jsmn.h

Go to the documentation of this file.

/*
 * MIT License
 *
 * Copyright (c) 2010 Serge Zaitsev
 *
 * 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.
 */
#ifndef JSMN_H
#define JSMN_H
 
#include <stddef.h>
 
#ifdef __cplusplus
extern "C" {
#endif
 
#ifdef JSMN_STATIC
#define JSMN_API static
#else
#define JSMN_API extern
#endif
 
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
};
 
typedef struct {
    jsmntype_t type;
    int start;
    int end;
    int size;
#ifdef JSMN_PARENT_LINKS
    int parent;
#endif
} jsmntok_t;
 
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;
 
JSMN_API void jsmn_init(jsmn_parser* parser);
 
JSMN_API int jsmn_parse(jsmn_parser* parser, const char* js, const size_t len, jsmntok_t* tokens, const unsigned int num_tokens);
 
#ifndef JSMN_HEADER
static jsmntok_t* jsmn_alloc_token(jsmn_parser* parser, jsmntok_t* tokens, const 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;
}
 
static void jsmn_fill_token(jsmntok_t* token, const jsmntype_t type, const int start, const int end)
{
    token->type = type;
    token->start = start;
    token->end = end;
    token->size = 0;
}
 
static int jsmn_parse_primitive(jsmn_parser* parser, const char* js, const size_t len, jsmntok_t* tokens, const 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;
}
 
static int jsmn_parse_string(jsmn_parser* parser, const char* js, const size_t len, jsmntok_t* tokens, const 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;
}
 
JSMN_API int jsmn_parse(jsmn_parser* parser, const char* js, const size_t len, jsmntok_t* tokens, const 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) {
                    jsmntok_t* t = &tokens[parser->toksuper];
#ifdef JSMN_STRICT
                    /* In strict mode an object or array can't become a key */
                    if (t->type == JSMN_OBJECT) {
                        return JSMN_ERROR_INVAL;
                    }
#endif
                    t->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) {
                    const 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;
}
 
JSMN_API void jsmn_init(jsmn_parser* parser)
{
    parser->pos = 0;
    parser->toknext = 0;
    parser->toksuper = -1;
}
 
#endif /* JSMN_HEADER */
 
#ifdef __cplusplus
}
#endif
 
#endif /* JSMN_H */