#include <string.h>
#include <stdio.h>
//#undef DEBUG_85
#define DEBUG_85
#ifdef DEBUG_85
#define say(a) fprintf(stderr, a)
#define say1(a,b) fprintf(stderr, a, b)
#define say2(a,b,c) fprintf(stderr, a, b, c)
#else
#define say(a) do { /* nothing */ } while (0)
#define say1(a,b) do { /* nothing */ } while (0)
#define say2(a,b,c) do { /* nothing */ } while (0)
#endif
static const char en85[] = {
'0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J',
'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T',
'U', 'V', 'W', 'X', 'Y', 'Z',
'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j',
'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't',
'u', 'v', 'w', 'x', 'y', 'z',
'!', '#', '$', '%', '&', '(', ')', '*', '+', '-',
';', '<', '=', '>', '?', '@', '^', '_', '`', '{',
'|', '}', '~'
};
static char de85[256];
static void prep_base85(void)
{
if (de85['Z'])
return;
int i;
for (i = 0; i < sizeof(en85); i++) {
int ch = en85[i];
de85[ch] = i + 1;
}
}
int decode_85(char *dst, const char *buffer, int len)
{
const char *start=buffer;
prep_base85();
say2("decoding=>(given len=%d,converted len=%d)",len,len/4*5);
say2(" decoding str:(%.*s)", len/4*5, buffer);
while (len) {
say1("\n(loop len=%d) ",len);
unsigned acc = 0;
int de, cnt = 4;
unsigned char ch;
do {
ch = *buffer++;
say1("%c",ch);
de = de85[ch];
if (--de < 0){
//return error("invalid base85 alphabet %c", ch);
say1("invalid base85 alphabet (%c)\n",ch); return -1;
}
acc = acc * 85 + de;
} while (--cnt);
ch = *buffer++;
say1("%c",ch);
de = de85[ch];
if (--de < 0){
//return error("invalid base85 alphabet %c", ch);
say("error -2\n"); return -2;
}
/* Detect overflow. */
if (0xffffffff / 85 < acc || 0xffffffff - de < (acc *= 85)){
//return error("invalid base85 sequence %.5s", buffer-5);
say("error -3\n"); return -3;
}
acc += de;
say1(" %08X", acc);
cnt = (len < 4) ? len : 4;
len -= cnt;
do {
acc = (acc << 8) | (acc >> 24);
*dst++ = acc;
} while (--cnt);
}
say1("\n",len);
//return 0;
return buffer-start;
}
//#ifdef DEBUG_85
int main(int ac, char **av)
{
char buf[1024];
if (!strcmp(av[1], "-e")) {
int len = strlen(av[2]);
encode_85(buf, av[2], len);
if (len <= 26) len = len + 'A' - 1;
else len = len + 'a' - 26 - 1;
printf("encoded:%c%s\n", len, buf);
return 0;
}
if (!strcmp(av[1], "-d")) {
int len = *av[2];
if ('A' <= len && len <= 'Z') len = len - 'A' + 1;
else len = len - 'a' + 26 + 1;
decode_85(buf, av[2]+1, len);
printf("decoded:%.*s\n", len, buf);
return 0;
}
if (!strcmp(av[1], "-t")) {
/*
char t[4] = { -1,-1,-1,-1 };
encode_85(buf, t, 4);
printf("encoded: D%s\n", buf);
return 0;
*/
char encoded[1024];
char decoded[1024];
const char instring[]="0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZa";
int encoded_len=encode_85(encoded,instring,strlen(instring));
decode_85(decoded,encoded,encoded_len);
say2("inlen=%d,outlen=%d",strlen(instring),encoded_len);
say1("\n%s\n",decoded);
return 0;
}
}
//#endif