X-Git-Url: https://git.distorted.org.uk/~mdw/mLib/blobdiff_plain/173ff44a439dc7cf51a3f7a433c4d0d444b59293..236f657b6dab66f31f4902cecfc03b4673f5bb98:/codec/baseconv.c

diff --git a/codec/baseconv.c b/codec/baseconv.c
new file mode 100644
index 0000000..1d50735
--- /dev/null
+++ b/codec/baseconv.c
@@ -0,0 +1,491 @@
+/* -*-c-*-
+ *
+ * Binary base-conversion encoding and decoding (base64, base32, etc.)
+ *
+ * (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 <ctype.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "alloc.h"
+#include "codec.h"
+#include "dstr.h"
+#include "sub.h"
+
+#include "base64.h"
+#include "base32.h"
+#include "hex.h"
+
+/*----- Important tables --------------------------------------------------*/
+
+/* --- Magic constants --- */
+
+#define NV -1				/* Not valid */
+#define PC -2				/* Padding character */
+#define NL -3				/* Newline character */
+
+/* --- Base64 --- */
+
+static const char
+  encodemap_base64[] =    { "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+			    "abcdefghijklmnopqrstuvwxyz"
+			    "0123456789+/" },
+  encodemap_file64[] =    { "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+			    "abcdefghijklmnopqrstuvwxyz"
+			    "0123456789+%" },
+  encodemap_base64url[] = { "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+			    "abcdefghijklmnopqrstuvwxyz"
+			    "0123456789-_" };
+
+static const signed char decodemap_base64[] = {
+  NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NL, NV, NV, NL, NV, NV,  /* 0x */
+  NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV,  /* 1x */
+  NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, 62, NV, NV, NV, 63,  /* 2x */
+  52, 53, 54, 55, 56, 57, 58, 59, 60, 61, NV, NV, NV, PC, NV, NV,  /* 3x */
+  NV,  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, NV, NV, NV, NV, NV,  /* 5x */
+  NV, 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, NV, NV, NV, NV, NV   /* 7x */
+}, decodemap_file64[] = {
+  NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NL, NV, NV, NL, NV, NV,  /* 0x */
+  NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV,  /* 1x */
+  NV, NV, NV, NV, NV, 63, NV, NV, NV, NV, NV, 62, NV, NV, NV, NV,  /* 2x */
+  52, 53, 54, 55, 56, 57, 58, 59, 60, 61, NV, NV, NV, PC, NV, NV,  /* 3x */
+  NV,  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, NV, NV, NV, NV, NV,  /* 5x */
+  NV, 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, NV, NV, NV, NV, NV   /* 7x */
+}, decodemap_base64url[] = {
+  NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NL, NV, NV, NL, NV, NV,  /* 0x */
+  NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV,  /* 1x */
+  NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, 62, NV, NV,  /* 2x */
+  52, 53, 54, 55, 56, 57, 58, 59, 60, 61, NV, NV, NV, PC, NV, NV,  /* 3x */
+  NV,  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, NV, NV, NV, NV, 63,  /* 5x */
+  NV, 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, NV, NV, NV, NV, NV   /* 7x */
+};
+
+/* --- Base32 --- */
+
+static const char
+  encodemap_base32[]   =    { "ABCDEFGHIJKLMNOPQRSTUVWXYZ234567" },
+  encodemap_base32hex[] =   { "0123456789ABCDEFGHIJKLMNOPQRSTUV" };
+
+static const signed char decodemap_base32[] = {
+  NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NL, NV, NV, NL, NV, NV,  /* 0x */
+  NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV,  /* 1x */
+  NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV,  /* 2x */
+  NV, NV, 26, 27, 28, 29, 30, 31, NV, NV, NV, NV, NV, PC, NV, NV,  /* 3x */
+  NV,  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, NV, NV, NV, NV, NV,  /* 5x */
+  NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV,  /* 6x */
+  NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV,  /* 7x */
+}, decodemap_base32hex[] = {
+  NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NL, NV, NV, NL, NV, NV,  /* 0x */
+  NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV,  /* 1x */
+  NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV,  /* 2x */
+   0,  1,  2,  3,  4,  5,  6,  7,  8,  9, NV, NV, NV, PC, NV, NV,  /* 3x */
+  NV, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24,  /* 4x */
+  25, 26, 27, 28, 29, 30, 31, NV, NV, NV, NV, NV, NV, NV, NV, NV,  /* 5x */
+  NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV,  /* 6x */
+  NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV,  /* 7x */
+};
+
+/* --- Hex --- */
+
+static const char
+  encodemap_hex[] =   { "0123456789ABCDEF" };
+
+static const signed char decodemap_hex[] = {
+  NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NL, NV, NV, NL, NV, NV,  /* 0x */
+  NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV,  /* 1x */
+  NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV,  /* 2x */
+   0,  1,  2,  3,  4,  5,  6,  7,  8,  9, NV, NV, NV, NV, NV, NV,  /* 3x */
+  NV, 10, 11, 12, 13, 14, 15, NV, NV, NV, NV, NV, NV, NV, NV, NV,  /* 4x */
+  NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV,  /* 5x */
+  NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV,  /* 6x */
+  NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV, NV,  /* 7x */
+};
+
+/*----- Base conversion macros --------------------------------------------*/
+
+/* --- @BASECONV@ --- *
+ *
+ * Arguments:	@x@ = an input digit of width @IWD@ bits
+ *		@iwd@ = input digit width in bits
+ *		@owd@ = output digit width in bits
+ *		@put@ = function or macro to output a digit
+ *
+ * Use:		Inserts the bits of @x@ into an accumulator.  As digits @y@
+ *		of with @owd@ become ready, @put(y)@ is invoked to emit them.
+ */
+
+#define BASECONV(x, iwd, owd, put) do {					\
+  a = (a << iwd) | x;							\
+  nb += iwd;								\
+  while (nb >= owd) {							\
+    nb -= owd;								\
+    put((a >> nb) & ((1 << owd) - 1));					\
+  }									\
+} while (0)
+
+/* --- @BASECONV_FLUSH@ --- *
+ *
+ * Arguments:	@iwd@ = input digit width in bits
+ *		@owd@ = output digit width in bits
+ *		@put@ = function or macro to output a digit
+ *
+ * Use:		Flushes remaining digits from the base-conversion shift
+ *		register.  The bits in the shift register are padded on the
+ *		right with zeros.  Digits of width @owd@ are emitted by
+ *		invoking @put@.
+ */
+
+#define BASECONV_FLUSH(iwd, owd, put) do {				\
+  if (nb) {								\
+    while (nb < owd) { a <<= iwd; nb += iwd; }				\
+    nb -= owd;								\
+    put((a >> nb) & ((1 << owd) - 1));					\
+  }									\
+} while (0)
+
+/* --- @BASECONV_PAD@ --- *
+ *
+ * Arguments:	@iwd@ = input digit width in bits
+ *		@owd@ = output digit width in bits
+ *		@pad@ = function or macro to output padding
+ *
+ * Use:		Invokes @pad@ sufficiently often to realign the shift
+ *		register.
+ */
+
+#define BASECONV_PAD(iwd, owd, pad) do {				\
+  for (;;) {								\
+    while (nb >= owd) { pad; nb -= owd; }				\
+    if (!nb) break;							\
+    nb += iwd;								\
+  }									\
+} while (0)
+
+#define NULL_PAD(iwd, owd, pad) do ; while (0)
+
+/*----- Lists of things to make -------------------------------------------*/
+
+#define CODECS(_)							\
+  /* NAME,      CTXN,    ACC */						\
+  _(base64,	base64,	acc)						\
+  _(file64,	base64,	acc)						\
+  _(base64url,	base64,	acc)						\
+  _(base32,	base32,	accl)						\
+  _(base32hex,	base32,	accl)						\
+  _(hex,	hex,	acc)
+
+#define CTXS(_)								\
+  /* CTXN,	WD,	ACC */						\
+  _(base64,	6,	acc)						\
+  _(base32,	5,	accl)						\
+  _(hex,	4,	acc)
+
+#define base64_PADDING BASECONV_PAD
+#define base64_FLAGMASK ~(CDCF_LOWERC | CDCF_IGNCASE)
+#define base64_FLAGXOR 0
+#define base64_OLDFLAGS CDCF_IGNJUNK
+
+#define base32_PADDING BASECONV_PAD
+#define base32_FLAGMASK ~0
+#define base32_FLAGXOR 0
+#define base32_OLDFLAGS CDCF_IGNJUNK
+
+#define hex_PADDING NULL_PAD
+#define hex_FLAGMASK ~0
+#define hex_FLAGXOR 0
+#define hex_OLDFLAGS (CDCF_IGNJUNK | CDCF_LOWERC)
+
+/*----- Data structures ---------------------------------------------------*/
+
+#define OBJ(ctxn, wd, acc)						\
+									\
+typedef struct ctxn##_codec {						\
+  codec c;								\
+  ctxn##_ctx ctx;							\
+  const char *encodemap;						\
+  const signed char *decodemap;						\
+} ctxn##_codec;
+
+CTXS(OBJ)
+
+/*----- State packing -----------------------------------------------------*
+ *
+ * These macros convert between the state required by the new encoding and
+ * decoding core and the old externally-visible context structures.  It's
+ * unpleasant, I know; maybe we can drop the old interface later.
+ */
+
+enum {
+  ST_MAIN,				/* Main decoding state */
+  ST_PAD,				/* Decoding trailing padding */
+  ST_END				/* Finished decoding */
+};
+
+#define STATE_UNPACK(acc)						\
+  unsigned long a = (ctx->acc >> 0) & 0xffff;				\
+  unsigned nb = (ctx->acc >> 16) & 0xff;				\
+  unsigned st = (ctx->acc >> 24) & 0xff;				\
+  unsigned f = ctx->qsz;
+
+#define STATE_PACK(acc) do {						\
+  ctx->acc = (((a & 0xffff) << 0) |					\
+	      (((unsigned long)nb & 0xff) << 16) |			\
+	      (((unsigned long)st & 0xff) << 24));			\
+} while (0)
+
+/*----- Main encoder and decoder ------------------------------------------*/
+
+#define WRAP(stuff) do {						\
+  if (maxln && lnlen >= maxln) {					\
+    dstr_puts(d, ctx->indent);						\
+    lnlen = 0;								\
+  }									\
+  stuff									\
+  lnlen++;								\
+} while (0)
+
+#define PUTWRAP(x) WRAP({						\
+  char ch = encodemap[x];						\
+  if (f & CDCF_LOWERC) ch = tolower((unsigned char)ch);			\
+  DPUTC(d, ch);								\
+})
+
+#define PADWRAP WRAP({ DPUTC(d, '='); })
+
+#define PUTRAW(x) DPUTC(d, x)
+
+#define ENCODER(ctxn, wd, acc)						\
+									\
+/* --- @CTXN_doencode@ --- *						\
+ *									\
+ * Arguments:	@CTXN_ctx *ctx@ = pointer to a context block		\
+ *		@const char *encodemap@ = pointer to encoding map	\
+ *		@const unsigned char *p@ = pointer to a source buffer	\
+ *		@size_t sz@ = size of the source buffer			\
+ *		@dstr *d@ = pointer to destination string		\
+ *									\
+ * Returns:	Zero on success, or @CDCERR_@ error code.		\
+ *									\
+ * Use:		Main encoder function.					\
+ */									\
+									\
+static int ctxn##_doencode(ctxn##_ctx *ctx, const char *encodemap,	\
+			   const unsigned char *p, size_t sz, dstr *d)	\
+{									\
+  STATE_UNPACK(acc);							\
+  const unsigned char *l = p + sz;					\
+  unsigned lnlen = ctx->lnlen, maxln = ctx->maxline;			\
+									\
+  if (p) {								\
+    while (p < l) BASECONV(*p++, 8, wd, PUTWRAP);			\
+  } else {								\
+    BASECONV_FLUSH(8, wd, PUTWRAP);					\
+    if (!(f & CDCF_NOEQPAD)) ctxn##_PADDING(8, wd, PADWRAP);		\
+  }									\
+									\
+  STATE_PACK(acc);							\
+  ctx->lnlen = lnlen;							\
+  return (0);								\
+}									\
+									\
+/* --- @CTXN_dodecode@ --- *						\
+ *									\
+ * Arguments:	@CTXN_ctx *ctx@ = pointer to a context block		\
+ *		@const signed char *decodemap@ = pointer to decode map	\
+ *		@const char *p@ = pointer to a source buffer		\
+ *		@size_t sz@ = size of the source buffer			\
+ *		@dstr *d@ = pointer to destination string		\
+ *									\
+ * Returns:	Zero on success, or @CDCERR_@ error code.		\
+ *									\
+ * Use:		Main decoder function.					\
+ */									\
+									\
+static int ctxn##_dodecode(ctxn##_ctx *ctx,				\
+			   const signed char *decodemap,		\
+			   const unsigned char *p, size_t sz, dstr *d)	\
+{									\
+  STATE_UNPACK(acc);							\
+  const unsigned char *l = p + sz;					\
+  int ch;								\
+  int x;								\
+									\
+  if (p) {								\
+    while (p < l) {							\
+      ch = *p++;							\
+      switch (f & (CDCF_LOWERC | CDCF_IGNCASE)) {			\
+	case 0:								\
+	  break;							\
+	case CDCF_LOWERC:						\
+	  if (isupper(ch)) goto badch;					\
+	default:							\
+	  ch = toupper(ch);						\
+      }									\
+      x = decodemap[ch];						\
+      switch (x) {							\
+	case NV:							\
+	badch:								\
+	  if (!(f & CDCF_IGNINVCH)) return (CDCERR_INVCH);		\
+	  break;							\
+	case PC:							\
+	  if (f & CDCF_IGNEQMID) break;					\
+	  if (f & CDCF_NOEQPAD) goto badch;				\
+	  if (st == ST_MAIN &&						\
+	      !(f & CDCF_IGNZPAD) && (a & ((1 << nb) - 1)))		\
+	    return (CDCERR_INVZPAD);					\
+	  st = ST_PAD;							\
+	  if (!(f & CDCF_IGNEQPAD)) {					\
+	    if (!nb) return (CDCERR_INVEQPAD);				\
+	    nb = (nb + wd)%8;						\
+	    st = ST_PAD;						\
+	  }								\
+	  break;							\
+	case NL:							\
+	  if (f & CDCF_IGNNEWL) break;					\
+	  return (CDCERR_INVCH);					\
+	default:							\
+	  if (st != ST_MAIN)						\
+	    return (CDCERR_INVEQPAD);					\
+	  BASECONV(x, wd, 8, PUTRAW);					\
+	  break;							\
+      }									\
+    }									\
+  } else {								\
+    if (st == ST_MAIN &&						\
+	!(f & CDCF_IGNZPAD) && (a & ((1 << nb) - 1)))			\
+      return (CDCERR_INVZPAD);						\
+    if (!(f & (CDCF_IGNEQPAD | CDCF_IGNEQMID | CDCF_NOEQPAD)) && nb)	\
+      return (CDCERR_INVEQPAD);						\
+  }									\
+									\
+  STATE_PACK(acc);							\
+  return (0);								\
+}
+
+CTXS(ENCODER)
+
+/*----- Codec implementation ----------------------------------------------*/
+
+#define OPS(ctxn, wd, acc)						\
+									\
+static int ctxn##_enc(codec *c, const void *p, size_t sz, dstr *d)	\
+{									\
+  ctxn##_codec *bc = (ctxn##_codec *)c;					\
+  return (ctxn##_doencode(&bc->ctx, bc->encodemap, p, sz, d));		\
+}									\
+									\
+static int ctxn##_dec(codec *c, const void *p, size_t sz, dstr *d)	\
+{									\
+  ctxn##_codec *bc = (ctxn##_codec *)c;					\
+  return (ctxn##_dodecode(&bc->ctx, bc->decodemap, p, sz, d));		\
+}									\
+									\
+static void ctxn##_destroy(codec *c)					\
+{									\
+  ctxn##_codec *bc = (ctxn##_codec *)c;					\
+  if (bc->ctx.indent) xfree((/*unconst*/ char *)bc->ctx.indent);	\
+  DESTROY(bc);								\
+}									\
+									\
+static codec *ctxn##_docreate(unsigned flags,				\
+			      const char *indent, unsigned maxline,	\
+			      const codec_ops *ops,			\
+			      const char *encodemap,			\
+			      const signed char *decodemap)		\
+{									\
+  ctxn##_codec *bc = CREATE(ctxn##_codec);				\
+  bc->c.ops = ops;							\
+  bc->ctx.acc = 0;							\
+  bc->ctx.qsz = (flags & ctxn##_FLAGMASK) ^ ctxn##_FLAGXOR;		\
+  bc->ctx.lnlen = 0;							\
+  bc->ctx.indent = indent ? xstrdup(indent) : 0;			\
+  bc->ctx.maxline = maxline;						\
+  bc->encodemap = encodemap;						\
+  bc->decodemap = decodemap;						\
+  return (&bc->c);							\
+}
+
+CTXS(OPS)
+
+#define CLASS(name, ctxn, acc)						\
+									\
+static const codec_ops							\
+  name##_encode_ops = { &name##_class, ctxn##_enc, ctxn##_destroy },	\
+  name##_decode_ops = { &name##_class, ctxn##_dec, ctxn##_destroy };	\
+									\
+static codec *name##_encoder(unsigned flags,				\
+			     const char *indent, unsigned maxline)	\
+{									\
+  return ctxn##_docreate(flags, indent, maxline,			\
+			 &name##_encode_ops,				\
+			 encodemap_##name,				\
+			 decodemap_##name);				\
+}									\
+									\
+static codec *name##_decoder(unsigned flags)				\
+{									\
+  return ctxn##_docreate(flags, 0, 0,					\
+			 &name##_decode_ops,				\
+			 encodemap_##name,				\
+			 decodemap_##name);				\
+}									\
+									\
+const codec_class name##_class =					\
+  { #name, name##_encoder, name##_decoder };
+
+CODECS(CLASS)
+
+/*----- Compatibility veneers ---------------------------------------------*/
+
+#define COMPAT(ctxn, wd, acc)						\
+									\
+void ctxn##_encode(ctxn##_ctx *ctx, const void *p, size_t sz, dstr *d)	\
+  { ctxn##_doencode(ctx, encodemap_##ctxn, p, sz, d); }			\
+									\
+void ctxn##_decode(ctxn##_ctx *ctx, const void *p, size_t sz, dstr *d)	\
+  { ctxn##_dodecode(ctx, decodemap_##ctxn, p, sz, d); }			\
+									\
+void ctxn##_init(ctxn##_ctx *ctx)					\
+{									\
+  ctx->acc = 0;								\
+  ctx->qsz = (ctxn##_OLDFLAGS & ctxn##_FLAGMASK) ^ ctxn##_FLAGXOR;	\
+  ctx->lnlen = 0;							\
+  ctx->indent = "\n";							\
+  ctx->maxline = 72;							\
+}
+
+CTXS(COMPAT)
+
+/*----- That's all, folks -------------------------------------------------*/