[mLib] / base64.c

/* -*-c-*-
 *
 * $Id: base64.c,v 1.2 1999/05/18 21:45:27 mdw Exp $
 *
 * Base64 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.
 */

/*----- Revision history --------------------------------------------------*
 *
 * $Log: base64.c,v $
 * Revision 1.2  1999/05/18 21:45:27  mdw
 * Allow Base64 encode and decode of arbitrary rubbish.
 *
 * Revision 1.1  1999/05/17 20:35:00  mdw
 * Base64 encoding and decoding support.
 *
 */

/*----- Header files ------------------------------------------------------*/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "base64.h"
#include "dstr.h"

/*----- Important tables --------------------------------------------------*/

static const char base64_encodeMap[] = { "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
					 "abcdefghijklmnopqrstuvwxyz" 
					 "0123456789+/" };

static const signed char base64_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, 62, -1, -1, -1, 63,  /* 2x */
  52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -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, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36 ,37, 38, 39, 40,  /* 6x */
  41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1   /* 7x */
};  

/*----- Main code ---------------------------------------------------------*/

/* --- @base64_encode@ --- *
 *
 * Arguments:	@base64_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 base64.  To flush out the final
 *		few characters (if necessary), pass a null source pointer.
 */

void base64_encode(base64_ctx *ctx,
		   const void *p, size_t sz,
		   dstr *d)
{
  if (p) {
    unsigned long acc = ctx->acc;
    unsigned qsz = ctx->qsz;
    const unsigned char *src = p;

    while (sz) {
      acc = (acc << 8) | *src++;
      qsz++;
      sz--;
      if (qsz == 3) {
	DPUTC(d, base64_encodeMap[(acc >> 18) & 0x3f]);
	DPUTC(d, base64_encodeMap[(acc >> 12) & 0x3f]);
	DPUTC(d, base64_encodeMap[(acc >>  6) & 0x3f]);
	DPUTC(d, base64_encodeMap[(acc >>  0) & 0x3f]);
	ctx->lnlen += 4;
	if (ctx->maxline && ctx->lnlen >= ctx->maxline) {
	  dstr_puts(d, ctx->indent);
	  ctx->lnlen = 0;
	}
	qsz = 0;
	acc = 0;
      }
    }

    ctx->acc = acc;
    ctx->qsz = qsz;
  } else {
    unsigned long acc = ctx->acc;
    unsigned qsz = ctx->qsz;

    switch (qsz) {
      case 0:
	break;
      case 1:
	acc <<= 16;
	DPUTC(d, base64_encodeMap[(acc >> 18) & 0x3f]);
	DPUTC(d, base64_encodeMap[(acc >> 12) & 0x3f]);
	DPUTC(d, '=');
	DPUTC(d, '=');
	ctx->lnlen += 4;
	break;
      case 2:
	acc <<= 8;
	DPUTC(d, base64_encodeMap[(acc >> 18) & 0x3f]);
	DPUTC(d, base64_encodeMap[(acc >> 12) & 0x3f]);
	DPUTC(d, base64_encodeMap[(acc >>  6) & 0x3f]);
	DPUTC(d, '=');
	ctx->lnlen += 4;
	break;
    }
    ctx->qsz = 0;
    ctx->acc = 0;
  }
}

/* --- @base64_decode@ --- *
 *
 * Arguments:	@base64_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 base64.  To flush out the final
 *		few characters (if necessary), pass a null source pointer.
 */

void base64_decode(base64_ctx *ctx,
		   const void *p, size_t sz,
		   dstr *d)
{
  if (p) {
    unsigned long acc = ctx->acc;
    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 = base64_decodeMap[ch];
      sz--;
      if (ch == -1)
	continue;

      /* --- Bung it in the accumulator --- */

      acc = (acc << 6) | ch;
      qsz++;

      /* --- Maybe write out a completed triplet --- */

      if (qsz == 4) {
	DPUTC(d, (acc >> 16) & 0xff);
	DPUTC(d, (acc >>  8) & 0xff);
	DPUTC(d, (acc >>  0) & 0xff);
	acc = 0;
	qsz = 0;
      }
    }

    ctx->acc = acc;
    ctx->qsz = qsz;
  } else {

    /* --- Notes about the tail-end bits --- *
     *
     * Ending Base64 decoding is messy.  The reference I'm using to define
     * the encoding, RFC1521 section 5.2, is a little hazy on exactly what to
     * do at the end.  It explains that I'm meant to ignore spurious `='
     * characters, and points out that I'm not guaranteed to see anything
     * interesting at the end.  I'll play safe here, and ignore all `='
     * characters, relying on my client to work out when to stop feeding me
     * data.  I'll use the queue size to work out how many tail-end bytes
     * I ought to write.
     */

    unsigned long acc = ctx->acc;
    unsigned qsz = ctx->qsz;

    /* --- Now fiddle with everything else --- */

    acc <<= 6 * (4 - qsz);
    qsz *= 6;
    while (qsz > 8) {
      DPUTC(d, (acc >> 16) & 0xff);
      acc <<= 8;
      qsz -= 8;
    }

    /* --- That seems to be good enough --- */

    ctx->qsz = 0;
    ctx->acc = 0;
  }
}

/* --- @base64_init@ --- *
 *
 * Arguments:	@base64_ctx *ctx@ = pointer to context block to initialize
 *
 * Returns:	---
 *
 * Use:		Initializes a base64 context properly.
 */

void base64_init(base64_ctx *ctx)
{
  ctx->acc = 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;
  base64_ctx ctx;
  void (*proc)(base64_ctx *, const unsigned char *, size_t, dstr *);
  size_t sz;

  dstr_create(&d);
  base64_init(&ctx);

  if (argc > 1 && strcmp(argv[1], "-d") == 0)
    proc = base64_decode;
  else {
    proc = base64_encode;
    putchar('\t');
    ctx.indent = "\n\t";
    ctx.maxline = 64;
  }

  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 == base64_encode)
    putchar('\n');

  return (0);
}

#endif

/*----- That's all, folks -------------------------------------------------*/
Commit	Line	Data
ceba1986	1	/* --c--
ceba1986	2	*
c601c4f1	3	* $Id: base64.c,v 1.2 1999/05/18 21:45:27 mdw Exp $
ceba1986	4	*
	5	* Base64 encoding and decoding.
	6	*
	7	* (c) 1997 Straylight/Edgeware
	8	*/
	9
	10	/----- Licensing notice --------------------------------------------------
	11	*
	12	* This file is part of the mLib utilities library.
	13	*
	14	* mLib is free software; you can redistribute it and/or modify
	15	* it under the terms of the GNU Library General Public License as
	16	* published by the Free Software Foundation; either version 2 of the
	17	* License, or (at your option) any later version.
	18	*
	19	* mLib is distributed in the hope that it will be useful,
	20	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	21	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	22	* GNU Library General Public License for more details.
	23	*
	24	* You should have received a copy of the GNU Library General Public
	25	* License along with mLib; if not, write to the Free
	26	* Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
	27	* MA 02111-1307, USA.
	28	*/
	29
	30	/----- Revision history --------------------------------------------------
	31	*
	32	* $Log: base64.c,v $
c601c4f1	33	* Revision 1.2 1999/05/18 21:45:27 mdw
	34	* Allow Base64 encode and decode of arbitrary rubbish.
	35	*
ceba1986	36	* Revision 1.1 1999/05/17 20:35:00 mdw
	37	* Base64 encoding and decoding support.
	38	*
	39	*/
	40
	41	/----- Header files ------------------------------------------------------/
	42
	43	#include <stdio.h>
	44	#include <stdlib.h>
	45	#include <string.h>
	46
	47	#include "base64.h"
	48	#include "dstr.h"
	49
	50	/----- Important tables --------------------------------------------------/
	51
	52	static const char base64_encodeMap[] = { "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
	53	"abcdefghijklmnopqrstuvwxyz"
	54	"0123456789+/" };
	55
	56	static const signed char base64_decodeMap[] = {
	57	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /* 0x */
	58	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /* 1x */
	59	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63, /* 2x */
	60	52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1, /* 3x */
	61	-1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, /* 4x */
	62	15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1, /* 5x */
	63	-1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36 ,37, 38, 39, 40, /* 6x */
	64	41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1 /* 7x */
	65	};
	66
	67	/----- Main code ---------------------------------------------------------/
	68
	69	/* --- @base64_encode@ --- *
	70	*
	71	* Arguments: @base64_ctx *ctx@ = pointer to a context block
c601c4f1	72	* @const void *p@ = pointer to a source buffer
ceba1986	73	* @size_t sz@ = size of the source buffer
	74	* @dstr *d@ = pointer to destination string
	75	*
	76	* Returns: ---
	77	*
	78	* Use: Encodes a binary string in base64. To flush out the final
	79	* few characters (if necessary), pass a null source pointer.
	80	*/
	81
	82	void base64_encode(base64_ctx *ctx,
c601c4f1	83	const void *p, size_t sz,
ceba1986	84	dstr *d)
ceba1986	85	{
c601c4f1	86	if (p) {
ceba1986	87	unsigned long acc = ctx->acc;
ceba1986	88	unsigned qsz = ctx->qsz;
c601c4f1	89	const unsigned char *src = p;
ceba1986	90
	91	while (sz) {
	92	acc = (acc << 8) \| *src++;
	93	qsz++;
	94	sz--;
	95	if (qsz == 3) {
c601c4f1	96	DPUTC(d, base64_encodeMap[(acc >> 18) & 0x3f]);
	97	DPUTC(d, base64_encodeMap[(acc >> 12) & 0x3f]);
	98	DPUTC(d, base64_encodeMap[(acc >> 6) & 0x3f]);
	99	DPUTC(d, base64_encodeMap[(acc >> 0) & 0x3f]);
ceba1986	100	ctx->lnlen += 4;
	101	if (ctx->maxline && ctx->lnlen >= ctx->maxline) {
	102	dstr_puts(d, ctx->indent);
	103	ctx->lnlen = 0;
	104	}
	105	qsz = 0;
	106	acc = 0;
	107	}
	108	}
	109
	110	ctx->acc = acc;
	111	ctx->qsz = qsz;
	112	} else {
	113	unsigned long acc = ctx->acc;
	114	unsigned qsz = ctx->qsz;
	115
	116	switch (qsz) {
	117	case 0:
	118	break;
	119	case 1:
	120	acc <<= 16;
c601c4f1	121	DPUTC(d, base64_encodeMap[(acc >> 18) & 0x3f]);
	122	DPUTC(d, base64_encodeMap[(acc >> 12) & 0x3f]);
	123	DPUTC(d, '=');
	124	DPUTC(d, '=');
ceba1986	125	ctx->lnlen += 4;
	126	break;
	127	case 2:
	128	acc <<= 8;
c601c4f1	129	DPUTC(d, base64_encodeMap[(acc >> 18) & 0x3f]);
	130	DPUTC(d, base64_encodeMap[(acc >> 12) & 0x3f]);
	131	DPUTC(d, base64_encodeMap[(acc >> 6) & 0x3f]);
	132	DPUTC(d, '=');
ceba1986	133	ctx->lnlen += 4;
	134	break;
	135	}
	136	ctx->qsz = 0;
	137	ctx->acc = 0;
	138	}
	139	}
	140
	141	/* --- @base64_decode@ --- *
	142	*
	143	* Arguments: @base64_ctx *ctx@ = pointer to a context block
c601c4f1	144	* @const void *p@ = pointer to a source buffer
ceba1986	145	* @size_t sz@ = size of the source buffer
	146	* @dstr *d@ = pointer to destination string
	147	*
	148	* Returns: ---
	149	*
	150	* Use: Decodes a binary string in base64. To flush out the final
	151	* few characters (if necessary), pass a null source pointer.
	152	*/
	153
	154	void base64_decode(base64_ctx *ctx,
c601c4f1	155	const void *p, size_t sz,
ceba1986	156	dstr *d)
ceba1986	157	{
c601c4f1	158	if (p) {
ceba1986	159	unsigned long acc = ctx->acc;
ceba1986	160	unsigned qsz = ctx->qsz;
c601c4f1	161	const char *src = p;
ceba1986	162	int ch;
	163
	164	while (sz) {
	165
	166	/* --- Get the next character and convert it --- */
	167
	168	ch = *src++;
	169	if (ch >= 128 \|\| ch < 0)
	170	ch = -1;
	171	else
	172	ch = base64_decodeMap[ch];
	173	sz--;
	174	if (ch == -1)
	175	continue;
	176
	177	/* --- Bung it in the accumulator --- */
	178
	179	acc = (acc << 6) \| ch;
	180	qsz++;
	181
	182	/* --- Maybe write out a completed triplet --- */
	183
	184	if (qsz == 4) {
c601c4f1	185	DPUTC(d, (acc >> 16) & 0xff);
	186	DPUTC(d, (acc >> 8) & 0xff);
	187	DPUTC(d, (acc >> 0) & 0xff);
ceba1986	188	acc = 0;
	189	qsz = 0;
	190	}
	191	}
	192
	193	ctx->acc = acc;
	194	ctx->qsz = qsz;
	195	} else {
	196
	197	/* --- Notes about the tail-end bits --- *
	198	*
	199	* Ending Base64 decoding is messy. The reference I'm using to define
	200	* the encoding, RFC1521 section 5.2, is a little hazy on exactly what to
	201	* do at the end. It explains that I'm meant to ignore spurious `='
	202	* characters, and points out that I'm not guaranteed to see anything
	203	* interesting at the end. I'll play safe here, and ignore all `='
	204	* characters, relying on my client to work out when to stop feeding me
	205	* data. I'll use the queue size to work out how many tail-end bytes
	206	* I ought to write.
	207	*/
	208
	209	unsigned long acc = ctx->acc;
	210	unsigned qsz = ctx->qsz;
	211
	212	/* --- Now fiddle with everything else --- */
	213
	214	acc <<= 6 * (4 - qsz);
	215	qsz *= 6;
	216	while (qsz > 8) {
c601c4f1	217	DPUTC(d, (acc >> 16) & 0xff);
ceba1986	218	acc <<= 8;
	219	qsz -= 8;
	220	}
	221
	222	/* --- That seems to be good enough --- */
	223
	224	ctx->qsz = 0;
	225	ctx->acc = 0;
	226	}
	227	}
	228
	229	/* --- @base64_init@ --- *
	230	*
	231	* Arguments: @base64_ctx *ctx@ = pointer to context block to initialize
	232	*
	233	* Returns: ---
	234	*
	235	* Use: Initializes a base64 context properly.
	236	*/
	237
	238	void base64_init(base64_ctx *ctx)
	239	{
	240	ctx->acc = 0;
	241	ctx->qsz = 0;
	242	ctx->lnlen = 0;
	243	ctx->indent = "\n";
	244	ctx->maxline = 72;
	245	}
	246
	247	/----- Test driver code --------------------------------------------------/
	248
	249	#ifdef TEST_RIG
	250
	251	int main(int argc, char *argv[])
	252	{
	253	unsigned char buf[BUFSIZ];
	254	dstr d;
	255	base64_ctx ctx;
	256	void (proc)(base64_ctx , const unsigned char , size_t, dstr );
	257	size_t sz;
	258
	259	dstr_create(&d);
	260	base64_init(&ctx);
	261
	262	if (argc > 1 && strcmp(argv[1], "-d") == 0)
	263	proc = base64_decode;
	264	else {
	265	proc = base64_encode;
	266	putchar('\t');
	267	ctx.indent = "\n\t";
	268	ctx.maxline = 64;
	269	}
	270
	271	do {
	272	sz = fread(buf, 1, sizeof(buf), stdin);
	273	if (sz) {
	274	proc(&ctx, buf, sz, &d);
	275	dstr_write(&d, stdout);
	276	dstr_destroy(&d);
	277	}
	278	} while (sz == sizeof(buf));
	279
	280	proc(&ctx, 0, 0, &d);
	281	dstr_write(&d, stdout);
282
283	if (proc == base64_encode)
284	putchar('\n');
285
286	return (0);
287	}
288
289	#endif
290
291	/----- That's all, folks -------------------------------------------------/