Andrew Boyson / crypto

A simple library to support serving https.

Dependents:   oldheating gps motorhome heating

pki/base64.c@0:be515c9019e3, 2019-07-25 (annotated)

Committer:
andrewboyson
Date:
Thu Jul 25 21:16:24 2019 +0000
Revision:
0:be515c9019e3
Pulled together existing modules from https and big numbers into this one. Added TLS PRF module.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
andrewboyson 0:be515c9019e3 1 #include <stdbool.h>
andrewboyson 0:be515c9019e3 2 #include <stdio.h>
andrewboyson 0:be515c9019e3 3 #include "base64.h"
andrewboyson 0:be515c9019e3 4
andrewboyson 0:be515c9019e3 5 char (*Base64ReadNextCharFunctionPointer)(void) = NULL;
andrewboyson 0:be515c9019e3 6
andrewboyson 0:be515c9019e3 7 static int get6bits()
andrewboyson 0:be515c9019e3 8 {
andrewboyson 0:be515c9019e3 9 while (true)
andrewboyson 0:be515c9019e3 10 {
andrewboyson 0:be515c9019e3 11 char c = Base64ReadNextCharFunctionPointer();
andrewboyson 0:be515c9019e3 12 if (c == 0 ) return -1; //EOF or an error
andrewboyson 0:be515c9019e3 13 else if (c == '-') return -1; //Finished
andrewboyson 0:be515c9019e3 14 else if (c == '=') return -1; //Padding
andrewboyson 0:be515c9019e3 15 else if (c == '/') return 63;
andrewboyson 0:be515c9019e3 16 else if (c == '+') return 62;
andrewboyson 0:be515c9019e3 17 else if (c >= 'a') return c - 'a' + 26;
andrewboyson 0:be515c9019e3 18 else if (c >= 'A') return c - 'A' + 0;
andrewboyson 0:be515c9019e3 19 else if (c >= '0') return c - '0' + 52;
andrewboyson 0:be515c9019e3 20 else continue;
andrewboyson 0:be515c9019e3 21 }
andrewboyson 0:be515c9019e3 22 }
andrewboyson 0:be515c9019e3 23
andrewboyson 0:be515c9019e3 24 static int last6 = 0;
andrewboyson 0:be515c9019e3 25 static int posn = 0;
andrewboyson 0:be515c9019e3 26 static bool finished = false;
andrewboyson 0:be515c9019e3 27 int Base64ReadByte()
andrewboyson 0:be515c9019e3 28 {
andrewboyson 0:be515c9019e3 29 if (finished) return -1;
andrewboyson 0:be515c9019e3 30
andrewboyson 0:be515c9019e3 31 /*
andrewboyson 0:be515c9019e3 32 L = last
andrewboyson 0:be515c9019e3 33 T = this
andrewboyson 0:be515c9019e3 34 out
andrewboyson 0:be515c9019e3 35 case 0 TTTTTTLL
andrewboyson 0:be515c9019e3 36 case 1 LLLLTTTT
andrewboyson 0:be515c9019e3 37 case 2 LLTTTTTT
andrewboyson 0:be515c9019e3 38 */
andrewboyson 0:be515c9019e3 39 int this6 = 0;
andrewboyson 0:be515c9019e3 40 int bits8 = 0;
andrewboyson 0:be515c9019e3 41
andrewboyson 0:be515c9019e3 42 switch (posn)
andrewboyson 0:be515c9019e3 43 {
andrewboyson 0:be515c9019e3 44 case 0: //We have no bits leftover
andrewboyson 0:be515c9019e3 45 {
andrewboyson 0:be515c9019e3 46 this6 = get6bits(); if (this6 == -1) return -1; //EOF or an error
andrewboyson 0:be515c9019e3 47 last6 = get6bits();
andrewboyson 0:be515c9019e3 48 if (last6 == -1)
andrewboyson 0:be515c9019e3 49 {
andrewboyson 0:be515c9019e3 50 last6 = 0;
andrewboyson 0:be515c9019e3 51 finished = true;
andrewboyson 0:be515c9019e3 52 }
andrewboyson 0:be515c9019e3 53 bits8 = this6 << 2;
andrewboyson 0:be515c9019e3 54 bits8 &= 0xFF;
andrewboyson 0:be515c9019e3 55 bits8 |= last6 >> 4;
andrewboyson 0:be515c9019e3 56
andrewboyson 0:be515c9019e3 57 posn = 1;
andrewboyson 0:be515c9019e3 58 break;
andrewboyson 0:be515c9019e3 59 }
andrewboyson 0:be515c9019e3 60 case 1: //We have 4 bits leftover
andrewboyson 0:be515c9019e3 61 {
andrewboyson 0:be515c9019e3 62 this6 = get6bits(); if (this6 == -1) return -1; //EOF or an error
andrewboyson 0:be515c9019e3 63
andrewboyson 0:be515c9019e3 64 bits8 = last6 << 4;
andrewboyson 0:be515c9019e3 65 bits8 &= 0xFF;
andrewboyson 0:be515c9019e3 66 bits8 |= this6 >> 2;
andrewboyson 0:be515c9019e3 67
andrewboyson 0:be515c9019e3 68 last6 = this6;
andrewboyson 0:be515c9019e3 69
andrewboyson 0:be515c9019e3 70 posn = 2;
andrewboyson 0:be515c9019e3 71 break;
andrewboyson 0:be515c9019e3 72 }
andrewboyson 0:be515c9019e3 73 case 2: //We have 2 bits leftover
andrewboyson 0:be515c9019e3 74 {
andrewboyson 0:be515c9019e3 75 this6 = get6bits(); if (this6 == -1) return -1; //EOF or an error
andrewboyson 0:be515c9019e3 76
andrewboyson 0:be515c9019e3 77 bits8 = last6 << 6;
andrewboyson 0:be515c9019e3 78 bits8 &= 0xFF;
andrewboyson 0:be515c9019e3 79 bits8 |= this6;
andrewboyson 0:be515c9019e3 80
andrewboyson 0:be515c9019e3 81 posn = 0;
andrewboyson 0:be515c9019e3 82 break;
andrewboyson 0:be515c9019e3 83 }
andrewboyson 0:be515c9019e3 84 }
andrewboyson 0:be515c9019e3 85
andrewboyson 0:be515c9019e3 86 return bits8;
andrewboyson 0:be515c9019e3 87 }
andrewboyson 0:be515c9019e3 88 int Base64SkipLine()
andrewboyson 0:be515c9019e3 89 {
andrewboyson 0:be515c9019e3 90 last6 = 0;
andrewboyson 0:be515c9019e3 91 posn = 0;
andrewboyson 0:be515c9019e3 92 finished = false;
andrewboyson 0:be515c9019e3 93
andrewboyson 0:be515c9019e3 94 while (true)
andrewboyson 0:be515c9019e3 95 {
andrewboyson 0:be515c9019e3 96 char c = Base64ReadNextCharFunctionPointer();
andrewboyson 0:be515c9019e3 97 if (c == 0 ) return -1; //EOF or an error
andrewboyson 0:be515c9019e3 98 else if (c == '\n') return 0; //EOL
andrewboyson 0:be515c9019e3 99 }
andrewboyson 0:be515c9019e3 100 }