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diff --git a/src/utils/strbuf.c b/src/utils/strbuf.c
index bc24fef5e54c19781c5cd4bef7c3a1036e897945..7d8bc5527f6138f7a1c8ad6cf6730c6445c3460b 100644 (file)
--- a/src/utils/strbuf.c
+++ b/src/utils/strbuf.c
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
+#include <string.h>
+
+#include <unistd.h>
+
+/* free memory if most of the buffer is unused */
+#define CHECK_SHRINK(strbuf) \
+ do { \
+ if ((strbuf)->pos < (strbuf)->size / 3) \
+ /* don't free all memory to avoid churn */ \
+ strbuf_resize((strbuf), 2 * (strbuf)->pos); \
+ } while (0)
/*
* private data structures
*/
static int
-strbuf_resize(sdb_strbuf_t *strbuf)
+strbuf_resize(sdb_strbuf_t *strbuf, size_t new_size)
{
char *tmp;
- assert(strbuf->size);
+ if (new_size <= strbuf->pos)
+ return -1;
- tmp = realloc(strbuf->string, 2 * strbuf->size);
+ tmp = realloc(strbuf->string, new_size);
if (! tmp)
return -1;
- strbuf->string = tmp;
- strbuf->size *= 2;
+ if (new_size)
+ strbuf->string = tmp;
+ else
+ strbuf->string = NULL;
+ strbuf->size = new_size;
return 0;
} /* strbuf_resize */
{
sdb_strbuf_t *strbuf;
- if (! size)
- return NULL;
-
strbuf = calloc(1, sizeof(*strbuf));
if (! strbuf)
return NULL;
- strbuf->string = malloc(size);
- if (! strbuf->string) {
- free(strbuf);
- return NULL;
+ strbuf->string = NULL;
+ if (size) {
+ strbuf->string = malloc(size);
+ if (! strbuf->string) {
+ free(strbuf);
+ return NULL;
+ }
+
+ strbuf->string[0] = '\0';
}
- strbuf->string[0] = '\0';
strbuf->size = size;
strbuf->pos = 0;
if (! strbuf)
return;
- free(strbuf->string);
+ if (strbuf->string)
+ free(strbuf->string);
free(strbuf);
} /* sdb_strbuf_destroy */
if ((! strbuf) || (! fmt))
return -1;
- assert(strbuf->string[strbuf->pos] == '\0');
+ assert((strbuf->size == 0) || (strbuf->string[strbuf->pos] == '\0'));
- if (strbuf->pos >= strbuf->size)
- if (strbuf_resize(strbuf))
+ if (! strbuf->size) {
+ /* use some arbitrary but somewhat reasonable default */
+ if (strbuf_resize(strbuf, 64))
+ return -1;
+ }
+ /* make sure to reserve space for the nul-byte */
+ else if (strbuf->pos >= strbuf->size - 1)
+ if (strbuf_resize(strbuf, 2 * strbuf->size))
return -1;
+ assert(strbuf->size && strbuf->string);
+ assert(strbuf->pos < strbuf->size);
+
/* 'ap' is invalid after calling vsnprintf; thus copy before using it */
va_copy(aq, ap);
status = vsnprintf(strbuf->string + strbuf->pos,
return status;
}
+ /* 'status' does not include nul-byte */
if ((size_t)status >= strbuf->size - strbuf->pos) {
- strbuf_resize(strbuf);
+ if (strbuf_resize(strbuf, strbuf->pos + (size_t)status + 1)) {
+ va_end(aq);
+ return -1;
+ }
/* reset string and try again */
strbuf->string[strbuf->pos] = '\0';
strbuf->pos += (size_t)status;
va_end(aq);
+
+ /* even though this function always appends to the existing buffer, the
+ * size might have previously been reset */
+ CHECK_SHRINK(strbuf);
+
return (ssize_t)status;
} /* sdb_strbuf_vappend */
if (! strbuf)
return -1;
- strbuf->string[0] = '\0';
- strbuf->pos = 0;
+ if (strbuf->size) {
+ strbuf->string[0] = '\0';
+ strbuf->pos = 0;
+ }
return sdb_strbuf_vappend(strbuf, fmt, ap);
} /* sdb_strbuf_vsprintf */
return status;
} /* sdb_strbuf_sprintf */
+ssize_t
+sdb_strbuf_memappend(sdb_strbuf_t *strbuf, const void *data, size_t n)
+{
+ if ((! strbuf) || (! data))
+ return -1;
+
+ assert((strbuf->size == 0) || (strbuf->string[strbuf->pos] == '\0'));
+
+ if (strbuf->pos + n + 1 >= strbuf->size) {
+ size_t newsize = strbuf->size * 2;
+
+ if (! newsize)
+ newsize = 64;
+ while (strbuf->pos + n + 1 >= newsize)
+ newsize *= 2;
+
+ if (strbuf_resize(strbuf, newsize))
+ return -1;
+ }
+
+ assert(strbuf->size && strbuf->string);
+ assert(strbuf->pos < strbuf->size);
+
+ memcpy((void *)(strbuf->string + strbuf->pos), data, n);
+ strbuf->pos += n;
+ strbuf->string[strbuf->pos] = '\0';
+
+ /* even though this function always appends to the existing buffer, the
+ * size might have previously been reset */
+ CHECK_SHRINK(strbuf);
+
+ return (ssize_t)n;
+} /* sdb_strbuf_memappend */
+
+ssize_t
+sdb_strbuf_memcpy(sdb_strbuf_t *strbuf, const void *data, size_t n)
+{
+ if ((! strbuf) || (! data))
+ return -1;
+
+ if (strbuf->size) {
+ strbuf->string[0] = '\0';
+ strbuf->pos = 0;
+ }
+
+ return sdb_strbuf_memappend(strbuf, data, n);
+} /* sdb_strbuf_memcpy */
+
+ssize_t
+sdb_strbuf_read(sdb_strbuf_t *strbuf, int fd, size_t n)
+{
+ ssize_t ret;
+
+ if (! strbuf)
+ return -1;
+
+ if (strbuf->pos + n + 1 >= strbuf->size)
+ if (strbuf_resize(strbuf, strbuf->pos + n + 1))
+ return -1;
+
+ ret = read(fd, strbuf->string + strbuf->pos, n);
+ if (ret > 0)
+ strbuf->pos += (size_t)ret;
+ return ret;
+} /* sdb_strbuf_read */
+
ssize_t
sdb_strbuf_chomp(sdb_strbuf_t *strbuf)
{
if (! strbuf)
return -1;
+ assert((!strbuf->size) || (strbuf->pos < strbuf->size));
+ assert(strbuf->pos <= strbuf->size);
+
while ((strbuf->pos > 0)
&& (strbuf->string[strbuf->pos - 1] == '\n')) {
--strbuf->pos;
return ret;
} /* sdb_strbuf_chomp */
+void
+sdb_strbuf_skip(sdb_strbuf_t *strbuf, size_t offset, size_t n)
+{
+ char *start;
+ size_t len;
+
+ if ((! strbuf) || (! n))
+ return;
+
+ if (offset >= strbuf->pos)
+ return;
+
+ len = strbuf->pos - offset;
+
+ if (n >= len) {
+ strbuf->string[offset] = '\0';
+ strbuf->pos = offset;
+ return;
+ }
+
+ assert(offset + n < strbuf->pos);
+ assert(offset < strbuf->pos);
+
+ start = strbuf->string + offset;
+ memmove(start, start + n, len - n);
+ strbuf->pos -= n;
+ strbuf->string[strbuf->pos] = '\0';
+
+ /* don't resize now but wait for the next write to avoid churn */
+} /* sdb_strbuf_skip */
+
+void
+sdb_strbuf_clear(sdb_strbuf_t *strbuf)
+{
+ if ((! strbuf) || (! strbuf->size))
+ return;
+
+ strbuf->string[0] = '\0';
+ strbuf->pos = 0;
+
+ /* don't resize now but wait for the next write to avoid churn */
+} /* sdb_strbuf_clear */
+
const char *
sdb_strbuf_string(sdb_strbuf_t *strbuf)
{
if (! strbuf)
return NULL;
+ if (! strbuf->size)
+ return "";
return strbuf->string;
} /* sdb_strbuf_string */
return strbuf->pos;
} /* sdb_strbuf_string */
+size_t
+sdb_strbuf_cap(sdb_strbuf_t *strbuf)
+{
+ if (! strbuf)
+ return 0;
+ return strbuf->size;
+} /* sdb_strbuf_cap */
+
/* vim: set tw=78 sw=4 ts=4 noexpandtab : */