+++ /dev/null
-/* -*-c-*-
- *
- * Base32 encoding and decoding.
- *
- * (c) 1997 Straylight/Edgeware
- */
-
-/*----- Licensing notice --------------------------------------------------*
- *
- * This file is part of the mLib utilities library.
- *
- * mLib is free software; you can redistribute it and/or modify
- * it under the terms of the GNU Library General Public License as
- * published by the Free Software Foundation; either version 2 of the
- * License, or (at your option) any later version.
- *
- * mLib is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU Library General Public License for more details.
- *
- * You should have received a copy of the GNU Library General Public
- * License along with mLib; if not, write to the Free
- * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
- * MA 02111-1307, USA.
- */
-
-/*----- Header files ------------------------------------------------------*/
-
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-
-#include "base32.h"
-#include "dstr.h"
-
-/*----- Important tables --------------------------------------------------*/
-
-static const char encodemap[] = { "ABCDEFGHIJKLMNOPQRSTUVWXYZ234567" };
-
-static const signed char decodemap[] = {
- -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /* 0x */
- -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /* 1x */
- -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /* 2x */
- -1, -1, 26, 27, 28, 29, 30, 31, -1, -1, -1, -1, -1, -1, -1, -1, /* 3x */
- -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, /* 4x */
- 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1, /* 5x */
- -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, /* 6x */
- 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1, /* 7x */
-};
-
-/*----- Main code ---------------------------------------------------------*/
-
-/* --- @base32_encode@ --- *
- *
- * Arguments: @base32_ctx *ctx@ = pointer to a context block
- * @const void *p@ = pointer to a source buffer
- * @size_t sz@ = size of the source buffer
- * @dstr *d@ = pointer to destination string
- *
- * Returns: ---
- *
- * Use: Encodes a binary string in base32. To flush out the final
- * few characters (if necessary), pass a null source pointer.
- */
-
-void base32_encode(base32_ctx *ctx,
- const void *p, size_t sz,
- dstr *d)
-{
- if (p) {
- unsigned long accl = ctx->accl, acch = ctx->acch;
- unsigned qsz = ctx->qsz;
- const unsigned char *src = p;
-
- while (sz) {
- acch = (acch << 8) | ((accl >> 24) & 0xff);
- accl = (accl << 8) | *src++;
- qsz++;
- sz--;
- if (qsz == 5) {
- DPUTC(d, encodemap[(acch >> 3) & 0x1f]);
- DPUTC(d, encodemap[((acch << 2) & 0x1c) | ((accl >> 30) & 0x03)]);
- DPUTC(d, encodemap[(accl >> 25) & 0x1f]);
- DPUTC(d, encodemap[(accl >> 20) & 0x1f]);
- DPUTC(d, encodemap[(accl >> 15) & 0x1f]);
- DPUTC(d, encodemap[(accl >> 10) & 0x1f]);
- DPUTC(d, encodemap[(accl >> 5) & 0x1f]);
- DPUTC(d, encodemap[(accl >> 0) & 0x1f]);
- ctx->lnlen += 8;
- if (ctx->maxline && ctx->lnlen >= ctx->maxline) {
- dstr_puts(d, ctx->indent);
- ctx->lnlen = 0;
- }
- qsz = 0;
- accl = acch = 0;
- }
- }
-
- ctx->acch = acch; ctx->accl = accl;
- ctx->qsz = qsz;
- } else {
- unsigned long accl = ctx->accl, acch = ctx->acch;
- unsigned qsz = ctx->qsz;
-
- if (qsz) {
- unsigned pad = 5 - qsz;
- if (pad > 3) {
- acch = accl << (pad * 8 - 32);
- accl = 0;
- } else {
- acch = (acch << (8 * pad)) | ((accl & 0xffffffff) >> (32 - 8 * pad));
- accl = accl << (8 * pad);
- }
- qsz = 40;
- pad *= 8;
- while (qsz > pad) {
- DPUTC(d, encodemap[(acch >> 3) & 0x1f]);
- acch = (acch << 5) | ((accl >> 27) & 0x1f);
- accl = (accl << 5);
- qsz -= 5;
- }
- while (qsz) {
- DPUTC(d, '=');
- qsz -= 5;
- }
- ctx->lnlen += 8;
- }
- ctx->qsz = 0;
- ctx->acch = ctx->accl = 0;
- }
-}
-
-/* --- @base32_decode@ --- *
- *
- * Arguments: @base32_ctx *ctx@ = pointer to a context block
- * @const void *p@ = pointer to a source buffer
- * @size_t sz@ = size of the source buffer
- * @dstr *d@ = pointer to destination string
- *
- * Returns: ---
- *
- * Use: Decodes a binary string in base32. To flush out the final
- * few characters (if necessary), pass a null source pointer.
- */
-
-void base32_decode(base32_ctx *ctx,
- const void *p, size_t sz,
- dstr *d)
-{
- if (p) {
- unsigned long accl = ctx->accl, acch = ctx->acch;
- unsigned qsz = ctx->qsz;
- const char *src = p;
- int ch;
-
- while (sz) {
-
- /* --- Get the next character and convert it --- */
-
- ch = *src++;
- if (ch >= 128 || ch < 0)
- ch = -1;
- else
- ch = decodemap[ch];
- sz--;
- if (ch == -1)
- continue;
-
- /* --- Bung it in the accumulator --- */
-
- acch = (acch << 5) | ((accl >> 27) & 0x1f);
- accl = (accl << 5) | ch;
- qsz++;
-
- /* --- Maybe write out a completed triplet --- */
-
- if (qsz == 8) {
- DPUTC(d, (acch >> 0) & 0xff);
- DPUTC(d, (accl >> 24) & 0xff);
- DPUTC(d, (accl >> 16) & 0xff);
- DPUTC(d, (accl >> 8) & 0xff);
- DPUTC(d, (accl >> 0) & 0xff);
- acch = accl = 0;
- qsz = 0;
- }
- }
-
- ctx->acch = acch; ctx->accl = accl;
- ctx->qsz = qsz;
- } else {
-
- /* --- Notes about the tail-end bits --- *
- *
- * I'll use the queue size to work out how many tail-end bytes I ought to
- * write. This isn't strictly right, but it's easier.
- */
-
- unsigned long acch = ctx->acch, accl = ctx->accl;
- unsigned qsz = ctx->qsz;
-
- /* --- Now fiddle with everything else --- *
- *
- * There's a bodge here for invalid encodings which have a funny number
- * of quintets in the final group. I'm not sure this is really worth
- * having, but it might save some unexpected behaviour. (Not that you
- * won't still get unexpected behaviour if the stream is completely
- * empty, of course.)
- */
-
- if (qsz) {
- unsigned pad = 8 - qsz;
- if (pad > 6) {
- acch = accl << (5 * pad - 32);
- accl = 0;
- } else {
- acch = (acch << (5 * pad)) | ((accl & 0xffffffff) >> (32 - 5 * pad));
- accl = accl << (5 * pad);
- }
-
- qsz *= 5;
- while (qsz >= 8) {
- DPUTC(d, acch & 0xff);
- acch = accl >> 24;
- accl <<= 8;
- qsz -= 8;
- }
- }
-
- /* --- That seems to be good enough --- */
-
- ctx->qsz = 0;
- ctx->acch = ctx->accl = 0;
- }
-}
-
-/* --- @base32_init@ --- *
- *
- * Arguments: @base32_ctx *ctx@ = pointer to context block to initialize
- *
- * Returns: ---
- *
- * Use: Initializes a base32 context properly.
- */
-
-void base32_init(base32_ctx *ctx)
-{
- ctx->accl = ctx->acch = 0;
- ctx->qsz = 0;
- ctx->lnlen = 0;
- ctx->indent = "\n";
- ctx->maxline = 72;
-}
-
-/*----- Test driver code --------------------------------------------------*/
-
-#ifdef TEST_RIG
-
-int main(int argc, char *argv[])
-{
- unsigned char buf[BUFSIZ];
- dstr d = DSTR_INIT;
- base32_ctx ctx;
- void (*proc)(base32_ctx *, const void *, size_t, dstr *);
- size_t sz;
-
- base32_init(&ctx);
-
- if (argc > 1 && strcmp(argv[1], "-d") == 0)
- proc = base32_decode;
- else {
- proc = base32_encode;
- putchar('\t');
- ctx.indent = "\n\t";
- ctx.maxline = 32;
- }
-
- do {
- sz = fread(buf, 1, sizeof(buf), stdin);
- if (sz) {
- proc(&ctx, buf, sz, &d);
- dstr_write(&d, stdout);
- dstr_destroy(&d);
- }
- } while (sz == sizeof(buf));
-
- proc(&ctx, 0, 0, &d);
- dstr_write(&d, stdout);
-
- if (proc == base32_encode)
- putchar('\n');
-
- return (0);
-}
-
-#endif
-
-/*----- That's all, folks -------------------------------------------------*/
~mdw / mLib / blobdiff