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authorThomas Helland <[email protected]>2017-05-15 21:36:52 +0200
committerThomas Helland <[email protected]>2017-09-26 18:24:33 +0200
commit7885bb684d8a1ee9fbdcf85603e1f923a3526b22 (patch)
tree3c9ec8598cf6948b60c557b2b1b6447bcc466855 /src/util/string_buffer.c
parent379b24a40d3d34ffdaaeb1b328f50e28ecb01468 (diff)
util: Add a string buffer implementation
Based on Vladislav Egorovs work on the preprocessor, but split out to a util functionality that should be universal. Setup, teardown, memory handling and general layout is modeled around the hash_table and the set, to make it familiar for everyone. A notable change is that this implementation is always null terminated. The rationale is that it will be less error-prone, as one might access the buffer directly, thereby reading a non-terminated string. Also, vsnprintf and friends prints the null-terminator. Signed-off-by: Thomas Helland <[email protected]> Tested-by: Dieter Nützel <Dieter at nuetzel-hh.de> Reviewed-by: Nicolai Hähnle <[email protected]> V2: Address review feedback from Timothy and Grazvydas - Fix MINGW preprocessor check - Changed len from uint to int - Make string argument const in append function - Move to header and inline append function - Add crimp_to_fit function for resizing buffer V3: Move include of ralloc to string_buffer.h V4: Use u_string.h for a cross-platform working vsnprintf V5: Remember to cast to char * in crimp function V6: Address review feedback from Nicolai - Handle !str->buf in buffer_create - Ensure va_end is always called in buffer_append_all - Add overflow check in buffer_append_len - Do not expose buffer_space_left, just remove it - Clarify why a loop is used in vprintf, change to for-loop - Add a va_copy to buffer_vprintf to fix failure to append arguments when having to resize the buffer for vsnprintf. V7: Address more review feedback from Nicolai - Add missing va_end corresponding to va_copy - Error check failure to allocate in crimp_to_fit
Diffstat (limited to 'src/util/string_buffer.c')
-rw-r--r--src/util/string_buffer.c148
1 files changed, 148 insertions, 0 deletions
diff --git a/src/util/string_buffer.c b/src/util/string_buffer.c
new file mode 100644
index 00000000000..c33173bfa08
--- /dev/null
+++ b/src/util/string_buffer.c
@@ -0,0 +1,148 @@
+/*
+ * Copyright © 2017 Thomas Helland
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ *
+ */
+
+#include "string_buffer.h"
+
+static bool
+ensure_capacity(struct _mesa_string_buffer *str, uint32_t needed_capacity)
+{
+ if (needed_capacity <= str->capacity)
+ return true;
+
+ /* Too small, double until we can fit the new string */
+ uint32_t new_capacity = str->capacity * 2;
+ while (needed_capacity > new_capacity)
+ new_capacity *= 2;
+
+ str->buf = reralloc_array_size(str, str->buf, sizeof(char), new_capacity);
+ if (str->buf == NULL)
+ return false;
+
+ str->capacity = new_capacity;
+ return true;
+}
+
+struct _mesa_string_buffer *
+_mesa_string_buffer_create(void *mem_ctx, uint32_t initial_capacity)
+{
+ struct _mesa_string_buffer *str;
+ str = ralloc(mem_ctx, struct _mesa_string_buffer);
+
+ if (str == NULL)
+ return NULL;
+
+ /* If no initial capacity is set then set it to something */
+ str->capacity = initial_capacity ? initial_capacity : 32;
+ str->buf = ralloc_array(str, char, str->capacity);
+
+ if (!str->buf) {
+ ralloc_free(str);
+ return NULL;
+ }
+
+ str->length = 0;
+ str->buf[str->length] = '\0';
+ return str;
+}
+
+bool
+_mesa_string_buffer_append_all(struct _mesa_string_buffer *str,
+ uint32_t num_args, ...)
+{
+ int i;
+ char* s;
+ va_list args;
+ va_start(args, num_args);
+ for (i = 0; i < num_args; i++) {
+ s = va_arg(args, char*);
+ if (!_mesa_string_buffer_append_len(str, s, strlen(s))) {
+ va_end(args);
+ return false;
+ }
+ }
+ va_end(args);
+ return true;
+}
+
+bool
+_mesa_string_buffer_append_len(struct _mesa_string_buffer *str,
+ const char *c, uint32_t len)
+{
+ uint32_t needed_length = str->length + len + 1;
+
+ /* Check if we're overflowing uint32_t */
+ if (needed_length < str->length)
+ return false;
+
+ if (!ensure_capacity(str, needed_length))
+ return false;
+
+ memcpy(str->buf + str->length, c, len);
+ str->length += len;
+ str->buf[str->length] = '\0';
+ return true;
+}
+
+bool
+_mesa_string_buffer_vprintf(struct _mesa_string_buffer *str,
+ const char *format, va_list args)
+{
+ /* We're looping two times to avoid duplicating code */
+ for (uint32_t i = 0; i < 2; i++) {
+ va_list arg_copy;
+ va_copy(arg_copy, args);
+ uint32_t space_left = str->capacity - str->length;
+
+ int32_t len = util_vsnprintf(str->buf + str->length,
+ space_left, format, arg_copy);
+ va_end(arg_copy);
+
+ /* Error in vsnprintf() or measured len overflows size_t */
+ if (unlikely(len < 0 || str->length + len + 1 < str->length))
+ return false;
+
+ /* There was enough space for the string; we're done */
+ if (len < space_left) {
+ str->length += len;
+ return true;
+ }
+
+ /* Not enough space, resize and retry */
+ ensure_capacity(str, str->length + len + 1);
+ }
+
+ return false;
+}
+
+bool
+_mesa_string_buffer_printf(struct _mesa_string_buffer *str,
+ const char *format, ...)
+{
+ bool res;
+ va_list args;
+ va_start(args, format);
+ res = _mesa_string_buffer_vprintf(str, format, args);
+ va_end(args);
+ return res;
+}