util.{hh,cc}: Split out strings.{hh,cc}

Change-Id: I4f642d1046d56b5db26f1b0296ee16a0e02d444a

1 files changed, 232 insertions, 0 deletions

diff --git a/src/libutil/strings.cc b/src/libutil/strings.cc
new file mode 100644
index 000000000..9cb319cce
--- /dev/null
+++ b/src/libutil/strings.cc
@@ -0,0 +1,232 @@
+#include "strings.hh"
+
+namespace nix {
+
+std::vector<char *> stringsToCharPtrs(const Strings & ss)
+{
+    std::vector<char *> res;
+    for (auto & s : ss) res.push_back((char *) s.c_str());
+    res.push_back(0);
+    return res;
+}
+
+
+template<class C> C tokenizeString(std::string_view s, std::string_view separators)
+{
+    C result;
+    auto pos = s.find_first_not_of(separators, 0);
+    while (pos != std::string_view::npos) {
+        auto end = s.find_first_of(separators, pos + 1);
+        if (end == std::string_view::npos) end = s.size();
+        result.insert(result.end(), std::string(s, pos, end - pos));
+        pos = s.find_first_not_of(separators, end);
+    }
+    return result;
+}
+
+template Strings tokenizeString(std::string_view s, std::string_view separators);
+template StringSet tokenizeString(std::string_view s, std::string_view separators);
+template std::vector<std::string> tokenizeString(std::string_view s, std::string_view separators);
+
+
+std::string chomp(std::string_view s)
+{
+    size_t i = s.find_last_not_of(" \n\r\t");
+    return i == std::string_view::npos ? "" : std::string(s, 0, i + 1);
+}
+
+
+std::string trim(std::string_view s, std::string_view whitespace)
+{
+    auto i = s.find_first_not_of(whitespace);
+    if (i == s.npos) return "";
+    auto j = s.find_last_not_of(whitespace);
+    return std::string(s, i, j == s.npos ? j : j - i + 1);
+}
+
+
+std::string replaceStrings(
+    std::string res,
+    std::string_view from,
+    std::string_view to)
+{
+    if (from.empty()) return res;
+    size_t pos = 0;
+    while ((pos = res.find(from, pos)) != std::string::npos) {
+        res.replace(pos, from.size(), to);
+        pos += to.size();
+    }
+    return res;
+}
+
+
+Rewriter::Rewriter(std::map<std::string, std::string> rewrites)
+    : rewrites(std::move(rewrites))
+{
+    for (const auto & [k, v] : this->rewrites) {
+        assert(!k.empty());
+        initials.push_back(k[0]);
+    }
+    std::ranges::sort(initials);
+    auto [firstDupe, end] = std::ranges::unique(initials);
+    initials.erase(firstDupe, end);
+}
+
+std::string Rewriter::operator()(std::string s)
+{
+    size_t j = 0;
+    while ((j = s.find_first_of(initials, j)) != std::string::npos) {
+        size_t skip = 1;
+        for (auto & [from, to] : rewrites) {
+            if (s.compare(j, from.size(), from) == 0) {
+                s.replace(j, from.size(), to);
+                skip = to.size();
+                break;
+            }
+        }
+        j += skip;
+    }
+    return s;
+}
+
+
+std::string toLower(const std::string & s)
+{
+    std::string r(s);
+    for (auto & c : r)
+        c = std::tolower(c);
+    return r;
+}
+
+
+std::string shellEscape(const std::string_view s)
+{
+    std::string r;
+    r.reserve(s.size() + 2);
+    r += "'";
+    for (auto & i : s)
+        if (i == '\'') r += "'\\''"; else r += i;
+    r += '\'';
+    return r;
+}
+
+constexpr char base64Chars[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
+
+std::string base64Encode(std::string_view s)
+{
+    std::string res;
+    res.reserve((s.size() + 2) / 3 * 4);
+    int data = 0, nbits = 0;
+
+    for (char c : s) {
+        data = data << 8 | (unsigned char) c;
+        nbits += 8;
+        while (nbits >= 6) {
+            nbits -= 6;
+            res.push_back(base64Chars[data >> nbits & 0x3f]);
+        }
+    }
+
+    if (nbits) res.push_back(base64Chars[data << (6 - nbits) & 0x3f]);
+    while (res.size() % 4) res.push_back('=');
+
+    return res;
+}
+
+
+std::string base64Decode(std::string_view s)
+{
+    constexpr char npos = -1;
+    constexpr std::array<char, 256> base64DecodeChars = [&]() {
+        std::array<char, 256>  result{};
+        for (auto& c : result)
+            c = npos;
+        for (int i = 0; i < 64; i++)
+            result[base64Chars[i]] = i;
+        return result;
+    }();
+
+    std::string res;
+    // Some sequences are missing the padding consisting of up to two '='.
+    //                    vvv
+    res.reserve((s.size() + 2) / 4 * 3);
+    unsigned int d = 0, bits = 0;
+
+    for (char c : s) {
+        if (c == '=') break;
+        if (c == '\n') continue;
+
+        char digit = base64DecodeChars[(unsigned char) c];
+        if (digit == npos)
+            throw Error("invalid character in Base64 string: '%c'", c);
+
+        bits += 6;
+        d = d << 6 | digit;
+        if (bits >= 8) {
+            res.push_back(d >> (bits - 8) & 0xff);
+            bits -= 8;
+        }
+    }
+
+    return res;
+}
+
+
+std::string stripIndentation(std::string_view s)
+{
+    size_t minIndent = 10000;
+    size_t curIndent = 0;
+    bool atStartOfLine = true;
+
+    for (auto & c : s) {
+        if (atStartOfLine && c == ' ')
+            curIndent++;
+        else if (c == '\n') {
+            if (atStartOfLine)
+                minIndent = std::max(minIndent, curIndent);
+            curIndent = 0;
+            atStartOfLine = true;
+        } else {
+            if (atStartOfLine) {
+                minIndent = std::min(minIndent, curIndent);
+                atStartOfLine = false;
+            }
+        }
+    }
+
+    std::string res;
+
+    size_t pos = 0;
+    while (pos < s.size()) {
+        auto eol = s.find('\n', pos);
+        if (eol == s.npos) eol = s.size();
+        if (eol - pos > minIndent)
+            res.append(s.substr(pos + minIndent, eol - pos - minIndent));
+        res.push_back('\n');
+        pos = eol + 1;
+    }
+
+    return res;
+}
+
+
+std::pair<std::string_view, std::string_view> getLine(std::string_view s)
+{
+    auto newline = s.find('\n');
+
+    if (newline == s.npos) {
+        return {s, ""};
+    } else {
+        auto line = s.substr(0, newline);
+        if (!line.empty() && line[line.size() - 1] == '\r')
+            line = line.substr(0, line.size() - 1);
+        return {line, s.substr(newline + 1)};
+    }
+}
+
+std::string showBytes(uint64_t bytes)
+{
+    return fmt("%.2f MiB", bytes / (1024.0 * 1024.0));
+}
+
+}