X-Git-Url: https://git.tokkee.org/?a=blobdiff_plain;f=src%2Futils%2Fstrbuf.c;h=d8a95ac42f60a4003d9cdf21924cbfbf2a5ccee1;hb=13fe0f9ec3d161fab7a015054649910541d75f5e;hp=a48f7bc5765959d38050bdf2f19c027a9765f789;hpb=6f6e12a94487f7bdf9efe2d5f1733684df6d75a6;p=sysdb.git

diff --git a/src/utils/strbuf.c b/src/utils/strbuf.c
index a48f7bc..d8a95ac 100644
--- a/src/utils/strbuf.c
+++ b/src/utils/strbuf.c
@@ -25,6 +25,7 @@
  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
+#include "sysdb.h"
 #include "utils/strbuf.h"
 
 #include <assert.h>
@@ -32,6 +33,18 @@
 #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(buf) \
+	do { \
+		if (((buf)->pos < (buf)->size / 3) \
+				&& (2 * (buf)->pos > (buf)->min_size)) \
+			/* don't free all memory to avoid churn */ \
+			strbuf_resize((buf), 2 * (buf)->pos); \
+	} while (0)
 
 /*
  * private data structures
@@ -41,6 +54,9 @@ struct sdb_strbuf {
 	char  *string;
 	size_t size;
 	size_t pos;
+
+	/* min size to shrink the buffer to */
+	size_t min_size;
 };
 
 /*
@@ -48,18 +64,29 @@ struct sdb_strbuf {
  */
 
 static int
-strbuf_resize(sdb_strbuf_t *strbuf)
+strbuf_resize(sdb_strbuf_t *buf, size_t new_size)
 {
+	size_t tmp_size;
 	char *tmp;
 
-	assert(strbuf->size);
+	if (new_size <= buf->pos)
+		return -1;
+
+	tmp_size = SDB_MAX(buf->size, buf->min_size);
+	if (! tmp_size)
+		tmp_size = 64;
+	while (tmp_size < new_size)
+		tmp_size *= 2;
 
-	tmp = realloc(strbuf->string, 2 * strbuf->size);
+	tmp = realloc(buf->string, new_size);
 	if (! tmp)
 		return -1;
 
-	strbuf->string = tmp;
-	strbuf->size *= 2;
+	if (new_size)
+		buf->string = tmp;
+	else
+		buf->string = NULL;
+	buf->size = new_size;
 	return 0;
 } /* strbuf_resize */
 
@@ -70,130 +97,288 @@ strbuf_resize(sdb_strbuf_t *strbuf)
 sdb_strbuf_t *
 sdb_strbuf_create(size_t size)
 {
-	sdb_strbuf_t *strbuf;
+	sdb_strbuf_t *buf;
 
-	if (! size)
+	buf = calloc(1, sizeof(*buf));
+	if (! buf)
 		return NULL;
 
-	strbuf = calloc(1, sizeof(*strbuf));
-	if (! strbuf)
-		return NULL;
+	buf->string = NULL;
+	if (size) {
+		buf->string = malloc(size);
+		if (! buf->string) {
+			free(buf);
+			return NULL;
+		}
 
-	strbuf->string = malloc(size);
-	if (! strbuf->string) {
-		free(strbuf);
-		return NULL;
+		buf->string[0] = '\0';
+		buf->min_size = size;
 	}
+	else
+		buf->min_size = 64;
 
-	strbuf->string[0] = '\0';
-	strbuf->size = size;
-	strbuf->pos  = 0;
+	buf->size = size;
+	buf->pos  = 0;
 
-	return strbuf;
+	return buf;
 } /* sdb_strbuf_create */
 
 void
-sdb_strbuf_destroy(sdb_strbuf_t *strbuf)
+sdb_strbuf_destroy(sdb_strbuf_t *buf)
 {
-	if (! strbuf)
+	if (! buf)
 		return;
 
-	free(strbuf->string);
-	free(strbuf);
+	if (buf->string)
+		free(buf->string);
+	free(buf);
 } /* sdb_strbuf_destroy */
 
 ssize_t
-sdb_strbuf_vappend(sdb_strbuf_t *strbuf, const char *fmt, va_list ap)
+sdb_strbuf_vappend(sdb_strbuf_t *buf, const char *fmt, va_list ap)
 {
 	va_list aq;
 	int status;
 
-	if ((! strbuf) || (! fmt))
+	if ((! buf) || (! fmt))
 		return -1;
 
-	assert(strbuf->string[strbuf->pos] == '\0');
+	assert((buf->size == 0) || (buf->string[buf->pos] == '\0'));
 
-	if (strbuf->pos >= strbuf->size)
-		if (strbuf_resize(strbuf))
+	if (! buf->size) {
+		/* use some arbitrary but somewhat reasonable default */
+		if (strbuf_resize(buf, 64))
 			return -1;
+	}
+	/* make sure to reserve space for the nul-byte */
+	else if (buf->pos >= buf->size - 1)
+		if (strbuf_resize(buf, 2 * buf->size))
+			return -1;
+
+	assert(buf->size && buf->string);
+	assert(buf->pos < buf->size);
 
 	/* 'ap' is invalid after calling vsnprintf; thus copy before using it */
 	va_copy(aq, ap);
-	status = vsnprintf(strbuf->string + strbuf->pos,
-			strbuf->size - strbuf->pos, fmt, ap);
+	status = vsnprintf(buf->string + buf->pos,
+			buf->size - buf->pos, fmt, ap);
 
 	if (status < 0) {
 		va_end(aq);
 		return status;
 	}
 
-	if ((size_t)status >= strbuf->size - strbuf->pos) {
-		strbuf_resize(strbuf);
+	/* 'status' does not include nul-byte */
+	if ((size_t)status >= buf->size - buf->pos) {
+		if (strbuf_resize(buf, buf->pos + (size_t)status + 1)) {
+			va_end(aq);
+			return -1;
+		}
 
 		/* reset string and try again */
-		strbuf->string[strbuf->pos] = '\0';
-		status = (int)sdb_strbuf_vappend(strbuf, fmt, aq);
+		buf->string[buf->pos] = '\0';
+		status = (int)sdb_strbuf_vappend(buf, fmt, aq);
 	}
 	else
-		strbuf->pos += (size_t)status;
+		buf->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(buf);
+
 	return (ssize_t)status;
 } /* sdb_strbuf_vappend */
 
 ssize_t
-sdb_strbuf_append(sdb_strbuf_t *strbuf, const char *fmt, ...)
+sdb_strbuf_append(sdb_strbuf_t *buf, const char *fmt, ...)
 {
 	va_list ap;
 	ssize_t status;
 
 	va_start(ap, fmt);
-	status = sdb_strbuf_vappend(strbuf, fmt, ap);
+	status = sdb_strbuf_vappend(buf, fmt, ap);
 	va_end(ap);
 
 	return status;
 } /* sdb_strbuf_append */
 
 ssize_t
-sdb_strbuf_vsprintf(sdb_strbuf_t *strbuf, const char *fmt, va_list ap)
+sdb_strbuf_vsprintf(sdb_strbuf_t *buf, const char *fmt, va_list ap)
 {
-	if (! strbuf)
+	if (! buf)
 		return -1;
 
-	strbuf->string[0] = '\0';
-	strbuf->pos = 0;
+	if (buf->size) {
+		buf->string[0] = '\0';
+		buf->pos = 0;
+	}
 
-	return sdb_strbuf_vappend(strbuf, fmt, ap);
+	return sdb_strbuf_vappend(buf, fmt, ap);
 } /* sdb_strbuf_vsprintf */
 
 ssize_t
-sdb_strbuf_sprintf(sdb_strbuf_t *strbuf, const char *fmt, ...)
+sdb_strbuf_sprintf(sdb_strbuf_t *buf, const char *fmt, ...)
 {
 	va_list ap;
 	ssize_t status;
 
 	va_start(ap, fmt);
-	status = sdb_strbuf_vsprintf(strbuf, fmt, ap);
+	status = sdb_strbuf_vsprintf(buf, fmt, ap);
 	va_end(ap);
 
 	return status;
 } /* sdb_strbuf_sprintf */
 
+ssize_t
+sdb_strbuf_memappend(sdb_strbuf_t *buf, const void *data, size_t n)
+{
+	if ((! buf) || (! data))
+		return -1;
+
+	assert((buf->size == 0) || (buf->string[buf->pos] == '\0'));
+
+	if (buf->pos + n + 1 > buf->size) {
+		if (strbuf_resize(buf, buf->pos + n + 1))
+			return -1;
+	}
+
+	assert(buf->size && buf->string);
+	assert(buf->pos < buf->size);
+
+	memcpy((void *)(buf->string + buf->pos), data, n);
+	buf->pos += n;
+	buf->string[buf->pos] = '\0';
+
+	/* even though this function always appends to the existing buffer, the
+	 * size might have previously been reset */
+	CHECK_SHRINK(buf);
+
+	return (ssize_t)n;
+} /* sdb_strbuf_memappend */
+
+ssize_t
+sdb_strbuf_memcpy(sdb_strbuf_t *buf, const void *data, size_t n)
+{
+	if ((! buf) || (! data))
+		return -1;
+
+	if (buf->size) {
+		buf->string[0] = '\0';
+		buf->pos = 0;
+	}
+
+	return sdb_strbuf_memappend(buf, data, n);
+} /* sdb_strbuf_memcpy */
+
+ssize_t
+sdb_strbuf_read(sdb_strbuf_t *buf, int fd, size_t n)
+{
+	ssize_t ret;
+
+	if (! buf)
+		return -1;
+
+	if (buf->pos + n + 1 >= buf->size)
+		if (strbuf_resize(buf, buf->pos + n + 1))
+			return -1;
+
+	ret = read(fd, buf->string + buf->pos, n);
+	if (ret > 0)
+		buf->pos += (size_t)ret;
+	return ret;
+} /* sdb_strbuf_read */
+
+ssize_t
+sdb_strbuf_chomp(sdb_strbuf_t *buf)
+{
+	ssize_t ret = 0;
+
+	if (! buf)
+		return -1;
+
+	assert((!buf->size) || (buf->pos < buf->size));
+	assert(buf->pos <= buf->size);
+
+	while ((buf->pos > 0)
+			&& (buf->string[buf->pos - 1] == '\n')) {
+		--buf->pos;
+		buf->string[buf->pos] = '\0';
+		++ret;
+	}
+
+	return ret;
+} /* sdb_strbuf_chomp */
+
+void
+sdb_strbuf_skip(sdb_strbuf_t *buf, size_t offset, size_t n)
+{
+	char *start;
+	size_t len;
+
+	if ((! buf) || (! n))
+		return;
+
+	if (offset >= buf->pos)
+		return;
+
+	len = buf->pos - offset;
+
+	if (n >= len) {
+		buf->string[offset] = '\0';
+		buf->pos = offset;
+		return;
+	}
+
+	assert(offset + n < buf->pos);
+	assert(offset < buf->pos);
+
+	start = buf->string + offset;
+	memmove(start, start + n, len - n);
+	buf->pos -= n;
+	buf->string[buf->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 *buf)
+{
+	if ((! buf) || (! buf->size))
+		return;
+
+	buf->string[0] = '\0';
+	buf->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)
+sdb_strbuf_string(sdb_strbuf_t *buf)
 {
-	if (! strbuf)
+	if (! buf)
 		return NULL;
-	return strbuf->string;
+	if (! buf->size)
+		return "";
+	return buf->string;
 } /* sdb_strbuf_string */
 
 size_t
-sdb_strbuf_len(sdb_strbuf_t *strbuf)
+sdb_strbuf_len(sdb_strbuf_t *buf)
 {
-	if (! strbuf)
+	if (! buf)
 		return 0;
-	return strbuf->pos;
+	return buf->pos;
 } /* sdb_strbuf_string */
 
+size_t
+sdb_strbuf_cap(sdb_strbuf_t *buf)
+{
+	if (! buf)
+		return 0;
+	return buf->size;
+} /* sdb_strbuf_cap */
+
 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */