On 14/09/2025 14:17, Pádraig Brady wrote:
There may be more cleanups I might do in this area,
but we should commit this fix anyway.
While it was fresh in my mind,
I refactored the overloaded use of ctx->i
as it was confusing to consider all the various uses of it.
In the attached there is explicit data and access functions
to read the pending data for each encoding.
cheers,
Padraig
From 684493106a5dca26d28494bf77d580b565b645a7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?P=C3=A1draig=20Brady?= <[email protected]>
Date: Mon, 15 Sep 2025 21:31:00 +0100
Subject: [PATCH] maint: basenc: refactor overloaded use of ctx->i member
* src/basenc.c (base_decode_context): Remove the shared "i" member,
instead using per encoding data and access functions
for tracking pending data.
---
src/basenc.c | 118 +++++++++++++++++++++++++++++++++------------------
1 file changed, 76 insertions(+), 42 deletions(-)
diff --git a/src/basenc.c b/src/basenc.c
index 49740a47b..35168f49b 100644
--- a/src/basenc.c
+++ b/src/basenc.c
@@ -281,11 +281,11 @@ struct base58_context
struct base2_decode_context
{
unsigned char octet;
+ int bit_pos;
};
struct base_decode_context
{
- int i; /* will be updated manually */
union {
struct base64_decode_context base64;
struct base32_decode_context base32;
@@ -323,21 +323,58 @@ no_padding (MAYBE_UNUSED struct base_decode_context *ctx)
{
return false;
}
+
+static int
+no_pending_length (MAYBE_UNUSED struct base_decode_context *ctx)
+{
+ return 0;
+}
#endif
#if BASE_TYPE == 42
static bool (*has_padding) (struct base_decode_context *ctx);
+static int (*get_pending_length) (struct base_decode_context *ctx);
static bool
base64_ctx_has_padding (struct base_decode_context *ctx)
{
- return ctx->i && ctx->ctx.base64.buf[ctx->i - 1] == '=';
+ return ctx->ctx.base64.i && ctx->ctx.base64.buf[ctx->ctx.base64.i - 1] == '=';
}
static bool
base32_ctx_has_padding (struct base_decode_context *ctx)
{
- return ctx->i && ctx->ctx.base32.buf[ctx->i - 1] == '=';
+ return ctx->ctx.base32.i && ctx->ctx.base32.buf[ctx->ctx.base32.i - 1] == '=';
+}
+
+static int
+base64_ctx_get_pending_length (struct base_decode_context *ctx)
+{
+ return ctx->ctx.base64.i;
+}
+
+static int
+base32_ctx_get_pending_length (struct base_decode_context *ctx)
+{
+ return ctx->ctx.base32.i;
+}
+
+static int
+base16_ctx_get_pending_length (MAYBE_UNUSED struct base_decode_context *ctx)
+{
+ return 1; /* Always check nibble state. */
+}
+
+static int
+z85_ctx_get_pending_length (struct base_decode_context *ctx)
+{
+ return ctx->ctx.z85.i;
+}
+
+static int
+base2_ctx_get_pending_length (struct base_decode_context *ctx)
+{
+ return ctx->ctx.base2.bit_pos;
}
#else
static bool
@@ -345,6 +382,12 @@ has_padding (struct base_decode_context *ctx)
{
return ctx->i && ctx->buf[ctx->i - 1] == '=';
}
+
+static int
+get_pending_length (struct base_decode_context *ctx)
+{
+ return ctx->i;
+}
#endif
@@ -355,7 +398,7 @@ static bool
decode_ctx_finalize (struct base_decode_context *ctx,
char *restrict *out, idx_t *outlen)
{
- if (ctx->i == 0)
+ if (get_pending_length (ctx) == 0)
{
*outlen = 0;
return true;
@@ -363,7 +406,8 @@ decode_ctx_finalize (struct base_decode_context *ctx,
/* Auto-pad input and flush the context */
char padbuf[8] ATTRIBUTE_NONSTRING = "========";
- idx_t auto_padding = REQUIRED_PADDING (ctx->i);
+ idx_t pending_len = get_pending_length (ctx);
+ idx_t auto_padding = REQUIRED_PADDING (pending_len);
idx_t n = *outlen;
bool result;
@@ -393,7 +437,6 @@ static void
base64_decode_ctx_init_wrapper (struct base_decode_context *ctx)
{
base64_decode_ctx_init (&ctx->ctx.base64);
- ctx->i = 0;
}
static bool
@@ -401,9 +444,7 @@ base64_decode_ctx_wrapper (struct base_decode_context *ctx,
char const *restrict in, idx_t inlen,
char *restrict out, idx_t *outlen)
{
- bool b = base64_decode_ctx (&ctx->ctx.base64, in, inlen, out, outlen);
- ctx->i = ctx->ctx.base64.i;
- return b;
+ return base64_decode_ctx (&ctx->ctx.base64, in, inlen, out, outlen);
}
static void
@@ -450,7 +491,6 @@ static void
base64url_decode_ctx_init_wrapper (struct base_decode_context *ctx)
{
base64_decode_ctx_init (&ctx->ctx.base64);
- ctx->i = 0;
init_inbuf (ctx);
}
@@ -480,11 +520,8 @@ base64url_decode_ctx_wrapper (struct base_decode_context *ctx,
++p;
}
- bool b = base64_decode_ctx (&ctx->ctx.base64, ctx->inbuf, inlen,
- out, outlen);
- ctx->i = ctx->ctx.base64.i;
-
- return b;
+ return base64_decode_ctx (&ctx->ctx.base64, ctx->inbuf, inlen,
+ out, outlen);
}
@@ -499,7 +536,6 @@ static void
base32_decode_ctx_init_wrapper (struct base_decode_context *ctx)
{
base32_decode_ctx_init (&ctx->ctx.base32);
- ctx->i = 0;
}
static bool
@@ -507,9 +543,7 @@ base32_decode_ctx_wrapper (struct base_decode_context *ctx,
char const *restrict in, idx_t inlen,
char *restrict out, idx_t *outlen)
{
- bool b = base32_decode_ctx (&ctx->ctx.base32, in, inlen, out, outlen);
- ctx->i = ctx->ctx.base32.i;
- return b;
+ return base32_decode_ctx (&ctx->ctx.base32, in, inlen, out, outlen);
}
/* ABCDEFGHIJKLMNOPQRSTUVWXYZ234567
@@ -579,7 +613,6 @@ static void
base32hex_decode_ctx_init_wrapper (struct base_decode_context *ctx)
{
base32_decode_ctx_init (&ctx->ctx.base32);
- ctx->i = 0;
init_inbuf (ctx);
}
@@ -603,11 +636,8 @@ base32hex_decode_ctx_wrapper (struct base_decode_context *ctx,
++in;
}
- bool b = base32_decode_ctx (&ctx->ctx.base32, ctx->inbuf, inlen,
- out, outlen);
- ctx->i = ctx->ctx.base32.i;
-
- return b;
+ return base32_decode_ctx (&ctx->ctx.base32, ctx->inbuf, inlen,
+ out, outlen);
}
/* With this approach this file works independent of the charset used
(think EBCDIC). However, it does assume that the characters in the
@@ -740,7 +770,6 @@ base16_decode_ctx_init (struct base_decode_context *ctx)
{
init_inbuf (ctx);
ctx->ctx.base16.nibble = -1;
- ctx->i = 1;
}
@@ -868,7 +897,6 @@ z85_decode_ctx_init (struct base_decode_context *ctx)
{
init_inbuf (ctx);
ctx->ctx.z85.i = 0;
- ctx->i = 1;
}
@@ -977,7 +1005,6 @@ z85_decode_ctx (struct base_decode_context *ctx,
ctx->ctx.z85.i = 0;
}
}
- ctx->i = ctx->ctx.z85.i;
return true;
}
@@ -1037,7 +1064,7 @@ base2_decode_ctx_init (struct base_decode_context *ctx)
{
init_inbuf (ctx);
ctx->ctx.base2.octet = 0;
- ctx->i = 0;
+ ctx->ctx.base2.bit_pos = 0;
}
@@ -1054,7 +1081,7 @@ base2lsbf_decode_ctx (struct base_decode_context *ctx,
if there is a dangling bit - we are missing some bits,
so return false - indicating an invalid input. */
if (inlen == 0)
- return ctx->i == 0;
+ return ctx->ctx.base2.bit_pos == 0;
while (inlen--)
{
@@ -1068,15 +1095,15 @@ base2lsbf_decode_ctx (struct base_decode_context *ctx,
return false;
bool bit = (*in == '1');
- ctx->ctx.base2.octet |= bit << ctx->i;
- ++ctx->i;
+ ctx->ctx.base2.octet |= bit << ctx->ctx.base2.bit_pos;
+ ++ctx->ctx.base2.bit_pos;
- if (ctx->i == 8)
+ if (ctx->ctx.base2.bit_pos == 8)
{
*out++ = ctx->ctx.base2.octet;
ctx->ctx.base2.octet = 0;
++*outlen;
- ctx->i = 0;
+ ctx->ctx.base2.bit_pos = 0;
}
++in;
@@ -1098,7 +1125,7 @@ base2msbf_decode_ctx (struct base_decode_context *ctx,
if there is a dangling bit - we are missing some bits,
so return false - indicating an invalid input. */
if (inlen == 0)
- return ctx->i == 0;
+ return ctx->ctx.base2.bit_pos == 0;
while (inlen--)
{
@@ -1112,17 +1139,16 @@ base2msbf_decode_ctx (struct base_decode_context *ctx,
return false;
bool bit = (*in == '1');
- if (ctx->i == 0)
- ctx->i = 8;
- --ctx->i;
- ctx->ctx.base2.octet |= bit << ctx->i;
+ if (ctx->ctx.base2.bit_pos == 0)
+ ctx->ctx.base2.bit_pos = 8;
+ --ctx->ctx.base2.bit_pos;
+ ctx->ctx.base2.octet |= bit << ctx->ctx.base2.bit_pos;
- if (ctx->i == 0)
+ if (ctx->ctx.base2.bit_pos == 0)
{
*out++ = ctx->ctx.base2.octet;
ctx->ctx.base2.octet = 0;
++*outlen;
- ctx->i = 0;
}
++in;
@@ -1279,7 +1305,6 @@ base58_decode_ctx_init (struct base_decode_context *ctx)
ctx->ctx.base58.size = 0;
ctx->ctx.base58.capacity = 0;
ctx->ctx.base58.buf = nullptr;
- ctx->i = 0;
}
static bool
@@ -1652,6 +1677,7 @@ main (int argc, char **argv)
#if BASE_TYPE == 42
required_padding = no_required_padding;
has_padding = no_padding;
+ get_pending_length = no_pending_length;
base_decode_ctx_finalize = decode_ctx_finalize;
switch (base_type)
@@ -1660,6 +1686,7 @@ main (int argc, char **argv)
base_length = base64_length_wrapper;
required_padding = base64_required_padding;
has_padding = base64_ctx_has_padding;
+ get_pending_length = base64_ctx_get_pending_length;
isubase = isubase64;
base_encode = base64_encode;
base_decode_ctx_init = base64_decode_ctx_init_wrapper;
@@ -1670,6 +1697,7 @@ main (int argc, char **argv)
base_length = base64_length_wrapper;
required_padding = base64_required_padding;
has_padding = base64_ctx_has_padding;
+ get_pending_length = base64_ctx_get_pending_length;
isubase = isubase64url;
base_encode = base64url_encode;
base_decode_ctx_init = base64url_decode_ctx_init_wrapper;
@@ -1680,6 +1708,7 @@ main (int argc, char **argv)
base_length = base32_length_wrapper;
required_padding = base32_required_padding;
has_padding = base32_ctx_has_padding;
+ get_pending_length = base32_ctx_get_pending_length;
isubase = isubase32;
base_encode = base32_encode;
base_decode_ctx_init = base32_decode_ctx_init_wrapper;
@@ -1690,6 +1719,7 @@ main (int argc, char **argv)
base_length = base32_length_wrapper;
required_padding = base32_required_padding;
has_padding = base32_ctx_has_padding;
+ get_pending_length = base32_ctx_get_pending_length;
isubase = isubase32hex;
base_encode = base32hex_encode;
base_decode_ctx_init = base32hex_decode_ctx_init_wrapper;
@@ -1698,6 +1728,7 @@ main (int argc, char **argv)
case BASE16_OPTION:
base_length = base16_length;
+ get_pending_length = base16_ctx_get_pending_length;
isubase = isubase16;
base_encode = base16_encode;
base_decode_ctx_init = base16_decode_ctx_init;
@@ -1706,6 +1737,7 @@ main (int argc, char **argv)
case BASE2MSBF_OPTION:
base_length = base2_length;
+ get_pending_length = base2_ctx_get_pending_length;
isubase = isubase2;
base_encode = base2msbf_encode;
base_decode_ctx_init = base2_decode_ctx_init;
@@ -1714,6 +1746,7 @@ main (int argc, char **argv)
case BASE2LSBF_OPTION:
base_length = base2_length;
+ get_pending_length = base2_ctx_get_pending_length;
isubase = isubase2;
base_encode = base2lsbf_encode;
base_decode_ctx_init = base2_decode_ctx_init;
@@ -1722,6 +1755,7 @@ main (int argc, char **argv)
case Z85_OPTION:
base_length = z85_length;
+ get_pending_length = z85_ctx_get_pending_length;
isubase = isuz85;
base_encode = z85_encode;
base_decode_ctx_init = z85_decode_ctx_init;
--
2.50.1
