/** * mds — A micro-display server * Copyright © 2014 Mattias Andrée (maandree@member.fsf.org) * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see . */ #include "string.h" #include #include #include /** * Get the length of a string * * @param string The string * @return The length of the string */ size_t string_length(const char32_t* restrict string) { size_t i = 0; while (string[i] > -1) i++; return i; } /** * Convert a NUL-terminated UTF-8 string to a -1-terminated UTF-32 string * * @param string The UTF-8 string * @return The string in UTF-32, `NULL` on error */ char32_t* string_decode(const char* restrict string) { size_t i, j, n, length = 0; char32_t* rc; /* Get the length of the UTF-32 string, excluding termination. */ for (i = 0; string[i]; i++) if ((string[i] & 0xC0) != 0x80) length++; /* Allocated UTF-32 string. */ if (xmalloc(rc, length + 1, char32_t)) return NULL; /* Convert to UTF-32. */ for (i = j = n = 0; string[i]; i++) { char c = string[i]; if (n) { rc[j] <<= 6, rc[j] |= c & 0x3F; if (--n == 0) j++; } else if ((c & 0xC0) == 0xC0) { while (c & 0x80) n++, c = (char)(c << 1); rc[j] = c >> n--; } else rc[j++] = c & 255; } /* -1-terminate and return. */ return rc[length] = -1, rc; } /** * Convert a -1-terminated UTF-32 string to a NUL-terminated Modified UTF-8 string * * Negative values apart from -1 are converted to 0x00 * * @param string The UTF-32 string * @return The string in UTF-8, `NULL` on error */ char* string_encode(const char32_t* restrict string) { size_t i, j, n = string_length(string); char* restrict rc; /* Allocated Modified UTF-8 string. */ if (xmalloc(rc, 7 * n + 1, char)) return NULL; /* Convert to Modified UTF-8. */ for (i = j = 0; i < n; i++) { #define _c(s) rc[j++] = (char)(((c >> (s)) & 0x3F) | 0x80) #define _t(s) (0 < c) && ((uint32_t)c < (uint32_t)(1ULL << s)) char32_t c = string[i]; if (c == 0) rc[j++] = (char)0xC0, rc[j++] = (char)0x80; else if (_t( 7)) rc[j++] = (char)c; else if (_t(11)) rc[j++] = (char)((c >> 6) | 0xC0), _c( 0); else if (_t(16)) rc[j++] = (char)((c >> 12) | 0xE0), _c( 6), _c( 0); else if (_t(21)) rc[j++] = (char)((c >> 18) | 0xF0), _c(12), _c( 6), _c( 0); /* UTF-8 actually ends here, fits 32 planes. */ else if (_t(26)) rc[j++] = (char)((c >> 24) | 0xF8), _c(18), _c(12), _c( 6), _c(0); else if (_t(31)) rc[j++] = (char)((c >> 30) | 0xFC), _c(24), _c(18), _c(12), _c(6), _c(0); /* The orginal UTF-8 specification ended here, fits 31 bits. * However, we added another byte so we can fit 32 bits * (actually we ca now fit 36 bits.) * However, we only needed this in `string_decode` which would * not require any changed, but we added it here for symmetry. */ else rc[j++] = (char)((c >> 30) | 0xFE), _c(30), _c(24), _c(18), _c(12), _c(6), _c(0); #undef _t #undef _c } /* NUL-terminate and return. */ return rc[j] = '\0', rc; } /** * Create duplicate of a string * * @param string The string * @return A duplicate of the strnig, `NULL` on error or if `string` is `NULL` */ char32_t* string_dup(const char32_t* restrict string) { size_t n; char32_t* rc; if (string == NULL) return NULL; n = string_length(string) + 1; rc = malloc(n * sizeof(char32_t)); if (rc == NULL) return NULL; memcpy(rc, string, n * sizeof(char32_t)); return rc; }