+/* -*-c-*-
+ *
+ * $Id: hex.c,v 1.1 2002/01/13 13:26:30 mdw Exp $
+ *
+ * Hexadecimal encoding and decoding.
+ *
+ * (c) 2001 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: hex.c,v $
+ * Revision 1.1 2002/01/13 13:26:30 mdw
+ * New hex encoding stuff.
+ *
+ */
+
+/*----- Header files ------------------------------------------------------*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "dstr.h"
+#include "hex.h"
+
+/*----- Important tables --------------------------------------------------*/
+
+static const char encodemap[] = { "0123456789abcdef" };
+
+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 */
+ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 1, -1, -1, -1, -1, -1, /* 3x */
+ -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1, /* 4x */
+ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /* 5x */
+ -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1, /* 6x */
+ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /* 7x */
+ };
+
+/*----- Main code ---------------------------------------------------------*/
+
+/* --- @hex_encode@ --- *
+ *
+ * Arguments: @hex_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 hex.
+ */
+
+void hex_encode(hex_ctx *ctx, const void *p, size_t sz, dstr *d)
+{
+ if (p) {
+ const unsigned char *src = p;
+
+ while (sz) {
+ unsigned x = *src++;
+ sz--;
+ DPUTC(d, encodemap[(x >> 4) & 0xf]);
+ DPUTC(d, encodemap[(x >> 0) & 0xf]);
+ ctx->lnlen += 2;
+ if (ctx->maxline && ctx->lnlen >= ctx->maxline) {
+ dstr_puts(d, ctx->indent);
+ ctx->lnlen = 0;
+ }
+ }
+ }
+}
+
+/* --- @hex_decode@ --- *
+ *
+ * Arguments: @hex_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 hex. Pass in a null source
+ * pointer when you thing you've finished.
+ */
+
+void hex_decode(hex_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 = decodemap[ch];
+ sz--;
+ if (ch == -1)
+ continue;
+
+ /* --- Bung it in the accumulator --- */
+
+ acc = (acc << 4) | ch;
+ qsz++;
+
+ /* --- Maybe write out a completed triplet --- */
+
+ if (qsz == 2) {
+ DPUTC(d, acc & 0xff);
+ acc = 0;
+ qsz = 0;
+ }
+ }
+
+ ctx->acc = acc;
+ ctx->qsz = qsz;
+ } else {
+ if (ctx->qsz)
+ DPUTC(d, ctx->acc << 4);
+ }
+}
+
+/* --- @hex_init@ --- *
+ *
+ * Arguments: @hex_ctx *ctx@ = pointer to context block to initialize
+ *
+ * Returns: ---
+ *
+ * Use: Initializes a hex context properly.
+ */
+
+void hex_init(hex_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 = DSTR_INIT;
+ hex_ctx ctx;
+ void (*proc)(hex_ctx *, const unsigned char *, size_t, dstr *);
+ size_t sz;
+
+ hex_init(&ctx);
+
+ if (argc > 1 && strcmp(argv[1], "-d") == 0)
+ proc = hex_decode;
+ else {
+ proc = hex_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 == hex_encode)
+ putchar('\n');
+
+ return (0);
+}
+
+#endif
+
+/*----- That's all, folks -------------------------------------------------*/
~mdw / mLib / commitdiff