util/string: sprintf_append_realloc to concatenate strings with realloc (8adbd909) · Commits · Public Repositories / spdk

include/spdk/string.h

+36 −0

Original line number	Diff line number	Diff line
		@@ -69,6 +69,42 @@ char spdk_sprintf_alloc(const char format, ...) __attribute__((format(printf,
		*/
		char spdk_vsprintf_alloc(const char format, va_list args);

		/**
		* Append string using vsprintf with automatic buffer re-allocation.
		*
		* The return value is the formatted string, in which the original string in
		* buffer is unchanged and the specified formatted string is appended.
		*
		* The returned string should be passed to free() when no longer needed.
		*
		* If buffer is NULL, the call is equivalent to spdk_sprintf_alloc().
		* If the call fails, the original buffer is left untouched.
		*
		* \param buffer Buffer which has a formatted string.
		* \param format Format for the string to print.
		*
		* \return the formatted string on success, or NULL on failure.
		*/
		char spdk_sprintf_append_realloc(char buffer, const char *format, ...);

		/**
		* Append string using vsprintf with automatic buffer re-allocation.
		* The return value is the formatted string, in which the original string in
		* buffer is unchanged and the specified formatted string is appended.
		*
		* The returned string should be passed to free() when no longer needed.
		*
		* If buffer is NULL, the call is equivalent to spdk_sprintf_alloc().
		* If the call fails, the original buffer is left untouched.
		*
		* \param buffer Buffer which has a formatted string.
		* \param format Format for the string to print.
		* \param args A value that identifies a variable arguments list.
		*
		* \return the formatted string on success, or NULL on failure.
		*/
		char spdk_vsprintf_append_realloc(char buffer, const char *format, va_list args);

		/**
		* Convert string to lowercase in place.
		*

lib/util/string.c

+40 −33

Original line number	Diff line number	Diff line
		@@ -36,47 +36,54 @@
		#include "spdk/string.h"

		char *
		spdk_vsprintf_alloc(const char *format, va_list args)
		spdk_vsprintf_append_realloc(char buffer, const char format, va_list args)
		{
		va_list args_copy;
		char *buf;
		size_t bufsize;
		int rc;

		/* Try with a small buffer first. */
		bufsize = 32;
		char *new_buffer;
		int orig_size = 0, new_size;

		/* Limit maximum buffer size to something reasonable so we don't loop forever. */
		while (bufsize <= 1024 * 1024) {
		buf = malloc(bufsize);
		if (buf == NULL) {
		return NULL;
		/* Original buffer size */
		if (buffer) {
		orig_size = strlen(buffer);
		}

		/* Necessary buffer size */
		va_copy(args_copy, args);
		rc = vsnprintf(buf, bufsize, format, args_copy);
		new_size = vsnprintf(NULL, 0, format, args_copy);
		va_end(args_copy);

		/*
		* If vsnprintf() returned a count within our current buffer size, we are done.
		* The count does not include the \0 terminator, so rc == bufsize is not OK.
		*/
		if (rc >= 0 && (size_t)rc < bufsize) {
		return buf;
		if (new_size < 0) {
		return NULL;
		}
		new_size += orig_size + 1;

		/*
		* vsnprintf() should return the required space, but some libc versions do not
		* implement this correctly, so just double the buffer size and try again.
		*
		* We don't need the data in buf, so rather than realloc(), use free() and malloc()
		* again to avoid a copy.
		*/
		free(buf);
		bufsize *= 2;
		new_buffer = realloc(buffer, new_size);
		if (new_buffer == NULL) {
		return NULL;
		}

		return NULL;
		vsnprintf(new_buffer + orig_size, new_size - orig_size, format, args);

		return new_buffer;
		}

		char *
		spdk_sprintf_append_realloc(char buffer, const char format, ...)
		{
		va_list args;
		char *ret;

		va_start(args, format);
		ret = spdk_vsprintf_append_realloc(buffer, format, args);
		va_end(args);

		return ret;
		}

		char *
		spdk_vsprintf_alloc(const char *format, va_list args)
		{
		return spdk_vsprintf_append_realloc(NULL, format, args);
		}

		char *

test/unit/lib/util/string.c/string_ut.c

+49 −1

Original line number	Diff line number	Diff line
		@@ -202,6 +202,53 @@ test_parse_capacity(void)
		CU_ASSERT(rc != 0);
		}

		static void
		test_sprintf_append_realloc(void)
		{
		char str1, str2, str3, str4;

		/* Test basic functionality. */
		str1 = spdk_sprintf_alloc("hello world\ngood morning\n" \
		"good afternoon\ngood evening\n");
		SPDK_CU_ASSERT_FATAL(str1 != NULL);

		str2 = spdk_sprintf_append_realloc(NULL, "hello world\n");
		SPDK_CU_ASSERT_FATAL(str2);

		str2 = spdk_sprintf_append_realloc(str2, "good morning\n");
		SPDK_CU_ASSERT_FATAL(str2);

		str2 = spdk_sprintf_append_realloc(str2, "good afternoon\n");
		SPDK_CU_ASSERT_FATAL(str2);

		str2 = spdk_sprintf_append_realloc(str2, "good evening\n");
		SPDK_CU_ASSERT_FATAL(str2);

		CU_ASSERT(strcmp(str1, str2) == 0);

		free(str1);
		free(str2);

		/* Test doubling buffer size. */
		str3 = spdk_sprintf_append_realloc(NULL, "aaaaaaaaaa\n");
		str3 = spdk_sprintf_append_realloc(str3, "bbbbbbbbbb\n");
		str3 = spdk_sprintf_append_realloc(str3, "cccccccccc\n");

		str4 = malloc(33 + 1);
		memset(&str4[0], 'a', 10);
		str4[10] = '\n';
		memset(&str4[11], 'b', 10);
		str4[21] = '\n';
		memset(&str4[22], 'c', 10);
		str4[32] = '\n';
		str4[33] = 0;

		CU_ASSERT(strcmp(str3, str4) == 0);

		free(str3);
		free(str4);
		}

		int
		main(int argc, char **argv)
		{
		@@ -221,7 +268,8 @@ main(int argc, char **argv)
		if (
		CU_add_test(suite, "test_parse_ip_addr", test_parse_ip_addr) == NULL \|\|
		CU_add_test(suite, "test_str_chomp", test_str_chomp) == NULL \|\|
		CU_add_test(suite, "test_parse_capacity", test_parse_capacity) == NULL) {
		CU_add_test(suite, "test_parse_capacity", test_parse_capacity) == NULL \|\|
		CU_add_test(suite, "test_sprintf_append_realloc", test_sprintf_append_realloc) == NULL) {
		CU_cleanup_registry();
		return CU_get_error();
		}