X-Git-Url: https://git.tokkee.org/?a=blobdiff_plain;f=src%2Futils%2Fstrbuf.c;h=7d8bc5527f6138f7a1c8ad6cf6730c6445c3460b;hb=42e0a931f1424c2d13794e3a064d328669ed7767;hp=c8e7e633a27452ade2e8bdb85f078cb542e9e63f;hpb=e292f5e4f78e892fa12cafcb837021b1db4a0057;p=sysdb.git

diff --git a/src/utils/strbuf.c b/src/utils/strbuf.c
index c8e7e63..7d8bc55 100644
--- a/src/utils/strbuf.c
+++ b/src/utils/strbuf.c
@@ -32,6 +32,17 @@
 #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
@@ -52,14 +63,17 @@ strbuf_resize(sdb_strbuf_t *strbuf, size_t new_size)
 {
 	char *tmp;
 
-	if (new_size <= strbuf->size)
-		return 0;
+	if (new_size <= strbuf->pos)
+		return -1;
 
 	tmp = realloc(strbuf->string, new_size);
 	if (! tmp)
 		return -1;
 
-	strbuf->string = tmp;
+	if (new_size)
+		strbuf->string = tmp;
+	else
+		strbuf->string = NULL;
 	strbuf->size = new_size;
 	return 0;
 } /* strbuf_resize */
@@ -116,9 +130,14 @@ sdb_strbuf_vappend(sdb_strbuf_t *strbuf, const char *fmt, va_list ap)
 
 	assert((strbuf->size == 0) || (strbuf->string[strbuf->pos] == '\0'));
 
-	if (strbuf->pos >= strbuf->size)
+	if (! strbuf->size) {
 		/* use some arbitrary but somewhat reasonable default */
-		if (strbuf_resize(strbuf, strbuf->size ? 2 * strbuf->size : 64))
+		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);
@@ -134,8 +153,12 @@ sdb_strbuf_vappend(sdb_strbuf_t *strbuf, const char *fmt, va_list ap)
 		return status;
 	}
 
+	/* 'status' does not include nul-byte */
 	if ((size_t)status >= strbuf->size - strbuf->pos) {
-		strbuf_resize(strbuf, (size_t)status + 1);
+		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';
@@ -145,6 +168,11 @@ sdb_strbuf_vappend(sdb_strbuf_t *strbuf, const char *fmt, va_list ap)
 		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 */
 
@@ -188,6 +216,72 @@ sdb_strbuf_sprintf(sdb_strbuf_t *strbuf, const char *fmt, ...)
 	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)
 {
@@ -196,7 +290,7 @@ sdb_strbuf_chomp(sdb_strbuf_t *strbuf)
 	if (! strbuf)
 		return -1;
 
-	assert(strbuf->size || (strbuf->pos < strbuf->size));
+	assert((!strbuf->size) || (strbuf->pos < strbuf->size));
 	assert(strbuf->pos <= strbuf->size);
 
 	while ((strbuf->pos > 0)
@@ -209,6 +303,49 @@ sdb_strbuf_chomp(sdb_strbuf_t *strbuf)
 	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)
 {
@@ -227,5 +364,13 @@ sdb_strbuf_len(sdb_strbuf_t *strbuf)
 	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 : */