git-commit-vandalism/strbuf.c
Jonathan Nieder 1368f65002 compat: helper for detecting unsigned overflow
The idiom (a + b < a) works fine for detecting that an unsigned
integer has overflowed, but a more explicit

	unsigned_add_overflows(a, b)

might be easier to read.

Define such a macro, expanding roughly to ((a) < UINT_MAX - (b)).
Because the expansion uses each argument only once outside of sizeof()
expressions, it is safe to use with arguments that have side effects.

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-02-10 13:47:56 -08:00

390 lines
7.7 KiB
C

#include "cache.h"
#include "refs.h"
int prefixcmp(const char *str, const char *prefix)
{
for (; ; str++, prefix++)
if (!*prefix)
return 0;
else if (*str != *prefix)
return (unsigned char)*prefix - (unsigned char)*str;
}
int suffixcmp(const char *str, const char *suffix)
{
int len = strlen(str), suflen = strlen(suffix);
if (len < suflen)
return -1;
else
return strcmp(str + len - suflen, suffix);
}
/*
* Used as the default ->buf value, so that people can always assume
* buf is non NULL and ->buf is NUL terminated even for a freshly
* initialized strbuf.
*/
char strbuf_slopbuf[1];
void strbuf_init(struct strbuf *sb, size_t hint)
{
sb->alloc = sb->len = 0;
sb->buf = strbuf_slopbuf;
if (hint)
strbuf_grow(sb, hint);
}
void strbuf_release(struct strbuf *sb)
{
if (sb->alloc) {
free(sb->buf);
strbuf_init(sb, 0);
}
}
char *strbuf_detach(struct strbuf *sb, size_t *sz)
{
char *res = sb->alloc ? sb->buf : NULL;
if (sz)
*sz = sb->len;
strbuf_init(sb, 0);
return res;
}
void strbuf_attach(struct strbuf *sb, void *buf, size_t len, size_t alloc)
{
strbuf_release(sb);
sb->buf = buf;
sb->len = len;
sb->alloc = alloc;
strbuf_grow(sb, 0);
sb->buf[sb->len] = '\0';
}
void strbuf_grow(struct strbuf *sb, size_t extra)
{
if (unsigned_add_overflows(extra, 1) ||
unsigned_add_overflows(sb->len, extra + 1))
die("you want to use way too much memory");
if (!sb->alloc)
sb->buf = NULL;
ALLOC_GROW(sb->buf, sb->len + extra + 1, sb->alloc);
}
void strbuf_trim(struct strbuf *sb)
{
char *b = sb->buf;
while (sb->len > 0 && isspace((unsigned char)sb->buf[sb->len - 1]))
sb->len--;
while (sb->len > 0 && isspace(*b)) {
b++;
sb->len--;
}
memmove(sb->buf, b, sb->len);
sb->buf[sb->len] = '\0';
}
void strbuf_rtrim(struct strbuf *sb)
{
while (sb->len > 0 && isspace((unsigned char)sb->buf[sb->len - 1]))
sb->len--;
sb->buf[sb->len] = '\0';
}
void strbuf_ltrim(struct strbuf *sb)
{
char *b = sb->buf;
while (sb->len > 0 && isspace(*b)) {
b++;
sb->len--;
}
memmove(sb->buf, b, sb->len);
sb->buf[sb->len] = '\0';
}
struct strbuf **strbuf_split(const struct strbuf *sb, int delim)
{
int alloc = 2, pos = 0;
char *n, *p;
struct strbuf **ret;
struct strbuf *t;
ret = xcalloc(alloc, sizeof(struct strbuf *));
p = n = sb->buf;
while (n < sb->buf + sb->len) {
int len;
n = memchr(n, delim, sb->len - (n - sb->buf));
if (pos + 1 >= alloc) {
alloc = alloc * 2;
ret = xrealloc(ret, sizeof(struct strbuf *) * alloc);
}
if (!n)
n = sb->buf + sb->len - 1;
len = n - p + 1;
t = xmalloc(sizeof(struct strbuf));
strbuf_init(t, len);
strbuf_add(t, p, len);
ret[pos] = t;
ret[++pos] = NULL;
p = ++n;
}
return ret;
}
void strbuf_list_free(struct strbuf **sbs)
{
struct strbuf **s = sbs;
while (*s) {
strbuf_release(*s);
free(*s++);
}
free(sbs);
}
int strbuf_cmp(const struct strbuf *a, const struct strbuf *b)
{
int len = a->len < b->len ? a->len: b->len;
int cmp = memcmp(a->buf, b->buf, len);
if (cmp)
return cmp;
return a->len < b->len ? -1: a->len != b->len;
}
void strbuf_splice(struct strbuf *sb, size_t pos, size_t len,
const void *data, size_t dlen)
{
if (unsigned_add_overflows(pos, len))
die("you want to use way too much memory");
if (pos > sb->len)
die("`pos' is too far after the end of the buffer");
if (pos + len > sb->len)
die("`pos + len' is too far after the end of the buffer");
if (dlen >= len)
strbuf_grow(sb, dlen - len);
memmove(sb->buf + pos + dlen,
sb->buf + pos + len,
sb->len - pos - len);
memcpy(sb->buf + pos, data, dlen);
strbuf_setlen(sb, sb->len + dlen - len);
}
void strbuf_insert(struct strbuf *sb, size_t pos, const void *data, size_t len)
{
strbuf_splice(sb, pos, 0, data, len);
}
void strbuf_remove(struct strbuf *sb, size_t pos, size_t len)
{
strbuf_splice(sb, pos, len, NULL, 0);
}
void strbuf_add(struct strbuf *sb, const void *data, size_t len)
{
strbuf_grow(sb, len);
memcpy(sb->buf + sb->len, data, len);
strbuf_setlen(sb, sb->len + len);
}
void strbuf_adddup(struct strbuf *sb, size_t pos, size_t len)
{
strbuf_grow(sb, len);
memcpy(sb->buf + sb->len, sb->buf + pos, len);
strbuf_setlen(sb, sb->len + len);
}
void strbuf_addf(struct strbuf *sb, const char *fmt, ...)
{
int len;
va_list ap;
if (!strbuf_avail(sb))
strbuf_grow(sb, 64);
va_start(ap, fmt);
len = vsnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, ap);
va_end(ap);
if (len < 0)
die("your vsnprintf is broken");
if (len > strbuf_avail(sb)) {
strbuf_grow(sb, len);
va_start(ap, fmt);
len = vsnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, ap);
va_end(ap);
if (len > strbuf_avail(sb)) {
die("this should not happen, your snprintf is broken");
}
}
strbuf_setlen(sb, sb->len + len);
}
void strbuf_expand(struct strbuf *sb, const char *format, expand_fn_t fn,
void *context)
{
for (;;) {
const char *percent;
size_t consumed;
percent = strchrnul(format, '%');
strbuf_add(sb, format, percent - format);
if (!*percent)
break;
format = percent + 1;
if (*format == '%') {
strbuf_addch(sb, '%');
format++;
continue;
}
consumed = fn(sb, format, context);
if (consumed)
format += consumed;
else
strbuf_addch(sb, '%');
}
}
size_t strbuf_expand_dict_cb(struct strbuf *sb, const char *placeholder,
void *context)
{
struct strbuf_expand_dict_entry *e = context;
size_t len;
for (; e->placeholder && (len = strlen(e->placeholder)); e++) {
if (!strncmp(placeholder, e->placeholder, len)) {
if (e->value)
strbuf_addstr(sb, e->value);
return len;
}
}
return 0;
}
void strbuf_addbuf_percentquote(struct strbuf *dst, const struct strbuf *src)
{
int i, len = src->len;
for (i = 0; i < len; i++) {
if (src->buf[i] == '%')
strbuf_addch(dst, '%');
strbuf_addch(dst, src->buf[i]);
}
}
size_t strbuf_fread(struct strbuf *sb, size_t size, FILE *f)
{
size_t res;
size_t oldalloc = sb->alloc;
strbuf_grow(sb, size);
res = fread(sb->buf + sb->len, 1, size, f);
if (res > 0)
strbuf_setlen(sb, sb->len + res);
else if (oldalloc == 0)
strbuf_release(sb);
return res;
}
ssize_t strbuf_read(struct strbuf *sb, int fd, size_t hint)
{
size_t oldlen = sb->len;
size_t oldalloc = sb->alloc;
strbuf_grow(sb, hint ? hint : 8192);
for (;;) {
ssize_t cnt;
cnt = xread(fd, sb->buf + sb->len, sb->alloc - sb->len - 1);
if (cnt < 0) {
if (oldalloc == 0)
strbuf_release(sb);
else
strbuf_setlen(sb, oldlen);
return -1;
}
if (!cnt)
break;
sb->len += cnt;
strbuf_grow(sb, 8192);
}
sb->buf[sb->len] = '\0';
return sb->len - oldlen;
}
#define STRBUF_MAXLINK (2*PATH_MAX)
int strbuf_readlink(struct strbuf *sb, const char *path, size_t hint)
{
size_t oldalloc = sb->alloc;
if (hint < 32)
hint = 32;
while (hint < STRBUF_MAXLINK) {
int len;
strbuf_grow(sb, hint);
len = readlink(path, sb->buf, hint);
if (len < 0) {
if (errno != ERANGE)
break;
} else if (len < hint) {
strbuf_setlen(sb, len);
return 0;
}
/* .. the buffer was too small - try again */
hint *= 2;
}
if (oldalloc == 0)
strbuf_release(sb);
return -1;
}
int strbuf_getwholeline(struct strbuf *sb, FILE *fp, int term)
{
int ch;
strbuf_grow(sb, 0);
if (feof(fp))
return EOF;
strbuf_reset(sb);
while ((ch = fgetc(fp)) != EOF) {
strbuf_grow(sb, 1);
sb->buf[sb->len++] = ch;
if (ch == term)
break;
}
if (ch == EOF && sb->len == 0)
return EOF;
sb->buf[sb->len] = '\0';
return 0;
}
int strbuf_getline(struct strbuf *sb, FILE *fp, int term)
{
if (strbuf_getwholeline(sb, fp, term))
return EOF;
if (sb->buf[sb->len-1] == term)
strbuf_setlen(sb, sb->len-1);
return 0;
}
int strbuf_read_file(struct strbuf *sb, const char *path, size_t hint)
{
int fd, len;
fd = open(path, O_RDONLY);
if (fd < 0)
return -1;
len = strbuf_read(sb, fd, hint);
close(fd);
if (len < 0)
return -1;
return len;
}