[Mesa-dev] [PATCH 1/9] util: Add a string buffer implementation
Timothy Arceri
tarceri at itsqueeze.com
Mon May 22 01:00:00 UTC 2017
On 22/05/17 08:28, Timothy Arceri wrote:
> On 22/05/17 06:49, Thomas Helland wrote:
>> Based on Vladislav Egorov's 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.
>> ---
>> src/util/Makefile.sources | 2 +
>> src/util/string_buffer.c | 180
>> ++++++++++++++++++++++++++++++++++++++++++++++
>> src/util/string_buffer.h | 75 +++++++++++++++++++
>> 3 files changed, 257 insertions(+)
>> create mode 100644 src/util/string_buffer.c
>> create mode 100644 src/util/string_buffer.h
>>
>> diff --git a/src/util/Makefile.sources b/src/util/Makefile.sources
>> index e9057343dc..cb46639c87 100644
>> --- a/src/util/Makefile.sources
>> +++ b/src/util/Makefile.sources
>> @@ -37,6 +37,8 @@ MESA_UTIL_FILES := \
>> simple_list.h \
>> slab.c \
>> slab.h \
>> + string_buffer.c \
>> + string_buffer.h \
>> string_to_uint_map.cpp \
>> string_to_uint_map.h \
>> strndup.h \
>> diff --git a/src/util/string_buffer.c b/src/util/string_buffer.c
>> new file mode 100644
>> index 0000000000..a500ffd389
>> --- /dev/null
>> +++ b/src/util/string_buffer.c
>> @@ -0,0 +1,180 @@
>> +/*
>> + * 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 "ralloc.h"
>> +#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, we have to resize our buffer.
>> + * 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 : 8;
>> + str->buf = ralloc_array(str, char, str->capacity);
>> + str->length = 0;
>> + str->buf[str->length] = '\0';
>> + return str;
>> +}
>> +
>> +void
>> +_mesa_string_buffer_destroy(struct _mesa_string_buffer *str)
>> +{
>> + ralloc_free(str);
>
> Using ralloc doesn't really gain us much in this util. Since the goal is
> performance it would probably make sense to avoid the extra overhead and
> just use regular memory functions.
Never mind. Looking at it's uses it makes more sense.
>
>> +}
>> +
>> +bool
>> +_mesa_string_buffer_append(struct _mesa_string_buffer *str, char *c)
>> +{
>> + return _mesa_string_buffer_append_len(str, c, strlen(c));
>> +}
>
> I'd move this to the header as an inlined function.
>
>> +
>> +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)))
>> + return false;
>> + }
>> + va_end(args);
>> + return true;
>> +}
>> +
>> +bool
>> +_mesa_string_buffer_append_len(struct _mesa_string_buffer *str,
>> + char *c, uint32_t len)
>> +{
>> + uint32_t needed_length = str->length + len + 1;
>> + 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;
>> +}
>> +
>> +void
>> +_mesa_string_buffer_clear(struct _mesa_string_buffer *str)
>> +{
>> + str->length = 0;
>> + str->buf[str->length] = '\0';
>> +}
>> +
>> +uint32_t
>> +_mesa_string_buffer_space_left(struct _mesa_string_buffer *str)
>> +{
>> + return str->capacity - str->length - 1;
>> +}
>> +
>> +bool
>> +_mesa_string_buffer_vprintf(struct _mesa_string_buffer *str,
>> + const char *format, va_list args)
>> +{
>> + uint32_t len;
>> + uint32_t end = str->length;
>> +
>> +#if (defined(_MSC_VER) && _MSC_VER < 1900) || __MINGW32__
>> + /* MSVC up to 2013 used non-standard vsnprintf() that returned -1
>> + * if the buffer wasn't large enough. Another non-standard function
>> + * _vscprintf() should be used to measure length of printf() output.
>> + */
>> + len = _vscprintf(format, args);
>> +
>> + /* Fail if an error happened in vscprintf() */
>> + if (unlikely(len < 0))
>> + return false;
>> +
>> + len = vsprintf(str->buf + end, format, args);
>> + str->length += len;
>> + return len >= 0;
>> +
>> +#else
>> + uint32_t size = MAX2(100, _mesa_string_buffer_space_left(str));
>> + while (1) {
>> + ensure_capacity(str, end + size + 1);
>> + len = vsnprintf(str->buf + end, size, format, args);
>> +
>> + /* Fail if an error happened in vsnprintf()
>> + * or if measured len overflows size_t
>> + */
>> + if (unlikely(len < 0 || str->length + len + 1 < str->length))
>> + return false;
>> +
>> + /* There was enough room for the string, so we're done */
>> + if (len < size) {
>> + str->length += len;
>> + return true;
>> + }
>> +
>> + /* Formatted string is too large for the buffer.
>> + * Increase the size and print again.
>> + */
>> + size = MAX2(size * 2, str->length + len);
>> + }
>> +#endif
>> +
>> +}
>> +
>> +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;
>> +}
>> diff --git a/src/util/string_buffer.h b/src/util/string_buffer.h
>> new file mode 100644
>> index 0000000000..f03e7841f3
>> --- /dev/null
>> +++ b/src/util/string_buffer.h
>> @@ -0,0 +1,75 @@
>> +/*
>> + * 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.
>> + *
>> + */
>> +#ifndef _STRING_BUFFER_H
>> +#define _STRING_BUFFER_H
>> +
>> +#include <stdbool.h>
>> +#include <stdint.h>
>> +#include <stdio.h>
>> +#include <string.h>
>> +
>> +struct _mesa_string_buffer {
>> + char *buf;
>> + uint32_t length;
>> + uint32_t capacity;
>> +};
>> +
>> +struct _mesa_string_buffer *
>> +_mesa_string_buffer_create(void *mem_ctx, uint32_t initial_capacity);
>> +
>> +void
>> +_mesa_string_buffer_destroy(struct _mesa_string_buffer *str);
>> +
>> +bool
>> +_mesa_string_buffer_append(struct _mesa_string_buffer *str, char *c);
>> +
>> +bool
>> +_mesa_string_buffer_append_all(struct _mesa_string_buffer *str,
>> + uint32_t num_args, ...);
>> +bool
>> +_mesa_string_buffer_append_len(struct _mesa_string_buffer *str,
>> + char *c, uint32_t len);
>> +
>> +static inline bool
>> +_mesa_string_buffer_append_char(struct _mesa_string_buffer *str, char c)
>> +{
>> + assert(str->capacity > 0 && ch != '\0');
>> + return _mesa_string_buffer_append_len(str, &c, 1);
>> +}
>> +
>> +void
>> +_mesa_string_buffer_clear(struct _mesa_string_buffer *str);
>> +
>> +uint32_t
>> +_mesa_string_buffer_space_left(struct _mesa_string_buffer *str);
>> +
>> +bool
>> +_mesa_string_buffer_vprintf(struct _mesa_string_buffer *str,
>> + const char *format, va_list args);
>> +
>> +bool
>> +_mesa_string_buffer_printf(struct _mesa_string_buffer *str,
>> + const char *format, ...);
>> +
>> +#endif /* _STRING_BUFFER_H */
>>
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