diff options
author | Thomas Helland <[email protected]> | 2017-05-15 21:36:52 +0200 |
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committer | Thomas Helland <[email protected]> | 2017-09-26 18:24:33 +0200 |
commit | 7885bb684d8a1ee9fbdcf85603e1f923a3526b22 (patch) | |
tree | 3c9ec8598cf6948b60c557b2b1b6447bcc466855 /src/util/string_buffer.c | |
parent | 379b24a40d3d34ffdaaeb1b328f50e28ecb01468 (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.c | 148 |
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; +} |