mirror of https://github.com/janet-lang/janet
597 lines
20 KiB
C
597 lines
20 KiB
C
/*
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* Copyright (c) 2018 Calvin Rose
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to
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* deal in the Software without restriction, including without limitation the
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* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
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* sell copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
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* IN THE SOFTWARE.
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*/
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#include <janet/janet.h>
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#include <stdlib.h>
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#include <errno.h>
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/*****************/
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/* JSON Decoding */
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/*****************/
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/* Check if a character is whitespace */
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static int white(uint8_t c) {
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return c == '\t' || c == '\n' || c == ' ' || c == '\r';
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}
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/* Skip whitespace */
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static void skipwhite(const char **p) {
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const char *cp = *p;
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for (;;) {
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if (white(*cp))
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cp++;
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else
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break;
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}
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*p = cp;
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}
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/* Get a hex digit value */
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static int hexdig(char dig) {
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if (dig >= '0' && dig <= '9')
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return dig - '0';
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if (dig >= 'a' && dig <= 'f')
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return 10 + dig - 'a';
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if (dig >= 'A' && dig <= 'F')
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return 10 + dig - 'A';
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return -1;
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}
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/* Read the hex value for a unicode escape */
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static char *decode_utf16_escape(const char *p, uint32_t *outpoint) {
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if (!p[0] || !p[1] || !p[2] || !p[3])
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return "unexpected end of source";
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int d1 = hexdig(p[0]);
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int d2 = hexdig(p[1]);
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int d3 = hexdig(p[2]);
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int d4 = hexdig(p[3]);
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if (d1 < 0 || d2 < 0 || d3 < 0 || d4 < 0)
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return "invalid hex digit";
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*outpoint = d4 | (d3 << 4) | (d2 << 8) | (d1 << 12);
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return NULL;
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}
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/* Parse a string */
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const char *decode_string(const char **p, Janet *out) {
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JanetBuffer *buffer = janet_buffer(0);
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const char *cp = *p;
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while (*cp != '"') {
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uint8_t b = (uint8_t) *cp;
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if (b < 32) return "invalid character in string";
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if (b == '\\') {
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cp++;
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switch(*cp) {
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default:
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return "unknown string escape";
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case 'b':
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b = '\b';
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break;
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case 'f':
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b = '\f';
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break;
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case 'n':
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b = '\n';
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break;
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case 'r':
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b = '\r';
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break;
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case 't':
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b = '\t';
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break;
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case '"':
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b = '"';
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break;
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case '\\':
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b = '\\';
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break;
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case 'u':
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{
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/* Get codepoint and check for surrogate pair */
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uint32_t codepoint;
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const char *err = decode_utf16_escape(cp + 1, &codepoint);
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if (err) return err;
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if (codepoint >= 0xDC00 && codepoint <= 0xDFFF) {
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return "unexpected utf-16 low surrogate";
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} else if (codepoint >= 0xD800 && codepoint <= 0xDBFF) {
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if (cp[5] != '\\') return "expected utf-16 low surrogate pair";
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if (cp[6] != 'u') return "expected utf-16 low surrogate pair";
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uint32_t lowsur;
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const char *err = decode_utf16_escape(cp + 7, &lowsur);
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if (err) return err;
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if (lowsur < 0xDC00 || lowsur > 0xDFFF)
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return "expected utf-16 low surrogate pair";
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codepoint = ((codepoint - 0xD800) << 10) +
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(lowsur - 0xDC00) + 0x10000;
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cp += 11;
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} else {
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cp += 5;
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}
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/* Write codepoint */
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if (codepoint <= 0x7F) {
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janet_buffer_push_u8(buffer, codepoint);
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} else if (codepoint <= 0x7FF) {
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janet_buffer_push_u8(buffer, ((codepoint >> 6) & 0x1F) | 0xC0);
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janet_buffer_push_u8(buffer, ((codepoint >> 0) & 0x3F) | 0x80);
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} else if (codepoint <= 0xFFFF) {
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janet_buffer_push_u8(buffer, ((codepoint >> 12) & 0x0F) | 0xE0);
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janet_buffer_push_u8(buffer, ((codepoint >> 6) & 0x3F) | 0x80);
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janet_buffer_push_u8(buffer, ((codepoint >> 0) & 0x3F) | 0x80);
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} else {
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janet_buffer_push_u8(buffer, ((codepoint >> 18) & 0x07) | 0xF0);
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janet_buffer_push_u8(buffer, ((codepoint >> 12) & 0x3F) | 0x80);
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janet_buffer_push_u8(buffer, ((codepoint >> 6) & 0x3F) | 0x80);
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janet_buffer_push_u8(buffer, ((codepoint >> 0) & 0x3F) | 0x80);
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}
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}
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continue;
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}
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}
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janet_buffer_push_u8(buffer, b);
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cp++;
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}
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*out = janet_stringv(buffer->data, buffer->count);
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*p = cp + 1;
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return NULL;
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}
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static const char *decode_one(const char **p, Janet *out, int depth) {
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/* Prevent stack overflow */
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if (depth > JANET_RECURSION_GUARD) goto recurdepth;
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/* Skip leading whitepspace */
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skipwhite(p);
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/* Main switch */
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switch (**p) {
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default:
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goto badchar;
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case '\0':
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goto eos;
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/* Numbers */
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case '-': case '0': case '1' : case '2': case '3' : case '4':
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case '5': case '6': case '7' : case '8': case '9':
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{
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errno = 0;
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char *end = NULL;
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double x = strtod(*p, &end);
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if (end == *p) goto badnum;
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*p = end;
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*out = janet_wrap_real(x);
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break;
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}
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/* false, null, true */
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case 'f':
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{
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const char *cp = *p;
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if (cp[1] != 'a' || cp[2] != 'l' || cp[3] != 's' || cp[4] != 'e')
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goto badident;
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*out = janet_wrap_false();
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*p = cp + 5;
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break;
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}
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case 'n':
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{
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const char *cp = *p;
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if (cp[1] != 'u' || cp[2] != 'l' || cp[3] != 'l')
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goto badident;
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*out = janet_wrap_nil();
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*p = cp + 4;
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break;
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}
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case 't':
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{
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const char *cp = *p;
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if (cp[1] != 'r' || cp[2] != 'u' || cp[3] != 'e')
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goto badident;
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*out = janet_wrap_true();
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*p = cp + 4;
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break;
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}
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/* String */
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case '"':
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{
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const char *cp = *p + 1;
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const char *start = cp;
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while (*cp >= 32 && *cp != '"' && *cp != '\\')
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cp++;
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/* Only use a buffer for strings with escapes, else just copy
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* memory from source */
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if (*cp == '\\') {
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*p = *p + 1;
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const char *err = decode_string(p, out);
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if (err) return err;
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break;
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}
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if (*cp != '"') goto badchar;
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*p = cp + 1;
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*out = janet_stringv((const uint8_t *)start, cp - start);
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break;
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}
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/* Array */
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case '[':
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{
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*p = *p + 1;
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JanetArray *array = janet_array(0);
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const char *err;
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Janet subval;
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skipwhite(p);
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while (**p != ']') {
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err = decode_one(p, &subval, depth + 1);
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if (err) return err;
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janet_array_push(array, subval);
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skipwhite(p);
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if (**p == ']') break;
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if (**p != ',') goto wantcomma;
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*p = *p + 1;
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}
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*p = *p + 1;
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*out = janet_wrap_array(array);
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}
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break;
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/* Object */
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case '{':
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{
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*p = *p + 1;
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JanetTable *table = janet_table(0);
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const char *err;
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Janet subkey, subval;
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skipwhite(p);
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while (**p != '}') {
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skipwhite(p);
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if (**p != '"') goto wantstring;
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err = decode_one(p, &subkey, depth + 1);
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if (err) return err;
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skipwhite(p);
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if (**p != ':') goto wantcolon;
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*p = *p + 1;
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err = decode_one(p, &subval, depth + 1);
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if (err) return err;
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janet_table_put(table, subkey, subval);
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skipwhite(p);
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if (**p == '}') break;
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if (**p != ',') goto wantcomma;
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*p = *p + 1;
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}
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*p = *p + 1;
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*out = janet_wrap_table(table);
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break;
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}
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}
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/* Good return */
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return NULL;
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/* Errors */
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recurdepth:
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return "recured too deeply";
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eos:
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return "unexpected end of source";
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badident:
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return "bad identifier";
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badnum:
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return "bad number";
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wantcomma:
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return "expected comma";
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wantcolon:
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return "expected colon";
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badchar:
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return "unexpected character";
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wantstring:
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return "expected json string";
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}
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static int json_decode(JanetArgs args) {
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Janet ret;
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JANET_FIXARITY(args, 1);
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const char *err;
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const char *start;
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const char *p;
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if (janet_checktype(args.v[0], JANET_BUFFER)) {
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JanetBuffer *buffer = janet_unwrap_buffer(args.v[0]);
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/* Ensure 0 padded */
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janet_buffer_push_u8(buffer, 0);
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start = p = (const char *)buffer->data;
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err = decode_one(&p, &ret, 0);
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buffer->count--;
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} else {
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const uint8_t *bytes;
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int32_t len;
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JANET_ARG_BYTES(bytes, len, args, 0);
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start = p = (const char *)bytes;
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err = decode_one(&p, &ret, 0);
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}
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/* Check trailing values */
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if (!err) {
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skipwhite(&p);
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if (*p)
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err = "unexpected extra token";
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}
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if (err) {
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JANET_THROWV(args, janet_wrap_string(janet_formatc(
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"decode error at postion %d: %s",
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p - start,
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err)));
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}
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JANET_RETURN(args, ret);
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}
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/*****************/
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/* JSON Encoding */
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/*****************/
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typedef struct {
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JanetBuffer *buffer;
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int32_t indent;
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const uint8_t *tab;
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const uint8_t *newline;
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int32_t tablen;
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int32_t newlinelen;
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} Encoder;
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static const char *encode_newline(Encoder *e) {
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if (janet_buffer_push_bytes(e->buffer, e->newline, e->newlinelen))
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return "buffer overflow";
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for (int32_t i = 0; i < e->indent; i++)
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if (janet_buffer_push_bytes(e->buffer, e->tab, e->tablen))
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return "buffer overflow";
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return NULL;
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}
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static const char *encode_one(Encoder *e, Janet x, int depth) {
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switch(janet_type(x)) {
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default:
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goto badtype;
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case JANET_NIL:
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{
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if (janet_buffer_push_cstring(e->buffer, "null"))
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goto overflow;
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}
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break;
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case JANET_FALSE:
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{
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if (janet_buffer_push_cstring(e->buffer, "false"))
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goto overflow;
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}
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break;
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case JANET_TRUE:
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{
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if (janet_buffer_push_cstring(e->buffer, "true"))
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goto overflow;
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}
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break;
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case JANET_INTEGER:
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{
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char cbuf[20];
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sprintf(cbuf, "%d", janet_unwrap_integer(x));
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if (janet_buffer_push_cstring(e->buffer, cbuf))
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goto overflow;
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}
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break;
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case JANET_REAL:
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{
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char cbuf[25];
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sprintf(cbuf, "%.17g", janet_unwrap_real(x));
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if (janet_buffer_push_cstring(e->buffer, cbuf))
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goto overflow;
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}
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break;
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case JANET_STRING:
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case JANET_SYMBOL:
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case JANET_BUFFER:
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{
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const uint8_t *bytes;
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const uint8_t *c;
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const uint8_t *end;
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int32_t len;
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janet_bytes_view(x, &bytes, &len);
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if (janet_buffer_push_u8(e->buffer, '"')) goto overflow;
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c = bytes;
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end = bytes + len;
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while (c < end) {
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/* get codepoint */
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uint32_t codepoint;
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if (*c < 0x80) {
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/* one byte */
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codepoint = *c++;
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} else if (*c < 0xE0) {
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/* two bytes */
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if (c + 2 > end) goto overflow;
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codepoint = ((c[0] & 0x1F) << 6) |
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(c[1] & 0x3F);
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c += 2;
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} else if (*c < 0xF0) {
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/* three bytes */
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if (c + 3 > end) goto overflow;
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codepoint = ((c[0] & 0x0F) << 12) |
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((c[1] & 0x3F) << 6) |
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(c[2] & 0x3F);
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c += 3;
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} else if (*c < 0xF8) {
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/* four bytes */
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if (c + 4 > end) goto overflow;
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codepoint = ((c[0] & 0x07) << 18) |
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((c[1] & 0x3F) << 12) |
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((c[3] & 0x3F) << 6) |
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(c[3] & 0x3F);
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c += 4;
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} else {
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/* invalid */
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goto invalidutf8;
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}
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/* write codepoint */
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if (codepoint > 0x1F && codepoint < 0x80) {
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/* Normal, no escape */
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if (codepoint == '\\' || codepoint == '"')
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if (janet_buffer_push_u8(e->buffer, '\\'))
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goto overflow;
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if (janet_buffer_push_u8(e->buffer, (uint8_t) codepoint))
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goto overflow;
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} else if (codepoint < 0x10000) {
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/* One unicode escape */
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uint8_t buf[6];
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buf[0] = '\\';
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buf[1] = 'u';
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buf[2] = (codepoint >> 12) & 0xF;
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buf[3] = (codepoint >> 8) & 0xF;
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buf[4] = (codepoint >> 4) & 0xF;
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buf[5] = codepoint & 0xF;
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if (janet_buffer_push_bytes(e->buffer, buf, sizeof(buf)))
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goto overflow;
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} else {
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/* Two unicode escapes (surrogate pair) */
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uint32_t hi, lo;
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uint8_t buf[12];
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hi = ((codepoint - 0x10000) >> 10) + 0xD800;
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lo = ((codepoint - 0x10000) & 0x3FF) + 0xDC00;
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buf[0] = '\\';
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buf[1] = 'u';
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buf[2] = (hi >> 12) & 0xF;
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buf[3] = (hi >> 8) & 0xF;
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buf[4] = (hi >> 4) & 0xF;
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buf[5] = hi & 0xF;
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buf[6] = '\\';
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buf[7] = 'u';
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buf[8] = (lo >> 12) & 0xF;
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buf[9] = (lo >> 8) & 0xF;
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buf[10] = (lo >> 4) & 0xF;
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buf[11] = lo & 0xF;
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if (janet_buffer_push_bytes(e->buffer, buf, sizeof(buf)))
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goto overflow;
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}
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}
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if (janet_buffer_push_u8(e->buffer, '"')) goto overflow;
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}
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break;
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case JANET_TUPLE:
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case JANET_ARRAY:
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{
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const char *err;
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const Janet *items;
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int32_t len;
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janet_indexed_view(x, &items, &len);
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if (janet_buffer_push_u8(e->buffer, '[')) goto overflow;
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e->indent++;
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if ((err = encode_newline(e))) return err;
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for (int32_t i = 0; i < len; i++) {
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if ((err = encode_newline(e))) return err;
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if ((err = encode_one(e, items[i], depth + 1)))
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return err;
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if (janet_buffer_push_u8(e->buffer, ','))
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goto overflow;
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}
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e->indent--;
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if (e->buffer->data[e->buffer->count - 1] == ',') {
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e->buffer->count--;
|
|
if ((err = encode_newline(e))) return err;
|
|
}
|
|
if (janet_buffer_push_u8(e->buffer, ']')) goto overflow;
|
|
}
|
|
break;
|
|
case JANET_TABLE:
|
|
case JANET_STRUCT:
|
|
{
|
|
const char *err;
|
|
const JanetKV *kvs;
|
|
int32_t count, capacity;
|
|
janet_dictionary_view(x, &kvs, &count, &capacity);
|
|
if (janet_buffer_push_u8(e->buffer, '{')) goto overflow;
|
|
e->indent++;
|
|
for (int32_t i = 0; i < capacity; i++) {
|
|
if (janet_checktype(kvs[i].key, JANET_NIL))
|
|
continue;
|
|
if (!janet_checktype(kvs[i].key, JANET_STRING))
|
|
return "only strings keys are allowed in objects";
|
|
if ((err = encode_newline(e))) return err;
|
|
if ((err = encode_one(e, kvs[i].key, depth + 1)))
|
|
return err;
|
|
const char *sep = e->tablen ? ": " : ":";
|
|
if (janet_buffer_push_cstring(e->buffer, sep))
|
|
goto overflow;
|
|
if ((err = encode_one(e, kvs[i].value, depth + 1)))
|
|
return err;
|
|
if (janet_buffer_push_u8(e->buffer, ','))
|
|
goto overflow;
|
|
}
|
|
e->indent--;
|
|
if (e->buffer->data[e->buffer->count - 1] == ',') {
|
|
e->buffer->count--;
|
|
if ((err = encode_newline(e))) return err;
|
|
}
|
|
if (janet_buffer_push_u8(e->buffer, '}')) goto overflow;
|
|
}
|
|
break;
|
|
}
|
|
return NULL;
|
|
|
|
/* Errors */
|
|
overflow:
|
|
return "buffer overflow";
|
|
badtype:
|
|
return "type not supported";
|
|
invalidutf8:
|
|
return "string contains invalid utf-8";
|
|
}
|
|
|
|
static int json_encode(JanetArgs args) {
|
|
JANET_MINARITY(args, 1);
|
|
JANET_MAXARITY(args, 3);
|
|
Encoder e;
|
|
e.indent = 0;
|
|
e.buffer = janet_buffer(10);
|
|
e.tab = NULL;
|
|
e.newline = NULL;
|
|
e.tablen = 0;
|
|
e.newlinelen = 0;
|
|
if (args.n >= 2) {
|
|
JANET_ARG_BYTES(e.tab, e.tablen, args, 1);
|
|
if (args.n >= 3) {
|
|
JANET_ARG_BYTES(e.newline, e.newlinelen, args, 2);
|
|
} else {
|
|
e.newline = (const uint8_t *)"\r\n";
|
|
e.newlinelen = 1;
|
|
}
|
|
}
|
|
const char *err = encode_one(&e, args.v[0], 0);
|
|
if (err) JANET_THROW(args, err);
|
|
JANET_RETURN_BUFFER(args, e.buffer);
|
|
}
|
|
|
|
/****************/
|
|
/* Module Entry */
|
|
/****************/
|
|
|
|
static const JanetReg cfuns[] = {
|
|
{"encode", json_encode},
|
|
{"decode", json_decode},
|
|
{NULL, NULL}
|
|
};
|
|
|
|
JANET_MODULE_ENTRY(JanetArgs args) {
|
|
JanetTable *env = janet_env(args);
|
|
janet_cfuns(env, "json", cfuns);
|
|
return 0;
|
|
}
|