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c848ef1e93
Estimated hours taken: 24
Reimplement string__format so that it uses less memory and it's
behaviour is closer to the C standard.
library/string.m:
Reimplement string__format. The new implementation parses the
format string building a control structure. The control structure
is then traversed to generate the output.
Implement string__to_char_list in C.
Implement string__append_list in C as this results in no garbage
being generated due to the creation of the intermediate strings,
which can be quite a significant saving.
Remove the string__append_list(out, in) mode as it generates an
infinite number of solutions.
Use MR_allocate_aligned_string_msg for all memory allocations.
runtime/mercury_string.h:
Add a new macro MR_allocate_aligned_string_msg which allocates
word aligned space for storage of a string in.
runtime/mercury_string.c:
Define a new function MR_make_string which provides sprintf like
functionality for creating MR_Strings. This function is safe from
buffer overflows providing the vsnprintf function is available.
runtime/Mmakefile:
Add mercury_string.c
configure.in:
Check for the vsnprintf function.
runtime/mercury_conf.h.in:
Define HAVE_VSNPRINTF.
65 lines
1.3 KiB
C
65 lines
1.3 KiB
C
/*
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** Copyright (C) 2000 The University of Melbourne.
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** This file may only be copied under the terms of the GNU Library General
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** Public License - see the file COPYING.LIB in the Mercury distribution.
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*/
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/* mercury_string.c - string handling */
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#include "mercury_imp.h"
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#include "mercury_string.h"
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MR_String
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MR_make_string(MR_Code *proclabel, const char *fmt, ...) {
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va_list ap;
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MR_String result;
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int n;
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#ifdef HAVE_VSNPRINTF
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/* Guess that 100 bytes should be sufficient */
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int size = 100;
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char *p;
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p = MR_NEW_ARRAY(char, size);
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while (1) {
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/* Try to print in the allocated space. */
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va_start(ap, fmt);
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n = vsnprintf(p, size, fmt, ap);
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va_end(ap);
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/* If that worked, return the string. */
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if (n > -1 && n < size) {
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break;
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}
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/* Else try again with more space. */
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if (n > -1) /* glibc 2.1 */
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/* precisely what is needed */
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size = n + 1;
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else /* glibc 2.0 */
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size *= 2; /* twice the old size */
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MR_RESIZE_ARRAY(p, char, size);
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}
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#else
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/* It is possible for this buffer to overflow */
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/* and then bad things may happen */
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char p[40960];
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va_start(ap, fmt);
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n = vsprintf(p, fmt, ap);
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va_end(ap);
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#endif
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MR_allocate_aligned_string_msg(result, strlen(p),
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proclabel);
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strcpy((char *) result, p);
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#ifdef HAVE_VFPRINTF
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MR_free(p);
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#endif
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return result;
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}
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