From 7885bb684d8a1ee9fbdcf85603e1f923a3526b22 Mon Sep 17 00:00:00 2001 From: Thomas Helland Date: Mon, 15 May 2017 21:36:52 +0200 Subject: [PATCH] util: Add a string buffer implementation MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit 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 Tested-by: Dieter Nützel Reviewed-by: Nicolai Hähnle 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 --- src/util/Makefile.sources | 2 + src/util/string_buffer.c | 148 ++++++++++++++++++++++++++++++++++++++ src/util/string_buffer.h | 104 +++++++++++++++++++++++++++ 3 files changed, 254 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 4ed4e39f039..c7f6516a992 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 \ strndup.h \ strtod.c \ strtod.h \ 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; +} diff --git a/src/util/string_buffer.h b/src/util/string_buffer.h new file mode 100644 index 00000000000..eaaf5f33dfd --- /dev/null +++ b/src/util/string_buffer.h @@ -0,0 +1,104 @@ +/* + * 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 "ralloc.h" +#include "u_string.h" +#include +#include +#include +#include + +#ifdef __cplusplus +extern "C" { +#endif + +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); + +static inline void +_mesa_string_buffer_destroy(struct _mesa_string_buffer *str) +{ + ralloc_free(str); +} + +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, + const char *c, uint32_t len); + +static inline bool +_mesa_string_buffer_append_char(struct _mesa_string_buffer *str, char c) +{ + return _mesa_string_buffer_append_len(str, &c, 1); +} + +static inline bool +_mesa_string_buffer_append(struct _mesa_string_buffer *str, const char *c) +{ + return _mesa_string_buffer_append_len(str, c, strlen(c)); +} + +static inline void +_mesa_string_buffer_clear(struct _mesa_string_buffer *str) +{ + str->length = 0; + str->buf[str->length] = '\0'; +} + +static inline void +_mesa_string_buffer_crimp_to_fit(struct _mesa_string_buffer *str) +{ + char *crimped = + (char *) reralloc_array_size(str, str->buf, sizeof(char), + str->capacity); + if (!crimped) + return; + + str->capacity = str->length + 1; + str->buf = crimped; +} + +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, ...); + +#ifdef __cplusplus +} /* extern "C" */ +#endif + +#endif /* _STRING_BUFFER_H */ -- 2.30.2