){
        ch = v;
        if (!stralloc_append(out, &ch)) {out->len = 0;return -1;}
    }
    return 1;
}

static const char hexchars[]="0123456789abcdef";

int base32_decodehex(stralloc *out, const unsigned char *in, unsigned int inlen){

    unsigned int i,v=0, vbits=0;
    unsigned char uch;
    unsigned char ch;

    if (!stralloc_copys(out,"")) return -1;

    for(i = 0; i < inlen; ++i){
        uch = base32values[in[i]];
        if (uch > 0x1f) {errno = error_proto; out->len = 0; return 0;}
        v |= uch << vbits;
        vbits += 5;

        if (vbits >= 8){
            ch = v;
            if (!stralloc_catb(out, hexchars + (ch >> 4), 1)) {out->len = 0; return -1;}
            if (!stralloc_catb(out, hexchars + (ch & 15), 1)) {out->len = 0; return -1;}
            vbits -= 8; v >>= 8;
        }
    }
    if (vbits){
        ch = v;
        if (!stralloc_catb(out, hexchars + (ch >> 4), 1)) {out->len = 0; return -1;}
        if (!stralloc_catb(out, hexchars + (ch & 15), 1)) {out->len = 0; return -1;}
    }
    return 1;
}

static const char base32chars[] = "0123456789bcdfghjklmnpqrstuvwxyz";

int base32_encode(stralloc *out, const unsigned char *in, unsigned int inlen){

    unsigned int j=0,v=0,bits=0;
    char ch;

    if (!stralloc_copys(out,"")) return -1;

    while (j < inlen){
        v |= in[j++] << bits;
        bits += 8;

        while (bits >= 5){
            ch = base32chars[v & 31];
            if (!stralloc_append(out, &ch)) {out->len = 0;return -1;}
            bits -= 5; v >>= 5;
        }
        
    }
    if (bits){
        ch = base32chars[v & 31];
        if (!stralloc_append(out, &ch)) {out->len = 0;return -1;}
        bits -= 5; v >>= 5;
    }
    return 1;
}