/**
* charset - character set conversion and validation routines
*
- * This module provides a collection (well, only one, at the moment) of
- * well-tested routines for dealing with character set nonsense.
- *
- * Validation functions:
- * - bool utf8_validate(const char *str, size_t length);
+ * This module provides a collection of well-tested routines
+ * for dealing with character set nonsense.
*
* Example:
* #include <err.h>
* #include <stdio.h>
+ * #include <stdlib.h>
* #include <string.h>
* #include <ccan/charset/charset.h>
* #include <ccan/grab_file/grab_file.h>
- * #include <ccan/talloc/talloc.h> // For talloc_free()
- *
- * int main(int argc, char *argv[])
+ * #include <ccan/talloc/talloc.h>
+ *
+ * static void print_json_string(const char *s);
+ * static bool parse_hex16(const char **sp, unsigned int *out);
+ *
+ * // Take a JSON-encoded string on input and print its literal value.
+ * int main(void)
* {
- * size_t len;
- * char *file;
- * bool valid;
- *
- * if (argc != 2)
- * err(1, "Expected exactly one argument");
- *
- * file = grab_file(NULL, argv[1], &len);
- * if (!file)
- * err(1, "Could not read file %s", argv[1]);
- *
- * valid = utf8_validate(file, len);
- * printf("File contents are %s UTF-8\n", valid ? "valid" : "invalid");
- *
- * talloc_free(file);
- *
+ * char *input;
+ * size_t length;
+ *
+ * input = grab_file(NULL, NULL, &length);
+ * if (!input)
+ * err(1, "Error reading input");
+ * if (!utf8_validate(input, length)) {
+ * fprintf(stderr, "Input contains invalid UTF-8\n");
+ * return 1;
+ * }
+ * if (strlen(input) != length) {
+ * fprintf(stderr, "Input contains null characters\n");
+ * return 1;
+ * }
+ *
+ * print_json_string(input);
+ *
+ * talloc_free(input);
* return 0;
* }
+ *
+ * static void print_json_string(const char *s)
+ * {
+ * char output_buffer[4];
+ *
+ * // Skip leading whitespace
+ * while (*s == ' ' || *s == '\t' || *s == '\n' || *s == '\r')
+ * s++;
+ *
+ * if (*s++ != '"') {
+ * fprintf(stderr, "Expected JSON string literal surrounded by double quotes.\n");
+ * exit(EXIT_FAILURE);
+ * }
+ *
+ * while (*s != '"') {
+ * unsigned char c = *s++;
+ * char *b = output_buffer;
+ *
+ * if (c == '\\') {
+ * c = *s++;
+ * switch (c) {
+ * case '"':
+ * case '\\':
+ * case '/':
+ * *b++ = c;
+ * break;
+ * case 'b': *b++ = '\b'; break;
+ * case 'f': *b++ = '\f'; break;
+ * case 'n': *b++ = '\n'; break;
+ * case 'r': *b++ = '\r'; break;
+ * case 't': *b++ = '\t'; break;
+ * case 'u': {
+ * unsigned int uc, lc;
+ *
+ * if (!parse_hex16(&s, &uc))
+ * goto syntax_error;
+ *
+ * if (uc >= 0xD800 && uc <= 0xDFFF) {
+ * // Handle UTF-16 surrogate pair (e.g. "\uD834\uDD1E").
+ * uchar_t unicode;
+ *
+ * if (*s++ != '\\' || *s++ != 'u' || !parse_hex16(&s, &lc))
+ * goto syntax_error;
+ *
+ * unicode = from_surrogate_pair(uc, lc);
+ * if (unicode == REPLACEMENT_CHARACTER) {
+ * fprintf(stderr, "Invalid surrogate pair.\n");
+ * exit(EXIT_FAILURE);
+ * }
+ *
+ * b += utf8_write_char(unicode, b);
+ * } else {
+ * // Handle ordinary Unicode escape (e.g. "\u266B").
+ * b += utf8_write_char(uc, b);
+ * }
+ *
+ * break;
+ * }
+ * default:
+ * goto syntax_error;
+ * }
+ * } else if (c <= 0x1F) {
+ * // Control characters are not allowed in string literals.
+ * goto syntax_error;
+ * } else {
+ * *b++ = c;
+ * }
+ *
+ * fwrite(output_buffer, 1, b - output_buffer, stdout);
+ * }
+ *
+ * putchar('\n');
+ * return;
+ *
+ * syntax_error:
+ * fprintf(stderr, "Syntax error in JSON string literal.\n");
+ * exit(EXIT_FAILURE);
+ * }
+ *
+ * static bool parse_hex16(const char **sp, unsigned int *out)
+ * {
+ * const char *s = *sp;
+ * unsigned int ret = 0;
+ * unsigned int i;
+ * unsigned int tmp;
+ * char c;
+ *
+ * for (i = 0; i < 4; i++)
+ * {
+ * c = *s++;
+ * if (c >= '0' && c <= '9')
+ * tmp = c - '0';
+ * else if (c >= 'A' && c <= 'F')
+ * tmp = c - 'A' + 10;
+ * else if (c >= 'a' && c <= 'f')
+ * tmp = c - 'a' + 10;
+ * else
+ * return false;
+ *
+ * ret <<= 4;
+ * ret += tmp;
+ * }
+ *
+ * *out = ret;
+ * *sp = s;
+ * return true;
+ * }
*
* Author: Joey Adams
- * Licence: MIT
+ * License: MIT
*/
int main(int argc, char *argv[])
{
projects / ccan / blobdiff