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Diffstat (limited to 'include/carefulputc.h')
| -rw-r--r-- | include/carefulputc.h | 153 |
1 files changed, 153 insertions, 0 deletions
diff --git a/include/carefulputc.h b/include/carefulputc.h new file mode 100644 index 0000000..54a02bf --- /dev/null +++ b/include/carefulputc.h @@ -0,0 +1,153 @@ +#ifndef UTIL_LINUX_CAREFULPUTC_H +#define UTIL_LINUX_CAREFULPUTC_H + +/* + * A putc() for use in write and wall (that sometimes are sgid tty). + * It avoids control characters in our locale, and also ASCII control + * characters. Note that the locale of the recipient is unknown. +*/ +#include <stdio.h> +#include <string.h> +#include <ctype.h> + +static inline int fputc_careful(int c, FILE *fp, const char fail) +{ + int ret; + + if (isprint(c) || c == '\a' || c == '\t' || c == '\r' || c == '\n') + ret = putc(c, fp); + else if (!isascii(c)) + ret = fprintf(fp, "\\%3o", (unsigned char)c); + else { + ret = putc(fail, fp); + if (ret != EOF) + ret = putc(c ^ 0x40, fp); + } + return (ret < 0) ? EOF : 0; +} + +/* + * Requirements enumerated via testing (V8, Firefox, IE11): + * + * var charsToEscape = []; + * for (var i = 0; i < 65535; i += 1) { + * try { + * JSON.parse('{"sample": "' + String.fromCodePoint(i) + '"}'); + * } catch (e) { + * charsToEscape.push(i); + * } + * } + */ +static inline void fputs_quoted_case_json(const char *data, FILE *out, int dir) +{ + const char *p; + + fputc('"', out); + for (p = data; p && *p; p++) { + + const unsigned char c = (unsigned char) *p; + + /* From http://www.json.org + * + * The double-quote and backslashes would break out a string or + * init an escape sequence if not escaped. + * + * Note that single-quotes and forward slashes, while they're + * in the JSON spec, don't break double-quoted strings. + */ + if (c == '"' || c == '\\') { + fputc('\\', out); + fputc(c, out); + continue; + } + + /* All non-control characters OK; do the case swap as required. */ + if (c >= 0x20) { + fputc(dir == 1 ? toupper(c) : + dir == -1 ? tolower(c) : *p, out); + continue; + } + + /* In addition, all chars under ' ' break Node's/V8/Chrome's, and + * Firefox's JSON.parse function + */ + switch (c) { + /* Handle short-hand cases to reduce output size. C + * has most of the same stuff here, so if there's an + * "Escape for C" function somewhere in the STL, we + * should probably be using it. + */ + case '\b': + fputs("\\b", out); + break; + case '\t': + fputs("\\t", out); + break; + case '\n': + fputs("\\n", out); + break; + case '\f': + fputs("\\f", out); + break; + case '\r': + fputs("\\r", out); + break; + default: + /* Other assorted control characters */ + fprintf(out, "\\u00%02x", c); + break; + } + } + fputc('"', out); +} + + +static inline void fputs_quoted_case(const char *data, FILE *out, int dir) +{ + const char *p; + + fputc('"', out); + for (p = data; p && *p; p++) { + if ((unsigned char) *p == 0x22 || /* " */ + (unsigned char) *p == 0x5c || /* \ */ + (unsigned char) *p == 0x60 || /* ` */ + (unsigned char) *p == 0x24 || /* $ */ + !isprint((unsigned char) *p) || + iscntrl((unsigned char) *p)) { + + fprintf(out, "\\x%02x", (unsigned char) *p); + } else + fputc(dir == 1 ? toupper(*p) : + dir == -1 ? tolower(*p) : + *p, out); + } + fputc('"', out); +} + +#define fputs_quoted(_d, _o) fputs_quoted_case(_d, _o, 0) +#define fputs_quoted_upper(_d, _o) fputs_quoted_case(_d, _o, 1) +#define fputs_quoted_lower(_d, _o) fputs_quoted_case(_d, _o, -1) + +#define fputs_quoted_json(_d, _o) fputs_quoted_case_json(_d, _o, 0) +#define fputs_quoted_json_upper(_d, _o) fputs_quoted_case_json(_d, _o, 1) +#define fputs_quoted_json_lower(_d, _o) fputs_quoted_case_json(_d, _o, -1) + +static inline void fputs_nonblank(const char *data, FILE *out) +{ + const char *p; + + for (p = data; p && *p; p++) { + if (isblank((unsigned char) *p) || + (unsigned char) *p == 0x5c || /* \ */ + !isprint((unsigned char) *p) || + iscntrl((unsigned char) *p)) { + + fprintf(out, "\\x%02x", (unsigned char) *p); + + } else + fputc(*p, out); + } +} + + +#endif /* _CAREFULPUTC_H */ |