src/strbuffer.c

   1 /*
   2  * Copyright (c) 2009-2012 Petri Lehtinen <petri@digip.org>
   3  *
   4  * Jansson is free software; you can redistribute it and/or modify
   5  * it under the terms of the MIT license. See LICENSE for details.
   6  */
   7
   8 #define _GNU_SOURCE
   9 #include <stdlib.h>
  10 #include <string.h>
  11 #include "jansson_private.h"
  12 #include "strbuffer.h"
  13
  14 #define STRBUFFER_MIN_SIZE  16
  15 #define STRBUFFER_FACTOR    2
  16 #define STRBUFFER_SIZE_MAX  ((size_t)-1)
  17
  18 int strbuffer_init(strbuffer_t *strbuff)
  19 {
  20     strbuff->size = STRBUFFER_MIN_SIZE;
  21     strbuff->length = 0;
  22
  23     strbuff->value = jsonp_malloc(strbuff->size);
  24     if(!strbuff->value)
  25         return -1;
  26
  27     /* initialize to empty */
  28     strbuff->value[0] = '\0';
  29     return 0;
  30 }
  31
  32 void strbuffer_close(strbuffer_t *strbuff)
  33 {
  34     jsonp_free(strbuff->value);
  35     strbuff->size = 0;
  36     strbuff->length = 0;
  37     strbuff->value = NULL;
  38 }
  39
  40 void strbuffer_clear(strbuffer_t *strbuff)
  41 {
  42     strbuff->length = 0;
  43     strbuff->value[0] = '\0';
  44 }
  45
  46 const char *strbuffer_value(const strbuffer_t *strbuff)
  47 {
  48     return strbuff->value;
  49 }
  50
  51 char *strbuffer_steal_value(strbuffer_t *strbuff)
  52 {
  53     char *result = strbuff->value;
  54     strbuffer_init(strbuff);
  55     return result;
  56 }
  57
  58 int strbuffer_append(strbuffer_t *strbuff, const char *string)
  59 {
  60     return strbuffer_append_bytes(strbuff, string, strlen(string));
  61 }
  62
  63 int strbuffer_append_byte(strbuffer_t *strbuff, char byte)
  64 {
  65     return strbuffer_append_bytes(strbuff, &byte, 1);
  66 }
  67
  68 int strbuffer_append_bytes(strbuffer_t *strbuff, const char *data, size_t size)
  69 {
  70     if(size >= strbuff->size - strbuff->length)
  71     {
  72         size_t new_size;
  73         char *new_value;
  74
  75         /* avoid integer overflow */
  76         if (strbuff->size > STRBUFFER_SIZE_MAX / STRBUFFER_FACTOR
  77             || size > STRBUFFER_SIZE_MAX - 1
  78             || strbuff->length > STRBUFFER_SIZE_MAX - 1 - size)
  79             return -1;
  80
  81         new_size = max(strbuff->size * STRBUFFER_FACTOR,
  82                        strbuff->length + size + 1);
  83
  84         new_value = jsonp_malloc(new_size);
  85         if(!new_value)
  86             return -1;
  87
  88         memcpy(new_value, strbuff->value, strbuff->length);
  89
  90         jsonp_free(strbuff->value);
  91         strbuff->value = new_value;
  92         strbuff->size = new_size;
  93     }
  94
  95     memcpy(strbuff->value + strbuff->length, data, size);
  96     strbuff->length += size;
  97     strbuff->value[strbuff->length] = '\0';
  98
  99     return 0;
 100 }
 101
 102 char strbuffer_pop(strbuffer_t *strbuff)
 103 {
 104     if(strbuff->length > 0) {
 105         char c = strbuff->value[--strbuff->length];
 106         strbuff->value[strbuff->length] = '\0';
 107         return c;
 108     }
 109     else
 110         return '\0';
 111 }