ref: c116550e6a41572796e4db65e4f6acbcb3d9d6f8
dir: /appl/spree/lib/base64.b/
implement Base64; include "base64.m"; PADCH: con '='; encode(b: array of byte): string { chmap := "ABCDEFGHIJKLMNOPQRSTUVWXYZ" + "abcdefghijklmnopqrstuvwxyz0123456789+/"; r := ""; blen := len b; full := (blen + 2)/ 3; rplen := (4*blen + 2) / 3; ip := 0; rp := 0; for (i:=0; i<full; i++) { word := 0; for (j:=2; j>=0; j--) if (ip < blen) word = word | int b[ip++] << 8*j; for (l:=3; l>=0; l--) if (rp < rplen) r[rp++] = chmap[(word >> (6*l)) & 16r3f]; else r[rp++] = PADCH; } return r; } # Decode a base 64 string to a byte stream # Must be a multiple of 4 characters in length decode(s: string): array of byte { tch: int; slen := len s; rlen := (3*slen+3)/4; if (slen >= 4 && s[slen-1] == PADCH) rlen--; if (slen >= 4 && s[slen-2] == PADCH) rlen--; r := array[rlen] of byte; full := slen / 4; sp := 0; rp := 0; for (i:=0; i<full; i++) { word := 0; for (j:=0; j<4; j++) { ch := s[sp++]; case ch { 'A' to 'Z' => tch = ch - 'A'; 'a' to 'z' => tch = ch - 'a' + 26; '0' to '9' => tch = ch - '0' + 52; '+' => tch = 62; '/' => tch = 63; * => tch = 0; } word = (word << 6) | tch; } for (l:=2; l>=0; l--) if (rp < rlen) r[rp++] = byte( (word >> 8*l) & 16rff); } return r; }