1 files changed, 448 insertions, 0 deletions
diff --git a/include/flatcc/portable/pbase64.h b/include/flatcc/portable/pbase64.h
new file mode 100644
index 0000000..a6812c4
--- /dev/null
+++ b/include/flatcc/portable/pbase64.h
@@ -0,0 +1,448 @@
+#ifndef PBASE64_H
+#define PBASE64_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <stdlib.h>
+
+/* Guarded to allow inclusion of pstdint.h first, if stdint.h is not supported. */
+#ifndef UINT8_MAX
+#include <stdint.h>
+#endif
+
+#define BASE64_EOK    0
+/* 0 or mure full blocks decoded, remaining content may be parsed with fresh buffer. */
+#define BASE64_EMORE  1
+/* The `src_len` argument is required when encoding. */
+#define BASE64_EARGS  2
+/* Unsupported mode, or modifier not supported by mode when encoding. */
+#define BASE64_EMODE  3
+/* Decoding ends at invalid tail length - either by source length or by non-alphabet symbol. */
+#define BASE64_ETAIL  4
+/* Decoding ends at valid tail length but last byte has non-zero bits where it shouldn't have. */
+#define BASE64_EDIRTY 5
+
+static inline const char *base64_strerror(int err);
+
+/* All codecs are URL safe. Only Crockford allow for non-canocical decoding. */
+enum {
+    /* Most common base64 codec, but not url friendly. */
+    base64_mode_rfc4648 = 0,
+
+    /*  URL safe version, '+' -> '-', '/' -> '_'. */
+    base64_mode_url = 1,
+
+    /*
+     * Skip ' ', '\r', and '\n' - we do not allow tab because common
+     * uses of base64 such as PEM do not allow tab.
+     */
+    base64_dec_modifier_skipspace = 32,
+
+    /* Padding is excluded by default. Not allowed for zbase64. */
+    base64_enc_modifier_padding = 128,
+
+    /* For internal use or to decide codec of mode. */
+    base64_modifier_mask = 32 + 64 + 128,
+};
+
+/* Encoded size with or without padding. */
+static inline size_t base64_encoded_size(size_t len, int mode);
+
+/*
+ * Decoded size assuming no padding.
+ * If `len` does include padding, the actual size may be less
+ * when decoding, but never more.
+ */
+static inline size_t base64_decoded_size(size_t len);
+
+/*
+ * `dst` must hold ceil(len * 4 / 3) bytes.
+ * `src_len` points to length of source and is updated with length of
+ * parse on both success and failure. If `dst_len` is not null
+ * it is used to store resulting output lengt withh length of decoded
+ * output on both success and failure.
+ * If `hyphen` is non-zero a hyphen is encoded every `hyphen` output bytes.
+ * `mode` selects encoding alphabet defaulting to Crockfords base64.
+ * Returns 0 on success.
+ *
+ * A terminal space can be added with `dst[dst_len++] = ' '` after the
+ * encode call. All non-alphabet can be used as terminators except the
+ * padding character '='. The following characters will work as
+ * terminator for all modes: { '\0', '\n', ' ', '\t' }. A terminator is
+ * optional when the source length is given to the decoder. Note that
+ * crockford also reserves a few extra characters for checksum but the
+ * checksum must be separate from the main buffer and is not supported
+ * by this library.
+ */
+static inline int base64_encode(uint8_t *dst, const uint8_t *src, size_t *dst_len, size_t *src_len, int mode);
+
+/*
+ * Decodes according to mode while ignoring encoding modifiers.
+ * `src_len` and `dst_len` are optional pointers. If `src_len` is set it
+ * must contain the length of the input, otherwise the input must be
+ * terminated with a non-alphabet character or valid padding (a single
+ * padding character is accepted) - if the src_len output is needed but
+ * not the input due to guaranteed termination, then set it to
+ * (size_t)-1. `dst_len` must contain length of output buffer if present
+ * and parse will fail with BASE64_EMORE after decoding a block multiple
+ * if dst_len is exhausted - the parse can thus be resumed after
+ * draining destination. `src_len` and `dst_len` are updated with parsed
+ * and decoded length, when present, on both success and failure.
+ * Returns 0 on success. Invalid characters are not considered errors -
+ * they simply terminate the parse, however, if the termination is not
+ * at a block multiple or a valid partial block length then BASE64_ETAIL
+ * without output holding the last full block, if any. BASE64_ETAIL is also
+ * returned if the a valid length holds non-zero unused tail bits.
+ */
+static inline int base64_decode(uint8_t *dst, const uint8_t *src, size_t *dst_len, size_t *src_len, int mode);
+
+static inline const char *base64_strerror(int err)
+{
+    switch (err) {
+    case BASE64_EOK: return "ok";
+    case BASE64_EARGS: return "invalid argument";
+    case BASE64_EMODE: return "invalid mode";
+    case BASE64_EMORE: return "destination full";
+    case BASE64_ETAIL: return "invalid tail length";
+    case BASE64_EDIRTY: return "invalid tail content";
+    default: return "unknown error";
+    }
+}
+
+static inline size_t base64_encoded_size(size_t len, int mode)
+{
+    size_t k = len % 3;
+    size_t n = (len * 4 / 3 + 3) & ~(size_t)3;
+    int pad = mode & base64_enc_modifier_padding;
+
+    if (!pad) {
+        switch (k) {
+        case 2:
+            n -= 1;
+            break;
+        case 1:
+            n -= 2;
+            break;
+        default:
+            break;
+        }
+    }
+    return n;
+}
+
+static inline size_t base64_decoded_size(size_t len)
+{
+    size_t k = len % 4;
+    size_t n = len / 4 * 3;
+
+    switch (k) {
+    case 3:
+        return n + 2;
+    case 2:
+        return n + 1;
+    case 1: /* Not valid without padding. */
+    case 0:
+    default:
+        return n;
+    }
+}
+
+static inline int base64_encode(uint8_t *dst, const uint8_t *src, size_t *dst_len, size_t *src_len, int mode)
+{
+    const uint8_t *rfc4648_alphabet            = (const uint8_t *)
+        "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
+    const uint8_t *url_alphabet                = (const uint8_t *)
+        "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_";
+
+    const uint8_t *T;
+    uint8_t *dst_base = dst;
+    int pad = mode & base64_enc_modifier_padding;
+    size_t len = 0;
+    int ret = BASE64_EMODE;
+
+    if (!src_len) {
+        ret = BASE64_EARGS;
+        goto done;
+    }
+    len = *src_len;
+    mode = mode & ~base64_modifier_mask;
+    switch (mode) {
+    case base64_mode_rfc4648:
+        T = rfc4648_alphabet;
+        break;
+    case base64_mode_url:
+        T = url_alphabet;
+        break;
+    default:
+        /* Invalid mode. */
+        goto done;
+    }
+
+    ret = BASE64_EOK;
+
+    /* Encodes 4 destination bytes from 3 source bytes. */
+    while (len >= 3) {
+        dst[0] = T[((src[0] >> 2))];
+        dst[1] = T[((src[0] << 4) & 0x30) | (src[1] >> 4)];
+        dst[2] = T[((src[1] << 2) & 0x3c) | (src[2] >> 6)];
+        dst[3] = T[((src[2] & 0x3f))];
+        len -= 3;
+        dst += 4;
+        src += 3;
+    }
+    /* Encodes 8 destination bytes from 1 to 4 source bytes, if any. */
+    switch(len) {
+    case 2:
+        dst[0] = T[((src[0] >> 2))];
+        dst[1] = T[((src[0] << 4) & 0x30) | (src[1] >> 4)];
+        dst[2] = T[((src[1] << 2) & 0x3c)];
+        dst += 3;
+        if (pad) {
+            *dst++ = '=';
+        }
+        break;
+    case 1:
+        dst[0] = T[((src[0] >> 2))];
+        dst[1] = T[((src[0] << 4) & 0x30)];
+        dst += 2;
+        if (pad) {
+            *dst++ = '=';
+            *dst++ = '=';
+        }
+        break;
+    default:
+        pad = 0;
+        break;
+    }
+    len = 0;
+done:
+    if (dst_len) {
+        *dst_len = (size_t)(dst - dst_base);
+    }
+    if (src_len) {
+        *src_len -= len;
+    }
+    return ret;
+}
+
+static inline int base64_decode(uint8_t *dst, const uint8_t *src, size_t *dst_len, size_t *src_len, int mode)
+{
+    static const uint8_t cinvalid = 64;
+    static const uint8_t cignore = 65;
+    static const uint8_t cpadding = 66;
+
+    /*
+     * 0..63: 6-bit encoded value.
+     * 64: flags non-alphabet symbols.
+     * 65: codes for ignored symbols.
+     * 66: codes for pad symbol '='.
+     * All codecs consider padding an optional terminator and if present
+     * consumes as many pad bytes as possible up to block termination,
+     * but does not fail if a block is not full.
+     *
+     * We do not currently have any ignored characters but we might
+     * add spaces as per MIME spec, but  assuming spaces only happen
+     * at block boundaries this is probalby better handled by repeated
+     * parsing.
+     */
+    static const uint8_t base64rfc4648_decode[256] = {
+        64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
+        64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
+        64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 62, 64, 64, 64, 63,
+        52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 64, 64, 64, 66, 64, 64,
+        64,  0,  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, 64, 64, 64, 64, 64,
+        64, 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, 64, 64, 64, 64, 64,
+        64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
+        64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
+        64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
+        64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
+        64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
+        64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
+        64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
+        64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64
+    };
+
+    static const uint8_t base64url_decode[256] = {
+        64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
+        64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
+        64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 62, 64, 64,
+        52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 64, 64, 64, 66, 64, 64,
+        64,  0,  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, 64, 64, 64, 64, 63,
+        64, 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, 64, 64, 64, 64, 64,
+        64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
+        64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
+        64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
+        64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
+        64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
+        64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
+        64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
+        64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64
+    };
+
+    static const uint8_t base64rfc4648_decode_skipspace[256] = {
+        64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 65, 64, 64, 65, 64, 64,
+        64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
+        65, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 62, 64, 64, 64, 63,
+        52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 64, 64, 64, 66, 64, 64,
+        64,  0,  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, 64, 64, 64, 64, 64,
+        64, 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, 64, 64, 64, 64, 64,
+        64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
+        64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
+        64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
+        64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
+        64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
+        64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
+        64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
+        64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64
+    };
+
+    static const uint8_t base64url_decode_skipspace[256] = {
+        64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 65, 64, 64, 65, 64, 64,
+        64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
+        65, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 62, 64, 64,
+        52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 64, 64, 64, 66, 64, 64,
+        64,  0,  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, 64, 64, 64, 64, 63,
+        64, 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, 64, 64, 64, 64, 64,
+        64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
+        64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
+        64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
+        64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
+        64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
+        64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
+        64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
+        64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64
+    };
+
+    int ret = BASE64_EOK;
+    size_t i, k;
+    uint8_t hold[4];
+    uint8_t *dst_base = dst;
+    size_t limit = (size_t)-1;
+    size_t len = (size_t)-1, mark;
+    const uint8_t *T = base64rfc4648_decode;
+    int skipspace = mode & base64_dec_modifier_skipspace;
+
+    if (src_len) {
+        len = *src_len;
+    }
+    mark = len;
+    mode = mode & ~base64_modifier_mask;
+    switch (mode) {
+    case base64_mode_rfc4648:
+        T = skipspace ? base64rfc4648_decode_skipspace : base64rfc4648_decode;
+        break;
+    case base64_mode_url:
+        T = skipspace ?  base64url_decode_skipspace : base64url_decode;
+        break;
+    default:
+        ret = BASE64_EMODE;
+        goto done;
+    }
+
+    if (dst_len && *dst_len > 0) {
+        limit = *dst_len;
+    }
+    while(limit > 0) {
+        for (i = 0; i < 4; ++i) {
+            if (len == i) {
+                k = i;
+                len -= i;
+                goto tail;
+            }
+            if ((hold[i] = T[src[i]]) >= cinvalid) {
+                if (hold[i] == cignore) {
+                    ++src;
+                    --len;
+                    --i;
+                    continue;
+                }
+                k = i;
+                /* Strip padding and ignore hyphen in padding, if present. */
+                if (hold[i] == cpadding) {
+                    ++i;
+                    while (i < len && i < 8) {
+                        if (T[src[i]] != cpadding && T[src[i]] != cignore) {
+                            break;
+                        }
+                        ++i;
+                    }
+                }
+                len -= i;
+                goto tail;
+            }
+        }
+        if (limit < 3) {
+            goto more;
+        }
+        dst[0] = (uint8_t)((hold[0] << 2) | (hold[1] >> 4));
+        dst[1] = (uint8_t)((hold[1] << 4) | (hold[2] >> 2));
+        dst[2] = (uint8_t)((hold[2] << 6) | (hold[3]));
+        dst += 3;
+        src += 4;
+        limit -= 3;
+        len -= 4;
+        mark = len;
+    }
+done:
+    if (dst_len) {
+        *dst_len = (size_t)(dst - dst_base);
+    }
+    if (src_len) {
+        *src_len -= mark;
+    }
+    return ret;
+
+tail:
+    switch (k) {
+    case 0:
+        break;
+    case 2:
+        if ((hold[1] << 4) & 0xff) {
+            goto dirty;
+        }
+        if (limit < 1) {
+            goto more;
+        }
+        dst[0] = (uint8_t)((hold[0] << 2) | (hold[1] >> 4));
+        dst += 1;
+        break;
+    case 3:
+        if ((hold[2] << 6) & 0xff) {
+            goto dirty;
+        }
+        if (limit < 2) {
+            goto more;
+        }
+        dst[0] = (uint8_t)((hold[0] << 2) | (hold[1] >> 4));
+        dst[1] = (uint8_t)((hold[1] << 4) | (hold[2] >> 2));
+        dst += 2;
+        break;
+    default:
+        ret = BASE64_ETAIL;
+        goto done;
+    }
+    mark = len;
+    goto done;
+dirty:
+    ret = BASE64_EDIRTY;
+    goto done;
+more:
+    ret = BASE64_EMORE;
+    goto done;
+}
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* PBASE64_H */