Display (Wayland): support fractional scale for KDE

src/util/base64.c

@@ -0,0 +1,115 @@
+#include "base64.h"
+
+// https://github.com/kostya/benchmarks/blob/master/base64/test-nolib.c#L145
+void ffBase64EncodeRaw(uint32_t size, const char *str, uint32_t *out_size, char *output)
+{
+    static const char chars[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
+    char *out = output;
+    const char *ends = str + (size - size % 3);
+    while (str != ends)
+    {
+        uint32_t n = __builtin_bswap32(*(uint32_t *)str);
+        *out++ = chars[(n >> 26) & 63];
+        *out++ = chars[(n >> 20) & 63];
+        *out++ = chars[(n >> 14) & 63];
+        *out++ = chars[(n >> 8) & 63];
+        str += 3;
+    }
+
+    if (size % 3 == 1)
+    {
+        uint64_t n = (uint64_t)*str << 16;
+        *out++ = chars[(n >> 18) & 63];
+        *out++ = chars[(n >> 12) & 63];
+        *out++ = '=';
+        *out++ = '=';
+    }
+    else if (size % 3 == 2)
+    {
+        uint64_t n = (uint64_t)*str++ << 16;
+        n |= (uint64_t)*str << 8;
+        *out++ = chars[(n >> 18) & 63];
+        *out++ = chars[(n >> 12) & 63];
+        *out++ = chars[(n >> 6) & 63];
+        *out++ = '=';
+    }
+    *out = '\0';
+    *out_size = (uint32_t)(out - output);
+}
+
+static char decode_table[256];
+
+void init_decode_table()
+{
+    uint8_t ch = 0;
+    do
+    {
+        int32_t code = -1;
+        if (ch >= 'A' && ch <= 'Z')
+            code = ch - 0x41;
+        if (ch >= 'a' && ch <= 'z')
+            code = ch - 0x47;
+        if (ch >= '0' && ch <= '9')
+            code = ch + 0x04;
+        if (ch == '+' || ch == '-')
+            code = 0x3E;
+        if (ch == '/' || ch == '_')
+            code = 0x3F;
+        decode_table[ch] = (char) code;
+    } while (ch++ < 0xFF);
+}
+
+#define next_char(x)                              \
+    char x = decode_table[(unsigned char)*str++]; \
+    if (x < 0)                                    \
+        return false;
+
+bool ffBase64DecodeRaw(uint32_t size, const char *str, uint32_t *out_size, char *output)
+{
+    if (*(uint64_t*) decode_table == 0)
+        init_decode_table();
+
+    char *out = output;
+    while (size > 0 && (str[size - 1] == '\n' || str[size - 1] == '\r' || str[size - 1] == '='))
+        size--;
+
+    const char *ends = str + size - 4;
+    while (true)
+    {
+        if (str > ends)
+            break;
+        while (*str == '\n' || *str == '\r')
+            str++;
+
+        if (str > ends)
+            break;
+        next_char(a);
+        next_char(b);
+        next_char(c);
+        next_char(d);
+
+        *out++ = (char)(a << 2 | b >> 4);
+        *out++ = (char)(b << 4 | c >> 2);
+        *out++ = (char)(c << 6 | d >> 0);
+    }
+
+    uint8_t mod = (uint8_t) (ends - str + 4) % 4;
+    if (mod == 2)
+    {
+        next_char(a);
+        next_char(b);
+        *out++ = (char)(a << 2 | b >> 4);
+    }
+    else if (mod == 3)
+    {
+        next_char(a);
+        next_char(b);
+        next_char(c);
+        *out++ = (char)(a << 2 | b >> 4);
+        *out++ = (char)(b << 4 | c >> 2);
+    }
+
+    *out = '\0';
+    *out_size = (uint32_t) (out - output);
+    return true;
+}

src/util/base64.h

@@ -0,0 +1,23 @@
+#pragma once
+
+#include "fastfetch.h"
+
+void ffBase64EncodeRaw(uint32_t size, const char *str, uint32_t *out_size, char *output);
+static inline FFstrbuf ffBase64EncodeStrbuf(const FFstrbuf* in)
+{
+    FFstrbuf out = ffStrbufCreateA(10 + in->length * 4 / 3);
+    ffBase64EncodeRaw(in->length, in->chars, &out.length, out.chars);
+    assert(out.length < out.allocated);
+
+    return out;
+}
+
+bool ffBase64DecodeRaw(uint32_t size, const char *str, uint32_t *out_size, char *output);
+static inline FFstrbuf ffBase64DecodeStrbuf(const FFstrbuf* in)
+{
+    FFstrbuf out = ffStrbufCreateA(10 + in->length * 3 / 4);
+    ffBase64DecodeRaw(in->length, in->chars, &out.length, out.chars);
+    assert(out.length < out.allocated);
+
+    return out;
+}