// // utils.c - Some helper code for debugging and error logging. //
#include
#include “utils.h”
// // Helper function to skip past all spaces (and comments) // Returns a pointer to the first non-space character. // public const char *afterspaces(const char *str, bool skipnl, const char end) { // Skip whitespace and comments: skip_whitespace: if (str >= end) return str; switch (str) { case ‘\r’: case ‘\n’: if (!skip_nl) break; attribute((fallthrough)); case ‘ ‘: case ‘\t’: { ++str; goto skipwhitespace; } case ‘#’: { while (str < end && *str != ‘\n’) ++str; goto skipwhitespace; } default: break; } return str; }
// // Return the first character after a valid BP name, or NULL if none is // found. // public const char *aftername(const char *str, const char end) { if (str >= end) return end; if (str == ‘|’) return &str[1]; if (*str == ‘^’ || *str == ‘‘ || *str == ‘$’) { return (&str[1] < end && str[1] == str) ? &str[2] : &str[1]; } if (!isalpha(str)) return NULL; for (++str; str < end; ++str) { if (!(isalnum(*str) || *str == ‘-’)) break; } return str; }
// // Check if a character is found and if so, move past it. // public bool matchchar(const char **str, char c, bool skipnl, const char *end) { const char *next = afterspaces(str, skip_nl, end); if (next >= end) return false; if (next == c) { *str = next + 1; return true; } return false; }
// // Check if a string is found and if so, move past it. // public bool matchstr(const char **str, const char *target, bool skipnl, const char *end) { const char *next = afterspaces(*str, skip_nl, end); if (next + strlen(target) > end) return false; if (strncmp(next, target, strlen(target)) == 0) { *str = &next[strlen(target)]; return true; } return false; }
// // Process a string escape sequence for a character and return the // character that was escaped. // Set *end = the first character past the end of the escape sequence. // public char unescapechar(const char *escaped, const char **after, const char end) { size_t len = 0; unsigned char ret = ‘\‘; if (escaped >= end) goto finished; ret = (unsigned char)escaped; ++len; switch (*escaped) { case ‘a’: ret = ‘\a’; break; case ‘b’: ret = ‘\b’; break; case ‘n’: ret = ‘\n’; break; case ‘r’: ret = ‘\r’; break; case ‘t’: ret = ‘\t’; break; case ‘v’: ret = ‘\v’; break; case ‘e’: ret = ‘\033’; break; case ‘\‘: ret = ‘\‘; break; case ‘x’: { // Hex static const unsigned char hextable[255] = { [‘0’] = 0x10, [‘1’] = 0x1, [‘2’] = 0x2, [‘3’] = 0x3, [‘4’] = 0x4, [‘5’] = 0x5, [‘6’] = 0x6, [‘7’] = 0x7, [‘8’] = 0x8, [‘9’] = 0x9, [‘a’] = 0xa, [‘b’] = 0xb, [‘c’] = 0xc, [‘d’] = 0xd, [‘e’] = 0xe, [‘f’] = 0xf, [‘A’] = 0xa, [‘B’] = 0xb, [‘C’] = 0xc, [‘D’] = 0xd, [‘E’] = 0xe, [‘F’] = 0xf, }; if (escaped + 2 >= end) { len = 0; goto finished; } else if (hextable[(int)escaped[1]] && hextable[(int)escaped[2]]) { ret = (hextable[(int)escaped[1]] << 4) | (hextable[(int)escaped[2]] & 0xF); len = 3; } break; } case ‘0’: case ‘1’: case ‘2’: case ‘3’: case ‘4’: case ‘5’: case ‘6’: case ‘7’: { // Octal ret = (unsigned char)(escaped[0] - ‘0’); if (escaped + 2 >= end) { len = 0; goto finished; } else if (‘0’ <= escaped[1] && escaped[1] <= ‘7’) { ++len; ret = (ret << 3) | (escaped[1] - ‘0’); if (‘0’ <= escaped[2] && escaped[2] <= ‘7’) { ++len; ret = (ret << 3) | (escaped[2] - ‘0’); } } break; } default: len = 0; goto finished; } finished: if (after) *after = &escaped[len]; return (char)ret; }
// // Free memory, but also set the pointer to NULL for safety // public void delete(void p) { if ((void *)p == NULL) errx(EXIT_FAILURE, “attempt to free(NULL)”); free((void **)p); *((void **)p) = NULL; }
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