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putty/utils.c

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29 KiB
C
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/*
* Platform-independent utility routines used throughout this code base.
*
* This file is linked into stand-alone test utilities which only want
* to include the things they really need, so functions in here should
* avoid depending on any functions outside it. Utility routines that
* are more tightly integrated into the main code should live in
* misc.c.
*/
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <limits.h>
#include <ctype.h>
#include <assert.h>
#include "defs.h"
#include "misc.h"
/*
* Parse a string block size specification. This is approximately a
* subset of the block size specs supported by GNU fileutils:
* "nk" = n kilobytes
* "nM" = n megabytes
* "nG" = n gigabytes
* All numbers are decimal, and suffixes refer to powers of two.
* Case-insensitive.
*/
unsigned long parse_blocksize(const char *bs)
{
char *suf;
unsigned long r = strtoul(bs, &suf, 10);
if (*suf != '\0') {
while (*suf && isspace((unsigned char)*suf)) suf++;
switch (*suf) {
case 'k': case 'K':
r *= 1024ul;
break;
case 'm': case 'M':
r *= 1024ul * 1024ul;
break;
case 'g': case 'G':
r *= 1024ul * 1024ul * 1024ul;
break;
case '\0':
default:
break;
}
}
return r;
}
/*
* Parse a ^C style character specification.
* Returns NULL in `next' if we didn't recognise it as a control character,
* in which case `c' should be ignored.
* The precise current parsing is an oddity inherited from the terminal
* answerback-string parsing code. All sequences start with ^; all except
* ^<123> are two characters. The ones that are worth keeping are probably:
* ^? 127
* ^@A-Z[\]^_ 0-31
* a-z 1-26
* <num> specified by number (decimal, 0octal, 0xHEX)
* ~ ^ escape
*/
char ctrlparse(char *s, char **next)
{
char c = 0;
if (*s != '^') {
*next = NULL;
} else {
s++;
if (*s == '\0') {
*next = NULL;
} else if (*s == '<') {
s++;
c = (char)strtol(s, next, 0);
if ((*next == s) || (**next != '>')) {
c = 0;
*next = NULL;
} else
(*next)++;
} else if (*s >= 'a' && *s <= 'z') {
c = (*s - ('a' - 1));
*next = s+1;
} else if ((*s >= '@' && *s <= '_') || *s == '?' || (*s & 0x80)) {
c = ('@' ^ *s);
*next = s+1;
} else if (*s == '~') {
c = '^';
*next = s+1;
}
}
return c;
}
/*
* Find a character in a string, unless it's a colon contained within
* square brackets. Used for untangling strings of the form
* 'host:port', where host can be an IPv6 literal.
*
* We provide several variants of this function, with semantics like
* various standard string.h functions.
*/
static const char *host_strchr_internal(const char *s, const char *set,
bool first)
{
int brackets = 0;
const char *ret = NULL;
while (1) {
if (!*s)
return ret;
if (*s == '[')
brackets++;
else if (*s == ']' && brackets > 0)
brackets--;
else if (brackets && *s == ':')
/* never match */ ;
else if (strchr(set, *s)) {
ret = s;
if (first)
return ret;
}
s++;
}
}
size_t host_strcspn(const char *s, const char *set)
{
const char *answer = host_strchr_internal(s, set, true);
if (answer)
return answer - s;
else
return strlen(s);
}
char *host_strchr(const char *s, int c)
{
char set[2];
set[0] = c;
set[1] = '\0';
return (char *) host_strchr_internal(s, set, true);
}
char *host_strrchr(const char *s, int c)
{
char set[2];
set[0] = c;
set[1] = '\0';
return (char *) host_strchr_internal(s, set, false);
}
#ifdef TEST_HOST_STRFOO
int main(void)
{
int passes = 0, fails = 0;
#define TEST1(func, string, arg2, suffix, result) do \
{ \
const char *str = string; \
unsigned ret = func(string, arg2) suffix; \
if (ret == result) { \
passes++; \
} else { \
printf("fail: %s(%s,%s)%s = %u, expected %u\n", \
#func, #string, #arg2, #suffix, ret, \
(unsigned)result); \
fails++; \
} \
} while (0)
TEST1(host_strchr, "[1:2:3]:4:5", ':', -str, 7);
TEST1(host_strrchr, "[1:2:3]:4:5", ':', -str, 9);
TEST1(host_strcspn, "[1:2:3]:4:5", "/:",, 7);
TEST1(host_strchr, "[1:2:3]", ':', == NULL, 1);
TEST1(host_strrchr, "[1:2:3]", ':', == NULL, 1);
TEST1(host_strcspn, "[1:2:3]", "/:",, 7);
TEST1(host_strcspn, "[1:2/3]", "/:",, 4);
TEST1(host_strcspn, "[1:2:3]/", "/:",, 7);
printf("passed %d failed %d total %d\n", passes, fails, passes+fails);
return fails != 0 ? 1 : 0;
}
/* Stubs to stop the rest of this module causing compile failures. */
static NORETURN void fatal_error(const char *p, ...)
{
va_list ap;
fprintf(stderr, "host_string_test: ");
va_start(ap, p);
vfprintf(stderr, p, ap);
va_end(ap);
fputc('\n', stderr);
exit(1);
}
void out_of_memory(void) { fatal_error("out of memory"); }
#endif /* TEST_HOST_STRFOO */
/*
* Trim square brackets off the outside of an IPv6 address literal.
* Leave all other strings unchanged. Returns a fresh dynamically
* allocated string.
*/
char *host_strduptrim(const char *s)
{
if (s[0] == '[') {
const char *p = s+1;
int colons = 0;
while (*p && *p != ']') {
if (isxdigit((unsigned char)*p))
/* OK */;
else if (*p == ':')
colons++;
else
break;
p++;
}
if (*p == '%') {
/*
* This delimiter character introduces an RFC 4007 scope
* id suffix (e.g. suffixing the address literal with
* %eth1 or %2 or some such). There's no syntax
* specification for the scope id, so just accept anything
* except the closing ].
*/
p += strcspn(p, "]");
}
if (*p == ']' && !p[1] && colons > 1) {
/*
* This looks like an IPv6 address literal (hex digits and
* at least two colons, plus optional scope id, contained
* in square brackets). Trim off the brackets.
*/
return dupprintf("%.*s", (int)(p - (s+1)), s+1);
}
}
/*
* Any other shape of string is simply duplicated.
*/
return dupstr(s);
}
/* ----------------------------------------------------------------------
* String handling routines.
*/
char *dupstr(const char *s)
{
char *p = NULL;
if (s) {
int len = strlen(s);
p = snewn(len + 1, char);
strcpy(p, s);
}
return p;
}
/* Allocate the concatenation of N strings. Terminate arg list with NULL. */
char *dupcat_fn(const char *s1, ...)
{
int len;
char *p, *q, *sn;
va_list ap;
len = strlen(s1);
va_start(ap, s1);
while (1) {
sn = va_arg(ap, char *);
if (!sn)
break;
len += strlen(sn);
}
va_end(ap);
p = snewn(len + 1, char);
strcpy(p, s1);
q = p + strlen(p);
va_start(ap, s1);
while (1) {
sn = va_arg(ap, char *);
if (!sn)
break;
strcpy(q, sn);
q += strlen(q);
}
va_end(ap);
return p;
}
void burnstr(char *string) /* sfree(str), only clear it first */
{
if (string) {
smemclr(string, strlen(string));
sfree(string);
}
}
int string_length_for_printf(size_t s)
{
/* Truncate absurdly long strings (should one show up) to fit
* within a positive 'int', which is what the "%.*s" format will
* expect. */
if (s > INT_MAX)
return INT_MAX;
return s;
}
/* Work around lack of va_copy in old MSC */
#if defined _MSC_VER && !defined va_copy
#define va_copy(a, b) TYPECHECK( \
(va_list *)0 == &(a) && (va_list *)0 == &(b), \
memcpy(&a, &b, sizeof(va_list)))
#endif
/* Also lack of vsnprintf before VS2015 */
#if defined _WINDOWS && \
!defined __MINGW32__ && \
!defined __WINE__ && \
_MSC_VER < 1900
#define vsnprintf _vsnprintf
#endif
/*
* Do an sprintf(), but into a custom-allocated buffer.
*
* Currently I'm doing this via vsnprintf. This has worked so far,
* but it's not good, because vsnprintf is not available on all
* platforms. There's an ifdef to use `_vsnprintf', which seems
* to be the local name for it on Windows. Other platforms may
* lack it completely, in which case it'll be time to rewrite
* this function in a totally different way.
*
* The only `properly' portable solution I can think of is to
* implement my own format string scanner, which figures out an
* upper bound for the length of each formatting directive,
* allocates the buffer as it goes along, and calls sprintf() to
* actually process each directive. If I ever need to actually do
* this, some caveats:
*
* - It's very hard to find a reliable upper bound for
* floating-point values. %f, in particular, when supplied with
* a number near to the upper or lower limit of representable
* numbers, could easily take several hundred characters. It's
* probably feasible to predict this statically using the
* constants in <float.h>, or even to predict it dynamically by
* looking at the exponent of the specific float provided, but
* it won't be fun.
*
* - Don't forget to _check_, after calling sprintf, that it's
* used at most the amount of space we had available.
*
* - Fault any formatting directive we don't fully understand. The
* aim here is to _guarantee_ that we never overflow the buffer,
* because this is a security-critical function. If we see a
* directive we don't know about, we should panic and die rather
* than run any risk.
*/
static char *dupvprintf_inner(char *buf, size_t oldlen, size_t *sizeptr,
const char *fmt, va_list ap)
{
size_t size = *sizeptr;
sgrowarrayn_nm(buf, size, oldlen, 512);
while (1) {
va_list aq;
va_copy(aq, ap);
int len = vsnprintf(buf + oldlen, size - oldlen, fmt, aq);
va_end(aq);
if (len >= 0 && len < size) {
/* This is the C99-specified criterion for snprintf to have
* been completely successful. */
*sizeptr = size;
return buf;
} else if (len > 0) {
/* This is the C99 error condition: the returned length is
* the required buffer size not counting the NUL. */
sgrowarrayn_nm(buf, size, oldlen + 1, len);
} else {
/* This is the pre-C99 glibc error condition: <0 means the
* buffer wasn't big enough, so we enlarge it a bit and hope. */
sgrowarray_nm(buf, size, size);
}
}
}
char *dupvprintf(const char *fmt, va_list ap)
{
size_t size = 0;
return dupvprintf_inner(NULL, 0, &size, fmt, ap);
}
char *dupprintf(const char *fmt, ...)
{
char *ret;
va_list ap;
va_start(ap, fmt);
ret = dupvprintf(fmt, ap);
va_end(ap);
return ret;
}
struct strbuf_impl {
size_t size;
struct strbuf visible;
bool nm; /* true if we insist on non-moving buffer resizes */
};
#define STRBUF_SET_UPTR(buf) \
((buf)->visible.u = (unsigned char *)(buf)->visible.s)
#define STRBUF_SET_PTR(buf, ptr) \
((buf)->visible.s = (ptr), STRBUF_SET_UPTR(buf))
void *strbuf_append(strbuf *buf_o, size_t len)
{
struct strbuf_impl *buf = container_of(buf_o, struct strbuf_impl, visible);
char *toret;
sgrowarray_general(
buf->visible.s, buf->size, buf->visible.len + 1, len, buf->nm);
STRBUF_SET_UPTR(buf);
toret = buf->visible.s + buf->visible.len;
buf->visible.len += len;
buf->visible.s[buf->visible.len] = '\0';
return toret;
}
void strbuf_shrink_to(strbuf *buf, size_t new_len)
{
assert(new_len <= buf->len);
buf->len = new_len;
buf->s[buf->len] = '\0';
}
void strbuf_shrink_by(strbuf *buf, size_t amount_to_remove)
{
assert(amount_to_remove <= buf->len);
buf->len -= amount_to_remove;
buf->s[buf->len] = '\0';
}
bool strbuf_chomp(strbuf *buf, char char_to_remove)
{
if (buf->len > 0 && buf->s[buf->len-1] == char_to_remove) {
strbuf_shrink_by(buf, 1);
return true;
}
return false;
}
static void strbuf_BinarySink_write(
BinarySink *bs, const void *data, size_t len)
{
strbuf *buf_o = BinarySink_DOWNCAST(bs, strbuf);
memcpy(strbuf_append(buf_o, len), data, len);
}
static strbuf *strbuf_new_general(bool nm)
{
struct strbuf_impl *buf = snew(struct strbuf_impl);
BinarySink_INIT(&buf->visible, strbuf_BinarySink_write);
buf->visible.len = 0;
buf->size = 512;
buf->nm = nm;
STRBUF_SET_PTR(buf, snewn(buf->size, char));
*buf->visible.s = '\0';
return &buf->visible;
}
strbuf *strbuf_new(void) { return strbuf_new_general(false); }
strbuf *strbuf_new_nm(void) { return strbuf_new_general(true); }
void strbuf_free(strbuf *buf_o)
{
struct strbuf_impl *buf = container_of(buf_o, struct strbuf_impl, visible);
if (buf->visible.s) {
smemclr(buf->visible.s, buf->size);
sfree(buf->visible.s);
}
sfree(buf);
}
char *strbuf_to_str(strbuf *buf_o)
{
struct strbuf_impl *buf = container_of(buf_o, struct strbuf_impl, visible);
char *ret = buf->visible.s;
sfree(buf);
return ret;
}
void strbuf_catfv(strbuf *buf_o, const char *fmt, va_list ap)
{
struct strbuf_impl *buf = container_of(buf_o, struct strbuf_impl, visible);
STRBUF_SET_PTR(buf, dupvprintf_inner(buf->visible.s, buf->visible.len,
&buf->size, fmt, ap));
buf->visible.len += strlen(buf->visible.s + buf->visible.len);
}
void strbuf_catf(strbuf *buf_o, const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
strbuf_catfv(buf_o, fmt, ap);
va_end(ap);
}
strbuf *strbuf_new_for_agent_query(void)
{
strbuf *buf = strbuf_new();
strbuf_append(buf, 4);
return buf;
}
void strbuf_finalise_agent_query(strbuf *buf_o)
{
struct strbuf_impl *buf = container_of(buf_o, struct strbuf_impl, visible);
assert(buf->visible.len >= 5);
PUT_32BIT_MSB_FIRST(buf->visible.u, buf->visible.len - 4);
}
/*
* Read an entire line of text from a file. Return a buffer
* malloced to be as big as necessary (caller must free).
*/
char *fgetline(FILE *fp)
{
char *ret = snewn(512, char);
size_t size = 512, len = 0;
while (fgets(ret + len, size - len, fp)) {
len += strlen(ret + len);
if (len > 0 && ret[len-1] == '\n')
break; /* got a newline, we're done */
sgrowarrayn_nm(ret, size, len, 512);
}
if (len == 0) { /* first fgets returned NULL */
sfree(ret);
return NULL;
}
ret[len] = '\0';
return ret;
}
/*
* Read an entire file into a BinarySink.
*/
bool read_file_into(BinarySink *bs, FILE *fp)
{
char buf[4096];
while (1) {
size_t retd = fread(buf, 1, sizeof(buf), fp);
if (retd == 0)
return !ferror(fp);
put_data(bs, buf, retd);
}
}
/*
* Perl-style 'chomp', for a line we just read with fgetline. Unlike
* Perl chomp, however, we're deliberately forgiving of strange
* line-ending conventions. Also we forgive NULL on input, so you can
* just write 'line = chomp(fgetline(fp));' and not bother checking
* for NULL until afterwards.
*/
char *chomp(char *str)
{
if (str) {
int len = strlen(str);
while (len > 0 && (str[len-1] == '\r' || str[len-1] == '\n'))
len--;
str[len] = '\0';
}
return str;
}
/* ----------------------------------------------------------------------
* Core base64 encoding and decoding routines.
*/
void base64_encode_atom(const unsigned char *data, int n, char *out)
{
static const char base64_chars[] =
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
unsigned word;
word = data[0] << 16;
if (n > 1)
word |= data[1] << 8;
if (n > 2)
word |= data[2];
out[0] = base64_chars[(word >> 18) & 0x3F];
out[1] = base64_chars[(word >> 12) & 0x3F];
if (n > 1)
out[2] = base64_chars[(word >> 6) & 0x3F];
else
out[2] = '=';
if (n > 2)
out[3] = base64_chars[word & 0x3F];
else
out[3] = '=';
}
int base64_decode_atom(const char *atom, unsigned char *out)
{
int vals[4];
int i, v, len;
unsigned word;
char c;
for (i = 0; i < 4; i++) {
c = atom[i];
if (c >= 'A' && c <= 'Z')
v = c - 'A';
else if (c >= 'a' && c <= 'z')
v = c - 'a' + 26;
else if (c >= '0' && c <= '9')
v = c - '0' + 52;
else if (c == '+')
v = 62;
else if (c == '/')
v = 63;
else if (c == '=')
v = -1;
else
return 0; /* invalid atom */
vals[i] = v;
}
if (vals[0] == -1 || vals[1] == -1)
return 0;
if (vals[2] == -1 && vals[3] != -1)
return 0;
if (vals[3] != -1)
len = 3;
else if (vals[2] != -1)
len = 2;
else
len = 1;
word = ((vals[0] << 18) |
(vals[1] << 12) | ((vals[2] & 0x3F) << 6) | (vals[3] & 0x3F));
out[0] = (word >> 16) & 0xFF;
if (len > 1)
out[1] = (word >> 8) & 0xFF;
if (len > 2)
out[2] = word & 0xFF;
return len;
}
/* ----------------------------------------------------------------------
* Generic routines to deal with send buffers: a linked list of
* smallish blocks, with the operations
*
* - add an arbitrary amount of data to the end of the list
* - remove the first N bytes from the list
* - return a (pointer,length) pair giving some initial data in
* the list, suitable for passing to a send or write system
* call
* - retrieve a larger amount of initial data from the list
* - return the current size of the buffer chain in bytes
*/
#define BUFFER_MIN_GRANULE 512
struct bufchain_granule {
struct bufchain_granule *next;
char *bufpos, *bufend, *bufmax;
};
static void uninitialised_queue_idempotent_callback(IdempotentCallback *ic)
{
unreachable("bufchain callback used while uninitialised");
}
void bufchain_init(bufchain *ch)
{
ch->head = ch->tail = NULL;
ch->buffersize = 0;
ch->ic = NULL;
ch->queue_idempotent_callback = uninitialised_queue_idempotent_callback;
}
void bufchain_clear(bufchain *ch)
{
struct bufchain_granule *b;
while (ch->head) {
b = ch->head;
ch->head = ch->head->next;
smemclr(b, sizeof(*b));
sfree(b);
}
ch->tail = NULL;
ch->buffersize = 0;
}
size_t bufchain_size(bufchain *ch)
{
return ch->buffersize;
}
void bufchain_set_callback_inner(
bufchain *ch, IdempotentCallback *ic,
void (*queue_idempotent_callback)(IdempotentCallback *ic))
{
ch->queue_idempotent_callback = queue_idempotent_callback;
ch->ic = ic;
}
void bufchain_add(bufchain *ch, const void *data, size_t len)
{
const char *buf = (const char *)data;
if (len == 0) return;
ch->buffersize += len;
while (len > 0) {
if (ch->tail && ch->tail->bufend < ch->tail->bufmax) {
size_t copylen = min(len, ch->tail->bufmax - ch->tail->bufend);
memcpy(ch->tail->bufend, buf, copylen);
buf += copylen;
len -= copylen;
ch->tail->bufend += copylen;
}
if (len > 0) {
size_t grainlen =
max(sizeof(struct bufchain_granule) + len, BUFFER_MIN_GRANULE);
struct bufchain_granule *newbuf;
newbuf = smalloc(grainlen);
newbuf->bufpos = newbuf->bufend =
(char *)newbuf + sizeof(struct bufchain_granule);
newbuf->bufmax = (char *)newbuf + grainlen;
newbuf->next = NULL;
if (ch->tail)
ch->tail->next = newbuf;
else
ch->head = newbuf;
ch->tail = newbuf;
}
}
if (ch->ic)
ch->queue_idempotent_callback(ch->ic);
}
void bufchain_consume(bufchain *ch, size_t len)
{
struct bufchain_granule *tmp;
assert(ch->buffersize >= len);
while (len > 0) {
int remlen = len;
assert(ch->head != NULL);
if (remlen >= ch->head->bufend - ch->head->bufpos) {
remlen = ch->head->bufend - ch->head->bufpos;
tmp = ch->head;
ch->head = tmp->next;
if (!ch->head)
ch->tail = NULL;
smemclr(tmp, sizeof(*tmp));
sfree(tmp);
} else
ch->head->bufpos += remlen;
ch->buffersize -= remlen;
len -= remlen;
}
}
ptrlen bufchain_prefix(bufchain *ch)
{
return make_ptrlen(ch->head->bufpos, ch->head->bufend - ch->head->bufpos);
}
void bufchain_fetch(bufchain *ch, void *data, size_t len)
{
struct bufchain_granule *tmp;
char *data_c = (char *)data;
tmp = ch->head;
assert(ch->buffersize >= len);
while (len > 0) {
int remlen = len;
assert(tmp != NULL);
if (remlen >= tmp->bufend - tmp->bufpos)
remlen = tmp->bufend - tmp->bufpos;
memcpy(data_c, tmp->bufpos, remlen);
tmp = tmp->next;
len -= remlen;
data_c += remlen;
}
}
void bufchain_fetch_consume(bufchain *ch, void *data, size_t len)
{
bufchain_fetch(ch, data, len);
bufchain_consume(ch, len);
}
bool bufchain_try_fetch_consume(bufchain *ch, void *data, size_t len)
{
if (ch->buffersize >= len) {
bufchain_fetch_consume(ch, data, len);
return true;
} else {
return false;
}
}
size_t bufchain_fetch_consume_up_to(bufchain *ch, void *data, size_t len)
{
if (len > ch->buffersize)
len = ch->buffersize;
if (len)
bufchain_fetch_consume(ch, data, len);
return len;
}
/* ----------------------------------------------------------------------
* Debugging routines.
*/
#ifdef DEBUG
extern void dputs(const char *); /* defined in per-platform *misc.c */
void debug_printf(const char *fmt, ...)
{
char *buf;
va_list ap;
va_start(ap, fmt);
buf = dupvprintf(fmt, ap);
dputs(buf);
sfree(buf);
va_end(ap);
}
void debug_memdump(const void *buf, int len, bool L)
{
int i;
const unsigned char *p = buf;
char foo[17];
if (L) {
int delta;
debug_printf("\t%d (0x%x) bytes:\n", len, len);
delta = 15 & (uintptr_t)p;
p -= delta;
len += delta;
}
for (; 0 < len; p += 16, len -= 16) {
dputs(" ");
if (L)
debug_printf("%p: ", p);
strcpy(foo, "................"); /* sixteen dots */
for (i = 0; i < 16 && i < len; ++i) {
if (&p[i] < (unsigned char *) buf) {
dputs(" "); /* 3 spaces */
foo[i] = ' ';
} else {
debug_printf("%c%02.2x",
&p[i] != (unsigned char *) buf
&& i % 4 ? '.' : ' ', p[i]
);
if (p[i] >= ' ' && p[i] <= '~')
foo[i] = (char) p[i];
}
}
foo[i] = '\0';
debug_printf("%*s%s\n", (16 - i) * 3 + 2, "", foo);
}
}
#endif /* def DEBUG */
#ifndef PLATFORM_HAS_SMEMCLR
/*
* Securely wipe memory.
*
* The actual wiping is no different from what memset would do: the
* point of 'securely' is to try to be sure over-clever compilers
* won't optimise away memsets on variables that are about to be freed
* or go out of scope. See
* https://buildsecurityin.us-cert.gov/bsi-rules/home/g1/771-BSI.html
*
* Some platforms (e.g. Windows) may provide their own version of this
* function.
*/
void smemclr(void *b, size_t n) {
volatile char *vp;
if (b && n > 0) {
/*
* Zero out the memory.
*/
memset(b, 0, n);
/*
* Perform a volatile access to the object, forcing the
* compiler to admit that the previous memset was important.
*
* This while loop should in practice run for zero iterations
* (since we know we just zeroed the object out), but in
* theory (as far as the compiler knows) it might range over
* the whole object. (If we had just written, say, '*vp =
* *vp;', a compiler could in principle have 'helpfully'
* optimised the memset into only zeroing out the first byte.
* This should be robust.)
*/
vp = b;
while (*vp) vp++;
}
}
#endif
bool smemeq(const void *av, const void *bv, size_t len)
{
const unsigned char *a = (const unsigned char *)av;
const unsigned char *b = (const unsigned char *)bv;
unsigned val = 0;
while (len-- > 0) {
val |= *a++ ^ *b++;
}
/* Now val is 0 iff we want to return 1, and in the range
* 0x01..0xFF iff we want to return 0. So subtracting from 0x100
* will clear bit 8 iff we want to return 0, and leave it set iff
* we want to return 1, so then we can just shift down. */
return (0x100 - val) >> 8;
}
int nullstrcmp(const char *a, const char *b)
{
if (a == NULL && b == NULL)
return 0;
if (a == NULL)
return -1;
if (b == NULL)
return +1;
return strcmp(a, b);
}
bool ptrlen_eq_string(ptrlen pl, const char *str)
{
size_t len = strlen(str);
return (pl.len == len && !memcmp(pl.ptr, str, len));
}
bool ptrlen_eq_ptrlen(ptrlen pl1, ptrlen pl2)
{
return (pl1.len == pl2.len && !memcmp(pl1.ptr, pl2.ptr, pl1.len));
}
int ptrlen_strcmp(ptrlen pl1, ptrlen pl2)
{
size_t minlen = pl1.len < pl2.len ? pl1.len : pl2.len;
if (minlen) { /* tolerate plX.ptr==NULL as long as plX.len==0 */
int cmp = memcmp(pl1.ptr, pl2.ptr, minlen);
if (cmp)
return cmp;
}
return pl1.len < pl2.len ? -1 : pl1.len > pl2.len ? +1 : 0;
}
bool ptrlen_startswith(ptrlen whole, ptrlen prefix, ptrlen *tail)
{
if (whole.len >= prefix.len &&
!memcmp(whole.ptr, prefix.ptr, prefix.len)) {
if (tail) {
tail->ptr = (const char *)whole.ptr + prefix.len;
tail->len = whole.len - prefix.len;
}
return true;
}
return false;
}
bool ptrlen_endswith(ptrlen whole, ptrlen suffix, ptrlen *tail)
{
if (whole.len >= suffix.len &&
!memcmp((char *)whole.ptr + (whole.len - suffix.len),
suffix.ptr, suffix.len)) {
if (tail) {
tail->ptr = whole.ptr;
tail->len = whole.len - suffix.len;
}
return true;
}
return false;
}
ptrlen ptrlen_get_word(ptrlen *input, const char *separators)
{
const char *p = input->ptr, *end = p + input->len;
ptrlen toret;
while (p < end && strchr(separators, *p))
p++;
toret.ptr = p;
while (p < end && !strchr(separators, *p))
p++;
toret.len = p - (const char *)toret.ptr;
size_t to_consume = p - (const char *)input->ptr;
assert(to_consume <= input->len);
input->ptr = (const char *)input->ptr + to_consume;
input->len -= to_consume;
return toret;
}
char *mkstr(ptrlen pl)
{
char *p = snewn(pl.len + 1, char);
memcpy(p, pl.ptr, pl.len);
p[pl.len] = '\0';
return p;
}
bool strstartswith(const char *s, const char *t)
{
return !strncmp(s, t, strlen(t));
}
bool strendswith(const char *s, const char *t)
{
size_t slen = strlen(s), tlen = strlen(t);
return slen >= tlen && !strcmp(s + (slen - tlen), t);
}
size_t encode_utf8(void *output, unsigned long ch)
{
unsigned char *start = (unsigned char *)output, *p = start;
if (ch < 0x80) {
*p++ = ch;
} else if (ch < 0x800) {
*p++ = 0xC0 | (ch >> 6);
*p++ = 0x80 | (ch & 0x3F);
} else if (ch < 0x10000) {
*p++ = 0xE0 | (ch >> 12);
*p++ = 0x80 | ((ch >> 6) & 0x3F);
*p++ = 0x80 | (ch & 0x3F);
} else {
*p++ = 0xF0 | (ch >> 18);
*p++ = 0x80 | ((ch >> 12) & 0x3F);
*p++ = 0x80 | ((ch >> 6) & 0x3F);
*p++ = 0x80 | (ch & 0x3F);
}
return p - start;
}
void write_c_string_literal(FILE *fp, ptrlen str)
{
for (const char *p = str.ptr; p < (const char *)str.ptr + str.len; p++) {
char c = *p;
if (c == '\n')
fputs("\\n", fp);
else if (c == '\r')
fputs("\\r", fp);
else if (c == '\t')
fputs("\\t", fp);
else if (c == '\b')
fputs("\\b", fp);
else if (c == '\\')
fputs("\\\\", fp);
else if (c == '"')
fputs("\\\"", fp);
else if (c >= 32 && c <= 126)
fputc(c, fp);
else
fprintf(fp, "\\%03o", (unsigned char)c);
}
}
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