gdbsupport/common-utils.h

   1 /* Shared general utility routines for GDB, the GNU debugger.
   2
   3    Copyright (C) 1986-2024 Free Software Foundation, Inc.
   4
   5    This file is part of GDB.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  19
  20 #ifndef COMMON_COMMON_UTILS_H
  21 #define COMMON_COMMON_UTILS_H
  22
  23 #include <string>
  24 #include <vector>
  25 #include "gdbsupport/byte-vector.h"
  26 #include "gdbsupport/gdb_unique_ptr.h"
  27 #include "gdbsupport/array-view.h"
  28 #include "poison.h"
  29 #include <string_view>
  30
  31 #if defined HAVE_LIBXXHASH
  32 #  include <xxhash.h>
  33 #else
  34 #  include "hashtab.h"
  35 #endif
  36
  37 /* xmalloc(), xrealloc() and xcalloc() have already been declared in
  38    "libiberty.h". */
  39
  40 /* Like xmalloc, but zero the memory.  */
  41 void *xzalloc (size_t);
  42
  43 /* Like asprintf and vasprintf, but return the string, throw an error
  44    if no memory.  */
  45 gdb::unique_xmalloc_ptr<char> xstrprintf (const char *format, ...)
  46      ATTRIBUTE_PRINTF (1, 2);
  47 gdb::unique_xmalloc_ptr<char> xstrvprintf (const char *format, va_list ap)
  48      ATTRIBUTE_PRINTF (1, 0);
  49
  50 /* Like snprintf, but throw an error if the output buffer is too small.  */
  51 int xsnprintf (char *str, size_t size, const char *format, ...)
  52      ATTRIBUTE_PRINTF (3, 4);
  53
  54 /* Returns a std::string built from a printf-style format string.  */
  55 std::string string_printf (const char* fmt, ...)
  56   ATTRIBUTE_PRINTF (1, 2);
  57
  58 /* Like string_printf, but takes a va_list.  */
  59 std::string string_vprintf (const char* fmt, va_list args)
  60   ATTRIBUTE_PRINTF (1, 0);
  61
  62 /* Like string_printf, but appends to DEST instead of returning a new
  63    std::string.  */
  64 std::string &string_appendf (std::string &dest, const char* fmt, ...)
  65   ATTRIBUTE_PRINTF (2, 3);
  66
  67 /* Like string_appendf, but takes a va_list.  */
  68 std::string &string_vappendf (std::string &dest, const char* fmt, va_list args)
  69   ATTRIBUTE_PRINTF (2, 0);
  70
  71 /* Make a copy of the string at PTR with LEN characters
  72    (and add a null character at the end in the copy).
  73    Uses malloc to get the space.  Returns the address of the copy.  */
  74
  75 char *savestring (const char *ptr, size_t len);
  76
  77 /* Extract the next word from ARG.  The next word is defined as either,
  78    everything up to the next space, or, if the next word starts with either
  79    a single or double quote, then everything up to the closing quote.  The
  80    enclosing quotes are not returned in the result string.  The pointer in
  81    ARG is updated to point to the first character after the end of the
  82    word, or, for quoted words, the first character after the closing
  83    quote.  */
  84
  85 std::string extract_string_maybe_quoted (const char **arg);
  86
  87 /* The strerror() function can return NULL for errno values that are
  88    out of range.  Provide a "safe" version that always returns a
  89    printable string.  This version is also thread-safe.  */
  90
  91 extern const char *safe_strerror (int);
  92
  93 /* Version of startswith that takes string_view arguments.  Return
  94    true if the start of STRING matches PATTERN, false otherwise.  */
  95
  96 static inline bool
  97 startswith (std::string_view string, std::string_view pattern)
  98 {
  99   return (string.length () >= pattern.length ()
 100           && strncmp (string.data (), pattern.data (), pattern.length ()) == 0);
 101 }
 102
 103 /* Version of startswith that takes a string_view for only one of its
 104    arguments.  Return true if STR starts with PREFIX, otherwise return
 105    false.  */
 106
 107 static inline bool
 108 startswith (const char *str, const std::string_view &prefix)
 109 {
 110   return strncmp (str, prefix.data (), prefix.length ()) == 0;
 111 }
 112
 113 /* Return true if the strings are equal.  */
 114
 115 static inline bool
 116 streq (const char *lhs, const char *rhs)
 117 {
 118   return strcmp (lhs, rhs) == 0;
 119 }
 120
 121 /* Compare C strings for std::sort.  */
 122
 123 static inline bool
 124 compare_cstrings (const char *str1, const char *str2)
 125 {
 126   return strcmp (str1, str2) < 0;
 127 }
 128
 129 ULONGEST strtoulst (const char *num, const char **trailer, int base);
 130
 131 /* Skip leading whitespace characters in INP, returning an updated
 132    pointer.  If INP is NULL, return NULL.  */
 133
 134 extern char *skip_spaces (char *inp);
 135
 136 /* A const-correct version of the above.  */
 137
 138 extern const char *skip_spaces (const char *inp);
 139
 140 /* Skip leading non-whitespace characters in INP, returning an updated
 141    pointer.  If INP is NULL, return NULL.  */
 142
 143 extern char *skip_to_space (char *inp);
 144
 145 /* A const-correct version of the above.  */
 146
 147 extern const char *skip_to_space (const char *inp);
 148
 149 /* Assumes that V is an argv for a program, and iterates through
 150    freeing all the elements.  */
 151 extern void free_vector_argv (std::vector<char *> &v);
 152
 153 /* Return true if VALUE is in [LOW, HIGH].  */
 154
 155 template <typename T>
 156 static bool
 157 in_inclusive_range (T value, T low, T high)
 158 {
 159   return value >= low && value <= high;
 160 }
 161
 162 /* Ensure that V is aligned to an N byte boundary (N's assumed to be a
 163    power of 2).  Round up/down when necessary.  Examples of correct
 164    use include:
 165
 166     addr = align_up (addr, 8); -- VALUE needs 8 byte alignment
 167     write_memory (addr, value, len);
 168     addr += len;
 169
 170    and:
 171
 172     sp = align_down (sp - len, 16); -- Keep SP 16 byte aligned
 173     write_memory (sp, value, len);
 174
 175    Note that uses such as:
 176
 177     write_memory (addr, value, len);
 178     addr += align_up (len, 8);
 179
 180    and:
 181
 182     sp -= align_up (len, 8);
 183     write_memory (sp, value, len);
 184
 185    are typically not correct as they don't ensure that the address (SP
 186    or ADDR) is correctly aligned (relying on previous alignment to
 187    keep things right).  This is also why the methods are called
 188    "align_..." instead of "round_..." as the latter reads better with
 189    this incorrect coding style.  */
 190
 191 extern ULONGEST align_up (ULONGEST v, int n);
 192 extern ULONGEST align_down (ULONGEST v, int n);
 193
 194 /* Convert hex digit A to a number, or throw an exception.  */
 195 extern int fromhex (int a);
 196
 197 /* HEX is a string of characters representing hexadecimal digits.
 198    Convert pairs of hex digits to bytes and store sequentially into
 199    BIN.  COUNT is the maximum number of characters to convert.  This
 200    will convert fewer characters if the number of hex characters
 201    actually seen is odd, or if HEX terminates before COUNT characters.
 202    Returns the number of characters actually converted.  */
 203 extern int hex2bin (const char *hex, gdb_byte *bin, int count);
 204
 205 /* Like the above, but return a gdb::byte_vector.  */
 206 gdb::byte_vector hex2bin (const char *hex);
 207
 208 /* Build a string containing the contents of BYTES.  Each byte is
 209    represented as a 2 character hex string, with spaces separating each
 210    individual byte.  */
 211
 212 extern std::string bytes_to_string (gdb::array_view<const gdb_byte> bytes);
 213
 214 /* See bytes_to_string above.  This takes a BUFFER pointer and LENGTH
 215    rather than an array view.  */
 216
 217 static inline std::string bytes_to_string (const gdb_byte *buffer,
 218                                            size_t length)
 219 {
 220   return bytes_to_string ({buffer, length});
 221 }
 222
 223 /* A fast hashing function.  This can be used to hash data in a fast way
 224    when the length is known.  If no fast hashing library is available, falls
 225    back to iterative_hash from libiberty.  START_VALUE can be set to
 226    continue hashing from a previous value.  */
 227
 228 static inline unsigned int
 229 fast_hash (const void *ptr, size_t len, unsigned int start_value = 0)
 230 {
 231 #if defined HAVE_LIBXXHASH
 232   return XXH64 (ptr, len, start_value);
 233 #else
 234   return iterative_hash (ptr, len, start_value);
 235 #endif
 236 }
 237
 238 namespace gdb
 239 {
 240
 241 /* Hash type for std::string_view.
 242
 243    Even after we switch to C++17 and dump our string_view implementation, we
 244    might want to keep this hash implementation if it's faster than std::hash
 245    for std::string_view.  */
 246
 247 struct string_view_hash
 248 {
 249   std::size_t operator() (std::string_view view) const
 250   {  return fast_hash (view.data (), view.length ()); }
 251 };
 252
 253 } /* namespace gdb */
 254
 255 #endif /* COMMON_COMMON_UTILS_H */