til_str: add preliminary growable string type

Preparation for eliminating open_memstream() usage...

3 files changed, 195 insertions, 1 deletions

diff --git a/src/Makefile.am b/src/Makefile.am
index b5f4e62..5da7150 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -1,7 +1,7 @@
 SUBDIRS = libs modules
 
 noinst_LTLIBRARIES = libtil.la
-libtil_la_SOURCES =  til.c til.h til_args.c til_args.h til_fb.c til_fb.h til_jenkins.c til_jenkins.h til_limits.h til_module_context.c til_module_context.h til_settings.h til_settings.c til_setup.c til_setup.h til_stream.c til_stream.h til_tap.h til_threads.c til_threads.h til_util.c til_util.h
+libtil_la_SOURCES =  til.c til.h til_args.c til_args.h til_fb.c til_fb.h til_jenkins.c til_jenkins.h til_limits.h til_module_context.c til_module_context.h til_settings.h til_settings.c til_setup.c til_setup.h til_str.c til_str.h til_stream.c til_stream.h til_tap.h til_threads.c til_threads.h til_util.c til_util.h
 libtil_la_CPPFLAGS = -I@top_srcdir@/src
 libtil_la_LIBADD = modules/blinds/libblinds.la modules/checkers/libcheckers.la modules/compose/libcompose.la modules/drizzle/libdrizzle.la modules/flui2d/libflui2d.la modules/julia/libjulia.la modules/meta2d/libmeta2d.la modules/mixer/libmixer.la modules/moire/libmoire.la modules/montage/libmontage.la modules/pixbounce/libpixbounce.la modules/plasma/libplasma.la modules/plato/libplato.la modules/ray/libray.la modules/rkt/librkt.la modules/roto/libroto.la modules/rtv/librtv.la modules/shapes/libshapes.la modules/snow/libsnow.la modules/sparkler/libsparkler.la modules/spiro/libspiro.la modules/stars/libstars.la modules/strobe/libstrobe.la modules/submit/libsubmit.la modules/swab/libswab.la modules/swarm/libswarm.la modules/voronoi/libvoronoi.la libs/grid/libgrid.la libs/puddle/libpuddle.la libs/ray/libray.la libs/rocket/librocket.la libs/sig/libsig.la libs/txt/libtxt.la libs/ascii/libascii.la libs/din/libdin.la
 
diff --git a/src/til_str.c b/src/til_str.c
new file mode 100644
index 0000000..442e923
--- /dev/null
+++ b/src/til_str.c
@@ -0,0 +1,180 @@
+#include <assert.h>
+#include <stdarg.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "til_str.h"
+#include "til_util.h"
+
+/* This implements very rudimentary growable strings, and hasn't been optimized at all.
+ *
+ * The impetus for adding this is to get rid of the open_memstream() usage which is mostly
+ * just being used as a convenient way to build up a buffer from format strings.  So this
+ * basically implements just that ability using variadic functions...
+ *
+ * Why no open_memstream()?  Because Windows, that's why.  For some reason even mingw doesn't
+ * have open_memstream().  FILE* I keep forgetting that you're dead to me.
+ */
+
+struct til_str_t {
+	struct {
+		size_t	allocated, used; /* used is length, including '\0' terminator */
+	} size;
+	char	*buf;
+};
+
+
+#define TIL_STR_MIN_SIZE	64
+
+
+/* alloc always returns a buf w/nul terminator present */
+static til_str_t * til_str_nulstr(size_t minsize)
+{
+	til_str_t	*str;
+
+	str = calloc(1, sizeof(*str));
+	if (!str)
+		return NULL;
+
+	str->size.used = 1;
+	str->size.allocated = MAX(minsize, TIL_STR_MIN_SIZE);
+
+	str->buf = calloc(1, str->size.allocated);
+	if (!str->buf) {
+		free(str);
+		return NULL;
+	}
+
+	return str;
+}
+
+
+/* allocate a new til_str, starting with a dup of seed, just use "" for an empty str, there is no NULL str */
+til_str_t * til_str_new(const char *seed)
+{
+	til_str_t	*str;
+	size_t		len;
+
+	assert(seed);
+
+	len = strlen(seed);
+	str = til_str_nulstr(len + 1);
+	if (!str)
+		return NULL;
+
+	memcpy(str->buf, seed, len);
+	str->size.used += len;
+
+	return str;
+}
+
+
+void * til_str_free(til_str_t *str)
+{
+	if (str) {
+		free(str->buf);
+		free(str);
+	}
+
+	return NULL;
+}
+
+
+/* allocate a new til_str from a fmt string + args */
+til_str_t * til_str_newf(const char *format, ...)
+{
+	til_str_t	*str;
+	va_list		ap;
+
+	assert(format);
+
+	va_start(ap, format);
+
+	str = til_str_nulstr(vsnprintf(NULL, 0, format, ap) + 1);
+	if (!str)
+		return NULL;
+
+	str->size.used += vsnprintf(str->buf, str->size.allocated, format, ap);
+
+	va_end(ap);
+
+	assert(str->size.used <= str->size.allocated);
+
+	return str;
+}
+
+
+/* append to an existing til_str_t from a fmt string + args */
+int til_str_appendf(til_str_t *str, const char *format, ...)
+{
+	size_t	len;
+	va_list	ap;
+
+	assert(str);
+	assert(format);
+
+	va_start(ap, format);
+	len = vsnprintf(NULL, 0, format, ap);
+	va_end(ap);
+
+	if (str->size.used + len > str->size.allocated) {
+		char	*new;
+
+		new = realloc(str->buf, str->size.used + len);
+		if (!new)
+			return -ENOMEM;
+
+		str->buf = new;
+		str->size.allocated = str->size.used + len;
+	}
+
+	va_start(ap, format);
+	str->size.used += vsnprintf(&str->buf[str->size.used - 1],
+				    str->size.allocated - (str->size.used - 1),
+				    format, ap);
+	va_end(ap);
+
+	assert(str->size.used <= str->size.allocated);
+
+	return 0;
+}
+
+
+/* strdup() the /used/ contents of str */
+char * til_str_strdup(const til_str_t *str)
+{
+	assert(str);
+
+	return strdup(str->buf);
+}
+
+
+/* a valid \0-terminated string is _always_ maintained @ str->buf so callers can just use it as a string..
+ * but must not hang onto that pointer across more til_str() calls on the same str.
+ */
+const char * til_str_buf(const til_str_t *str, size_t *res_len)
+{
+	assert(str);
+
+	if (res_len)
+		*res_len = str->size.used;
+
+	return str->buf;
+}
+
+
+/* for when you just want the buf without the dup overhead, and don't need the str anymore */
+char * til_str_to_buf(til_str_t *str, size_t *res_len)
+{
+	char	*buf;
+
+	assert(str);
+
+	if (res_len)
+		*res_len = str->size.used;
+
+	buf = str->buf;
+	free(str);
+
+	return buf;
+}
diff --git a/src/til_str.h b/src/til_str.h
new file mode 100644
index 0000000..e653884
--- /dev/null
+++ b/src/til_str.h
@@ -0,0 +1,14 @@
+#ifndef _TIL_STR_H
+#define _TIL_STR_H
+
+typedef struct til_str_t til_str_t;
+
+til_str_t * til_str_new(const char *seed);
+void * til_str_free(til_str_t *str);
+til_str_t * til_str_newf(const char *format, ...);
+int til_str_appendf(til_str_t *str, const char *format, ...);
+char * til_str_strdup(const til_str_t *str);
+const char * til_str_buf(const til_str_t *str, size_t *res_len);
+char * til_str_to_buf(til_str_t *str, size_t *res_len);
+
+#endif