gdbsupport/common-utils.h

   1 /* Shared general utility routines for GDB, the GNU debugger.
   2
   3    Copyright (C) 1986-2023 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 "gdb_string_view.h"
  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 (gdb::string_view string, gdb::string_view pattern)
  98 {
  99   return (string.length () >= pattern.length ()
 100           && strncmp (string.data (), pattern.data (), pattern.length ()) == 0);
 101 }
 102
 103 /* Return true if the strings are equal.  */
 104
 105 static inline bool
 106 streq (const char *lhs, const char *rhs)
 107 {
 108   return strcmp (lhs, rhs) == 0;
 109 }
 110
 111 /* Compare C strings for std::sort.  */
 112
 113 static inline bool
 114 compare_cstrings (const char *str1, const char *str2)
 115 {
 116   return strcmp (str1, str2) < 0;
 117 }
 118
 119 ULONGEST strtoulst (const char *num, const char **trailer, int base);
 120
 121 /* Skip leading whitespace characters in INP, returning an updated
 122    pointer.  If INP is NULL, return NULL.  */
 123
 124 extern char *skip_spaces (char *inp);
 125
 126 /* A const-correct version of the above.  */
 127
 128 extern const char *skip_spaces (const char *inp);
 129
 130 /* Skip leading non-whitespace characters in INP, returning an updated
 131    pointer.  If INP is NULL, return NULL.  */
 132
 133 extern char *skip_to_space (char *inp);
 134
 135 /* A const-correct version of the above.  */
 136
 137 extern const char *skip_to_space (const char *inp);
 138
 139 /* Assumes that V is an argv for a program, and iterates through
 140    freeing all the elements.  */
 141 extern void free_vector_argv (std::vector<char *> &v);
 142
 143 /* Return true if VALUE is in [LOW, HIGH].  */
 144
 145 template <typename T>
 146 static bool
 147 in_inclusive_range (T value, T low, T high)
 148 {
 149   return value >= low && value <= high;
 150 }
 151
 152 /* Ensure that V is aligned to an N byte boundary (N's assumed to be a
 153    power of 2).  Round up/down when necessary.  Examples of correct
 154    use include:
 155
 156     addr = align_up (addr, 8); -- VALUE needs 8 byte alignment
 157     write_memory (addr, value, len);
 158     addr += len;
 159
 160    and:
 161
 162     sp = align_down (sp - len, 16); -- Keep SP 16 byte aligned
 163     write_memory (sp, value, len);
 164
 165    Note that uses such as:
 166
 167     write_memory (addr, value, len);
 168     addr += align_up (len, 8);
 169
 170    and:
 171
 172     sp -= align_up (len, 8);
 173     write_memory (sp, value, len);
 174
 175    are typically not correct as they don't ensure that the address (SP
 176    or ADDR) is correctly aligned (relying on previous alignment to
 177    keep things right).  This is also why the methods are called
 178    "align_..." instead of "round_..." as the latter reads better with
 179    this incorrect coding style.  */
 180
 181 extern ULONGEST align_up (ULONGEST v, int n);
 182 extern ULONGEST align_down (ULONGEST v, int n);
 183
 184 /* Convert hex digit A to a number, or throw an exception.  */
 185 extern int fromhex (int a);
 186
 187 /* HEX is a string of characters representing hexadecimal digits.
 188    Convert pairs of hex digits to bytes and store sequentially into
 189    BIN.  COUNT is the maximum number of characters to convert.  This
 190    will convert fewer characters if the number of hex characters
 191    actually seen is odd, or if HEX terminates before COUNT characters.
 192    Returns the number of characters actually converted.  */
 193 extern int hex2bin (const char *hex, gdb_byte *bin, int count);
 194
 195 /* Like the above, but return a gdb::byte_vector.  */
 196 gdb::byte_vector hex2bin (const char *hex);
 197
 198 /* Build a string containing the contents of BYTES.  Each byte is
 199    represented as a 2 character hex string, with spaces separating each
 200    individual byte.  */
 201
 202 extern std::string bytes_to_string (gdb::array_view<const gdb_byte> bytes);
 203
 204 /* See bytes_to_string above.  This takes a BUFFER pointer and LENGTH
 205    rather than an array view.  */
 206
 207 static inline std::string bytes_to_string (const gdb_byte *buffer,
 208                                            size_t length)
 209 {
 210   return bytes_to_string ({buffer, length});
 211 }
 212
 213 /* A fast hashing function.  This can be used to hash data in a fast way
 214    when the length is known.  If no fast hashing library is available, falls
 215    back to iterative_hash from libiberty.  START_VALUE can be set to
 216    continue hashing from a previous value.  */
 217
 218 static inline unsigned int
 219 fast_hash (const void *ptr, size_t len, unsigned int start_value = 0)
 220 {
 221 #if defined HAVE_LIBXXHASH
 222   return XXH64 (ptr, len, start_value);
 223 #else
 224   return iterative_hash (ptr, len, start_value);
 225 #endif
 226 }
 227
 228 namespace gdb
 229 {
 230
 231 /* Hash type for gdb::string_view.
 232
 233    Even after we switch to C++17 and dump our string_view implementation, we
 234    might want to keep this hash implementation if it's faster than std::hash
 235    for std::string_view.  */
 236
 237 struct string_view_hash
 238 {
 239   std::size_t operator() (gdb::string_view view) const
 240   {  return fast_hash (view.data (), view.length ()); }
 241 };
 242
 243 } /* namespace gdb */
 244
 245 #endif /* COMMON_COMMON_UTILS_H */