https://github.com/zserge/jsmn

Files at this revision

API Documentation at this revision

Comitter:
dvddnr
Date:
Wed Jan 24 11:03:28 2018 +0000
Commit message:
first release

Changed in this revision

jsmn.c Show annotated file Show diff for this revision Revisions of this file
jsmn.h Show annotated file Show diff for this revision Revisions of this file
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jsmn.c	Wed Jan 24 11:03:28 2018 +0000
@@ -0,0 +1,314 @@
+#include "jsmn.h"
+
+/**
+ * Allocates a fresh unused token from the token pull.
+ */
+static jsmntok_t *jsmn_alloc_token(jsmn_parser *parser,
+		jsmntok_t *tokens, size_t num_tokens) {
+	jsmntok_t *tok;
+	if (parser->toknext >= num_tokens) {
+		return NULL;
+	}
+	tok = &tokens[parser->toknext++];
+	tok->start = tok->end = -1;
+	tok->size = 0;
+#ifdef JSMN_PARENT_LINKS
+	tok->parent = -1;
+#endif
+	return tok;
+}
+
+/**
+ * Fills token type and boundaries.
+ */
+static void jsmn_fill_token(jsmntok_t *token, jsmntype_t type,
+                            int start, int end) {
+	token->type = type;
+	token->start = start;
+	token->end = end;
+	token->size = 0;
+}
+
+/**
+ * Fills next available token with JSON primitive.
+ */
+static int jsmn_parse_primitive(jsmn_parser *parser, const char *js,
+		size_t len, jsmntok_t *tokens, size_t num_tokens) {
+	jsmntok_t *token;
+	int start;
+
+	start = parser->pos;
+
+	for (; parser->pos < len && js[parser->pos] != '\0'; parser->pos++) {
+		switch (js[parser->pos]) {
+#ifndef JSMN_STRICT
+			/* In strict mode primitive must be followed by "," or "}" or "]" */
+			case ':':
+#endif
+			case '\t' : case '\r' : case '\n' : case ' ' :
+			case ','  : case ']'  : case '}' :
+				goto found;
+		}
+		if (js[parser->pos] < 32 || js[parser->pos] >= 127) {
+			parser->pos = start;
+			return JSMN_ERROR_INVAL;
+		}
+	}
+#ifdef JSMN_STRICT
+	/* In strict mode primitive must be followed by a comma/object/array */
+	parser->pos = start;
+	return JSMN_ERROR_PART;
+#endif
+
+found:
+	if (tokens == NULL) {
+		parser->pos--;
+		return 0;
+	}
+	token = jsmn_alloc_token(parser, tokens, num_tokens);
+	if (token == NULL) {
+		parser->pos = start;
+		return JSMN_ERROR_NOMEM;
+	}
+	jsmn_fill_token(token, JSMN_PRIMITIVE, start, parser->pos);
+#ifdef JSMN_PARENT_LINKS
+	token->parent = parser->toksuper;
+#endif
+	parser->pos--;
+	return 0;
+}
+
+/**
+ * Fills next token with JSON string.
+ */
+static int jsmn_parse_string(jsmn_parser *parser, const char *js,
+		size_t len, jsmntok_t *tokens, size_t num_tokens) {
+	jsmntok_t *token;
+
+	int start = parser->pos;
+
+	parser->pos++;
+
+	/* Skip starting quote */
+	for (; parser->pos < len && js[parser->pos] != '\0'; parser->pos++) {
+		char c = js[parser->pos];
+
+		/* Quote: end of string */
+		if (c == '\"') {
+			if (tokens == NULL) {
+				return 0;
+			}
+			token = jsmn_alloc_token(parser, tokens, num_tokens);
+			if (token == NULL) {
+				parser->pos = start;
+				return JSMN_ERROR_NOMEM;
+			}
+			jsmn_fill_token(token, JSMN_STRING, start+1, parser->pos);
+#ifdef JSMN_PARENT_LINKS
+			token->parent = parser->toksuper;
+#endif
+			return 0;
+		}
+
+		/* Backslash: Quoted symbol expected */
+		if (c == '\\' && parser->pos + 1 < len) {
+			int i;
+			parser->pos++;
+			switch (js[parser->pos]) {
+				/* Allowed escaped symbols */
+				case '\"': case '/' : case '\\' : case 'b' :
+				case 'f' : case 'r' : case 'n'  : case 't' :
+					break;
+				/* Allows escaped symbol \uXXXX */
+				case 'u':
+					parser->pos++;
+					for(i = 0; i < 4 && parser->pos < len && js[parser->pos] != '\0'; i++) {
+						/* If it isn't a hex character we have an error */
+						if(!((js[parser->pos] >= 48 && js[parser->pos] <= 57) || /* 0-9 */
+									(js[parser->pos] >= 65 && js[parser->pos] <= 70) || /* A-F */
+									(js[parser->pos] >= 97 && js[parser->pos] <= 102))) { /* a-f */
+							parser->pos = start;
+							return JSMN_ERROR_INVAL;
+						}
+						parser->pos++;
+					}
+					parser->pos--;
+					break;
+				/* Unexpected symbol */
+				default:
+					parser->pos = start;
+					return JSMN_ERROR_INVAL;
+			}
+		}
+	}
+	parser->pos = start;
+	return JSMN_ERROR_PART;
+}
+
+/**
+ * Parse JSON string and fill tokens.
+ */
+int jsmn_parse(jsmn_parser *parser, const char *js, size_t len,
+		jsmntok_t *tokens, unsigned int num_tokens) {
+	int r;
+	int i;
+	jsmntok_t *token;
+	int count = parser->toknext;
+
+	for (; parser->pos < len && js[parser->pos] != '\0'; parser->pos++) {
+		char c;
+		jsmntype_t type;
+
+		c = js[parser->pos];
+		switch (c) {
+			case '{': case '[':
+				count++;
+				if (tokens == NULL) {
+					break;
+				}
+				token = jsmn_alloc_token(parser, tokens, num_tokens);
+				if (token == NULL)
+					return JSMN_ERROR_NOMEM;
+				if (parser->toksuper != -1) {
+					tokens[parser->toksuper].size++;
+#ifdef JSMN_PARENT_LINKS
+					token->parent = parser->toksuper;
+#endif
+				}
+				token->type = (c == '{' ? JSMN_OBJECT : JSMN_ARRAY);
+				token->start = parser->pos;
+				parser->toksuper = parser->toknext - 1;
+				break;
+			case '}': case ']':
+				if (tokens == NULL)
+					break;
+				type = (c == '}' ? JSMN_OBJECT : JSMN_ARRAY);
+#ifdef JSMN_PARENT_LINKS
+				if (parser->toknext < 1) {
+					return JSMN_ERROR_INVAL;
+				}
+				token = &tokens[parser->toknext - 1];
+				for (;;) {
+					if (token->start != -1 && token->end == -1) {
+						if (token->type != type) {
+							return JSMN_ERROR_INVAL;
+						}
+						token->end = parser->pos + 1;
+						parser->toksuper = token->parent;
+						break;
+					}
+					if (token->parent == -1) {
+						if(token->type != type || parser->toksuper == -1) {
+							return JSMN_ERROR_INVAL;
+						}
+						break;
+					}
+					token = &tokens[token->parent];
+				}
+#else
+				for (i = parser->toknext - 1; i >= 0; i--) {
+					token = &tokens[i];
+					if (token->start != -1 && token->end == -1) {
+						if (token->type != type) {
+							return JSMN_ERROR_INVAL;
+						}
+						parser->toksuper = -1;
+						token->end = parser->pos + 1;
+						break;
+					}
+				}
+				/* Error if unmatched closing bracket */
+				if (i == -1) return JSMN_ERROR_INVAL;
+				for (; i >= 0; i--) {
+					token = &tokens[i];
+					if (token->start != -1 && token->end == -1) {
+						parser->toksuper = i;
+						break;
+					}
+				}
+#endif
+				break;
+			case '\"':
+				r = jsmn_parse_string(parser, js, len, tokens, num_tokens);
+				if (r < 0) return r;
+				count++;
+				if (parser->toksuper != -1 && tokens != NULL)
+					tokens[parser->toksuper].size++;
+				break;
+			case '\t' : case '\r' : case '\n' : case ' ':
+				break;
+			case ':':
+				parser->toksuper = parser->toknext - 1;
+				break;
+			case ',':
+				if (tokens != NULL && parser->toksuper != -1 &&
+						tokens[parser->toksuper].type != JSMN_ARRAY &&
+						tokens[parser->toksuper].type != JSMN_OBJECT) {
+#ifdef JSMN_PARENT_LINKS
+					parser->toksuper = tokens[parser->toksuper].parent;
+#else
+					for (i = parser->toknext - 1; i >= 0; i--) {
+						if (tokens[i].type == JSMN_ARRAY || tokens[i].type == JSMN_OBJECT) {
+							if (tokens[i].start != -1 && tokens[i].end == -1) {
+								parser->toksuper = i;
+								break;
+							}
+						}
+					}
+#endif
+				}
+				break;
+#ifdef JSMN_STRICT
+			/* In strict mode primitives are: numbers and booleans */
+			case '-': case '0': case '1' : case '2': case '3' : case '4':
+			case '5': case '6': case '7' : case '8': case '9':
+			case 't': case 'f': case 'n' :
+				/* And they must not be keys of the object */
+				if (tokens != NULL && parser->toksuper != -1) {
+					jsmntok_t *t = &tokens[parser->toksuper];
+					if (t->type == JSMN_OBJECT ||
+							(t->type == JSMN_STRING && t->size != 0)) {
+						return JSMN_ERROR_INVAL;
+					}
+				}
+#else
+			/* In non-strict mode every unquoted value is a primitive */
+			default:
+#endif
+				r = jsmn_parse_primitive(parser, js, len, tokens, num_tokens);
+				if (r < 0) return r;
+				count++;
+				if (parser->toksuper != -1 && tokens != NULL)
+					tokens[parser->toksuper].size++;
+				break;
+
+#ifdef JSMN_STRICT
+			/* Unexpected char in strict mode */
+			default:
+				return JSMN_ERROR_INVAL;
+#endif
+		}
+	}
+
+	if (tokens != NULL) {
+		for (i = parser->toknext - 1; i >= 0; i--) {
+			/* Unmatched opened object or array */
+			if (tokens[i].start != -1 && tokens[i].end == -1) {
+				return JSMN_ERROR_PART;
+			}
+		}
+	}
+
+	return count;
+}
+
+/**
+ * Creates a new parser based over a given  buffer with an array of tokens
+ * available.
+ */
+void jsmn_init(jsmn_parser *parser) {
+	parser->pos = 0;
+	parser->toknext = 0;
+	parser->toksuper = -1;
+}
+
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jsmn.h	Wed Jan 24 11:03:28 2018 +0000
@@ -0,0 +1,76 @@
+#ifndef __JSMN_H_
+#define __JSMN_H_
+
+#include <stddef.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * JSON type identifier. Basic types are:
+ * 	o Object
+ * 	o Array
+ * 	o String
+ * 	o Other primitive: number, boolean (true/false) or null
+ */
+typedef enum {
+	JSMN_UNDEFINED = 0,
+	JSMN_OBJECT = 1,
+	JSMN_ARRAY = 2,
+	JSMN_STRING = 3,
+	JSMN_PRIMITIVE = 4
+} jsmntype_t;
+
+enum jsmnerr {
+	/* Not enough tokens were provided */
+	JSMN_ERROR_NOMEM = -1,
+	/* Invalid character inside JSON string */
+	JSMN_ERROR_INVAL = -2,
+	/* The string is not a full JSON packet, more bytes expected */
+	JSMN_ERROR_PART = -3
+};
+
+/**
+ * JSON token description.
+ * type		type (object, array, string etc.)
+ * start	start position in JSON data string
+ * end		end position in JSON data string
+ */
+typedef struct {
+	jsmntype_t type;
+	int start;
+	int end;
+	int size;
+#ifdef JSMN_PARENT_LINKS
+	int parent;
+#endif
+} jsmntok_t;
+
+/**
+ * JSON parser. Contains an array of token blocks available. Also stores
+ * the string being parsed now and current position in that string
+ */
+typedef struct {
+	unsigned int pos; /* offset in the JSON string */
+	unsigned int toknext; /* next token to allocate */
+	int toksuper; /* superior token node, e.g parent object or array */
+} jsmn_parser;
+
+/**
+ * Create JSON parser over an array of tokens
+ */
+void jsmn_init(jsmn_parser *parser);
+
+/**
+ * Run JSON parser. It parses a JSON data string into and array of tokens, each describing
+ * a single JSON object.
+ */
+int jsmn_parse(jsmn_parser *parser, const char *js, size_t len,
+		jsmntok_t *tokens, unsigned int num_tokens);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __JSMN_H_ */