src/util/string_buffer.c

   1 /*
   2  * Copyright © 2017 Thomas Helland
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the next
  12  * paragraph) shall be included in all copies or substantial portions of the
  13  * Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  21  * IN THE SOFTWARE.
  22  *
  23  */
  24
  25 #include "string_buffer.h"
  26
  27 static bool
  28 ensure_capacity(struct _mesa_string_buffer *str, uint32_t needed_capacity)
  29 {
  30    if (needed_capacity <= str->capacity)
  31       return true;
  32
  33    /* Too small, double until we can fit the new string */
  34    uint32_t new_capacity = str->capacity * 2;
  35    while (needed_capacity > new_capacity)
  36       new_capacity *= 2;
  37
  38    str->buf = reralloc_array_size(str, str->buf, sizeof(char), new_capacity);
  39    if (str->buf == NULL)
  40       return false;
  41
  42    str->capacity = new_capacity;
  43    return true;
  44 }
  45
  46 struct _mesa_string_buffer *
  47 _mesa_string_buffer_create(void *mem_ctx, uint32_t initial_capacity)
  48 {
  49    struct _mesa_string_buffer *str;
  50    str = ralloc(mem_ctx, struct _mesa_string_buffer);
  51
  52    if (str == NULL)
  53       return NULL;
  54
  55    /* If no initial capacity is set then set it to something */
  56    str->capacity = initial_capacity ? initial_capacity : 32;
  57    str->buf = ralloc_array(str, char, str->capacity);
  58
  59    if (!str->buf) {
  60       ralloc_free(str);
  61       return NULL;
  62    }
  63
  64    str->length = 0;
  65    str->buf[str->length] = '\0';
  66    return str;
  67 }
  68
  69 bool
  70 _mesa_string_buffer_append_all(struct _mesa_string_buffer *str,
  71                                uint32_t num_args, ...)
  72 {
  73    int i;
  74    char* s;
  75    va_list args;
  76    va_start(args, num_args);
  77    for (i = 0; i < num_args; i++) {
  78       s = va_arg(args, char*);
  79       if (!_mesa_string_buffer_append_len(str, s, strlen(s))) {
  80          va_end(args);
  81          return false;
  82       }
  83    }
  84    va_end(args);
  85    return true;
  86 }
  87
  88 bool
  89 _mesa_string_buffer_append_len(struct _mesa_string_buffer *str,
  90                                const char *c, uint32_t len)
  91 {
  92    uint32_t needed_length = str->length + len + 1;
  93
  94    /* Check if we're overflowing uint32_t */
  95    if (needed_length < str->length)
  96       return false;
  97
  98    if (!ensure_capacity(str, needed_length))
  99       return false;
 100
 101    memcpy(str->buf + str->length, c, len);
 102    str->length += len;
 103    str->buf[str->length] = '\0';
 104    return true;
 105 }
 106
 107 bool
 108 _mesa_string_buffer_vprintf(struct _mesa_string_buffer *str,
 109                             const char *format, va_list args)
 110 {
 111    /* We're looping two times to avoid duplicating code */
 112    for (uint32_t i = 0; i < 2; i++) {
 113       va_list arg_copy;
 114       va_copy(arg_copy, args);
 115       uint32_t space_left = str->capacity - str->length;
 116
 117       int32_t len = vsnprintf(str->buf + str->length,
 118                                    space_left, format, arg_copy);
 119       va_end(arg_copy);
 120
 121       /* Error in vsnprintf() or measured len overflows size_t */
 122       if (unlikely(len < 0 || str->length + len + 1 < str->length))
 123          return false;
 124
 125       /* There was enough space for the string; we're done */
 126       if (len < space_left) {
 127          str->length += len;
 128          return true;
 129       }
 130
 131       /* Not enough space, resize and retry */
 132       ensure_capacity(str, str->length + len + 1);
 133    }
 134
 135    return false;
 136 }
 137
 138 bool
 139 _mesa_string_buffer_printf(struct _mesa_string_buffer *str,
 140                             const char *format, ...)
 141 {
 142    bool res;
 143    va_list args;
 144    va_start(args, format);
 145    res = _mesa_string_buffer_vprintf(str, format, args);
 146    va_end(args);
 147    return res;
 148 }