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allow literal \0 - \9 in regsub if there is no matching sub-expression

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This commit is contained in:
zimoch
2018-07-10 11:07:29 +02:00
parent d69c74bc8f
commit 19467bd5d5
3 changed files with 47 additions and 33 deletions
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19
doc/formats.html
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@ -564,8 +564,8 @@ in architecture specific RELEASE.Common.<em>arch</em> files.
If the regular expression is not anchored, i.e. does not start with
<code>^</code>, leading non-matching input is skipped.
A maximum of <em>width</em> bytes is matched, if specified.
If <em>precision</em> is given, it specifies the sub-expression whose match
is retuned.
If <em>precision</em> is given, it specifies the sub-expression in <code>()</code>
whose match is retuned.
Otherwise the complete match is returned.
In any case, the complete match is consumed from the input buffer.
If the expression contains a <code>/</code> it must be escaped like <code>\/</code>.
@ -586,12 +586,19 @@ as a post-processor for output.
</p>
<p>
Matches of the <em>regex</em> are replaced by the string <em>subst</em> with all
<code>&</code> or <code>\0</code> in <em>subst</em> replaced with the match itself and all
<code>\1</code> through <code>\9</code> replaced with the match of the corresponding sub-expression.
<code>&</code> in <em>subst</em> replaced with the match itself and all
<code>\1</code> through <code>\9</code> replaced with the match of the corresponding
sub-expression <span class="new"> if such a sub-expression exists.
Due to limitations of the parser, <code>\1</code> and <code>\x01</code> are the same
which makes it difficult to use literal bytes with values lower than 10 in <em>subst</em>.
Therefore <code>\0</code> aways means a literal byte (incompatible change from earlier version!)
and <code>\1</code> through <code>\9</code> mean literal bytes if they are larger than
the number of sub-expressions.
</span>
To get a literal <code>&</code> or <code>\</code> or <code>/</code> in the substitution write
<code>\&</code> or <code>\\</code> or <code>\/</code>.
There is no way to specify literal bytes with values less or equal to 9 in the
substitution!
</p>
<p>
If <em>width</em> is specified, it limits the number of characters processed.

59
src/RegexpConverter.cc
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@ -32,7 +32,6 @@
run-time leak.
- A maximum of 9 subexpressions is supported. Only one of them can
be the result of the match.
- vxWorks and maybe other OS don't have a PCRE library. Provide one?
*/
class RegexpConverter : public StreamFormatConverter
@ -54,9 +53,9 @@ parse(const StreamFormat& fmt, StreamBuffer& info,
}
if (fmt.prec > 9)
{
error("Subexpression index %d too big (>9)\n", fmt.prec);
error("Sub-expression index %d too big (>9)\n", fmt.prec);
return false;
}
}
StreamBuffer pattern;
while (*source != '/')
@ -81,22 +80,30 @@ parse(const StreamFormat& fmt, StreamBuffer& info,
}
source++;
debug("regexp = \"%s\"\n", pattern.expand()());
const char* errormsg;
int eoffset;
pcre* code = pcre_compile(pattern(), 0,
&errormsg, &eoffset, NULL);
int nsubexpr;
pcre* code = pcre_compile(pattern(), 0, &errormsg, &eoffset, NULL);
if (!code)
{
error("%s after \"%s\"\n", errormsg, pattern.expand(0, eoffset)());
return false;
}
pcre_fullinfo(code, NULL, PCRE_INFO_CAPTURECOUNT, &nsubexpr);
if (fmt.prec > nsubexpr)
{
error("Sub-expression index is %d but pattern has only %d sub-expression\n", fmt.prec, nsubexpr);
return false;
}
info.append(&code, sizeof(code));
if (fmt.flags & alt_flag)
{
StreamBuffer subst;
debug("check for subst in \"%s\"\n", StreamBuffer(source).expand()());
debug("check for subst in \"%s\"\n", StreamBuffer(source).expand()());
while (*source != '/')
{
if (!*source) {
@ -122,15 +129,15 @@ scanString(const StreamFormat& fmt, const char* input,
int ovector[30];
int rc;
unsigned int l;
const char* info = fmt.info;
pcre* code = extract<pcre*>(info);
int length = fmt.width > 0 ? fmt.width : strlen(input);
int subexpr = fmt.prec > 0 ? fmt.prec : 0;
debug("input = \"%s\"\n", input);
debug("length=%d\n", length);
rc = pcre_exec(code, NULL, input, length, 0, 0, ovector, 30);
debug("pcre_exec match \"%.*s\" result = %d\n", length, input, rc);
if ((subexpr && rc <= subexpr) || rc < 0)
@ -152,7 +159,7 @@ scanString(const StreamFormat& fmt, const char* input,
}
memcpy(value, input + ovector[subexpr*2], l);
value[l] = '\0';
return ovector[1]; // consume input until end of match
return ovector[1]; // consume input until end of match
}
static void regsubst(const StreamFormat& fmt, StreamBuffer& buffer, long start)
@ -167,19 +174,19 @@ static void regsubst(const StreamFormat& fmt, StreamBuffer& buffer, long start)
length = buffer.length() - start;
if (fmt.width && fmt.width < length)
length = fmt.width;
if (fmt.flags & sign_flag)
if (fmt.flags & left_flag)
start = buffer.length() - length;
debug("regsubst buffer=\"%s\", start=%ld, length=%ld, subst = \"%s\"\n",
buffer.expand()(), start, length, subst);
buffer.expand()(), start, length, StreamBuffer(subst).expand()());
for (c = 0, n = 1; c < length; n++)
{
rc = pcre_exec(code, NULL, buffer(start+c), length-c, 0, 0, ovector, 30);
debug("pcre_exec match \"%.*s\" result = %d\n", (int)length-c, buffer(start+c), rc);
if (rc < 0) // no match
debug("pcre_exec match \"%s\" result = %d\n", buffer.expand(start+c, length-c)(), rc);
if (rc < 0) // no match
return;
if (!(fmt.flags & sign_flag) && n < fmt.prec) // without + flag
{
// do not yet replace this match
@ -188,24 +195,24 @@ static void regsubst(const StreamFormat& fmt, StreamBuffer& buffer, long start)
}
// replace & by match in subst
l = ovector[1] - ovector[0];
debug("start = \"%s\"\n", buffer(start+c));
debug("match = \"%.*s\"\n", l, buffer(start+c+ovector[0]));
debug("before [%d]= \"%s\"\n", ovector[0], buffer.expand(start+c,ovector[0])());
debug("match [%d]= \"%s\"\n", l, buffer.expand(start+c+ovector[0],l)());
for (r = 1; r < rc; r++)
debug("sub%d = \"%.*s\"\n", r, ovector[r*2+1]-ovector[r*2], buffer(start+c+ovector[r*2]));
debug("rest = \"%s\"\n", buffer(start+c+ovector[1]));
debug("sub%d = \"%s\"\n", r, buffer.expand(start+c+ovector[r*2], ovector[r*2+1]-ovector[r*2])());
debug("after = \"%s\"\n", buffer.expand(start+c+ovector[1])());
s = subst;
debug("subs = \"%s\"\n", s.expand()());
debug("subs = \"%s\"\n", s.expand()());
for (r = 0; r < s.length(); r++)
{
debug("check \"%s\"\n", s.expand(r)());
if (s[r] == esc)
{
unsigned char ch = s[r+1];
if (ch < 9) // escaped 0 - 9 : replace with subexpr
if (c != 0 && ch < rc) // escaped 1 - 9 : replace with subexpr
{
ch *= 2;
rl = ovector[ch+1] - ovector[ch];
debug("replace \\%d: \"%.*s\"\n", ch/2, rl, buffer(start+c+ovector[ch]));
debug("replace \\%d: \"%s\"\n", ch/2, buffer.expand(start+c+ovector[ch], rl)());
s.replace(r, 2, buffer(start+c+ovector[ch]), rl);
r += rl - 1;
}
@ -214,12 +221,12 @@ static void regsubst(const StreamFormat& fmt, StreamBuffer& buffer, long start)
}
else if (s[r] == '&') // unescaped & : replace with match
{
debug("replace &: \"%.*s\"\n", l, buffer(start+c+ovector[0]));
debug("replace &: \"%s\"\n", buffer.expand(start+c+ovector[0], l)());
s.replace(r, 1, buffer(start+c+ovector[0]), l);
r += l - 1;
}
else continue;
debug("subs = \"%s\"\n", s());
debug("subs = \"%s\"\n", s.expand()());
}
buffer.replace(start+c+ovector[0], l, s);
length += s.length() - l;

2
src/devStream.h
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@ -23,7 +23,7 @@
#define STREAM_MAJOR 2
#define STREAM_MINOR 7
#define STREAM_PATCHLEVEL 12
#define STREAM_PATCHLEVEL 13
#if defined(__vxworks) || defined(vxWorks)
#include <vxWorks.h>