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diff --git a/lib/printfrr.h b/lib/printfrr.h
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+/*
+ * Copyright (c) 2019 David Lamparter, for NetDEF, Inc.
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#ifndef _FRR_PRINTFRR_H
+#define _FRR_PRINTFRR_H
+
+#include <stddef.h>
+#include <stdarg.h>
+#include <stdint.h>
+
+#include "compiler.h"
+#include "memory.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct fmt_outpos {
+ unsigned int off_start, off_end;
+};
+
+struct fbuf {
+ char *buf;
+ char *pos;
+ size_t len;
+
+ struct fmt_outpos *outpos;
+ size_t outpos_n, outpos_i;
+};
+
+#define at(a, b) PRINTFRR(a, b)
+#define atn(a, b) \
+ at(a, b) __attribute__((nonnull(1) _RET_NONNULL))
+#define atm(a, b) \
+ atn(a, b) __attribute__((malloc))
+
+/* return value is length needed for the full string (excluding \0) in all
+ * cases. The functions write as much as they can, but continue regardless,
+ * so the return value is independent of buffer length. Both bprintfrr and
+ * snprintf also accept NULL as output buffer.
+ */
+
+/* bprintfrr does NOT null terminate! use sparingly (only provided since it's
+ * the most direct interface) - useful for incrementally building long text
+ * (call bprintfrr repeatedly with the same buffer)
+ */
+ssize_t vbprintfrr(struct fbuf *out, const char *fmt, va_list) at(2, 0);
+ssize_t bprintfrr(struct fbuf *out, const char *fmt, ...) at(2, 3);
+
+/* these do null terminate like their snprintf cousins */
+ssize_t vsnprintfrr(char *out, size_t sz, const char *fmt, va_list) at(3, 0);
+ssize_t snprintfrr(char *out, size_t sz, const char *fmt, ...) at(3, 4);
+
+/* c = continue / concatenate (append at the end of the string)
+ * return value is would-be string length (regardless of buffer length),
+ * i.e. includes already written chars */
+ssize_t vcsnprintfrr(char *out, size_t sz, const char *fmt, va_list) at(3, 0);
+ssize_t csnprintfrr(char *out, size_t sz, const char *fmt, ...) at(3, 4);
+
+/* memory allocations don't fail in FRR, so you always get something here.
+ * (in case of error, returns a strdup of the format string) */
+char *vasprintfrr(struct memtype *mt, const char *fmt, va_list) atm(2, 0);
+char *asprintfrr(struct memtype *mt, const char *fmt, ...) atm(2, 3);
+
+/* try to use provided buffer (presumably from stack), allocate if it's too
+ * short. Must call XFREE(mt, return value) if return value != out.
+ */
+char *vasnprintfrr(struct memtype *mt, char *out, size_t sz,
+ const char *fmt, va_list) atn(4, 0);
+char *asnprintfrr(struct memtype *mt, char *out, size_t sz,
+ const char *fmt, ...) atn(4, 5);
+
+#define printfrr(fmt, ...) \
+ do { \
+ char buf[256], *out; \
+ out = asnprintfrr(MTYPE_TMP, buf, sizeof(buf), fmt, \
+ ##__VA_ARGS__); \
+ fputs(out, stdout); \
+ if (out != buf) \
+ XFREE(MTYPE_TMP, out); \
+ } while (0)
+
+#undef at
+#undef atm
+#undef atn
+
+/* extension specs must start with a capital letter (this is a restriction
+ * for both performance's and human understanding's sake.)
+ *
+ * Note that the entire thing mostly works because a letter directly following
+ * a %p print specifier is extremely unlikely to occur (why would you want to
+ * print "0x12345678HELLO"?) Normally, you'd expect spacing or punctuation
+ * after a placeholder. That also means that neither of those works well for
+ * extension purposes, e.g. "%p{foo}" is reasonable to see actually used.
+ *
+ * TODO: would be nice to support a "%pF%dF" specifier that consumes 2
+ * arguments, e.g. to pass an integer + a list of known values... can be
+ * done, but a bit tricky.
+ */
+#define printfrr_ext_char(ch) ((ch) >= 'A' && (ch) <= 'Z')
+
+struct printfrr_eargs;
+
+struct printfrr_ext {
+ /* embedded string to minimize cache line pollution */
+ char match[8];
+
+ /* both can be given, if not the code continues searching
+ * (you can do %pX and %dX in 2 different entries)
+ *
+ * return value: number of bytes that would be printed if the buffer
+ * was large enough. be careful about not under-reporting this;
+ * otherwise asnprintf() & co. will get broken. Returning -1 means
+ * something went wrong & default %p/%d handling should be executed.
+ *
+ * to consume extra input flags after %pXY, increment *fmt. It points
+ * at the first character after %pXY at entry. Convention is to make
+ * those flags lowercase letters or numbers.
+ */
+ ssize_t (*print_ptr)(struct fbuf *buf, struct printfrr_eargs *info,
+ const void *);
+ ssize_t (*print_int)(struct fbuf *buf, struct printfrr_eargs *info,
+ uintmax_t);
+};
+
+/* additional information passed to extended formatters */
+
+struct printfrr_eargs {
+ /* position in the format string. Points to directly after the
+ * extension specifier. Increment when consuming extra "flag
+ * characters".
+ */
+ const char *fmt;
+
+ /* %.1234x / %.*x
+ * not POSIX compatible when used with %p, will cause warnings from
+ * GCC & clang. Usable with %d. Not used by the printfrr() itself
+ * for extension specifiers, so essentially available as a "free"
+ * parameter. -1 if not specified. Value in the format string
+ * cannot be negative, but negative values can be passed with %.*x
+ */
+ int precision;
+
+ /* %1234x / %*x
+ * regular width specification. Internally handled by printfrr(), set
+ * to 0 if consumed by the extension in order to suppress standard
+ * width/padding behavior. 0 if not specified.
+ *
+ * NB: always positive, even if a negative value is passed in with
+ * %*x. (The sign is used for the - flag.)
+ */
+ int width;
+
+ /* %#x
+ * "alternate representation" flag, not POSIX compatible when used
+ * with %p or %d, will cause warnings from GCC & clang. Not used by
+ * printfrr() itself for extension specifiers.
+ */
+ bool alt_repr;
+
+ /* %-x
+ * left-pad flag. Internally handled by printfrr() if width is
+ * nonzero. Only use if the extension sets width to 0.
+ */
+ bool leftadj;
+};
+
+/* for any extension that needs a buffer length */
+
+static inline ssize_t printfrr_ext_len(struct printfrr_eargs *ea)
+{
+ ssize_t rv;
+
+ if (ea->precision >= 0)
+ rv = ea->precision;
+ else if (ea->width >= 0) {
+ rv = ea->width;
+ ea->width = -1;
+ } else
+ rv = -1;
+
+ return rv;
+}
+
+/* no locking - must be called when single threaded (e.g. at startup.)
+ * this restriction hopefully won't be a huge bother considering normal usage
+ * scenarios...
+ */
+void printfrr_ext_reg(const struct printfrr_ext *);
+
+#define printfrr_ext_autoreg_p(matchs, print_fn) \
+ static ssize_t print_fn(struct fbuf *, struct printfrr_eargs *, \
+ const void *); \
+ static const struct printfrr_ext _printext_##print_fn = { \
+ .match = matchs, \
+ .print_ptr = print_fn, \
+ }; \
+ static void _printreg_##print_fn(void) __attribute__((constructor)); \
+ static void _printreg_##print_fn(void) \
+ { \
+ printfrr_ext_reg(&_printext_##print_fn); \
+ } \
+ MACRO_REQUIRE_SEMICOLON()
+
+#define printfrr_ext_autoreg_i(matchs, print_fn) \
+ static ssize_t print_fn(struct fbuf *, struct printfrr_eargs *, \
+ uintmax_t); \
+ static const struct printfrr_ext _printext_##print_fn = { \
+ .match = matchs, \
+ .print_int = print_fn, \
+ }; \
+ static void _printreg_##print_fn(void) __attribute__((constructor)); \
+ static void _printreg_##print_fn(void) \
+ { \
+ printfrr_ext_reg(&_printext_##print_fn); \
+ } \
+ MACRO_REQUIRE_SEMICOLON()
+
+/* fbuf helper functions - note all 3 of these return the length that would
+ * be written regardless of how much space was available in the buffer, as
+ * needed for implementing printfrr extensions. (They also accept NULL buf
+ * for that.)
+ */
+
+static inline ssize_t bputs(struct fbuf *buf, const char *str)
+{
+ size_t len = strlen(str);
+ size_t ncopy;
+
+ if (!buf)
+ return len;
+
+ ncopy = MIN(len, (size_t)(buf->buf + buf->len - buf->pos));
+ memcpy(buf->pos, str, ncopy);
+ buf->pos += ncopy;
+
+ return len;
+}
+
+static inline ssize_t bputch(struct fbuf *buf, char ch)
+{
+ if (buf && buf->pos < buf->buf + buf->len)
+ *buf->pos++ = ch;
+ return 1;
+}
+
+static inline ssize_t bputhex(struct fbuf *buf, uint8_t val)
+{
+ static const char hexch[] = "0123456789abcdef";
+
+ if (buf && buf->pos < buf->buf + buf->len)
+ *buf->pos++ = hexch[(val >> 4) & 0xf];
+ if (buf && buf->pos < buf->buf + buf->len)
+ *buf->pos++ = hexch[val & 0xf];
+ return 2;
+}
+
+/* %pVA extension, equivalent to Linux kernel %pV */
+
+struct va_format {
+ const char *fmt;
+ va_list *va;
+};
+
+#ifdef _FRR_ATTRIBUTE_PRINTFRR
+#pragma FRR printfrr_ext "%pFB" (struct fbuf *)
+#pragma FRR printfrr_ext "%pVA" (struct va_format *)
+
+#pragma FRR printfrr_ext "%pHX" (signed char *)
+#pragma FRR printfrr_ext "%pHX" (unsigned char *)
+#pragma FRR printfrr_ext "%pHX" (void *)
+#pragma FRR printfrr_ext "%pHS" (signed char *)
+#pragma FRR printfrr_ext "%pHS" (unsigned char *)
+#pragma FRR printfrr_ext "%pHS" (void *)
+
+#pragma FRR printfrr_ext "%pSE" (char *)
+#pragma FRR printfrr_ext "%pSQ" (char *)
+
+#pragma FRR printfrr_ext "%pTS" (struct timespec *)
+#pragma FRR printfrr_ext "%pTV" (struct timeval *)
+#pragma FRR printfrr_ext "%pTT" (time_t *)
+#endif
+
+/* when using non-ISO-C compatible extension specifiers... */
+
+#ifdef _FRR_ATTRIBUTE_PRINTFRR
+#define FMT_NSTD_BEGIN
+#define FMT_NSTD_END
+#else /* !_FRR_ATTRIBUTE_PRINTFRR */
+#define FMT_NSTD_BEGIN \
+ _Pragma("GCC diagnostic push") \
+ _Pragma("GCC diagnostic ignored \"-Wformat\"") \
+ /* end */
+#define FMT_NSTD_END \
+ _Pragma("GCC diagnostic pop") \
+ /* end */
+#endif
+
+#define FMT_NSTD(expr) \
+ ({ \
+ FMT_NSTD_BEGIN \
+ typeof(expr) _v; \
+ _v = expr; \
+ FMT_NSTD_END \
+ _v; \
+ }) \
+ /* end */
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif