From cb4dfc98a7b89f76bcebfdbcfaa23fea12123f12 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Niels=20M=C3=B6ller?= <nisse@lysator.liu.se>
Date: Mon, 28 Oct 2002 23:07:35 +0100
Subject: [PATCH] (struct hex_decode_ctx): New hex decoding functions.
(sexp_get_raw_char): New function. (sexp_get_char): Use sexp_get_raw_char.
Rev: src/nettle/examples/sexp-conv.c:1.9
---
examples/sexp-conv.c | 120 +++++++++++++++++++++++++++++++++++++------
1 file changed, 103 insertions(+), 17 deletions(-)
diff --git a/examples/sexp-conv.c b/examples/sexp-conv.c
index 2acde89c..952eacca 100644
--- a/examples/sexp-conv.c
+++ b/examples/sexp-conv.c
@@ -62,15 +62,92 @@ enum sexp_coding
SEXP_BASE64,
SEXP_HEX,
};
-
+
+
+/* Hex functions should move out, eventually */
+struct hex_decode_ctx
+{
+ unsigned word;
+ unsigned count;
+};
+
+static void
+hex_decode_init(struct hex_decode_ctx *ctx)
+{
+ ctx->word = ctx->count = 0;
+}
+
+enum { HEX_INVALID = -1, HEX_SPACE=-2 };
+
+/* Returns -1 on error. */
+static int
+hex_decode_single(struct hex_decode_ctx *ctx,
+ uint8_t *dst,
+ uint8_t src)
+{
+ static const signed char hex_decode_table[0x80] =
+ {
+ -1, -1, -1, -1, -1, -1, -1, -1, -1, -2, -2, -1, -1, -2, -1, -1,
+ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+ -2, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, -1, -1, -1, -1, -1, -1,
+ -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+ -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+ };
+
+ int digit;
+ if (src >= 0x80)
+ return -1;
+
+ /* FIXME: This code could use more clever choices of constants. */
+ digit = hex_decode_table[src];
+ switch (digit)
+ {
+ case -1:
+ return -1;
+ case -2:
+ return 0;
+ default:
+ assert(digit >= 0);
+ assert(digit < 0x10);
+
+ if (ctx->count)
+ {
+ *dst = (ctx->word << 4) | digit;
+ ctx->count = 0;
+ return 1;
+ }
+ else
+ {
+ ctx->word = digit;
+ ctx->count = 1;
+ return 0;
+ }
+ }
+}
+
+static int
+hex_decode_status(struct hex_decode_ctx *ctx)
+{
+ return !ctx->count;
+}
+
struct sexp_input
{
FILE *f;
enum sexp_coding coding;
/* Used in transport mode */
- struct base64_decode_ctx base64;
+ union {
+ struct base64_decode_ctx base64;
+ struct hex_decode_ctx hex;
+ };
+ /* Terminator for current coding */
+ uint8_t terminator;
+
/* Type of current token */
enum sexp_token token;
@@ -114,6 +191,23 @@ sexp_output_init(struct sexp_output *output, FILE *f, enum sexp_mode mode)
/* Input */
+/* Returns zero at EOF */
+static int
+sexp_get_raw_char(struct sexp_input *input, uint8_t *out)
+{
+ int c = getc(input->f);
+
+ if (c < 0)
+ {
+ if (ferror(input->f))
+ die("Read error: %s\n", strerror(errno));
+
+ return 0;
+ }
+ *out = c;
+ return 1;
+}
+
/* Returns 1 on success. For special tokens,
* return 0 and set input->token accordingly. */
static int
@@ -125,8 +219,9 @@ sexp_get_char(struct sexp_input *input, uint8_t *out)
for (;;)
{
int done;
- int c = getc(input->f);
- if (c < 0)
+ uint8_t c;
+
+ if (!sexp_get_raw_char(input, &c))
die("Unexpected end of file in base64 data.\n");
if (c == '}')
@@ -145,21 +240,12 @@ sexp_get_char(struct sexp_input *input, uint8_t *out)
return 1;
}
case SEXP_PLAIN:
- {
- int c = getc(input->f);
+ if (sexp_get_raw_char(input, out))
+ return 1;
- if (c < 0)
- {
- if (ferror(input->f))
- die("Read error: %s\n", strerror(errno));
-
- input->token = SEXP_EOF;
- return 0;
- }
+ input->token = SEXP_EOF;
+ return 0;
- *out = c;
- return 1;
- }
case SEXP_HEX:
/* Not yet implemented */
abort();
--
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