/**
* \file cook.c
*
* This file contains the routines that deal with processing quoted strings
* into an internal format.
*
* @addtogroup autoopts
* @{
*/
/*
* This file is part of AutoOpts, a companion to AutoGen.
* AutoOpts is free software.
* AutoOpts is Copyright (C) 1992-2018 by Bruce Korb - all rights reserved
*
* AutoOpts is available under any one of two licenses. The license
* in use must be one of these two and the choice is under the control
* of the user of the license.
*
* The GNU Lesser General Public License, version 3 or later
* See the files "COPYING.lgplv3" and "COPYING.gplv3"
*
* The Modified Berkeley Software Distribution License
* See the file "COPYING.mbsd"
*
* These files have the following sha256 sums:
*
* 8584710e9b04216a394078dc156b781d0b47e1729104d666658aecef8ee32e95 COPYING.gplv3
* 4379e7444a0e2ce2b12dd6f5a52a27a4d02d39d247901d3285c88cf0d37f477b COPYING.lgplv3
* 13aa749a5b0a454917a944ed8fffc530b784f5ead522b1aacaf4ec8aa55a6239 COPYING.mbsd
*/
/*=export_func ao_string_cook_escape_char
* private:
*
* what: escape-process a string fragment
* arg: + char const * + pzScan + points to character after the escape +
* arg: + char * + pRes + Where to put the result byte +
* arg: + unsigned int + nl_ch + replacement char if scanned char is \n +
*
* ret-type: unsigned int
* ret-desc: The number of bytes consumed processing the escaped character.
*
* doc:
*
* This function converts "t" into "\t" and all your other favorite
* escapes, including numeric ones: hex and ocatal, too.
* The returned result tells the caller how far to advance the
* scan pointer (passed in). The default is to just pass through the
* escaped character and advance the scan by one.
*
* Some applications need to keep an escaped newline, others need to
* suppress it. This is accomplished by supplying a '\n' replacement
* character that is different from \n, if need be. For example, use
* 0x7F and never emit a 0x7F.
*
* err: @code{NULL} is returned if the string is mal-formed.
=*/
unsigned int
ao_string_cook_escape_char(char const * pzIn, char * pRes, uint_t nl)
{
unsigned int res = 1;
switch (*pRes = *pzIn++) {
case NUL: /* NUL - end of input string */
return 0;
case '\r':
if (*pzIn != NL)
return 1;
res++;
/* FALLTHROUGH */
case NL: /* NL - emit newline */
*pRes = (char)nl;
return res;
case 'a': *pRes = '\a'; break;
case 'b': *pRes = '\b'; break;
case 'f': *pRes = '\f'; break;
case 'n': *pRes = NL; break;
case 'r': *pRes = '\r'; break;
case 't': *pRes = '\t'; break;
case 'v': *pRes = '\v'; break;
case 'x':
case 'X': /* HEX Escape */
if (IS_HEX_DIGIT_CHAR(*pzIn)) {
char z[4];
unsigned int ct = 0;
do {
z[ct] = pzIn[ct];
if (++ct >= 2)
break;
} while (IS_HEX_DIGIT_CHAR(pzIn[ct]));
z[ct] = NUL;
*pRes = (char)strtoul(z, NULL, 16);
return ct + 1;
}
break;
case '0': case '1': case '2': case '3':
case '4': case '5': case '6': case '7':
{
/*
* IF the character copied was an octal digit,
* THEN set the output character to an octal value.
* The 3 octal digit result might exceed 0xFF, so check it.
*/
char z[4];
unsigned long val;
unsigned int ct = 0;
z[ct++] = *--pzIn;
while (IS_OCT_DIGIT_CHAR(pzIn[ct])) {
z[ct] = pzIn[ct];
if (++ct >= 3)
break;
}
z[ct] = NUL;
val = strtoul(z, NULL, 8);
if (val > 0xFF)
val = 0xFF;
*pRes = (char)val;
return ct;
}
default: /* quoted character is result character */;
}
return res;
}
/**
* count newlines between start and end
*/
static char *
nl_count(char * start, char * end, int * lnct_p)
{
while (start < end) {
if (*(start++) == NL)
(*lnct_p)++;
}
return end;
}
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
*
* A quoted string has been found.
* Find the end of it and compress any escape sequences.
*/
static bool
contiguous_quote(char ** pps, char * pq, int * lnct_p)
{
char * ps = *pps + 1;
for (;;) {
while (IS_WHITESPACE_CHAR(*ps))
if (*(ps++) == NL)
(*lnct_p)++;
/*
* IF the next character is a quote character,
* THEN we will concatenate the strings.
*/
switch (*ps) {
case '"':
case '\'':
*pq = *(ps++); /* assign new quote character and return */
*pps = ps;
return true;
case '/':
/*
* Allow for a comment embedded in the concatenated string.
*/
switch (ps[1]) {
default:
goto fail_return;
case '/':
/*
* Skip to end of line
*/
ps = strchr(ps, NL);
if (ps == NULL)
goto fail_return;
break;
case '*':
ps = nl_count(ps + 2, strstr(ps + 2, "*/"), lnct_p);
if (ps == NULL)
goto fail_return;
ps += 2;
}
continue;
default:
/*
* The next non-whitespace character is not a quote.
* The series of quoted strings has come to an end.
*/
*pps = ps;
return false;
}
}
fail_return:
*pps = NULL;
return false;
}
/*=export_func ao_string_cook
* private:
*
* what: concatenate and escape-process strings
* arg: + char * + pzScan + The *MODIFIABLE* input buffer +
* arg: + int * + lnct_p + The (possibly NULL) pointer to a line count +
*
* ret-type: char *
* ret-desc: The address of the text following the processed strings.
* The return value is NULL if the strings are ill-formed.
*
* doc:
*
* A series of one or more quoted strings are concatenated together.
* If they are quoted with double quotes (@code{"}), then backslash
* escapes are processed per the C programming language. If they are
* single quote strings, then the backslashes are honored only when they
* precede another backslash or a single quote character.
*
* err: @code{NULL} is returned if the string(s) is/are mal-formed.
=*/
char *
ao_string_cook(char * pzScan, int * lnct_p)
{
int l = 0;
char q = *pzScan;
/*
* It is a quoted string. Process the escape sequence characters
* (in the set "abfnrtv") and make sure we find a closing quote.
*/
char * pzD = pzScan++;
char * pzS = pzScan;
if (lnct_p == NULL)
lnct_p = &l;
for (;;) {
/*
* IF the next character is the quote character, THEN we may end the
* string. We end it unless the next non-blank character *after* the
* string happens to also be a quote. If it is, then we will change
* our quote character to the new quote character and continue
* condensing text.
*/
while (*pzS == q) {
*pzD = NUL; /* This is probably the end of the line */
if (! contiguous_quote(&pzS, &q, lnct_p))
return pzS;
}
/*
* We are inside a quoted string. Copy text.
*/
switch (*(pzD++) = *(pzS++)) {
case NUL:
return NULL;
case NL:
(*lnct_p)++;
break;
case '\\':
/*
* IF we are escaping a new line,
* THEN drop both the escape and the newline from
* the result string.
*/
if (*pzS == NL) {
pzS++;
pzD--;
(*lnct_p)++;
}
/*
* ELSE IF the quote character is '"' or '`',
* THEN we do the full escape character processing
*/
else if (q != '\'') {
unsigned int ct;
ct = ao_string_cook_escape_char(pzS, pzD-1, (uint_t)NL);
if (ct == 0)
return NULL;
pzS += ct;
} /* if (q != '\'') */
/*
* OTHERWISE, we only process "\\", "\'" and "\#" sequences.
* The latter only to easily hide preprocessing directives.
*/
else switch (*pzS) {
case '\\':
case '\'':
case '#':
pzD[-1] = *pzS++;
}
} /* switch (*(pzD++) = *(pzS++)) */
} /* for (;;) */
}
/** @}
*
* Local Variables:
* mode: C
* c-file-style: "stroustrup"
* indent-tabs-mode: nil
* End:
* end of autoopts/cook.c */