summaryrefslogtreecommitdiff
path: root/strfunc.c
blob: 5929aae5e4d0a528370310a8b9847162458ad3f2 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
/*
 * strfunc.c
 *
 * String transformation functions
 */

#include "nasmlib.h"
#include "nasm.h"

/*
 * Convert a string in UTF-8 format to UTF-16LE
 */
static size_t utf8_to_16le(uint8_t *str, size_t len, char *op)
{
#define EMIT(x) do { if (op) { WRITESHORT(op,x); } outlen++; } while(0)

    size_t outlen = 0;
    int expect = 0;
    uint8_t c;
    uint32_t v = 0, vmin = 0;

    while (len--) {
	c = *str++;

	if (expect) {
	    if ((c & 0xc0) != 0x80) {
		expect = 0;
		return -1;
	    } else {
		v = (v << 6) | (c & 0x3f);
		if (!--expect) {
		    if (v < vmin || v > 0x10ffff ||
			(v >= 0xd800 && v <= 0xdfff)) {
			return -1;
		    } else if (v > 0xffff) {
			v -= 0x10000;
			EMIT(0xd800 | (v >> 10));
			EMIT(0xdc00 | (v & 0x3ff));
		    } else {
			EMIT(v);
		    }
		}
		continue;
	    }
	}

	if (c < 0x80) {
	    EMIT(c);
	} else if (c < 0xc0 || c >= 0xfe) {
	    /* Invalid UTF-8 */
	    return -1;
	} else if (c < 0xe0) {
	    v = c & 0x1f;
	    expect = 1;
	    vmin = 0x80;
	} else if (c < 0xf0) {
	    v = c & 0x0f;
	    expect = 2;
	    vmin = 0x800;
	} else if (c < 0xf8) {
	    v = c & 0x07;
	    expect = 3;
	    vmin = 0x10000;
	} else if (c < 0xfc) {
	    v = c & 0x03;
	    expect = 4;
	    vmin = 0x200000;
	} else {
	    v = c & 0x01;
	    expect = 5;
	    vmin = 0x4000000;
	}
    }

    return expect ? (size_t)-1 : outlen << 1;

#undef EMIT
}

/*
 * Convert a string in UTF-8 format to UTF-32LE
 */
static size_t utf8_to_32le(uint8_t *str, size_t len, char *op)
{
#define EMIT(x) do { if (op) { WRITELONG(op,x); } outlen++; } while(0)

    size_t outlen = 0;
    int expect = 0;
    uint8_t c;
    uint32_t v = 0, vmin = 0;

    while (len--) {
	c = *str++;

	if (expect) {
	    if ((c & 0xc0) != 0x80) {
		return -1;
	    } else {
		v = (v << 6) | (c & 0x3f);
		if (!--expect) {
		    if (v < vmin || (v >= 0xd800 && v <= 0xdfff)) {
			return -1;
		    } else {
			EMIT(v);
		    }
		}
		continue;
	    }
	}

	if (c < 0x80) {
	    EMIT(c);
	} else if (c < 0xc0 || c >= 0xfe) {
	    /* Invalid UTF-8 */
	    return -1;
	} else if (c < 0xe0) {
	    v = c & 0x1f;
	    expect = 1;
	    vmin = 0x80;
	} else if (c < 0xf0) {
	    v = c & 0x0f;
	    expect = 2;
	    vmin = 0x800;
	} else if (c < 0xf8) {
	    v = c & 0x07;
	    expect = 3;
	    vmin = 0x10000;
	} else if (c < 0xfc) {
	    v = c & 0x03;
	    expect = 4;
	    vmin = 0x200000;
	} else {
	    v = c & 0x01;
	    expect = 5;
	    vmin = 0x4000000;
	}
    }

    return expect ? (size_t)-1 : outlen << 2;

#undef EMIT
}

typedef size_t (*transform_func)(uint8_t *, size_t, char *);

/*
 * Apply a specific string transform and return it in a nasm_malloc'd
 * buffer, returning the length.  On error, returns (size_t)-1 and no
 * buffer is allocated.
 */
size_t string_transform(char *str, size_t len, char **out, enum strfunc func)
{
    /* This should match enum strfunc in nasm.h */
    static const transform_func str_transforms[] = {
	utf8_to_16le,
	utf8_to_32le,
    };
    transform_func transform = str_transforms[func];
    size_t outlen;
    uint8_t *s = (uint8_t *)str;
    char *buf;

    outlen = transform(s, len, NULL);
    if (outlen == (size_t)-1)
	return -1;

    *out = buf = nasm_malloc(outlen+1);
    buf[outlen] = '\0';		/* Forcibly null-terminate the buffer */
    return transform(s, len, buf);
}