--- /dev/null
+/*
+ Copyright (C) 2011 Joseph A. Adams (joeyadams3.14159@gmail.com)
+ All rights reserved.
+
+ Permission is hereby granted, free of charge, to any person obtaining a copy
+ of this software and associated documentation files (the "Software"), to deal
+ in the Software without restriction, including without limitation the rights
+ to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ copies of the Software, and to permit persons to whom the Software is
+ furnished to do so, subject to the following conditions:
+
+ The above copyright notice and this permission notice shall be included in
+ all copies or substantial portions of the Software.
+
+ THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ THE SOFTWARE.
+*/
+
+#include "json.h"
+
+#include <assert.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define out_of_memory() do { \
+ fprintf(stderr, "Out of memory.\n"); \
+ exit(EXIT_FAILURE); \
+ } while (0)
+
+/* Sadly, strdup is not portable. */
+static char *json_strdup(const char *str)
+{
+ char *ret = (char*) malloc(strlen(str) + 1);
+ if (ret == NULL)
+ out_of_memory();
+ strcpy(ret, str);
+ return ret;
+}
+
+/* String buffer */
+
+typedef struct
+{
+ char *cur;
+ char *end;
+ char *start;
+} SB;
+
+static void sb_init(SB *sb)
+{
+ sb->start = (char*) malloc(17);
+ if (sb->start == NULL)
+ out_of_memory();
+ sb->cur = sb->start;
+ sb->end = sb->start + 16;
+}
+
+/* sb and need may be evaluated multiple times. */
+#define sb_need(sb, need) do { \
+ if ((sb)->end - (sb)->cur < (need)) \
+ sb_grow(sb, need); \
+ } while (0)
+
+static void sb_grow(SB *sb, int need)
+{
+ size_t length = sb->cur - sb->start;
+ size_t alloc = sb->end - sb->start;
+
+ do {
+ alloc *= 2;
+ } while (alloc < length + need);
+
+ sb->start = (char*) realloc(sb->start, alloc + 1);
+ if (sb->start == NULL)
+ out_of_memory();
+ sb->cur = sb->start + length;
+ sb->end = sb->start + alloc;
+}
+
+static void sb_put(SB *sb, const char *bytes, int count)
+{
+ sb_need(sb, count);
+ memcpy(sb->cur, bytes, count);
+ sb->cur += count;
+}
+
+#define sb_putc(sb, c) do { \
+ if ((sb)->cur >= (sb)->end) \
+ sb_grow(sb, 1); \
+ *(sb)->cur++ = (c); \
+ } while (0)
+
+static void sb_puts(SB *sb, const char *str)
+{
+ sb_put(sb, str, strlen(str));
+}
+
+static char *sb_finish(SB *sb)
+{
+ *sb->cur = 0;
+ assert(sb->start <= sb->cur && strlen(sb->start) == (size_t)(sb->cur - sb->start));
+ return sb->start;
+}
+
+static void sb_free(SB *sb)
+{
+ free(sb->start);
+}
+
+/*
+ * Unicode helper functions
+ *
+ * These are taken from the ccan/charset module and customized a bit.
+ * Putting them here means the compiler can (choose to) inline them,
+ * and it keeps ccan/json from having a dependency.
+ */
+
+/*
+ * Type for Unicode codepoints.
+ * We need our own because wchar_t might be 16 bits.
+ */
+typedef uint32_t uchar_t;
+
+/*
+ * Validate a single UTF-8 character starting at @s.
+ * The string must be null-terminated.
+ *
+ * If it's valid, return its length (1 thru 4).
+ * If it's invalid or clipped, return 0.
+ *
+ * This function implements the syntax given in RFC3629, which is
+ * the same as that given in The Unicode Standard, Version 6.0.
+ *
+ * It has the following properties:
+ *
+ * * All codepoints U+0000..U+10FFFF may be encoded,
+ * except for U+D800..U+DFFF, which are reserved
+ * for UTF-16 surrogate pair encoding.
+ * * UTF-8 byte sequences longer than 4 bytes are not permitted,
+ * as they exceed the range of Unicode.
+ * * The sixty-six Unicode "non-characters" are permitted
+ * (namely, U+FDD0..U+FDEF, U+xxFFFE, and U+xxFFFF).
+ */
+static int utf8_validate_cz(const char *s)
+{
+ unsigned char c = *s++;
+
+ if (c <= 0x7F) { /* 00..7F */
+ return 1;
+ } else if (c <= 0xC1) { /* 80..C1 */
+ /* Disallow overlong 2-byte sequence. */
+ return 0;
+ } else if (c <= 0xDF) { /* C2..DF */
+ /* Make sure subsequent byte is in the range 0x80..0xBF. */
+ if (((unsigned char)*s++ & 0xC0) != 0x80)
+ return 0;
+
+ return 2;
+ } else if (c <= 0xEF) { /* E0..EF */
+ /* Disallow overlong 3-byte sequence. */
+ if (c == 0xE0 && (unsigned char)*s < 0xA0)
+ return 0;
+
+ /* Disallow U+D800..U+DFFF. */
+ if (c == 0xED && (unsigned char)*s > 0x9F)
+ return 0;
+
+ /* Make sure subsequent bytes are in the range 0x80..0xBF. */
+ if (((unsigned char)*s++ & 0xC0) != 0x80)
+ return 0;
+ if (((unsigned char)*s++ & 0xC0) != 0x80)
+ return 0;
+
+ return 3;
+ } else if (c <= 0xF4) { /* F0..F4 */
+ /* Disallow overlong 4-byte sequence. */
+ if (c == 0xF0 && (unsigned char)*s < 0x90)
+ return 0;
+
+ /* Disallow codepoints beyond U+10FFFF. */
+ if (c == 0xF4 && (unsigned char)*s > 0x8F)
+ return 0;
+
+ /* Make sure subsequent bytes are in the range 0x80..0xBF. */
+ if (((unsigned char)*s++ & 0xC0) != 0x80)
+ return 0;
+ if (((unsigned char)*s++ & 0xC0) != 0x80)
+ return 0;
+ if (((unsigned char)*s++ & 0xC0) != 0x80)
+ return 0;
+
+ return 4;
+ } else { /* F5..FF */
+ return 0;
+ }
+}
+
+/* Validate a null-terminated UTF-8 string. */
+static bool utf8_validate(const char *s)
+{
+ int len;
+
+ for (; *s != 0; s += len) {
+ len = utf8_validate_cz(s);
+ if (len == 0)
+ return false;
+ }
+
+ return true;
+}
+
+/*
+ * Read a single UTF-8 character starting at @s,
+ * returning the length, in bytes, of the character read.
+ *
+ * This function assumes input is valid UTF-8,
+ * and that there are enough characters in front of @s.
+ */
+static int utf8_read_char(const char *s, uchar_t *out)
+{
+ const unsigned char *c = (const unsigned char*) s;
+
+ assert(utf8_validate_cz(s));
+
+ if (c[0] <= 0x7F) {
+ /* 00..7F */
+ *out = c[0];
+ return 1;
+ } else if (c[0] <= 0xDF) {
+ /* C2..DF (unless input is invalid) */
+ *out = ((uchar_t)c[0] & 0x1F) << 6 |
+ ((uchar_t)c[1] & 0x3F);
+ return 2;
+ } else if (c[0] <= 0xEF) {
+ /* E0..EF */
+ *out = ((uchar_t)c[0] & 0xF) << 12 |
+ ((uchar_t)c[1] & 0x3F) << 6 |
+ ((uchar_t)c[2] & 0x3F);
+ return 3;
+ } else {
+ /* F0..F4 (unless input is invalid) */
+ *out = ((uchar_t)c[0] & 0x7) << 18 |
+ ((uchar_t)c[1] & 0x3F) << 12 |
+ ((uchar_t)c[2] & 0x3F) << 6 |
+ ((uchar_t)c[3] & 0x3F);
+ return 4;
+ }
+}
+
+/*
+ * Write a single UTF-8 character to @s,
+ * returning the length, in bytes, of the character written.
+ *
+ * @unicode must be U+0000..U+10FFFF, but not U+D800..U+DFFF.
+ *
+ * This function will write up to 4 bytes to @out.
+ */
+static int utf8_write_char(uchar_t unicode, char *out)
+{
+ unsigned char *o = (unsigned char*) out;
+
+ assert(unicode <= 0x10FFFF && !(unicode >= 0xD800 && unicode <= 0xDFFF));
+
+ if (unicode <= 0x7F) {
+ /* U+0000..U+007F */
+ *o++ = unicode;
+ return 1;
+ } else if (unicode <= 0x7FF) {
+ /* U+0080..U+07FF */
+ *o++ = 0xC0 | unicode >> 6;
+ *o++ = 0x80 | (unicode & 0x3F);
+ return 2;
+ } else if (unicode <= 0xFFFF) {
+ /* U+0800..U+FFFF */
+ *o++ = 0xE0 | unicode >> 12;
+ *o++ = 0x80 | (unicode >> 6 & 0x3F);
+ *o++ = 0x80 | (unicode & 0x3F);
+ return 3;
+ } else {
+ /* U+10000..U+10FFFF */
+ *o++ = 0xF0 | unicode >> 18;
+ *o++ = 0x80 | (unicode >> 12 & 0x3F);
+ *o++ = 0x80 | (unicode >> 6 & 0x3F);
+ *o++ = 0x80 | (unicode & 0x3F);
+ return 4;
+ }
+}
+
+/*
+ * Compute the Unicode codepoint of a UTF-16 surrogate pair.
+ *
+ * @uc should be 0xD800..0xDBFF, and @lc should be 0xDC00..0xDFFF.
+ * If they aren't, this function returns false.
+ */
+static bool from_surrogate_pair(uint16_t uc, uint16_t lc, uchar_t *unicode)
+{
+ if (uc >= 0xD800 && uc <= 0xDBFF && lc >= 0xDC00 && lc <= 0xDFFF) {
+ *unicode = 0x10000 + ((((uchar_t)uc & 0x3FF) << 10) | (lc & 0x3FF));
+ return true;
+ } else {
+ return false;
+ }
+}
+
+/*
+ * Construct a UTF-16 surrogate pair given a Unicode codepoint.
+ *
+ * @unicode must be U+10000..U+10FFFF.
+ */
+static void to_surrogate_pair(uchar_t unicode, uint16_t *uc, uint16_t *lc)
+{
+ uchar_t n;
+
+ assert(unicode >= 0x10000 && unicode <= 0x10FFFF);
+
+ n = unicode - 0x10000;
+ *uc = ((n >> 10) & 0x3FF) | 0xD800;
+ *lc = (n & 0x3FF) | 0xDC00;
+}
+
+#define is_space(c) ((c) == '\t' || (c) == '\n' || (c) == '\r' || (c) == ' ')
+#define is_digit(c) ((c) >= '0' && (c) <= '9')
+
+static bool parse_value (const char **sp, JsonNode **out);
+static bool parse_string (const char **sp, char **out);
+static bool parse_number (const char **sp, double *out);
+static bool parse_array (const char **sp, JsonNode **out);
+static bool parse_object (const char **sp, JsonNode **out);
+static bool parse_hex16 (const char **sp, uint16_t *out);
+
+static bool expect_literal (const char **sp, const char *str);
+static void skip_space (const char **sp);
+
+static void emit_value (SB *out, const JsonNode *node);
+static void emit_value_indented (SB *out, const JsonNode *node, const char *space, int indent_level);
+static void emit_string (SB *out, const char *str);
+static void emit_number (SB *out, double num);
+static void emit_array (SB *out, const JsonNode *array);
+static void emit_array_indented (SB *out, const JsonNode *array, const char *space, int indent_level);
+static void emit_object (SB *out, const JsonNode *object);
+static void emit_object_indented (SB *out, const JsonNode *object, const char *space, int indent_level);
+
+static int write_hex16(char *out, uint16_t val);
+
+static JsonNode *mknode(JsonTag tag);
+static void append_node(JsonNode *parent, JsonNode *child);
+static void prepend_node(JsonNode *parent, JsonNode *child);
+static void append_member(JsonNode *object, char *key, JsonNode *value);
+
+/* Assertion-friendly validity checks */
+static bool tag_is_valid(unsigned int tag);
+static bool number_is_valid(const char *num);
+
+JsonNode *json_decode(const char *json)
+{
+ const char *s = json;
+ JsonNode *ret;
+
+ skip_space(&s);
+ if (!parse_value(&s, &ret))
+ return NULL;
+
+ skip_space(&s);
+ if (*s != 0) {
+ json_delete(ret);
+ return NULL;
+ }
+
+ return ret;
+}
+
+char *json_encode(const JsonNode *node)
+{
+ return json_stringify(node, NULL);
+}
+
+char *json_encode_string(const char *str)
+{
+ SB sb;
+ sb_init(&sb);
+
+ emit_string(&sb, str);
+
+ return sb_finish(&sb);
+}
+
+char *json_stringify(const JsonNode *node, const char *space)
+{
+ SB sb;
+ sb_init(&sb);
+
+ if (space != NULL)
+ emit_value_indented(&sb, node, space, 0);
+ else
+ emit_value(&sb, node);
+
+ return sb_finish(&sb);
+}
+
+void json_delete(JsonNode *node)
+{
+ if (node != NULL) {
+ json_remove_from_parent(node);
+
+ switch (node->tag) {
+ case JSON_STRING:
+ free(node->string_);
+ break;
+ case JSON_ARRAY:
+ case JSON_OBJECT:
+ {
+ JsonNode *child, *next;
+ for (child = node->children.head; child != NULL; child = next) {
+ next = child->next;
+ json_delete(child);
+ }
+ break;
+ }
+ default:;
+ }
+
+ free(node);
+ }
+}
+
+bool json_validate(const char *json)
+{
+ const char *s = json;
+
+ skip_space(&s);
+ if (!parse_value(&s, NULL))
+ return false;
+
+ skip_space(&s);
+ if (*s != 0)
+ return false;
+
+ return true;
+}
+
+JsonNode *json_find_element(JsonNode *array, int index)
+{
+ JsonNode *element;
+ int i = 0;
+
+ if (array == NULL || array->tag != JSON_ARRAY)
+ return NULL;
+
+ json_foreach(element, array) {
+ if (i == index)
+ return element;
+ i++;
+ }
+
+ return NULL;
+}
+
+JsonNode *json_find_member(JsonNode *object, const char *name)
+{
+ JsonNode *member;
+
+ if (object == NULL || object->tag != JSON_OBJECT)
+ return NULL;
+
+ json_foreach(member, object)
+ if (strcmp(member->key, name) == 0)
+ return member;
+
+ return NULL;
+}
+
+JsonNode *json_first_child(const JsonNode *node)
+{
+ if (node != NULL && (node->tag == JSON_ARRAY || node->tag == JSON_OBJECT))
+ return node->children.head;
+ return NULL;
+}
+
+static JsonNode *mknode(JsonTag tag)
+{
+ JsonNode *ret = (JsonNode*) calloc(1, sizeof(JsonNode));
+ if (ret == NULL)
+ out_of_memory();
+ ret->tag = tag;
+ return ret;
+}
+
+JsonNode *json_mknull(void)
+{
+ return mknode(JSON_NULL);
+}
+
+JsonNode *json_mkbool(bool b)
+{
+ JsonNode *ret = mknode(JSON_BOOL);
+ ret->bool_ = b;
+ return ret;
+}
+
+static JsonNode *mkstring(char *s)
+{
+ JsonNode *ret = mknode(JSON_STRING);
+ ret->string_ = s;
+ return ret;
+}
+
+JsonNode *json_mkstring(const char *s)
+{
+ return mkstring(json_strdup(s));
+}
+
+JsonNode *json_mknumber(double n)
+{
+ JsonNode *node = mknode(JSON_NUMBER);
+ node->number_ = n;
+ return node;
+}
+
+JsonNode *json_mkarray(void)
+{
+ return mknode(JSON_ARRAY);
+}
+
+JsonNode *json_mkobject(void)
+{
+ return mknode(JSON_OBJECT);
+}
+
+static void append_node(JsonNode *parent, JsonNode *child)
+{
+ child->parent = parent;
+ child->prev = parent->children.tail;
+ child->next = NULL;
+
+ if (parent->children.tail != NULL)
+ parent->children.tail->next = child;
+ else
+ parent->children.head = child;
+ parent->children.tail = child;
+}
+
+static void prepend_node(JsonNode *parent, JsonNode *child)
+{
+ child->parent = parent;
+ child->prev = NULL;
+ child->next = parent->children.head;
+
+ if (parent->children.head != NULL)
+ parent->children.head->prev = child;
+ else
+ parent->children.tail = child;
+ parent->children.head = child;
+}
+
+static void append_member(JsonNode *object, char *key, JsonNode *value)
+{
+ value->key = key;
+ append_node(object, value);
+}
+
+void json_append_element(JsonNode *array, JsonNode *element)
+{
+ assert(array->tag == JSON_ARRAY);
+ assert(element->parent == NULL);
+
+ append_node(array, element);
+}
+
+void json_prepend_element(JsonNode *array, JsonNode *element)
+{
+ assert(array->tag == JSON_ARRAY);
+ assert(element->parent == NULL);
+
+ prepend_node(array, element);
+}
+
+void json_append_member(JsonNode *object, const char *key, JsonNode *value)
+{
+ assert(object->tag == JSON_OBJECT);
+ assert(value->parent == NULL);
+
+ append_member(object, json_strdup(key), value);
+}
+
+void json_prepend_member(JsonNode *object, const char *key, JsonNode *value)
+{
+ assert(object->tag == JSON_OBJECT);
+ assert(value->parent == NULL);
+
+ value->key = json_strdup(key);
+ prepend_node(object, value);
+}
+
+void json_remove_from_parent(JsonNode *node)
+{
+ JsonNode *parent = node->parent;
+
+ if (parent != NULL) {
+ if (node->prev != NULL)
+ node->prev->next = node->next;
+ else
+ parent->children.head = node->next;
+ if (node->next != NULL)
+ node->next->prev = node->prev;
+ else
+ parent->children.tail = node->prev;
+
+ free(node->key);
+
+ node->parent = NULL;
+ node->prev = node->next = NULL;
+ node->key = NULL;
+ }
+}
+
+static bool parse_value(const char **sp, JsonNode **out)
+{
+ const char *s = *sp;
+
+ switch (*s) {
+ case 'n':
+ if (expect_literal(&s, "null")) {
+ if (out)
+ *out = json_mknull();
+ *sp = s;
+ return true;
+ }
+ return false;
+
+ case 'f':
+ if (expect_literal(&s, "false")) {
+ if (out)
+ *out = json_mkbool(false);
+ *sp = s;
+ return true;
+ }
+ return false;
+
+ case 't':
+ if (expect_literal(&s, "true")) {
+ if (out)
+ *out = json_mkbool(true);
+ *sp = s;
+ return true;
+ }
+ return false;
+
+ case '"': {
+ char *str;
+ if (parse_string(&s, out ? &str : NULL)) {
+ if (out)
+ *out = mkstring(str);
+ *sp = s;
+ return true;
+ }
+ return false;
+ }
+
+ case '[':
+ if (parse_array(&s, out)) {
+ *sp = s;
+ return true;
+ }
+ return false;
+
+ case '{':
+ if (parse_object(&s, out)) {
+ *sp = s;
+ return true;
+ }
+ return false;
+
+ default: {
+ double num;
+ if (parse_number(&s, out ? &num : NULL)) {
+ if (out)
+ *out = json_mknumber(num);
+ *sp = s;
+ return true;
+ }
+ return false;
+ }
+ }
+}
+
+static bool parse_array(const char **sp, JsonNode **out)
+{
+ const char *s = *sp;
+ JsonNode *ret = out ? json_mkarray() : NULL;
+ JsonNode *element;
+
+ if (*s++ != '[')
+ goto failure;
+ skip_space(&s);
+
+ if (*s == ']') {
+ s++;
+ goto success;
+ }
+
+ for (;;) {
+ if (!parse_value(&s, out ? &element : NULL))
+ goto failure;
+ skip_space(&s);
+
+ if (out)
+ json_append_element(ret, element);
+
+ if (*s == ']') {
+ s++;
+ goto success;
+ }
+
+ if (*s++ != ',')
+ goto failure;
+ skip_space(&s);
+ }
+
+success:
+ *sp = s;
+ if (out)
+ *out = ret;
+ return true;
+
+failure:
+ json_delete(ret);
+ return false;
+}
+
+static bool parse_object(const char **sp, JsonNode **out)
+{
+ const char *s = *sp;
+ JsonNode *ret = out ? json_mkobject() : NULL;
+ char *key;
+ JsonNode *value;
+
+ if (*s++ != '{')
+ goto failure;
+ skip_space(&s);
+
+ if (*s == '}') {
+ s++;
+ goto success;
+ }
+
+ for (;;) {
+ if (!parse_string(&s, out ? &key : NULL))
+ goto failure;
+ skip_space(&s);
+
+ if (*s++ != ':')
+ goto failure_free_key;
+ skip_space(&s);
+
+ if (!parse_value(&s, out ? &value : NULL))
+ goto failure_free_key;
+ skip_space(&s);
+
+ if (out)
+ append_member(ret, key, value);
+
+ if (*s == '}') {
+ s++;
+ goto success;
+ }
+
+ if (*s++ != ',')
+ goto failure;
+ skip_space(&s);
+ }
+
+success:
+ *sp = s;
+ if (out)
+ *out = ret;
+ return true;
+
+failure_free_key:
+ if (out)
+ free(key);
+failure:
+ json_delete(ret);
+ return false;
+}
+
+bool parse_string(const char **sp, char **out)
+{
+ const char *s = *sp;
+ SB sb;
+ char throwaway_buffer[4];
+ /* enough space for a UTF-8 character */
+ char *b;
+
+ if (*s++ != '"')
+ return false;
+
+ if (out) {
+ sb_init(&sb);
+ sb_need(&sb, 4);
+ b = sb.cur;
+ } else {
+ b = throwaway_buffer;
+ }
+
+ while (*s != '"') {
+ unsigned char c = *s++;
+
+ /* Parse next character, and write it to b. */
+ 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':
+ {
+ uint16_t uc, lc;
+ uchar_t unicode;
+
+ if (!parse_hex16(&s, &uc))
+ goto failed;
+
+ if (uc >= 0xD800 && uc <= 0xDFFF) {
+ /* Handle UTF-16 surrogate pair. */
+ if (*s++ != '\\' || *s++ != 'u' || !parse_hex16(&s, &lc))
+ goto failed; /* Incomplete surrogate pair. */
+ if (!from_surrogate_pair(uc, lc, &unicode))
+ goto failed; /* Invalid surrogate pair. */
+ } else if (uc == 0) {
+ /* Disallow "\u0000". */
+ goto failed;
+ } else {
+ unicode = uc;
+ }
+
+ b += utf8_write_char(unicode, b);
+ break;
+ }
+ default:
+ /* Invalid escape */
+ goto failed;
+ }
+ } else if (c <= 0x1F) {
+ /* Control characters are not allowed in string literals. */
+ goto failed;
+ } else {
+ /* Validate and echo a UTF-8 character. */
+ int len;
+
+ s--;
+ len = utf8_validate_cz(s);
+ if (len == 0)
+ goto failed; /* Invalid UTF-8 character. */
+
+ while (len--)
+ *b++ = *s++;
+ }
+
+ /*
+ * Update sb to know about the new bytes,
+ * and set up b to write another character.
+ */
+ if (out) {
+ sb.cur = b;
+ sb_need(&sb, 4);
+ b = sb.cur;
+ } else {
+ b = throwaway_buffer;
+ }
+ }
+ s++;
+
+ if (out)
+ *out = sb_finish(&sb);
+ *sp = s;
+ return true;
+
+failed:
+ if (out)
+ sb_free(&sb);
+ return false;
+}
+
+/*
+ * The JSON spec says that a number shall follow this precise pattern
+ * (spaces and quotes added for readability):
+ * '-'? (0 | [1-9][0-9]*) ('.' [0-9]+)? ([Ee] [+-]? [0-9]+)?
+ *
+ * However, some JSON parsers are more liberal. For instance, PHP accepts
+ * '.5' and '1.'. JSON.parse accepts '+3'.
+ *
+ * This function takes the strict approach.
+ */
+bool parse_number(const char **sp, double *out)
+{
+ const char *s = *sp;
+
+ /* '-'? */
+ if (*s == '-')
+ s++;
+
+ /* (0 | [1-9][0-9]*) */
+ if (*s == '0') {
+ s++;
+ } else {
+ if (!is_digit(*s))
+ return false;
+ do {
+ s++;
+ } while (is_digit(*s));
+ }
+
+ /* ('.' [0-9]+)? */
+ if (*s == '.') {
+ s++;
+ if (!is_digit(*s))
+ return false;
+ do {
+ s++;
+ } while (is_digit(*s));
+ }
+
+ /* ([Ee] [+-]? [0-9]+)? */
+ if (*s == 'E' || *s == 'e') {
+ s++;
+ if (*s == '+' || *s == '-')
+ s++;
+ if (!is_digit(*s))
+ return false;
+ do {
+ s++;
+ } while (is_digit(*s));
+ }
+
+ if (out)
+ *out = strtod(*sp, NULL);
+
+ *sp = s;
+ return true;
+}
+
+static void skip_space(const char **sp)
+{
+ const char *s = *sp;
+ while (is_space(*s))
+ s++;
+ *sp = s;
+}
+
+static void emit_value(SB *out, const JsonNode *node)
+{
+ assert(tag_is_valid(node->tag));
+ switch (node->tag) {
+ case JSON_NULL:
+ sb_puts(out, "null");
+ break;
+ case JSON_BOOL:
+ sb_puts(out, node->bool_ ? "true" : "false");
+ break;
+ case JSON_STRING:
+ emit_string(out, node->string_);
+ break;
+ case JSON_NUMBER:
+ emit_number(out, node->number_);
+ break;
+ case JSON_ARRAY:
+ emit_array(out, node);
+ break;
+ case JSON_OBJECT:
+ emit_object(out, node);
+ break;
+ default:
+ assert(false);
+ }
+}
+
+void emit_value_indented(SB *out, const JsonNode *node, const char *space, int indent_level)
+{
+ assert(tag_is_valid(node->tag));
+ switch (node->tag) {
+ case JSON_NULL:
+ sb_puts(out, "null");
+ break;
+ case JSON_BOOL:
+ sb_puts(out, node->bool_ ? "true" : "false");
+ break;
+ case JSON_STRING:
+ emit_string(out, node->string_);
+ break;
+ case JSON_NUMBER:
+ emit_number(out, node->number_);
+ break;
+ case JSON_ARRAY:
+ emit_array_indented(out, node, space, indent_level);
+ break;
+ case JSON_OBJECT:
+ emit_object_indented(out, node, space, indent_level);
+ break;
+ default:
+ assert(false);
+ }
+}
+
+static void emit_array(SB *out, const JsonNode *array)
+{
+ const JsonNode *element;
+
+ sb_putc(out, '[');
+ json_foreach(element, array) {
+ emit_value(out, element);
+ if (element->next != NULL)
+ sb_putc(out, ',');
+ }
+ sb_putc(out, ']');
+}
+
+static void emit_array_indented(SB *out, const JsonNode *array, const char *space, int indent_level)
+{
+ const JsonNode *element = array->children.head;
+ int i;
+
+ if (element == NULL) {
+ sb_puts(out, "[]");
+ return;
+ }
+
+ sb_puts(out, "[\n");
+ while (element != NULL) {
+ for (i = 0; i < indent_level + 1; i++)
+ sb_puts(out, space);
+ emit_value_indented(out, element, space, indent_level + 1);
+
+ element = element->next;
+ sb_puts(out, element != NULL ? ",\n" : "\n");
+ }
+ for (i = 0; i < indent_level; i++)
+ sb_puts(out, space);
+ sb_putc(out, ']');
+}
+
+static void emit_object(SB *out, const JsonNode *object)
+{
+ const JsonNode *member;
+
+ sb_putc(out, '{');
+ json_foreach(member, object) {
+ emit_string(out, member->key);
+ sb_putc(out, ':');
+ emit_value(out, member);
+ if (member->next != NULL)
+ sb_putc(out, ',');
+ }
+ sb_putc(out, '}');
+}
+
+static void emit_object_indented(SB *out, const JsonNode *object, const char *space, int indent_level)
+{
+ const JsonNode *member = object->children.head;
+ int i;
+
+ if (member == NULL) {
+ sb_puts(out, "{}");
+ return;
+ }
+
+ sb_puts(out, "{\n");
+ while (member != NULL) {
+ for (i = 0; i < indent_level + 1; i++)
+ sb_puts(out, space);
+ emit_string(out, member->key);
+ sb_puts(out, ": ");
+ emit_value_indented(out, member, space, indent_level + 1);
+
+ member = member->next;
+ sb_puts(out, member != NULL ? ",\n" : "\n");
+ }
+ for (i = 0; i < indent_level; i++)
+ sb_puts(out, space);
+ sb_putc(out, '}');
+}
+
+void emit_string(SB *out, const char *str)
+{
+ bool escape_unicode = false;
+ const char *s = str;
+ char *b;
+
+ assert(utf8_validate(str));
+
+ /*
+ * 14 bytes is enough space to write up to two
+ * \uXXXX escapes and two quotation marks.
+ */
+ sb_need(out, 14);
+ b = out->cur;
+
+ *b++ = '"';
+ while (*s != 0) {
+ unsigned char c = *s++;
+
+ /* Encode the next character, and write it to b. */
+ switch (c) {
+ case '"':
+ *b++ = '\\';
+ *b++ = '"';
+ break;
+ case '\\':
+ *b++ = '\\';
+ *b++ = '\\';
+ break;
+ case '\b':
+ *b++ = '\\';
+ *b++ = 'b';
+ break;
+ case '\f':
+ *b++ = '\\';
+ *b++ = 'f';
+ break;
+ case '\n':
+ *b++ = '\\';
+ *b++ = 'n';
+ break;
+ case '\r':
+ *b++ = '\\';
+ *b++ = 'r';
+ break;
+ case '\t':
+ *b++ = '\\';
+ *b++ = 't';
+ break;
+ default: {
+ int len;
+
+ s--;
+ len = utf8_validate_cz(s);
+
+ if (len == 0) {
+ /*
+ * Handle invalid UTF-8 character gracefully in production
+ * by writing a replacement character (U+FFFD)
+ * and skipping a single byte.
+ *
+ * This should never happen when assertions are enabled
+ * due to the assertion at the beginning of this function.
+ */
+ assert(false);
+ if (escape_unicode) {
+ strcpy(b, "\\uFFFD");
+ b += 6;
+ } else {
+ *b++ = 0xEF;
+ *b++ = 0xBF;
+ *b++ = 0xBD;
+ }
+ s++;
+ } else if (c < 0x1F || (c >= 0x80 && escape_unicode)) {
+ /* Encode using \u.... */
+ uint32_t unicode;
+
+ s += utf8_read_char(s, &unicode);
+
+ if (unicode <= 0xFFFF) {
+ *b++ = '\\';
+ *b++ = 'u';
+ b += write_hex16(b, unicode);
+ } else {
+ /* Produce a surrogate pair. */
+ uint16_t uc, lc;
+ assert(unicode <= 0x10FFFF);
+ to_surrogate_pair(unicode, &uc, &lc);
+ *b++ = '\\';
+ *b++ = 'u';
+ b += write_hex16(b, uc);
+ *b++ = '\\';
+ *b++ = 'u';
+ b += write_hex16(b, lc);
+ }
+ } else {
+ /* Write the character directly. */
+ while (len--)
+ *b++ = *s++;
+ }
+
+ break;
+ }
+ }
+
+ /*
+ * Update *out to know about the new bytes,
+ * and set up b to write another encoded character.
+ */
+ out->cur = b;
+ sb_need(out, 14);
+ b = out->cur;
+ }
+ *b++ = '"';
+
+ out->cur = b;
+}
+
+static void emit_number(SB *out, double num)
+{
+ /*
+ * This isn't exactly how JavaScript renders numbers,
+ * but it should produce valid JSON for reasonable numbers
+ * preserve precision well enough, and avoid some oddities
+ * like 0.3 -> 0.299999999999999988898 .
+ */
+ char buf[64];
+ sprintf(buf, "%.16g", num);
+
+ if (number_is_valid(buf))
+ sb_puts(out, buf);
+ else
+ sb_puts(out, "null");
+}
+
+static bool tag_is_valid(unsigned int tag)
+{
+ return (/* tag >= JSON_NULL && */ tag <= JSON_OBJECT);
+}
+
+static bool number_is_valid(const char *num)
+{
+ return (parse_number(&num, NULL) && *num == '\0');
+}
+
+static bool expect_literal(const char **sp, const char *str)
+{
+ const char *s = *sp;
+
+ while (*str != '\0')
+ if (*s++ != *str++)
+ return false;
+
+ *sp = s;
+ return true;
+}
+
+/*
+ * Parses exactly 4 hex characters (capital or lowercase).
+ * Fails if any input chars are not [0-9A-Fa-f].
+ */
+static bool parse_hex16(const char **sp, uint16_t *out)
+{
+ const char *s = *sp;
+ uint16_t ret = 0;
+ uint16_t i;
+ uint16_t 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;
+ }
+
+ if (out)
+ *out = ret;
+ *sp = s;
+ return true;
+}
+
+/*
+ * Encodes a 16-bit number into hexadecimal,
+ * writing exactly 4 hex chars.
+ */
+static int write_hex16(char *out, uint16_t val)
+{
+ const char *hex = "0123456789ABCDEF";
+
+ *out++ = hex[(val >> 12) & 0xF];
+ *out++ = hex[(val >> 8) & 0xF];
+ *out++ = hex[(val >> 4) & 0xF];
+ *out++ = hex[ val & 0xF];
+
+ return 4;
+}
+
+bool json_check(const JsonNode *node, char errmsg[256])
+{
+ #define problem(...) do { \
+ if (errmsg != NULL) \
+ snprintf(errmsg, 256, __VA_ARGS__); \
+ return false; \
+ } while (0)
+
+ if (node->key != NULL && !utf8_validate(node->key))
+ problem("key contains invalid UTF-8");
+
+ if (!tag_is_valid(node->tag))
+ problem("tag is invalid (%u)", node->tag);
+
+ if (node->tag == JSON_BOOL) {
+ if (node->bool_ != false && node->bool_ != true)
+ problem("bool_ is neither false (%d) nor true (%d)", (int)false, (int)true);
+ } else if (node->tag == JSON_STRING) {
+ if (node->string_ == NULL)
+ problem("string_ is NULL");
+ if (!utf8_validate(node->string_))
+ problem("string_ contains invalid UTF-8");
+ } else if (node->tag == JSON_ARRAY || node->tag == JSON_OBJECT) {
+ JsonNode *head = node->children.head;
+ JsonNode *tail = node->children.tail;
+
+ if (head == NULL || tail == NULL) {
+ if (head != NULL)
+ problem("tail is NULL, but head is not");
+ if (tail != NULL)
+ problem("head is NULL, but tail is not");
+ } else {
+ JsonNode *child;
+ JsonNode *last = NULL;
+
+ if (head->prev != NULL)
+ problem("First child's prev pointer is not NULL");
+
+ for (child = head; child != NULL; last = child, child = child->next) {
+ if (child == node)
+ problem("node is its own child");
+ if (child->next == child)
+ problem("child->next == child (cycle)");
+ if (child->next == head)
+ problem("child->next == head (cycle)");
+
+ if (child->parent != node)
+ problem("child does not point back to parent");
+ if (child->next != NULL && child->next->prev != child)
+ problem("child->next does not point back to child");
+
+ if (node->tag == JSON_ARRAY && child->key != NULL)
+ problem("Array element's key is not NULL");
+ if (node->tag == JSON_OBJECT && child->key == NULL)
+ problem("Object member's key is NULL");
+
+ if (!json_check(child, errmsg))
+ return false;
+ }
+
+ if (last != tail)
+ problem("tail does not match pointer found by starting at head and following next links");
+ }
+ }
+
+ return true;
+
+ #undef problem
+}
projects / ccan / blobdiff