/src/lighttpd1.4/src/base64.c

Source (jump to first uncovered line)
#include "first.h"

#include "base64.h"

/* reverse mapping:
 * >= 0: base64 value
 * -1: invalid character
 * -2: skip character (whitespace/control)
 * -3: padding
 */

/* BASE64_STANDARD: "A-Z a-z 0-9 + /" maps to 0-63, pad with "=" */
static const char base64_standard_table[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
static const signed char base64_standard_reverse_table[] = {
/*   0   1   2   3   4   5   6   7   8   9   A   B   C   D   E   F */
  -1, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, /* 0x00 - 0x0F */
  -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, /* 0x10 - 0x1F */
  -2, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63, /* 0x20 - 0x2F */
  52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -3, -1, -1, /* 0x30 - 0x3F */
  -1,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14, /* 0x40 - 0x4F */
  15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1, /* 0x50 - 0x5F */
  -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, /* 0x60 - 0x6F */
  41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1, /* 0x70 - 0x7F */
};

/* BASE64_URL: "A-Z a-z 0-9 - _" maps to 0-63, pad with "=" */
static const char base64_url_table[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_=";
static const signed char base64_url_reverse_table[] = {
/*   0   1   2   3   4   5   6   7   8   9   A   B   C   D   E   F */
  -1, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, /* 0x00 - 0x0F */
  -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, /* 0x10 - 0x1F */
  -2, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, /* 0x20 - 0x2F */
  52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -3, -1, -1, /* 0x30 - 0x3F */
  -1,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14, /* 0x40 - 0x4F */
  15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, 63, /* 0x50 - 0x5F */
  -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, /* 0x60 - 0x6F */
  41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1, /* 0x70 - 0x7F */
};

size_t li_base64_dec(unsigned char * const result, const size_t out_length, const char * const in, const size_t in_length, const base64_charset charset) {
    const unsigned char *un = (const unsigned char *)in;
    const unsigned char * const end = un + in_length;
    const signed char * const base64_reverse_table = (charset)
      ? base64_url_reverse_table                     /* BASE64_URL */
      : base64_standard_reverse_table;               /* BASE64_STANDARD */

    int_fast32_t ch = 0;
    int_fast32_t out4 = 0;
    size_t i = 0;
    size_t out_pos = 0;
    for (; un < end; ++un) {
        ch = (*un < 128) ? base64_reverse_table[*un] : -1;
        if (__builtin_expect( (ch < 0), 0)) {
            /* skip formatted base64; skip whitespace ('\r' '\n' '\t' ' ')*/
            if (-2 == ch) /*(loose check; skip ' ', all ctrls not \127 or \0)*/
                continue; /* skip character */
            break;
        }

        out4 = (out4 << 6) | ch;
        if ((++i & 3) == 0) {
            result[out_pos]   = (out4 >> 16) & 0xFF;
            result[out_pos+1] = (out4 >>  8) & 0xFF;
            result[out_pos+2] = (out4      ) & 0xFF;
            out_pos += 3;
            out4 = 0;
        }
    }

    /* permit base64 string ending with pad chars (ch == -3); not checking
     * for one or two pad chars + optional whitespace reaches in_length) */
    /* permit base64 string truncated before in_length (*un == '\0') */
    switch (un == end || ch == -3 || *un != '\0' ? (i & 3) : 1) {
      case 3:
        result[out_pos++] = (out4 >> 10);
        out4 <<= 2;
        __attribute_fallthrough__
      case 2:
        result[out_pos++] = (out4 >> 4) & 0xFF;
        __attribute_fallthrough__
      case 0:
        force_assert(out_pos <= out_length);
        return out_pos;
      case 1: /* pad char or str end can only come after 2+ base64 chars */
      default:
        return 0; /* invalid character, abort */
    }
}

size_t li_base64_enc(char * const restrict out, const size_t out_length, const unsigned char * const restrict in, const size_t in_length, const base64_charset charset, const int pad) {
  size_t i;
  size_t out_pos = 0;
  uint_fast32_t v;
  const char* const base64_table = (charset)
    ? base64_url_table             /* BASE64_URL */
    : base64_standard_table;       /* BASE64_STANDARD */
  const char padchar = base64_table[64]; /* padding char */

  /* check overflows */
  /* 1073741823 is max num full_tuples to avoid overflow in uint32_t;
   * and (1 GB - 1) is ridiculously large for base64-encoded data */
  force_assert(in_length <= 3221225469); /* (3221225469+2) / 3 * 4 < UINT32_MAX */
  force_assert((in_length+2)/3*4 <= out_length);

  for (i = 2; i < in_length; i += 3) {
    v = (in[i-2] << 16) | (in[i-1] << 8) | in[i];
    out[out_pos+0] = base64_table[(v >> 18) & 0x3f];
    out[out_pos+1] = base64_table[(v >> 12) & 0x3f];
    out[out_pos+2] = base64_table[(v >>  6) & 0x3f];
    out[out_pos+3] = base64_table[(v      ) & 0x3f];
    out_pos += 4;
  }

  switch (in_length - (i-2)) {
  case 0:
  default:
    break;
  case 1:
    {
      /* pretend in[i-1] = in[i] = 0, don't write last two (out_pos+3, out_pos+2) characters */
      v = (in[i-2] << 4);
      out[out_pos+0] = base64_table[(v >> 6) & 0x3f];
      out[out_pos+1] = base64_table[(v     ) & 0x3f];
      if (pad) {
        out[out_pos+2] = out[out_pos+3] = padchar;
        out_pos += 4;
      }
      else
        out_pos += 2;
    }
    break;
  case 2:
    {
      /* pretend in[i] = 0, don't write last (out_pos+3) character */
      v = (in[i-2] << 10) | (in[i-1] << 2);
      out[out_pos+0] = base64_table[(v >> 12) & 0x3f];
      out[out_pos+1] = base64_table[(v >>  6) & 0x3f];
      out[out_pos+2] = base64_table[(v      ) & 0x3f];
      if (pad) {
        out[out_pos+3] = padchar;
        out_pos += 4;
      }
      else
        out_pos += 3;
    }
    break;
  }

  return out_pos;
}


char* buffer_append_base64_enc(buffer *out, const unsigned char* in, size_t in_length, base64_charset charset, int pad) {
    const size_t reserve = (in_length+2)/3*4;
    char * const result = buffer_string_prepare_append(out, reserve);
    const size_t out_pos =
      li_base64_enc(result, reserve, in, in_length, charset, pad);

    buffer_commit(out, out_pos);

    return result;
}


unsigned char* buffer_append_base64_decode(buffer *out, const char* in, size_t in_length, base64_charset charset) {
    const size_t reserve = 3*(in_length/4) + 3;
    unsigned char * const result = (unsigned char *)
      buffer_string_prepare_append(out, reserve);
    const size_t out_pos =
      li_base64_dec(result, reserve, in, in_length, charset);

    buffer_commit(out, out_pos);

    return (out_pos || !in_length) ? result : NULL;
}

Coverage Report

Created: 2025-07-18 06:13

Line	Count	Source (jump to first uncovered line)
1		#include "first.h"
2
3		#include "base64.h"
4
5		/* reverse mapping:
6		* >= 0: base64 value
7		* -1: invalid character
8		* -2: skip character (whitespace/control)
9		* -3: padding
10		*/
11
12		/* BASE64_STANDARD: "A-Z a-z 0-9 + /" maps to 0-63, pad with "=" */
13		static const char base64_standard_table[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
14		static const signed char base64_standard_reverse_table[] = {
15		/* 0 1 2 3 4 5 6 7 8 9 A B C D E F */
16		-1, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, /* 0x00 - 0x0F */
17		-2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, /* 0x10 - 0x1F */
18		-2, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63, /* 0x20 - 0x2F */
19		52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -3, -1, -1, /* 0x30 - 0x3F */
20		-1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, /* 0x40 - 0x4F */
21		15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1, /* 0x50 - 0x5F */
22		-1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, /* 0x60 - 0x6F */
23		41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1, /* 0x70 - 0x7F */
24		};
25
26		/* BASE64_URL: "A-Z a-z 0-9 - _" maps to 0-63, pad with "=" */
27		static const char base64_url_table[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_=";
28		static const signed char base64_url_reverse_table[] = {
29		/* 0 1 2 3 4 5 6 7 8 9 A B C D E F */
30		-1, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, /* 0x00 - 0x0F */
31		-2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, /* 0x10 - 0x1F */
32		-2, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, /* 0x20 - 0x2F */
33		52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -3, -1, -1, /* 0x30 - 0x3F */
34		-1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, /* 0x40 - 0x4F */
35		15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, 63, /* 0x50 - 0x5F */
36		-1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, /* 0x60 - 0x6F */
37		41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1, /* 0x70 - 0x7F */
38		};
39
40	0	size_t li_base64_dec(unsigned char * const result, const size_t out_length, const char * const in, const size_t in_length, const base64_charset charset) {
41	0	const unsigned char un = (const unsigned char )in;
42	0	const unsigned char * const end = un + in_length;
43	0	const signed char * const base64_reverse_table = (charset)
44	0	? base64_url_reverse_table /* BASE64_URL */
45	0	: base64_standard_reverse_table; /* BASE64_STANDARD */
46
47	0	int_fast32_t ch = 0;
48	0	int_fast32_t out4 = 0;
49	0	size_t i = 0;
50	0	size_t out_pos = 0;
51	0	for (; un < end; ++un) {
52	0	ch = (un < 128) ? base64_reverse_table[un] : -1;
53	0	if (__builtin_expect( (ch < 0), 0)) {
54		/* skip formatted base64; skip whitespace ('\r' '\n' '\t' ' ')*/
55	0	if (-2 == ch) /(loose check; skip ' ', all ctrls not \127 or \0)/
56	0	continue; /* skip character */
57	0	break;
58	0	}
59
60	0	out4 = (out4 << 6) \| ch;
61	0	if ((++i & 3) == 0) {
62	0	result[out_pos] = (out4 >> 16) & 0xFF;
63	0	result[out_pos+1] = (out4 >> 8) & 0xFF;
64	0	result[out_pos+2] = (out4 ) & 0xFF;
65	0	out_pos += 3;
66	0	out4 = 0;
67	0	}
68	0	}
69
70		/* permit base64 string ending with pad chars (ch == -3); not checking
71		* for one or two pad chars + optional whitespace reaches in_length) */
72		/* permit base64 string truncated before in_length (un == '\0') /
73	0	switch (un == end \|\| ch == -3 \|\| *un != '\0' ? (i & 3) : 1) {
74	0	case 3:
75	0	result[out_pos++] = (out4 >> 10);
76	0	out4 <<= 2;
77	0	__attribute_fallthrough__
78	0	case 2:
79	0	result[out_pos++] = (out4 >> 4) & 0xFF;
80	0	__attribute_fallthrough__
81	0	case 0:
82	0	force_assert(out_pos <= out_length);
83	0	return out_pos;
84	0	case 1: /* pad char or str end can only come after 2+ base64 chars */
85	0	default:
86	0	return 0; /* invalid character, abort */
87	0	}
88	0	}
89
90	0	size_t li_base64_enc(char * const restrict out, const size_t out_length, const unsigned char * const restrict in, const size_t in_length, const base64_charset charset, const int pad) {
91	0	size_t i;
92	0	size_t out_pos = 0;
93	0	uint_fast32_t v;
94	0	const char* const base64_table = (charset)
95	0	? base64_url_table /* BASE64_URL */
96	0	: base64_standard_table; /* BASE64_STANDARD */
97	0	const char padchar = base64_table[64]; /* padding char */
98
99		/* check overflows */
100		/* 1073741823 is max num full_tuples to avoid overflow in uint32_t;
101		* and (1 GB - 1) is ridiculously large for base64-encoded data */
102	0	force_assert(in_length <= 3221225469); /* (3221225469+2) / 3 * 4 < UINT32_MAX */
103	0	force_assert((in_length+2)/3*4 <= out_length);
104
105	0	for (i = 2; i < in_length; i += 3) {
106	0	v = (in[i-2] << 16) \| (in[i-1] << 8) \| in[i];
107	0	out[out_pos+0] = base64_table[(v >> 18) & 0x3f];
108	0	out[out_pos+1] = base64_table[(v >> 12) & 0x3f];
109	0	out[out_pos+2] = base64_table[(v >> 6) & 0x3f];
110	0	out[out_pos+3] = base64_table[(v ) & 0x3f];
111	0	out_pos += 4;
112	0	}
113
114	0	switch (in_length - (i-2)) {
115	0	case 0:
116	0	default:
117	0	break;
118	0	case 1:
119	0	{
120		/* pretend in[i-1] = in[i] = 0, don't write last two (out_pos+3, out_pos+2) characters */
121	0	v = (in[i-2] << 4);
122	0	out[out_pos+0] = base64_table[(v >> 6) & 0x3f];
123	0	out[out_pos+1] = base64_table[(v ) & 0x3f];
124	0	if (pad) {
125	0	out[out_pos+2] = out[out_pos+3] = padchar;
126	0	out_pos += 4;
127	0	}
128	0	else
129	0	out_pos += 2;
130	0	}
131	0	break;
132	0	case 2:
133	0	{
134		/* pretend in[i] = 0, don't write last (out_pos+3) character */
135	0	v = (in[i-2] << 10) \| (in[i-1] << 2);
136	0	out[out_pos+0] = base64_table[(v >> 12) & 0x3f];
137	0	out[out_pos+1] = base64_table[(v >> 6) & 0x3f];
138	0	out[out_pos+2] = base64_table[(v ) & 0x3f];
139	0	if (pad) {
140	0	out[out_pos+3] = padchar;
141	0	out_pos += 4;
142	0	}
143	0	else
144	0	out_pos += 3;
145	0	}
146	0	break;
147	0	}
148
149	0	return out_pos;
150	0	}
151
152
153	0	char* buffer_append_base64_enc(buffer out, const unsigned char in, size_t in_length, base64_charset charset, int pad) {
154	0	const size_t reserve = (in_length+2)/3*4;
155	0	char * const result = buffer_string_prepare_append(out, reserve);
156	0	const size_t out_pos =
157	0	li_base64_enc(result, reserve, in, in_length, charset, pad);
158
159	0	buffer_commit(out, out_pos);
160
161	0	return result;
162	0	}
163
164
165	0	unsigned char* buffer_append_base64_decode(buffer out, const char in, size_t in_length, base64_charset charset) {
166	0	const size_t reserve = 3*(in_length/4) + 3;
167	0	unsigned char * const result = (unsigned char *)
168	0	buffer_string_prepare_append(out, reserve);
169	0	const size_t out_pos =
170	0	li_base64_dec(result, reserve, in, in_length, charset);
171
172	0	buffer_commit(out, out_pos);
173
174	0	return (out_pos \|\| !in_length) ? result : NULL;
175	0	}